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Using high-resolution micro-CT imaging at 2.98 μm/voxel, we compared the percolation of hydrogen in gas injection with gas expansion for a hydrogen-brine system in Bentheimer sandstone at 1 MPa and 20 °C, representing hydrogen storage in an aquifer. We introduced dimensionless numbers to quantify the contribution of advection and expansion to displacement. We analysed the 3D spatial distribution of gas and its displacement in both cases and demonstrated that in gas injection, hydrogen can only advance from a connected cluster in an invasion-percolation type process, while in gas expansion, hydrogen can access more of the pore space even from disconnected clusters. The average gas saturation in the sample increased from 30% to 50% by gas expansion, and we estimated that 10% of the expanded volume is attributed to hydrogen exsolution from the brine. This work emphasises the importance of studying the combined effects of pressure decline and gas withdrawal in hydrogen storage to assess the influence of gas expansion on remobilising trapped gases. [Display omitted] • High-resolution X-ray imaging studied hydrogen injection and expansion in a sandstone. • Disconnected gas clusters can expand and reconnect during pressure decline. • Gas expansion increased the average gas saturation from 30% to 50% as pressure declined. • Hydrogen exsolution from brine increased the expanded gas volume by 10%. • Hydrogen accessed more of the larger pores by expansion than by injection. [ABSTRACT FROM AUTHOR]

The active injection system was designed to study the explosion flame propagation behavior of premixed CH 4 /H 2 /air mixtures in the closed tube with inert gas injection. The injection of inert gases (N 2 , CO 2 , and air) was controlled by the injection time, t inject , which is set from 0 ms to 210 ms. The effects of injection disturbance and inert gas dilution on flame morphology, flame tip dynamics, and overpressure build-up have been investigated. Results show that the injection of inert gas into premixed CH 4 /H 2 /air flame wrinkles the early laminar flame, changing the flame structure. The increase in t inject shortens the flame propagation time and increases the maximum explosion pressure, but the maximum value is attained at t inject = 120 ms. The linear relationship between maximum explosion pressure and maximum flame tip velocity is presented. The addition of inert gas dilutes the fuel-air mixture, but the inert gas shows some inhibition effect on the turbulent explosion flame propagation at t inject > 120 ms. The injection disturbance plays a dominant role in the flame propagation process compared to inert gas dilutions. Finally, the effect of Darrieus-Landau and Rayleigh-Taylor instabilities on explosion flame propagation behavior has been examined. The injection of inert gas into premixed CH 4 /H 2 /air flames creates local turbulence, enhances flame instabilities, and provides positive feedback on the flame's acceleration and oscillation. • Effect of inert gas injection on premixed CH 4 /H 2 /air explosions is investigated. • The injection disturbance plays a dominant role in explosion flame propagation behavior. • The injection of inert gas shortens flame propagation time and increases the explosion pressure. • Effect of inert gas type and injection time on explosion parameters are confirmed. • Injecting inert gas into the explosion flame changes the DL and RT instabilities. [ABSTRACT FROM AUTHOR]

The effect of external gas injection near the plume on the performance of a microwave discharge cathode is investigated. Experiments were conducted under two gas injection conditions: gas addition and gas distribution. Gas distribution tended to lead to better performance than gas addition. In the gas distribution experiments, the total gas consumption was kept constant, the internal gas flow rate was reduced, and external gas was supplied. The electron current increased from 0.26 to 0.49 A at 35 V when the microwave power was 15 W. When the sum of the internal and external gas flow rates was held constant, external gas injection lowered the neutralization costs and increased the gas utilization efficiency. The neutralization current was successfully increased by 48 % at 12 W of microwave power compared with 8 W of microwave power with the same level of naturalization cost and gas utilization efficiency. The electron temperature and plasma density in the plume, as measured using a Langmuir probe, suggested that an increase of ionization in the plume by the external gas injection enhanced the cathode's performance. • Supplying gas into the plume of a microwave discharge cathode improves its performance. • Neutralization current increased by 58 % with external gas injection. • External gas injection decrease naturalization cost and increase gas utilization efficiency. • An increase of ionization in the plume by the external gas injection enhanced the cathode's performance. [ABSTRACT FROM AUTHOR]

The power to gas (P2G) equipment serves as a critical linkage in integrated energy systems that foster bidirectional energy flow to enhance the share of renewable energy and curb uncertainty. By bringing together P2G hydrogen production and hydrogen injection into gas grid technology, the energy conversion loss associated with P2G applications can be significantly reduced. Nonetheless, the strict criteria concerning hydrogen blending ratios pose limitations on the integration of renewable energy. This paper proposes a comprehensive energy system model that couples gas grid hydrogen injection with a hybrid P2G process, aiming to reduce energy conversion losses and overcome the constraints posed by hydrogen blending ratios. This approach promotes the efficient utilization of renewable energy in integrated energy systems (IES). For wind power uncertainty, a scenario analysis method combining Latin hypercube sampling and scenario curtailment 0–1 algorithm is employed. The model's nonlinear constraints are linearized through piecewise linearization, transforming the problem into a mixed-integer programming one for solution simulation results demonstrate that the application of the hybrid P2G process in IES systems with hydrogen injection into gas grid technology reduces certain energy conversion stages and cost inputs compared to using only power to hydrogen conversion. This approach shows significant improvements in economic and environmental performance. The hybrid P2G scheme reduces the hydrogen blending ratio of the system to the minimum operating cost from 12 % to 6 %. At the same time, its minimum value is 20.1 thousand USD lower than that of the scheme using only power to hydrogen conversion, which is about 4.7 % of the total cost. [Display omitted] • An IES based on hybrid P2G and hydrogen injection into gas grid is proposed. • The conversion rate is used to analyze the effect of renewable energy consumption. • The 0–1 algorithm is used to curtailment scenarios to capture the uncertainties. • A multi-scenario model is constructed to optimize capacities and operation. • The optimal economic performance is achieved at the hydrogen blending ratio of 6 %. [ABSTRACT FROM AUTHOR]

The production and utilization of hydrogen (H 2) as a clean energy source offer a promising solution towards achieving net-zero carbon emissions. Utilizing sandstone formations for geological hydrogen storage presents a viable option for the practical implementation of the hydrogen economy, offering both safe and large-scale containment capabilities. Accurate assessment of gas displacement behavior in porous media plays a critical role in understanding gas saturation, gas residual, and long-term storage duration. However, there are limited studies available on dynamic displacements for hydrogen storage applications. This study aims to enhance the understanding of gas flow behavior in sandstone rocks for different gas types and determine the role of capillary pressure and gas wettability during hydrogen storage. A series of gas core-flooding experiments are performed on a brine-saturated sandstone core sample using three different gases (CO 2 , CH 4, and H 2). X-ray scanning technique is applied to detect the gas saturation and gas residual after the core-flooding experiments. The results indicate that the average gas saturation ranges between 25 and 40%, with zero gas residual for all gases, suggesting that the gas residuals in this clean sandstone sample are unaffected by the gas type. Initially, the capillary pressure profile for the sample displayed low brine saturation at 200 psi, indicating very low capillary pressure in the sample due to the high permeability and large pore radius, despite the strong water-wetting behavior of the sample. Moreover, the obtained results indicate the high potential for gas recovery (especially for hydrogen during withdrawal cycles), and the high displacement efficiency in sandstone rocks. The reported low gas residual suggests that the wettability of the rock is not affected by gas injection, and it appears that the wettability and capillary pressure are not the controlling factors for gas storage in this sandstone sample. This observation suggests that the structural trapping mechanism is most likely to be the dominant trapping mechanism in this shallow high permeable sandstone rock. Also, the injection of cushion gases such as CO 2 and CH 4 indicated similar results to hydrogen injection, due to the low capillary pressure and high permeability in this sandstone sample. The findings of this study can greatly enhance the understanding of gas injection, displacement behavior, and gas residuals in sandstone rocks related to underground hydrogen storage. • The behavior of gas injection and dynamic displacements in sandstone reservoirs are investigated vis X-ray core-flooding. • CO 2 displayed an average gas saturation of 40%, while the average gas saturation for H 2 and CH 4 ranged between 25 and 30%. • The residual gas saturations in the sample were almost zero for all gases. • The rock wettability was not affected by gas injection. • Structural trapping mechanism appears to be the dominant trapping mechanism for shallow high-permeable sandstone rocks. [ABSTRACT FROM AUTHOR]

A continuous injection of gaseous water propellant into a magnetron-type sputtering propulsion device is performed in a pseudo manner by using a combination of two high-speed solenoid-type pulsed valves and a low-pressure gas reservoir. The gas injection system provides a temporally averaged gas flow rate of about 5–10 sccm with adjustment of the repetition frequencies of the pulsed valves, while the previously used single valve system attached to a liquid water tank has caused excessive gas injection. A discharge is sustained by a high voltage dc power supply; the discharge current has pulsation synchronized with the pulsed valve repetition. A temporally averaged force induced by the magnetron sputtering thruster and exerted on a pendulum plate downstream of the thruster is measured; the results are in good agreement with the previously reported force measurement under precisely controlled gas flow rate using a commercial mass flow controller. Therefore, the precise control of the gaseous water propellant with the compact gas feeding system is achieved, while maintaining a similar thruster performance to that with the mass flow controller. • The double pulsed valves system provides the precise control of the gaseous water. • The magnetron sputtering thruster is properly operated with the pulsed valves system. • The thrust-to-power ratio of 3–4 mN/kW is obtained. [ABSTRACT FROM AUTHOR]

