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The preparation of MgO-stabilized ZrO2 powders was based on combustion synthesis between Mg powders and CO2 with ZrO2 powders as the diluent. The effects of the diluent content on the combustion process parameters, phase composition, microstructure, and high-temperature stability were systemically investigated. As the diluent content increased, the reaction temperature, propagation velocity, and MgO content decreased. The reactant powders underwent different reaction processes and were transformed into different phase compositions due to the change in diluent content. The obtained MgO-stabilized ZrO2 powders exhibited excellent high-temperature stability up to 1400 °C.

Моделирование горения является ключевым аспектом полномасштабного трехмерного моделирования современных и перспективных двигателей для авиационно-космических силовых установок. В данной работе изучается возможность решения задач химической кинетики с использованием искусственных нейронных сетей. С помощью классических численных методов были построены наборы обучающих данных. Выбирая среди различных архитектур многослойных нейронных сетей и настраивая их параметры, мы разработали достаточно простую модель, способную решить эту проблему. Полученная нейронная сеть работает в рекурсивном режиме и может предсказывать поведение химической многовидовой динамической системы за много шагов. Combustion process simulations are the key aspect enabling full-scale 3D simulations of advanced aerospace engines. This work studies solving chemical kinetics problems with artificial neural networks. The training datasets were generated by classical numerical methods. Choosing a multi-layer neural network architecture and fine-tuning its parameters, we developed a simple model that can solve the problem. The neural network obtained works is recursive, and by running many iterations it can predict the behavior of a chemical multimodal dynamic system.&nbsp

In this study, a high-speed imaging technique for recording spectral radiative images at high temporal–spatial resolutions were proposed to visualize the combustion process of a single coal particl...

In order to investigate a viable approach to achieving high efficiencies and low nitrogen oxide (NOX) emissions, this paper presents the application of a homogeneous charge compression ignition (HCCI) engine and the partially premixed combustion (PPC) mode applied to a heavy diesel engine. The effect of carbon dioxide (CO2) fraction on combustion parameters was analyzed and discussed in detail. For this purpose, on the one hand, ANSYS CHEMKIN-Pro software was used to perform simulations of a closed homogeneous reactor under conditions relevant to HCCI engines, and on the other hand, ANSYS-Fluent software was used by adding a CO2 fraction varying from 20% to 58% to methane fuel to study 2D flow simulation by applying a PPC combustion mode to predict the distribution of various output parameters such as in-cylinder temperature, in-cylinder pressure and emissions. In comparison with the two presented models, it was found that the HCCI engine showed a lower NOX level than the PPC mode and this was due to the lower in-cylinder temperature in the HCCI engine.

A two-dimensional numerical simulation study is conducted to investigate the combustion process of n-heptane spray in a porous medium burner (PMB) based on the previous experimental work performed ...

The availability of liquid fossil fuels is dwindling. Alternative fuels for CNG and CPO biodiesel that can be used in DF engines are the solution. However, the use of this fuel has reduced engine p...

In this study, we have carried out to modeling by mathematical equations the environment of the combustion chamber under some conditions using the software MATLAB in order to make an adequate algorithm of resolution and get solution of the different equations that taken part in the phenomenon of combustion, so the first was to identifies the kind of the fuel to use in that model (taking Methane as fuel combustion) and minimizing the reduction of novice gas burned is in priority, for this, we want to establish the optimal values to take to preserve the environment, especially from CO2 and CO emissions, secondly, its nature according to the equivalent ratio (lean, stoichiometric or rich mixture), all variations of equivalent ratio, the third idea is to retrace the ways of a different product of the reaction and see their variations compared to the equivalent ratio, once traced, we can improvise which exact place in the reaction, a product will be finished either in the form of a gas or to decompose in order to bind to another and form another component. We also discussed the percentage of O2 and H2O emissions for an interesting viewpoint of the environmental aspect of hydrocarbon’s chemical reaction. Another additional part will be dedicated to the process of flameless combustion to write its mathematical equation, compare it with the so-called traditional one, and see the variations in the temperature according to the equivalent ratio.