Gas distribution networks traditionally maintain constant pressure setpoints at regulating stations, ensuring a consistent supply to end-users with a high safety margin. However, the prospect of hydrogen injection in the gas networks necessitates rethinking operational strategies. This study examines the environmental and fluid-dynamic implications of implementing a smart pressure management approach in regulating stations within a distribution network with a localized hydrogen injection. The research introduces a novel simulation-based optimization algorithm, incorporating a steady-state fluid-dynamic model with hydrogen tracking, used to optimize the pressure setpoints in the stations. The algorithm is applied to a two-pressure levels looped gas network with multiple gas supply nodes and a single hydrogen injection. The test case results reveal that utilizing dynamic pressure setpoints leads to a 22% increase in hydrogen penetration compared to standard operation. Therefore, this study highlights that smart pressure modulation in a gas network with hydrogen injection can unlock a latent decarbonization potential, while simultaneously adhering to safety limits. [Display omitted] • Pressure modulation can increase hydrogen absorption in a distribution network. • Pressure modulation influences the gas flows in the network. • The modulation range is larger when the demand is higher. • At peak demand hydrogen injection is constrained by the node with the minimum pressure. • At minimum demand hydrogen injection is constrained by the gas quality constraint. [ABSTRACT FROM AUTHOR]

The air-booster vacuum preloading method is considered a reasonable choice for alleviating clogging problems. However, research on the air-boost mode during the early consolidation stage is still lacking. In this study, a series of comparative experiments were designed to investigate the effects of applying different pressures and durations on the consolidation characteristics of dredged soil and clogging at two consolidation stages using indoor model tests and microscopic tests. The experimental results showed that the air-boost modes of low pressure and short duration should be adopted during the early consolidation stage, and as the continuous consolidation, the pressure and duration should be increased. Moreover, early gas injection had a more significant effect on alleviating clogging of the prefabricated horizontal drain (PHD), and the pore diameter of dredged soil was also smaller. The research results are an important guide for air-booster vacuum preloading to dewater high-moisture dredged soil. • The implementation of early gas injection is an effective measure in the realm of air-booster vacuum preloading. • Early gas injection can delay the formation time of clogging. • Low pressure and short duration should be used in the early consolidation stage. • This study can provide a new reference for related air-booster vacuum preloading. [ABSTRACT FROM AUTHOR]

Oil recovery in natural fracture reservoirs can be improved by reducing the capillary force during the gravity drainage process in matrix-fracture system. In the current study, a modified gas was generated via dissolution of low molecular weight poly(dimethyl siloxane) (PDMS, average M w 3780 g/mol, 10000 – 50000 ppm) in CO 2 to enhance oil recovery at 50 °C or 70 °C and 3000 psi. Cloud point measurements indicated that PDMS dissolved in CO 2 at pressures less than 3000 psi, which was below the minimum miscibility pressure (MMP) of ∼3600 psi at 70 °C determined with the vanishing interfacial technique. The solution density increased from 669.6 kg/m3 for pure CO 2 to 780.3 kg/m3 for CO 2 /PDMS (50000 ppm) at 70 °C and 3000 psi, thereby reducing the density difference between the CO 2 -rich fluid and crude oil (ρ o =865.2 kg/m3) in matrix-fracture system. Also, CO 2 -oil interfacial tension (IFT) was reduced from 65 to 15 dyn/cm via the dissolution of 50000 ppm PDMS in CO 2. Therefore, it led to the CO 2 diffusion coefficient increased in both reservoir-fluid saturated porous media and bulk oil scenarios 3–4 fold and 4–7 fold respectively in comparison to pure CO 2 injection. These PDMS-induced changes reduced the capillary effects in gas-invaded zone, which consequently led to an increase in oil recovery of 25% points (from 31% to 56%) compared to pure CO 2 injection in the case of capillary continuity during gravity drainage tests. For the field-scale, because the PDMS can dissolve in CO 2 at pressures and temperatures which are commensurate with CO 2 EOR, it is a promising CO 2 -philic chemical for increasing CO 2 density and improving CO 2 diffusion coefficient in gas invaded zone compared to conventional CO 2 injection. • The effect of CO 2 -soluble polymers on oil recovery in gas invaded zone. • PDMS is soluble in CO 2 at pressure commensurate with CO 2 -EOR. • The density difference reduced in matrix-fracture system during CO 2 /PDMS injection. • The gas diffusion coefficients increased (4-7 fold) during CO 2 /PDMS injection. • 25% additional oil recovery was achieved during CO 2 /PDMS in the gas invaded zone. [ABSTRACT FROM AUTHOR]

• MSW gasification by hot recycling BFG is proposed to prepare syngas. • The energy efficiency of the proposed process is as high as 81.29 %. • The investigated influencing factors have coupled effect on syngas formation. • 25.95 vol% H 2 and 37.20 vol% CO are achieved for the proposed process. Waste-to-energy is one of the most effective methods to save energy and reduce carbon emissions. This paper proposes a novel process of municipal solid waste (MSW) gasification by hot recycling blast furnace gas (BFG) coupled with in-situ decarburization to prepare blast furnace injection of hydrogen-rich gas. MSW gasification by the hot BFG is conducted by using Aspen Plus software coupled with equilibrium model or kinetic model. Compared to the equilibrium model, kinetic simulation results exhibit good agreement with the experimental results. Moreover, the technological analysis is also performed to investigate the coupled effects of gasification temperature, MSW/BFG ratio, and steam/MSW ratio on the H 2 -rich syngas generated from MSW gasification. The results reveal that all the investigated influencing factors have been found with a significant effect on the H 2 -rich syngas formation. The 25.95 vol% of H 2 and 37.20 vol% of CO during MSW gasification by the hot BFG are achieved at a gasification temperature of 900 °C, steam/MSW ratio of 0.46 kg/kg, and MSW/BFG ratio of 0.34 kg/Nm3. [ABSTRACT FROM AUTHOR]

The reversible operation of a commercialized molten carbonate fuel cell as an electrolyzer is attractive to store the surplus of renewable energy and convert CO 2 into valuable fuel, like syngas (H 2 and CO). This work aims to assess this capability by developing a model for the co-electrolysis of CO 2 and H 2 O in the molten carbonate electrolysis cell (MCEC). Furthermore, a 1 MW power-to-gas system is simulated and optimized to maximize the process efficiency via a profound sensitivity analysis and a pinch heat integration analysis. The study's results reveal that when CO 2 electrolysis occurs, there is a risk of reaching the limiting current density at lower values, thus affecting the cell's performance. As for the simulation, the process yields an efficiency of 68.87% with an electrolyzer's power density of 0.082 W/cm2 per cell, producing 1.3 tons/day of methane gas ready for injection into the natural gas network. • Co-electrolysis of H 2 O and CO 2 in a molten carbonate electrolyzer was modelled. • 1 MW power-to-gas system is simulated and optimized via a sensitivity analysis. • Process yields an efficiency of 68.87% with 1.3 tons/day methane gas production. • The electrolyzer operates at a power density of 0.082 W/cm2 per cell. [ABSTRACT FROM AUTHOR]

This paper attempts to give a broad overview on technologies progress status, effects, perspectives, and issues associated to H 2 NG widespread applications. It deepens and completes the content of previous reviews by including hitherto unreviewed aspects as far as possible. To do so, a holistic approach has been used by surveying technical, energy, environmental, economic and safety issues related to the hydrogen mixtures' use. This review aims to provide support for a broader understanding of the problem, starting from the simple list of mixtures properties up to their impact on both NG pipelines and end-use devices. Hydrogen injection affects several blend characteristics and gas network parameters. Mixing limits are also related to Wobbe index variations and safety aspects due to the flashback risk. Numerous works have shown that hydrogen fractions of 10% allow parameters to be kept within acceptable ranges, and up to 20% are not related to significant risks. • Review of studies on hydrogen-enriched natural gas blends. • Power-to-Gas concept and motivation for hydrogen injection into the gas grid. • Effects of hydrogen in gas pipelines and hydrogen embrittlement issues. • Analysis of effects on end use devices and discussion of safety issues. • Economics aspects and price of hydrogen-methane blends. [ABSTRACT FROM AUTHOR]

The intensification of energy shortage has accelerated the development of unconventional oil and gas resources, during which complex problems of organic solid precipitation often occur. The precipitation behavior of organic solid such as asphaltene and wax play an important role in the optimization of reservoir production. However, there is still a lack of comprehensive understanding of the precipitation mechanism and interaction between asphaltene and wax, especially under high temperature and pressure. A self-designed precipitation apparatus based on backscattered light was utilized to achieve this objective. The effects of temperature range 30–120 ℃, pressure range 5–85 MPa, gas-oil ratio of 150，300 and 500 sm3/sm3 and injection gas of CH 4 , CO 2 and N 2 on organic solid precipitation in condensate oil-gas system were studied by physical simulation. The results revealed that asphaltene precipitated separately at high temperature, and asphaltene and wax co-precipitated at low temperature. Based on the observed precipitation behavior, a co-precipitation mechanism of asphaltene and wax under high-pressure conditions was proposed: Asphaltene particles precipitated first, providing nucleation sites for wax absorption, growth, and cross-linking as the pressure decreased. Moreover, the depressurization induced phase separation during oil and gas production resulted in the extraction of light components, reducing the solubility of wax and exacerbating reservoir damage caused by the precipitation of organic solid. Increasing the gas-oil ratio led to higher amounts of organic solid precipitation and shifted the pressure at which precipitation occurred. Furthermore, the miscibility of injection medium and condensate oil will also significantly affect organic matter precipitation, and the potential damage to the reservoir can be shown as follows: N 2 ＞CO 2 ＞CH 4. • Use of backscattered light to monitor the precipitation behavior of organic solid. • Effects of different factors on the precipitation characteristics of organic solids in condensate oil & gas system. • At low temperature, asphaltene and wax co-precipitate; At high temperature, asphaltene precipitates separately. • Asphaltene precipitation provides crystallization sites for waxy nucleation and growth. [ABSTRACT FROM AUTHOR]

In oil production companies, corrosion is a common issue with various adverse economic and environmental consequences. Active well production fluid always comprises inherently corrosive and highly corrosive substances. There are a variety of treatment techniques to prohibit corrosion, such as chemical treatment, cathodic protection, and paint-based corrosion inhibitors. El Hamra Oil Company produces crude oil from three main locations. The research group noticed several downhole localized corrosion problems in the artificial lift system. This paper presents a case study to quantify the extra operation cost of periodically replacing the entire tubing string, renting the pulling unit, and production deferring. The research quantifies the economic impacts after corrosion inhibitor is injected downhole using the carrier line technique (CLT). The results show that the company saved more than 672 K $ during three years of using downhole chemical treatment; dramatically decreasing the regular corrosion incidents in three active wells. The actual profits are expected to increase exponentially for the following years, meanwhile reducing the environmental impacts to meet Egypt's strategy towards sustainable goals in 2030. [ABSTRACT FROM AUTHOR]

• Static gas wave refrigerator (SGWR) realizes gas refrigeration through pulsed shock waves and expansion waves generated by pressure energy. • Full feedback jet oscillator as the pulsed jet trigger. Its switching mechanism is illustrated, and the structure is optimized. • The oscillation frequency can be well estimated through the jet switching frequency simplified equation derived. • The jet frequency control method can make the gas wave tube operate at the refrigeration's peak frequency, thus improving SGWR refrigeration efficiency. Static gas wave refrigeration (SGWR) is a mechanic equipment with no moving parts which realize refrigeration by working on gas through pressure energy. This paper introduces full feedback jet oscillator as the jet distributor of the gas wave refrigerator and shows the switching mechanism of the oscillator in detail through dynamics description. The range of influence of wedge distance (distance between wedge tip and the nozzle) on the pressure retention rate and frequency at the oscillator outlet is discussed, and a SGWR experiment platform is set up to make comparison of the pressure waveform as well as cooling efficiency of the impulse jet from two oscillators with different wedge distance in the gas wave tube. The result shows that jet oscillator performance varies along with the wedge distance, thus influencing the cooling efficiency. To expand the efficient operation range, the principle of jet frequency changing and the impact of narrowing the oscillator structure on jet frequency are discussed in detail, the variation rule equation of the jet switching frequency is derived. Matching experiments of jet oscillator and size of gas wave tube have been conducted under conditions of specific frequency and variable frequency. It is concluded that there exists fluctuation value in gas wave tube refrigeration efficiency versus gas injection frequency curve, which can be up to 15% or more. Based on the present results, the jet frequency control method can make the gas wave tube operate at the refrigeration's peak frequency, thus improving SGWR refrigeration efficiency. [ABSTRACT FROM AUTHOR]

Gas injection technology is frequently used to enhance oil recovery, and asphaltene deposition is inevitable during this process, except that different gases have different effects on asphaltene deposition. This paper studied the impact of varying injection gases (CO 2 , CH 4 , and N 2) on asphaltene deposition characteristics under reservoir conditions. The results show that the effect of different injection gases on asphaltene deposition is differently related to the oil-gas miscibility state. In the injection of CO 2 and CH 4 , asphaltene gradually precipitates and deposits on the fluid-carrying surfaces. When the oil and gas are completely miscible, asphaltene precipitation is prevented, and the crude oil reaches a new equilibrium state. CO 2 has a solubility higher than that of CH 4 with oil. It was found that the pressure at which CO 2 mixes well with the oil can be reduced by 46–55%, the dissolution rate increased by 1.6 times, and the asphaltene precipitation amount also increased by 1.76 times compared to that with CH 4 injection. Finally, it was found that the N 2 injection has a minor influence on crude oil's stability (minimal asphaltene deposition). • This research provides a new method for monitoring asphaltene deposition behavior. • Integration of Dynamic light scattering and HTHP PVT systems. • Asphaltene deposition analyzed at HTHP conditions during three gases injection. • The risk of asphaltene deposition in different gases injection are evaluated. [ABSTRACT FROM AUTHOR]

Early seal failure occurs frequently in the of CO 2 injection well packer, which is mainly manifested as failure of packer rubber, which seriously affects the normal production of gas well. Aiming at the packer rubber of CO 2 injection well, three factors affecting the seal failure of packer rubber were selected, namely temperature, pressure and decompression velocity and the sensitivity of each factor was analyzed by orthogonal experimental design. The results show that the mechanical properties of rubber decrease gradually with the increase of temperature, pressure, and decompression velocity. With the increase of the decompression velocity, the surface of the rubber gradually formed small bubbles, large bubbles and even bubble cracking phenomenon, rubber sealing performance parameters are significantly worse; the main cause of early packer seal failure is the gas injection well was suddenly released, and the gas that could not exude in the rubber in a short time expanded and formed bubbles or even burst under the action of the pressure difference between inside and outside. The optimal decompression velocity is obtained to keep the packer rubber seal well in the downhole corrosion environment, which provides a basis for the determination of the construction parameters of CO 2 injection well. [ABSTRACT FROM AUTHOR]

This study presents an experimental investigation of the characteristics of a ventilated supercavitating flow using high-temperature injection gas (VSHTG). Experiments are conducted in the cavitation tunnel located at the Chungnam National University in South Korea. Ventilation gas heated up to 773 K (500 °C) is injected behind a disk-type cavitator. The geometric characteristics of the VSHTG appearing with the temperature rise are captured using a high-speed camera, and the temperature characteristics inside the ventilated supercavity are measured using two K-type thermocouple temperature sensors. A theoretical physical model hypothesis is proposed, which is used to explain the VSHTG geometry variation with the increase in temperature and predict the thermodynamic effect caused by the injection high-temperature gas. Finally, the liquid–gas interface deformation of the VSHTG is examined using a colorimetric analysis. The results show that hot gas injection may increase the length of the supercavity and also make the liquid–gas interface unstable. A theoretical model of the thermodynamic effects is proposed and gives good agreement with the measurements. However, the findings should be further verified through additional studies including numerical analysis and experiments in a larger test section with the lower blockage ratio. • 773 K hot gas ventilated supercavitating flow was investigated. • The supercavity-lenght increases due to thermodynamic effects. • The liquid-gas interface becomes unstable as the injection gas temperature increases. [ABSTRACT FROM AUTHOR]

Mixture formation is one of the greatest challenges for the development of robust and efficient hydrogen-fueled internal combustion engines. In many reviews and research papers, authors pointed out that direct injection (DI) has noteworthy advantages over a port fuel injection (PFI), such as higher power output, higher efficiency, the possibility of mixture stratification to control NO x -formation and reduce heat losses and above all to mitigate combustion abnormalities such as back-firing and pre-ignitions. When considering pressurized gas tanks for on-vehicle hydrogen storage, a low-pressure (LP) injection system is advantageous since the tank capacity can be better exploited accordingly. The low gas density upstream of the injector requires cross-sectional areas far larger than any other injectors for direct injection in today's gasoline or diesel engines. The injector design proposed in this work consists of a flat valve seat to enable the achievement of lifetime requirements in heavy-duty applications. The gas supply pressure is used as the energy source for the actuation of the valve plate by means of a pneumatic actuator. This article describes the design and the performed tests carried out to prove the concept readiness of the new LP-DI-injector. • Direct injection of gaseous hydrogen at pressure levels of 20 bar. • Scalable design to meet flow requirements for heavy-duty applications with different cylinder displacements. • Design featuring a flat seat with a ceramic valve plate to achieve a high level of wear resistance. • Pneumatic actuation using a solenoid actuated pilot valve. • Concept readiness proved by means of rig testing and fired engine testing. [ABSTRACT FROM AUTHOR]

In this study, with the aim of reducing the energy consumption in the production of HHO gas for use in the combustion process of diesel fuel, different modes of gas production were investigated using electrolyzers. According to previous studies, the energy consumption rate of the electrolyzer to produce a high volumetric flow of HHO gas is very high. This high rate will restrict the use of equipment such as high-capacity batteries. The effects of HHO gas injection at the idle speed of the engine at a low temperature were evaluated. Because in this situation, the engine makes high air pollution. The results showed that the percentage of CO, CO2, HC, and NOX gases decreased by 66%, 33%, 38%, and 11%, respectively. On the other hand, the amount of O2 gas in the exhaust increased by 18%. These results were reported for HHO gas injection from 10 to 45 ml/s. The performance of Group Method of Data Handling (GMDH) neural network was desirable in modeling diesel engine pollutants. Because the Root-Mean-Square Error (RMSE) criterion for all evaluated gases is less than 0.32. The GMDH neural network was used for modeling the operation of the diesel engine with HHO supplemental fuel. The GMDH results showed that this artificial network can measure all engine exhaust gases. It can be used as a sensor and virtual simulator for this diesel engine with HHO supplemental fuel. [Display omitted] • The percentage of CO gas decreased by 66%. • The amount of HC gas concentration reduced by 38%. • DC current with a duty cycle of 90% had the highest efficiency. • The predictability of the GMDH model was acceptable. [ABSTRACT FROM AUTHOR]

For the final disposal of reactor graphite a quantitative characterization of its radioactivity is needed. In this work an emphasis is placed on the isotope 14C, an isotope accessible to AMS measurements. Reactor graphite can be highly activated and therefore difficult to measure without the risk of contaminating the AMS setup. Using an Elemental Analyzer (EA), a Gas Injection System (GIS) and the 6 MV AMS system of the Institute for Nuclear Physics, University of Cologne, we automated the measurement process for gaseous, diluted samples. The presented work shows the first steps to verify the possibility of gas dilution and provides a comparison to samples with known concentrations of 14C. In the future, our system will provide a high sample throughput of gas-diluted probes with high activities. [ABSTRACT FROM AUTHOR]

Gas injection has emerged over the recent decades as a promising technology to enhance oil recovery in various fields worldwide. The efficiency and success of a gas injection operation can be assessed through a number of vital experimental studies. Interfacial Tension (IFT) between the injected gas and the displacing fluid is a key parameter playing an eminent role in the foregoing studies. The main scope of this work is making a progress in modeling the IFTs between diverse n-alkanes and Methane (CH 4), Carbon Dioxide (CO 2), and Nitrogen (N 2) natural gases. For this purpose, two smart AI-based approaches of Cascaded Feedforward Neural Network (CFNN) and Decision Tree Learning (DT) were used to simultaneously model the IFTs between foregoing immiscible binary systems as a function of pressure, temperature, the gases properties, and the properties of the liquid. Several statistical measures and graphical descriptions were employed to aid the accuracy analysis of the proposed models. Both developed CFNN and DT networks represented desirable close-to-reality predictions in all binary systems. Besides, CFNN established itself as the most robust model for all studies binary systems with RMSE values of 0.5924, 0.5649, and 0.5870 mN/m, and R2 values of 0.9902, 0.9910, and 0.9904 for the train, test, and overall data, respectively. [ABSTRACT FROM AUTHOR]

Hydrogen storage in lined rock cavern (LRC) provides versatile site selection, safety, and stability, making it a crucial option. In this study, a thermodynamic mathematical model was established to describe hydrogen storage in LRC. This model is based on the principles of mass, momentum, and energy conservation while accounting for the authentic compressibility of hydrogen. The thermodynamic fluctuations throughout the seasonal cycle in LRC were computed using the COMSOL Multiphysics software. The results indicate that when the hydrogen storage reaches the operating pressure, the lower the cushion gas pressure, the greater the hydrogen injection amount, and the higher the utilization rate of storage capacity. With a cushion gas pressure of 3 MPa, the storage capacity utilization rate exceeds that at 15 MPa by 41 %. The injection rate of 0.5 kg/s results in a temperature increase of 12 °C compared to 0.27 kg/s, indicating twice the temperature rise at the 0.27 kg/s injection rate. An increase in injection temperature corresponds to higher temperature within the hydrogen storage cavern upon completion of gas injection, thereby reducing the time needed for gas injection to reach maximum operating pressure. A lower initial cavern temperature results in a longer time for hydrogen storage to reach maximum operating pressure. [ABSTRACT FROM AUTHOR]

We investigate unsteady, two-dimensional laminar fluid flow around cylinders, focusing on understanding the impact of injecting methane gas through two diametrically opposite arcs on the cylinder in the crossflow of the second fluid. This study encompasses applications in mixing and dispersion, which are crucial in various technological and natural processes. Our analysis addresses velocity field's contribution to the spatiotemporal distribution of transported quantities. We observed that mixing induces a transition from laminar to turbulent flow. Depending on the injected-to-crossflow velocity ratios, the wake vortices downstream of cylinder arrays separate from or connect to the injected gas. This phenomenon significantly impacts mixing efficiency caused by asymmetric vortical flow structures and their interactions. In this study, the effective Reynolds number was computed at the outlet to account for the increase of momentum due to the gas injection, and it showed a monotonic rise with increasing injected gas velocity. Particularly, we observed a linear increase in the effective Reynolds number with increasing ϵ (velocity ratio parameter) for the single cylinder case, however, it exhibits a non-linear behavior for the multiple cylinders case due to complex flow interactions and enhanced mixing. We further analyzed flow disturbance using a participation number, a statistical characterization of the system's spatial distribution of kinetic energy. Surprisingly, the participation number decreases with the increase in ϵ. This decrease indicates a highly localized and inhomogeneous distribution of kinetic energy in the system, increased tortuosity, and possibly the first sign of the inertial to turbulent transition in the system. • Enhance mixing and asymmetry of the flow for gas injection case. • Linear growth and non linear growth of the R e e f f with the intensity of the gas injection. • Non symmetric pressure distribution on obstacle-s arcs for the fluid flow with injections. • Decreasing behavior of the energy localization for high R e case. [ABSTRACT FROM AUTHOR]

The generation of multi-functional capsules often requires the sequential deposition of different components on the surface of bubbles or drops. Batch-based methods lack fine control over the capsule sizes, including risk of fusion, and cannot ensure identical environments for each capsule. To overcome these issues, different micro/milli-fluidic methods have been developed in the past. However, a major challenge remains in combining an explicit and flexible control over the capsule generation and their residence time in the different solutions within the same device. Using for the first time the example of bubbles covered by layers of oppositely charged polyelectrolytes (PSS/PAH), we introduce an original millifluidic Lab-on-a-Chip device with two novel functions: (1) Size and separation of the bubbles are tuned at constant flow conditions via gas injection through a movible, circular dispense tip into the cross-flow of a rectangular channel. We provide a detailed exploration of the bubbling parameters together with physical justification of the observations. (2) The device exploits gravity to make the generated bubbles rise between horizontally stacked millifluidic chips containing each the controlled flow of a specific polyelectrolyte solution. In analogy with electric circuits, we show how the flow resistance of each chip can be adapted such that bubbles move smoothly between them while avoiding undesired mixing of the solutions. We show first examples of obtained multilayer capsules and discuss their peculiar features, in particular, their outstanding stability with respect to coalescence and dissolution. While our methods use polyelectrolyte assembly on bubbles, they can be readily transferred to other types of solutions or even to drops and particles. [Display omitted] • New millifluidic method exploits mobile dispensing tip to tune bubbling. • Bubble size and spacing are independently controlled. • Novel method moves bubbles between strata of a millifluidic chip by gravity. • Flow of bubbles through alternating strata creates multilayer PSS/PAH capsules. • Obtained capsules have lifetimes of the order of several months. [ABSTRACT FROM AUTHOR]

The high-pressure hydrogen direct injection technology with diesel pilot ignition based on concentric biaxial needle injector is an advanced technology for low carbonization transformation of heavy power machinery at present, but it is faced with the problem that the pilot injection has a significant fluctuation of the main gas injection mass. Therefore, this paper describes the fluctuation rule of gas injection mass in detail, reveals the fluctuation mechanism through the characteristics of pressure oscillation in the system, and proposes an innovative prediction algorithm. It is found that the diesel pressure oscillation induced by pilot injection is the direct factor causing the fluctuation of gas injection mass. The fluctuation has the opposite trend to the diesel pressure oscillation, and both show the trend of underdamped cosine function oscillation. On this basis, a prediction algorithm for the fluctuation characteristics is established, which includes four main sub-algorithms. Among them, a sub-algorithm for predicting the fluctuation period is constructed based on the electro-hydraulic modeling method, a sub-algorithm for calibration of the underdamped dissipation system is constructed by using the real-time fitting and historical data iteration method, and a sub-algorithm for designing phase difference based on the real-time perceived fuel sound velocity. Finally, two-dimensional fitting is used to calibrate the amplitude and build a bridge between pressure oscillation and gas injection mass fluctuation. The results show that the prediction algorithm has high accuracy in almost all the common injection conditions. The regression determination coefficient (R 2) of the predicted value and the measured value is 0.9118, and the root mean square error (RMSE) is 2.013 mg. Through the construction of the gas injection mass fluctuation prediction algorithm model, to achieve the accurate prediction of the gas injection mass, can provide feedback data for the advanced control strategy and provide certain basis for accurate control of the gas injection mass. • The gas injection mass fluctuation prediction algorithm is realized. • The trend of under-damped cosine fluctuation with the change of interval time between the pilot and main injection. • The oscillation of diesel pressure is the direct factor affecting the fluctuation of gas injection mass. • The hybrid drive of model and perception iteration can predict the fluctuation of gas injection mass. [ABSTRACT FROM AUTHOR]

Probabilistic analyses using random fields are increasingly performed in geotechnical fields; however, they focus on random fields in natural soils. Comparatively, few studies have been conducted regarding random field variations in improved ground. An innovative technique for treating loess–the pneumatic vibratory probe compaction method is used in this study. The effects of different construction techniques on the spatial variability of improved ground and bearing capacity are investigated by varying the pneumatic injection pressure and treatment interval. To determine the posteriori parameter of the effective friction angle of a loess random field, Bayes' theorem and the transitional Markov chain Monte Carlo algorithm are applied. Subsequently, a random finite element analysis is performed. Based on the results, the maximum increase in bearing capacity and the minimum dispersion are achieved at a jet pressure of 0.6 MPa under a treatment interval of 1.4 m. Furthermore, the probability of failure is reduced to the lowest possible level. • A new resonance technology for treating loess. • Using the TMCMC algorithm to solve the random field parameters of loess strength parameters. • Evaluated the impact of different gas injection levels on the random field characteristics of loess. • A random finite element analysis was used to compare the bearing capacity characteristics before and after treatment. [ABSTRACT FROM AUTHOR]

• The effect of blending pattern on hydrogen concentration distribution is studied. • Hydrogen is injected from the bottom at an angle of 120° to facilitate full mixing. • The hydrogen proportion is not directly related to the local enrichment. • Increasing the kinetic energy ratio to 1.2 can improve the mixing uniformity. After hydrogen injected into a natural gas pipeline, the inner flow field of the pipeline will change greatly and hydrogen may be locally enriched. This is an important reason for the hydrogen-induced cracking of the pipeline. Therefore, there is an urgent need to investigate the effect of blending patterns on hydrogen concentration distribution in a methane-hydrogen pipeline. At this work, a multi-angle hydrogen injection model that is different from the traditional T-junction is established to understand the factor of hydrogen blending ratio and geometry (diameter ratio, hydrogen injection angle) on the blending effects. Firstly, the model is validated with experimental data under the corresponding conditions and then pure hydrogen injected into the natural gas pipeline under different injection patterns is analyzed computationally. The result shows that hydrogen injected from the bottom with angle α = 120 ° is helpful to form a low hydrogen concentration zone at the bottom of the pipeline and has the best blending effect compared to other angles. Based on the 120 ° model, the blending effect can be further improved by increasing the kinetic energy ratio to 1.2. This study can provide some references for improving the blending uniformity of hydrogen-blended natural gas pipelines, enhancing the safety of blending operation and preventing hydrogen embrittlement. [ABSTRACT FROM AUTHOR]

In carbon geo-sequestration, CO 2 were injected into the reservoir, separating considerable amount of carbon emissions form the atmosphere. Conformance control is one of the key factors affecting carbon sequestration efficiency because high mobility contrast and reservoir heterogeneity would reduce sweep efficiency, leading to poor sequestration efficiency. In this work, the conformance control of non-chemical microbubble in low permeability reservoir was experimental investigated and acquired data was employed for reservoir simulation. Then, reservoir simulations were performed to investigated the sequestration performance of CO 2 microbubble. The effect of conformance control, reservoir heterogeneity, gas-liquid ratio and reservoir dip angle were comprehensively analyzed. The results indicated that microbubble can achieve higher total sequestration amount than CO 2 gas injection due to superior conformance control, especially in heterogenous reservoir and reservoir with dip angle. Finally, the numerical simulation was performed to predict the ripening of capillary trapped microbubble at geological time scale after injection. To establish the relationship between reservoir simulation and microbubbles ripening simulation, the function between reservoir permeability and simulation parameters is first time introduced. The simulation results demonstrate that microbubbles can maximize capillary trapping, effectively delaying the formation of a gas cap, and reducing the risk of leakage in low permeability reservoirs. In general, simulation results demonstrate that CO 2 microbubble is a superior carbon sequestration technology with higher efficiency and safety. This study provides valuable insights and guidelines for field applications of non-chemical CO 2 microbubble assisted carbon geo-sequestration. • The conformance control of non-chemical CO 2 microbubbles was investigated. • The implicit texture model was employed to investigate microbubbles migration in reservoir. • The affecting factors of microbubble-assisted carbon geo-sequestration were identified. • Microbubble-assisted geo-sequestration can delay the formation of a gas cap in low permeability reservoirs. [ABSTRACT FROM AUTHOR]

In this paper, a "process-based" 3-phase model is applied to explore how multiphase fluid flow behaviour in two non-uniform wettability systems, named weakly oil-wet (WOW) and mixed-wet large (MWL), change when gas and oil move towards miscibility (σ go → 0). In the course of the theoretical development, we indicate how parts of the theory have been validated and confirmed satisfactorily by summarising experimental data from the literature. To demonstrate how the complexities of the three-phase physics interact with the system wettability, we use a capillary bundle (CB) model for the porous medium. This is sufficient to show the main processes which occur in the transition from immiscible to miscible behaviour. Even although the CB model is the simplest possible case for a porous medium, the results demonstrate a high level of unpredictable complexity which cover key parameters of the physics of 3-phase flow within porous media. In addition, for each case, the results point to the specific physical parameter that controls the phase separation lines. In some cases, gas injection or oil injection in a WOW system, the phase displacement changes quite radically as the system goes towards miscibility since there is a transition in wetting order from O/W/G to O/G/W. The differences and similarities between saturation paths in WOW and MWL are described in detail. For a given pore size distribution (PSD), the 3-phase displacements are controlled by the parameters of the rock wettability structure (see text) and the 3 interfacial tensions. Moving towards miscibility, 3-phase fluid displacement for gas injection and oil invasion are controlled by IFTs, while for water flooding, wettability structure plays the key role at all miscibility conditions. Although the simple CB model cannot describe all phenomena, such as phase trapping, the phase displacement paths, still the pore occupancies are qualitatively correct. Results of various phase injection in WOW are broadly consistent with pore occupancy sequences observations from pore scale X-Ray image analysis in literature despite simplicity of the theory which is validated in terms of its underling physics. [Display omitted] [ABSTRACT FROM AUTHOR]

• The Beam Line Vessel and its components are modeled by Solidworks, the vessel pressure distribution, and adsorption uniformity of the crysorption pump are analyzed by simulation using the Molflow software. • The performance of the south cryopump is tested experimentally using in-situ measurement method. • With the continuous injection of gas, the adsorption probability of the cryopump decreases, so the pumping speed of the cryopump will decrease. • Due to the limited capacity of cryopump adsorption, it is necessary to regenerate the cryopump near the maximum. The cryogenic vacuum system is an important subsystem of Comprehensive Research Facility for Fusion Technology Negative Neutral Beam Injector, which provides vacuum environment support for various experiments related to the beam generation and transport process. In the paper, a simulation and experimental study of the Comprehensive Research Facility for Fusion Reactor Negative Neutral Beam Injector (CRAFT NNBI) cryopump performance has been carried out. The Beam Line Vessel (BLV) and its components are modeled by Solidworks, the pressure distribution, gas molecular velocity distribution and adsorption uniformity of the crysorption pump in the BLV are analyzed by simulation using the Molflow software, at the same time, the performance of the south cryopump is tested experimentally using in-situ measurement method. The simulation results show that the average pressure near the Neutralizer is 8.5*10-3 Pa, the average pressure near the Electrical Residual Ion Dump (ERID) is 8*10-3 Pa, and the average pressure near the Calorimeter is 9*10-3 Pa. The adsorption percentage fluctuates around 12%, which indicates that single structure plays the function of adsorption efficiently, the theoretical pumping speed of the south cryopump on H2 was calculated to be 7.34*105 L/s, total theoretical pumping speed of two cryopumps can reach 3.67*106 L/s. The experimental results showed that when the south cryopump was operation, the pressures near the Neutralizer were 2.8*10-2 Pa, the pressures near the ERID were 2.7*10-2 Pa, and the pressures near the Calorimeter were 7*10-3 Pa, the actual pumping speed of the south cryopump on H2 was 6.37*105 L/s, total actual pumping speed of two cryopumps can reach 3.1*106 L/s. [ABSTRACT FROM AUTHOR]

Radioactive aerosol may be released from the molten core during a severe accident in a nuclear power plant. Pool scrubbing, a representative aerosol scrubbing process incorporated in several severe accident scenarios, has been modeled in MELCOR. Under gas injection conditions with a low Weber number, gas flow regimes above the nozzle are globule and swarm. Based on visual scrubbing experiments, we investigated the gas flow and aerosol scrubbing characteristics under low-Weber-number injection conditions. We systematically analyzed the relationship between scrubbing efficiency and gas flow behavior through experiments and the applicability of the aerosol scrubbing model in MELCOR to different pool scrubbing conditions. Also, the variation of the globule and swarm shapes with the inlet pressure was obtained to evaluate the applicability of the gas flow model in MELCOR. Additionally, the bubble size distribution and Sauter average diameter were used to characterize the swarm flow characteristics based on the image processing results. Finally, we used a modified scrubbing model to compare the experimental results and evaluate the most suitable swarm characterization parameters. [Display omitted] • The relationship between scrubbing efficiency and gas flow behavior was analyzed. • The applicability of the gas flow and aerosol scrubbing model in MELCOR was evaluated. • The modified models were used to evaluate the swarm characterization parameter. [ABSTRACT FROM AUTHOR]

Exploitation of natural gas hydrates provides an alternative way to address energy crisis. Dilute CO 2 gas (13–30mol%CO 2 with remaining N 2 /Air) injection into CH 4 hydrates for hydrate swapping (SW) allows cheaper and more practical CH 4 recovery and in-situ CO 2 sequestration. However, the roles of N 2 /Air in dilute CO 2 gas during exploitation remain unknown. It is unclear whether depressurization should be coupled after SW and continued below CH 4 hydrate stability pressure. This work employed multistep depressurization (MD) to dissociate the mixed hydrates formed after SW from 86.5 to 97.9 bar at 0.7–1.2 °C in bulk-water and sandpack with CH 4 hydrate saturation of 4.1–25.3 %. Effects of N 2 /Air on exploitation were investigated by examining hydrate morphologies and gas compositions. Morphological results in bulk-water indicated higher N 2 fraction in 20mol%CO 2 /N 2 triggered more CO 2 -rich hydrate reformation and CH 4 -rich hydrate dissociation. Exploitation results in sandpack indicated 13mol%CO 2 /N 2 produced the highest CH 4 swapping percent (46.6 %) and CO 2 hydrate sequestration percent (29.1 %). Air exerted weaker promoting effects on exploitation compared with equivalent N 2. The promotion of N 2 /Air on exploitation was dominated by dilute CO 2 gas injection altering mixed hydrate equilibrium which varied with time-dependent gaseous compositions during MD. l -methionine of 3000 ppm had stronger promoting effects on CO 2 sequestration in sandpack than bulk-water depending on mass transfer and water availability. Ceasing points (13.9–31.4 bar) suggested MD could be continued below CH 4 /above CO 2 hydrate stability pressures and before water production. For the first time, this study provided insights into the roles of N 2 /Air to determine injection gas types and depressurization schemes for efficient and safe hydrate exploitation in gas-rich hydrate-bearing sediment. [Display omitted] • The roles of N 2 /Air in exploitation of CH 4 -rich hydrate are studied. • CO 2 -rich hydrate reformation above CH 4 hydrate stability pressure is observed. • CH 4 -rich hydrate dissociation above CH 4 hydrate stability pressure is observed. • l -methionine of 3000 ppm efficiently enhances CO 2 sequestration in low-water system. • Ceasing points of multistep depressurization are decided in bulk-water and sandpack. [ABSTRACT FROM AUTHOR]

• Feasibility of storing the acid gas produced from facilities into basal sand aquifer. • Using a wellbore-aquifer-compositional model to investigate pressure induced around faults. • Simulation of plume migration, pressure changes, and CO 2 storage capacity. • Incorporating fault transmissibility, solubility, salinity, hysteresis, trapping and compositional tracking. • Substantial pressure increases around the sealing fault can be observed. • Relocating storage site away from fault or using a horizontal well to mitigate pressure buildup. This study investigates the feasibility of storing the acid gas produced from the oil and gas facilities in Southern Saskatchewan into the Basal Sand aquifer using a coupled wellbore-aquifer-compositional reservoir model. The simulations investigate the pressure change around the fault in proximity of the primary storage location incorporating the influence of reservoir permeability, fault transmissibility, and wellbore configuration, on the factors critical to safe and efficient storage, such as plume migration, pressure changes, and CO 2 storage capacity. A compositional fluid model created using an equation of state was integrated into the reservoir model. Simultaneous incorporation of fault transmissibility, phase solubility, water salinity, temporal in-situ hysteresis and structural trapping, and in-situ compositional tracking of individual gas components is considered as the main novelty of this work. The main challenge of the study was the lack of available data to characterize the aquifer. To this end, a comprehensive workflow of reservoir studies and modeling was applied to reduce the uncertainties and evaluate the site selection. The Basal sand scoping models reveal that the aquifer is expected to handle the required disposal volume given its extent. The injected acid gas plume migrates laterally and preferentially towards the northwest, away from the fault, owing to the aquifer's geological structure. CO 2 remains entirely in the supercritical state, offering storage advantages due to its lower volume. The reservoir permeability significantly impacts the pressure patterns with lower permeability formations triggering higher wellhead injection pressures. Substantial pressure increases around the sealing fault can be observed. Pressure changes of 110 kPa (16 psi) to over 400 kPa (58 psi) were observed at the fault segment after 20 years of continuous gas injection for the expected range of reservoir properties. Mitigation strategies to minimize the increase in fault pressure entail relocating the injection site away from the fault or utilizing a horizontal well trajectory and using an observation well near the fault for monitoring any pressure buildup and slippage. [ABSTRACT FROM AUTHOR]

• A physical simulation platform for gas injection and brine discharge is established. • The temperature of brine affects crystallization more than the gas/water injection. • A higher flow rate can enhance scouring effect to alleviate crystallization. • A built-in U-shaped pipe backflushing method for unblocking is proposed. Salt cavern gas storage (SCGS) not only holds promise for CO 2 storage but also helps combat climate change by providing a reliable and adaptable solution for storing natural gas. Herein, this capability facilitates the integration of renewable energy sources and helps decrease greenhouse gas emissions from fossil fuel-based power generation. Firstly, a physical simulation platform for gas injection and brine discharge was developed to investigate the crystallization mechanism and devise preventive measures for constructing SCGS. Secondly, the study involved analyzing the mechanism of brine crystallization and determining experimental parameters using similarity theory. Furthermore, the effects of gas/water injection temperature, brine temperature in the salt cavern, flow rate, and pipe wall roughness on brine crystallization were examined. Finally, preventive measures were suggested to address issues related to crystallization and blockage. Results indicate that a 10℃ increase in gas/ water injection temperature leads to an average decrease of 26.56 % in the crystallization rate, while a corresponding increase of 186.16 % occurs for brine temperature. Heating the injected gas/water and opting for shallow strata for SCGS construction can alleviate crystallization. The crystallization rate initially increases and then decreases with flow rate, with a preferable flow rate exceeding 96 m3/h to prevent crystal adhesion and enhance scouring effects. Therefore, crystallization in the middle of the brine discharge pipe warrants special attention. Significantly reducing pipe wall roughness can effec- tively minimize crystallization, highlighting the importance of developing erosion-resistant coatings. Moreover, a proposed small U-shaped pipe backflushing method aims to solve blockages, along with preliminary application suggestions. [ABSTRACT FROM AUTHOR]

High-load reactors face a significant challenge with fatty acid accumulation. Although injecting acidogenic gas (H 2 and CO 2) into methanogenic reactors improves biogas production, its mechanisms and stability enhancement remain unclear. Therefore, this study investigated the potential of using acidogenic gas to enhance methane production and system stability in a high substrate-loading co-digestion system with decreasing hydraulic retention time (HRT) and its regulatory role by considering biological pathways. Acidogenic gas injection effectively managed volatile fatty acid accumulation, with a concomitant increase in methane production from 0.042 to 0.066 L/L h as HRT decreased (16–8 days). However, the methane yield decreased from 611 to 460 mL/g volatile solids. Microbial community analysis revealed an increased abundance of hydrogenotrophic methanogens, along with several acidogenic and syntrophic fatty acid oxidizing consortia with decreasing HRT. The HRT10.67 sample exhibited the highest microbial species diversity and richness in the methanogenic reactor. Metabolomics analysis showed acidogenic gas reduced energy synthesis related to the tri-carboxylic acid cycle and oxidative phosphorylation while profoundly regulating the metabolism of amino acids, lipids, fatty acids, membrane transporters and inhibitory substances, thereby strengthening methane metabolism pathways. This study provides valuable insights into the roles of acidogenic gas in regulating energy metabolism to enhance methane production and offers potential opportunities for improving lipid and protein degradation. • H 2 content increased from 30 to 53 % as HRT decreased from 16 to 8 days. • Organic matter removal was slightly decreased by acidogenic gas injection (AGI). • AGI improved CH 4 production and yield, but the improvement decreased at lower HRT. • AGI increased abundance of hydrogenotrophic methanogens and syntrophic bacteria. • AGI triggered amino acid and lipid metabolism, reducing energy-related synthesis. [ABSTRACT FROM AUTHOR]

• The new impure CO 2 -crude oil correlation integrates the ratio of the specific injection gas mole fraction to the crude oil mole fraction as the novel independent variables. • Both linear and nonlinear regression methodologies were utilized to formulate empirical correlations for MMP prediction. • The new correlation can be linearized to the greatest extent and such linearization illustrates the fundamental concepts more distinctly. • The new correlation delves into the specific interactions between injection gas components and crude oil components, identifying which components dominate in the miscible process. CO 2 flooding is a widely-used technique for enhancing oil production, with miscible CO 2 flooding exhibiting higher recovery potential compared to both immiscible and near-miscible CO 2 flooding. However, the problem of insufficient CO 2 supply is increasingly critical in many reservoirs. When faced with a shortage of gas supply, the key to the successful implementation of miscible CO 2 flooding lies in accurately predicting the MMP of impure CO 2. This study leverages MMP data derived from both experimental and simulation results, utilizing both linear and nonlinear regression methodologies to formulate empirical correlations for MMP prediction. In addition, ridge regression is used to solve collinearity problem. Compared with former investigations, the impure CO 2 correlation proposed in this study integrates the ratio of the specific injection gas mole fraction to the crude oil mole fraction as novel independent variables. This inclusion reflects the actual interaction between the specific injection gas and crude oil during the miscibility process. Furthermore, the correlation can be linearized to the greatest extent through this way and such linearization illustrates the fundamental concepts more distinctly, offering a more practical and comprehensible approach. This formula combines the prediction of the minimum miscible pressure with the interaction mechanism of the miscible process, and the dominant factors in the miscible process can be determined. In terms of reducing the minimum miscible pressure, the interaction between C 4 + C 5 in the injected gas and C 1 + N 2 in the crude oil component is the strongest, while the interaction between N 2 in the injected gas and C 2-6 in the crude oil was most significant in increasing the minimum miscible pressure by comparison. The correlations presented for impure CO 2 yield an average absolute deviation of 2.18 % and sustain a relative deviation within ± 10 %, surpassing previously published correlations. This study highlights the accuracy and effectiveness of the developed correlations for estimating MMP for impure CO 2. The suggested MMP correlation offers a practical and efficient means of determining MMP for the implementation of impure CO 2 miscible flooding in the field. [ABSTRACT FROM AUTHOR]

• Catalytic free efficient dry reforming of methane through thermal plasma. • Production of syngas from a novel graphite cathode thermal plasma torch. • CO 2 and CH 4 conversion of 82% and 88% was achieved. • Maximum selectivity of H 2 (66 %) and CO (83 %) with a specific energy of 179.3 kJ/mol. • External CH 4 injection offers a superior energy conversion efficiency of 51% The urgent need for innovative technologies to actively mitigate the rising levels of greenhouse gases in the earth's atmosphere has become imperative. Thermal plasma-based dry reforming of methane (CH 4) into syngas (H 2 and CO) is an efficient method for the reuse and conversion of greenhouse gases. In this work, a novel DC non-transferred arc thermal plasma torch made of graphite cathode is designed to reform the greenhouse gases into value-added syngas, utilizing a constant discharge current of 70 A. Ar and CO 2 gases were used to generate and stabilize the plasma jet. Different mole ratios (1, 1.5, and 2) of CH 4 gas were introduced by internal and external mode of injection to mix the plasma and studied the reforming process. The optical emission spectra of the plasma jet were captured at the exit of the torch nozzle to study the emission characteristics of plasma and estimate the temperature. Thermodynamics studies were carried out to understand the thermal decomposition of CO 2 -CH 4 mixtures in the dry reforming process and assess the impact of increasing CH 4 mole ratio on syngas yield and solid carbon formation. Gas chromatography-mass spectrometer (GC–MS) was used to analyze the conversion efficiency and selectivity of the processed gases. Results revealed that the conversion efficiency of CO 2 (70–82 %) and CH 4 (80–88 %) and selectivity of H 2 (65–66 %) and CO (82–83 %) slightly varied with increasing CH 4 mole ratio while injecting the CH 4 internally, and a similar trend was observed in external injection as well. Maximum conversion efficiency of 51 % was achieved by introducing 1 mol of CH 4 externally with the specific energy of 179.3 kJ/mol, which was 28.4 % higher than internal injection. [ABSTRACT FROM AUTHOR]

• CO 2 flooding shows different in low permeability reservoir with medium viscous oil. • Influence factors on CO 2 flooding are ranked using Spearman correlation analysis. • Oil recovery prediction of CO 2 flooding is built using multiple linear regression. CO 2 flooding for enhanced oil recovery has been successfully applied throughout the world, however, most of its application are conducted in low, ultra-low and tight reservoirs with light oil. Studies focused on low permeability reservoirs with medium viscous oil are merely reported. Based on these special formation and oil characteristics of Niuquanhu Block, China, CO 2 -oil interactions and CO 2 flooding characteristics are compared with the light oil using PVT analysis and core flooding experiments. The influencing factors of CO 2 flooding are then studied using core flooding experiments, and their influences on oil recovery are ranked using a Spearman method. The results show the interactions between CO 2 and medium viscous oil are stronger compared with light oil. When 70 mol% CO 2 is dissolved in medium viscous oil, a 58 % viscosity reduction and a 35.5 % oil swelling are obtained, which is 1.49 times and 1.75 times that of light oil. The CO 2 flooding results show that the oil recovery of low permeability reservoir with medium viscous oil is only 51.11 %, which is 0.92 times and 0.72 times that of high permeability reservoir with medium viscous oil, and low permeability reservoir with light oil, respectively. When the low permeability and the medium viscous oil are present at the same time, a gas-compression period is observed at the initial oil-production stage, which is a disadvantage for CO 2 flooding. According to the results of series CO 2 flooding experiments and the analysis of Spearman method, the influencing factors on oil recovery are ranked as back pressure > permeability ratio > gas injection rate > permeability. A higher back pressure is beneficial for enhanced oil recovery, however, a higher permeability ratio will shorten the effective period of CO 2 flooding. Based on the ranked factors, a prediction model of oil recovery for CO 2 flooding is built using multiple linear regression method, and an optimal model is proposed as E R = 0.6941 - 5.7706 1 P + 0.3855 Q V k + 0.0005 K - 0.0004 V k. which provides a well-fitting between predicted oil recovery and actual oil recovery. The findings revealed in this paper can provide a technical support for CO 2 flooding in similar low permeability reservoirs with medium viscous oil. [ABSTRACT FROM AUTHOR]

A long-term gas injection test on Callovo-Oxfordian claystone (COx) has been performed by the British Geological Survey (BGS), and it is simulated with a coupled hydro-mechanical model. The approach is implemented in the software CODE_BRIGHT, considering a spatially correlated heterogeneous field of initial porosity. The correlation length is assumed to change in different directions. An important feature of this approach is that material properties such as elastic modulus, diffusivity and intrinsic permeability are functions of porosity, leading to the emergence of heterogeneity and anisotropy of these properties. An embedded fracture model is adopted to describe significant changes of intrinsic permeability due to the opening of apertures, caused by gas pressure-induced deformations. Sensitivity analyses have been conducted with respect to parameters in the embedded fracture model, guard ring volume, diffusivity and the sample orientation to understand gas migration mechanisms through COx. The results show that the adopted approach can capture the observations of the experiment. • A long-term gas injection test on COx is simulated in CODE_BRIGHT. • A heterogeneous and spatially correlated field of porosity is generated. • Other properties are defined as a function of porosity, becoming heterogeneous. • Intrinsic permeability changes due to induced deformations are considered. • Sensitivity analyses were conducted to understand gas migration mechanisms. [ABSTRACT FROM AUTHOR]

Vortex induced vibration (VIV) experienced during flow past a cylinder can reduce equipment performance and in some cases lead to failure. Previous studies have shown that the injection of bubbles in the flow over a cylinder typically leads to a monotonic increase in shedding frequency with void fraction, however, a satisfactory explanation for this phenomenon has not been proposed. Unexplained scatter in the data exists, including that the increase in shedding frequency is not universal. More research is needed to characterize the influence of bubbles on the wake structure, and subsequent shift in shedding frequency. To this aim, the effect of bubbles on the structure of the wake and VIV was examined over two values of Reynolds number, R e D = 100 , 000 and 160,000. Time-resolved particle image velocimetry (TR-PIV), proper orthogonal decomposition (POD) and spectral proper orthogonal decomposition (SPOD) of the wake structures, vibration of the cylinder, and bubble image velocimetry (BIV) were used to assess the flow topology changes under the influence of gas injection. Using SPOD/POD analysis in the near wake, it was found that the primary Karman shedding frequency decreased with the injection of gas, from a Strouhal number of St = 0.2 to St = 0. 17 − 0. 18 ; the width of the spectral peak was found to increase with void fraction. Notably, the vibration of the cylinder at the primary Karman shedding frequency was suppressed following the injection of gas, even at spanwise-averaged volumetric qualities below 0.01%. This suppression occurred regardless of if gas was concentrated locally near the centerline of the channel, or along the span. BIV data suggests that gas accumulation in the near wake, driven by the high velocity vertical motion of gas, serves to uncouple the cylinder motion from the formation of the vortex street downstream while promoting faster wake recovery. [Display omitted] • Time-resolved flow and vibration measurements taken for a cylinder in two-phase flow. • Cylinder vibration can be attenuated at volumetric qualities below 0.01%. • A decrease in the shedding frequency is observed following bubble injection. • Potential mechanisms are proposed for the attenuation of the cylinder vibration. [ABSTRACT FROM AUTHOR]

Oil production in most of the old reservoirs is expected to decline, and this will create a gap between the supply and demand of oil in the world. Meanwhile, there are still huge volumes of hydrocarbons in unconventional reservoirs. Intensive technological approaches are needed to ensure adequate oil is recovered than developing other new fields that are more expensive economically. Therefore, there is a rising interest in developing effective improved oil recovery techniques to increase oil recovery from the depleted oil fields or unconventional oil resources. This study mainly intends to compare between the water alternating gas (WAG) and the water huff-n-puff techniques for oil recovery in a tight oil reservoir, based on their effectiveness, their recoveries, economical factors, as well as assessing the factors that affect the recovery based on both of the techniques. The modelling and designing of the reservoir for the Jilin tight oil field and its simulation were performed by the ECLIPSE 300 software. The result showed that, after the simulation of 2922 days, WAG has better results than using a water huff-and-puff technique by providing a total of 30,453.271 Sm3 of the total field oil and the water huff-and-puff method has a total field oil production of 1,726.389 Sm3. Besides good oil recovery, the WAG method has shown higher water production compared with that of the water huff-and-puff method, with 46157.715 Sm3, whereas the water huff-and-puff method has only produced a total field water of 138.874 Sm3 for the whole 2922 days of simulation. Furthermore, the WAG best mode that shows an optimum oil recovery efficiency of 47.40% is an injection mode by starting with water injection followed by gas injection (CO 2) for 1-year cycle each. Thus, WAG is a preferential candidate for the development of tight oil reservoirs. [ABSTRACT FROM AUTHOR]

The deployment of intermittent renewables in distributed energy systems has to be managed so as to maximise local energy self-consumption. This paper deals with the application of sector coupling strategies to increase energy self-consumption and decarbonise urban energy districts. The aim of this work is to investigate the combined implementation of Power-to-Gas and Power-to-Heat strategies in Renewable Energy Communities. Power-to-Power, Power-to-Heat and Power-to-Gas systems, along with their combined adoption, have been implemented in a residential community under different renewable excess conditions. For each strategy, the storage system's size has been optimised and the configurations have been compared in energy, environmental and economic terms. The Power-to-Heat strategy is the most cost-effective solution, although it presents intrinsic limitations. The Power-to-Gas configuration involves the hydrogen injection into the gas grid, thus exploiting the local network as a free storage system. Higher self-consumption can be achieved; nevertheless, energy and emissions savings are lower due to the electrolyser poor efficiency. The combined application of the two sector coupling strategies allows the strategies individual advantages to be exploited and the limitations of both to be overcome. Furthermore, this solution leads to higher self-consumption and lower annual costs than conventional electric batteries. • Sector coupling strategies for improving self-consumption in energy communities. • Combined implementation of Power-to-Heat and Power-to-Gas systems. • Analysis of energy storage systems in two renewable excess conditions. • Assessment of energy, environmental and economic impacts. • Self-consumption based tariffs in accordance with the Italian incentive scheme. [ABSTRACT FROM AUTHOR]

In traffic transportation, the use of low-carbon fuels is the key to being carbon-neutral. Hydrogen-enhanced natural gas gets more and more attention, but practical engines fueled with it often suffer from low engine power output. In this study, the inner mechanism of hydrogen direct injection on methane combustion was optically studied based on a dual-fuel supply system. Simultaneous pressure acquisition and high-speed direct photography were used to analyze engine performance and flame characteristics. The results show that lean combustion can improve methane engine's thermal efficiency, but is limited by cyclic variations under high excess air coefficient conditions. Hydrogen addition mainly acts as an ignition promoter for methane lean combustion, as a result, the lean combustion limit and thermal efficiency can be improved. As for hydrogen injection timing, late injection can increase the in-cylinder turbulence intensity but also the inhomogeneity, so a suitable injection timing is needed for improving the engine's performance. Besides, late hydrogen injection is more effective under lean conditions because of the reduced mixture inhomogeneity. The current study shall give some insights into the controlling strategies for natural gas/hydrogen engines. • Effect of hydrogen injection on methane combustion was optically studied. • Hydrogen addition mainly acts as an ignition promoter for methane lean combustion. • Suitable late injection can improve the natural gas/hydrogen engine's performance. • Late hydrogen injection is more effective under lean conditions. [ABSTRACT FROM AUTHOR]

In this paper, based on a High-pressure direct injection (HPDI) dual-fuel valve, the schlieren imaging method combined with laser-induced fluorescence imaging method (PLIF) are used to investigate the macroscopic structure and concentration distribution characteristics of a high-pressure gas jet under different injection pressure ratio (NPR) and gas injection moment (Ti). The data processing method for macroscopic structure and concentration distribution of gas jet is optimized, and a new concentration partition method for the gas jet is proposed. The results show that comparing the gas jet penetration and volume correlation equations from Hamzehloo A and Vuorinen V, the correlation coefficients of ultra-high and small NPR conditions are quite different due to the different development processes of the shock wave structure. With the improvement of NPR, the influence on gas jet penetration is decreasing, which is the same as the conclusion of previous research. In this paper, the later stage of gas jet is divided into four regions: the Mach disk core region (A), the concentration rapidly decreasing region (B), the low concentration diffusion region (C), and the edge mixing region (D). The A and B regions are highly correlated with the shock wave structure of the under-expanded gas jet. The increase of NPR and Ti has a great promotion effect on the length and concentration distribution of regions A and B but has rarely effect on regions C and D. The transverse concentration gradient in regions A and B presents a Gaussian distribution structure. The average concentration descent gradient (G ¯) in region A is about 4 times that in region B. The transverse concentrations of C and D gradually converge under the action of air turbulence. Under different Ti conditions, the length proportion of regions A and D rarely changed, while the length proportion of regions B and C presents a negative correlation. The G ¯ in regions A and B are positively correlated with Ti, but the concentration increase rate keeps decreasing. The range of concentration fluctuation regions in regions C and D keeps expanding with the increase of Ti, indicating that the uniformity of gas jet concentration distribution keeps improving. • The shock wave structure can affect the development law of gas jet macroscopic structure. • Gas jet can be divided into four regions according to the concentration gradient. • The gas jet concentration distribution is related to the shock wave structure. [ABSTRACT FROM AUTHOR]

In this study, we numerically investigated the formation of bubbles by gas injection through an orifice in a stagnant liquid column and the flow field surrounding the bubbles after detachment under several flow conditions. To this end, we employed an enhanced coupling method that combines the advantages of mass conservation property of the volume-of-fluid (VOF) method with the boundedness and continuity of a conservative level-set (LS) function for multiphase computations to achieve a smoothened and sharpened interface. The coupling method was integrated into an incompressible Navier–Stokes solver to investigate the bubbling flow under various injection conditions. The simulated results were first validated against the experimental data of a benchmark test case to assess its reliability. The capability of the solver was also confirmed by examining the computed results and comparing them with those of the other studies. Subsequently, we simulated bubbling flow under different injected gas conditions and several orifice radii. The simulated results indicated that at low gas injection flow rates, the detachment time of bubbles, pinched off the orifice rim, could be predicted depending on the orifice radius and volume flow rate of the gas, whereas orifice radius had a notable influence on the detached volume of bubbles. In addition, the gas injection flow rate had a significant influence on the pressure field surrounding the bubbles after detachment, which is useful for studying of the bubbling flows and for the optimal design of small-scale systems. • An efficient coupling method for interface simulations on small scales. • Detached time of bubble could be predicted based on orifice radius and volume flow rate. • Remarkable influences of gas flow rate on shapes and pressure field surrounding bubbles after detachment are presented. [ABSTRACT FROM AUTHOR]

This study proposes a multi-objective mathematical programming model to design an oil supply chain network at three levels: upstream, midstream and downstream. It includes oil wells, gas injection wells, production units, refineries, gas injection centers, distribution centers, export and import terminals. The proposed model optimizes all three economic, social and environmental goals at the same time. Drilling injection and production wells, transportation costs, production costs, gas injection center costs, as well as fixed and annual costs of refineries and distribution centers are all minimized in the economic dimension. The environmental dimension of sustainability reduces greenhouse gas emissions, while the social dimension of sustainability increases job opportunities. The optimization of associated petroleum gas injection operations into the reservoir is also taken into account in this study. The proposed model considers the uncertainty of critical parameters and employs a robust possibilistic hybrid approach to deal with it, as well as an interactive fuzzy approach to solve it. A case study in Iran is used to evaluate the suggested model's performance. In comparison to the single-objective economic model, the results of solving the model show that taking sustainability into account has reduced greenhouse gas emissions and increased job opportunities. The crude oil extraction potential increases in each period when gas injection optimization and reservoir pressure are taken into account. Furthermore, the cost of the supply chain grows as the amount of uncertainty in the suggested model rises. As a result, the uncertainty of system parameters must be considered. • A multi-objective sustainable model for designing an oil supply chain is proposed. • Gas injection optimization is considered to enhance oil recovery in the model. • To deal with parameter uncertainty, a robust probabilistic approach is applied. • To solve the multi-objective model, an interactive fuzzy approach is used. • Real data from Iran is used to validate the suggested model. [ABSTRACT FROM AUTHOR]

Heavy oil reservoirs are much more challenging to be exploited by water flooding than conventional oil reservoirs because of high viscosity. However, gas injection has advantages such as viscosity reduction, oil swelling, extraction, and interfacial tension reduction. Furthermore, it is more economical than thermal recovery methods. Previous pressure depletion testing has proved that nitrogen(N 2) can form a foamy oil flow in the solution gas drive stage. In addition, crude oil has sufficient mobility under high-temperature conditions in relatively deep, heavy oil reservoirs. In this study, the feasibility of N 2 huff-n-puff in heavy oil reservoirs was determined by observing the flow behavior and oil recovery factor through huff-n-puff tests in a two-dimensional planar model and a real-time, high-pressure visual cell. Stable foamy oil flow can be formed, and the overall recovery can reach 35.73 % when the pressure depletion rate was 16 kPa/min. The advantage of nitrogen huff-n-puff is high early production, and the application of nitrogen huff-n-puff in the early stage is not only low in cost but also highly efficient in production. Nitrogen huff-n-puff forms some large-contact-area gas chambers that can enhance the effect of using other high-cost solvents in the later stage. The results of this study can provide some theoretical basis and technical guidance for the application of nitrogen huff-n-puff in relatively deep, heavy oil reservoirs. • A method of nitrogen huff-n-puff to enhance heavy oil was proposed. • The main mechanism of nitrogen huff-n-puff in heavy oil was studied. • The flow state of oil and gas was observed in real-time by a visual cell. • Our work provided useful insights on economical efficient development of heavy oil. [ABSTRACT FROM AUTHOR]

The high flammability of hydrogen gas gives it a steady flow without throttling in engines while operating. Such engines also include different induction/injection methods. Hydrogen fuels are encouraging fuel for applications of diesel engines in dual fuel mode operation. Engines operating with dual fuel can replace pilot injection of liquid fuel with gaseous fuels, significantly being eco-friendly. Lower particulate matter (PM) and nitrogen oxides (NO x) emissions are the significant advantages of operating with dual fuel. Consequently, fuels used in the present work are renewable and can generate power for different applications. Hydrogen being gaseous fuel acts as an alternative and shows fascinating use along with diesel to operate the engines with lower emissions. Such engines can also be operated either by injection or induction on compression of gaseous fuels for combustion by initiating with the pilot amount of biodiesel. Present work highlights the experimental investigation conducted on dual fuel mode operation of diesel engine using Neem Oil Methyl Ester (NeOME) and producer gas with enriched hydrogen gas combination. Experiments were performed at four different manifold hydrogen gas injection timings of TDC, 5°aTDC, 10°aTDC and 15°aTDC and three injection durations of 30°CA, 60°CA, and 90°CA. Compared to baseline operation, improvement in engine performance was evaluated in combustion and its emission characteristics. Current experimental investigations revealed that the 10°aTDC hydrogen manifold injection with 60°CA injection duration showed better performance. The BTE of diesel + PG and NeOME + PG operation was found to be 28% and 23%, respectively, and the emissions level were reduced to 25.4%, 14.6%, 54.6%, and 26.8% for CO, HC, smoke, and NO x , respectively. • Influence of the hydrogen flow rate on combustion and emission of (CI) engine studied. • Hydrogen gas manifold injection was set in three distinct proportions. • Brake thermal efficiency increased at maximal conditions of operation and 9 lpm flow rate. • The addition of hydrogen to NeOME + PG combination improves the brake thermal efficiency. • Highest BTE for the hydrogen gas manifold injection at 10° a TDC and duration 60° CA. [ABSTRACT FROM AUTHOR]

Al-based fully amorphous coatings with low porosity were successfully produced via warm spraying, combining numerical simulation and experimental validation. A warm spray gun model, employing computational fluid dynamics, was developed to simulate the warm spraying process. The study delved into the effects of reactant flow rate, oxygen/fuel (O/F) ratio, coolant flow rate, spray distance, particle size, particle shape, particle injection velocity, and particle injection angle on the gas flow field parameters (pressure, temperature, and velocity) and particle in-flight behaviors (temperature, velocity, and in-flight trajectory). The optimum spraying parameters (OSP) predicted by the simulation results were determined: 0.008740 kg/s for reactant flow rate, 2.7 for the O/F ratio, 0.007356 kg/s for coolant flow rate, 142 mm for spraying distance, 10–35 μm for particle size range, spherical for particle shape, 10 m/s for particle injection velocity, and 0° for particle injection angle. Subsequently, warm spraying experiments based on the OSP yielded Al-based fully amorphous coatings with a porosity of 0.08 %. This work provides valuable insights for the production of Al-based fully amorphous coatings with minimal porosity through warm spraying. • A warm spray gun model was established based on the computational fluid dynamics method. • The effect of spraying parameters on gas flow fields and particle in-fight behaviors was studied. • The optimum spraying parameters were predicted by the simulation results. • The Al-based fully amorphous coatings with 0.08 % porosity were prepared by warm spraying experiments. [ABSTRACT FROM AUTHOR]