To accurately model the Direct Injection Spark Ignition (DISI) combustion process, it is important to account for the effects of the spark energy discharge process. The proximity of the injected fuel spray and spark electrodes leads to steep gradients in local velocities and equivalence ratios, particularly under cold-start conditions when multiple injection strategies are employed. The variations in the local properties at the spark plug location play a significant role in the growth of the initial flame kernel established by the spark and its subsequent evolution into a turbulent flame. In the present work, an ignition model is presented that is compatible with the G-Equation combustion model, which responds to the effects of spark energy discharge and the associated plasma expansion effects. The model is referred to as the Plasma Velocity on G-surface (PVG) model, and it uses the G-surface to capture the early kernel growth. The model derives its theory from the Discrete Particle Ignition (DPIK) model, which accounts for the effects of electrode heat transfer, spark energy, and chemical heat release from the fuel on the early flame kernel growth. The local turbulent flame speed has been calculated based on the instantaneous location of the flame kernel on the Borghi-Peters regime diagram. The model has been validated against the experimental measurements given by Maly and Vogel,1 and the constant volume flame growth measurements provided by Nwagwe et al.2 Multi-cycle simulations were performed in CONVERGE3 using the PVG ignition model in combination with the G-Equation-based GLR4 model in a RANS framework to capture the combustion characteristics of a DISI engine. Good agreements with the experimental pressure trace and apparent heat-release rates were obtained. Additionally, the PVG ignition model was observed to substantially reduce the sensitivity of the default G-sourcing ignition method employed by CONVERGE.

The effects of the split ratio on the mixture formation and combustion process of a diesel spray in a constant-volume chamber were experimentally investigated. A commercial seven-hole injector was used in this experiment. The effects of the mass-dependent split ratio and dwell time were observed when the total fuel injection was 5.0 mg/hole. Three split ratios were considered: 3:7, 5:5 and 7:3, while the dwell time of 120 µs was fixed for every condition. A laser absorption-scattering technique was adopted to examine the formation of mixtures with regarding to the equivalence ratio. A high-speed video camera was used to observe natural flame luminosity, and a two-colour pyrometer system was employed to evaluate the temperature and soot concentrations in the flame. Among the distribution ratios tested in this study, the 7:3 split ratio exhibited the best performance for the lean mixture formation considering the overall equivalence ratio distribution. The air entrainment wave at the end of injection timing of the first injection caused the fuel near the nozzle to lean at a rapid rate. The soot formation process for the 3:7 and 5:5 split ratios was observed because the second injection fuel caught the flame of the previous injections; this deteriorated the combustion region and influenced soot formation. The result also revealed that for the 7:3 split ratio, accelerated the soot deduction rate to the cycle of soot oxidation during the combustion period.

The reduction of NOx emission in the combustion process is of vital importance to satisfy the increasingly strict NOx emission standards. Although substantial progress has been made for fuel NO red...

The issues of combustion processes and the organization of the combustion workflow in diesel engines are relevant in view of the tightening of economic and environmental requirements for them. The problem of saving liquid fuels remains one of the most acute in the provision of fuel and energy resources. The development of highly efficient methods for organizing work processes when burning natural gas in a compressed or cryogenic state in the cylinders of internal combustion piston engines and determining ways to further reduce toxic emissions, increase fuel efficiency and reliability in promising gas engines is an urgent task. Mathematical modeling of liquid fuel combustion is a complex task, since it requires taking into account a large number of complex interrelated processes and phenomena. The article presents a simple 3-D model of cylinder diesel tractor engine D 144, the re- sults of numerical simulation of combustion of liquid and gaseous fuel in the cylinder of the diesel engine D-144. The article presents the results of modeling, including graphs of the dependence of nitrogen oxides, particles in outgoing gases, depending on the consumption of gaseous fuel in the form of pure methane. Additionally, tempe- rature and velocity contours are shown. The corresponding conclusions are made.

Onsite mine fire generates large volumes of heat-affected coal in Jharia coalfields, India. Direct utilization of such heat-affected coal in thermal utilities is not feasible as such coal does not have the desirable volatile matter required for combustion. In the present work, experimental studies have been carried out to investigate the possible utilization of such heat-affected coal in thermal utilities by blending with other coal. Heat-affected coal (31% ash and 5300 kcal/kg GCV) collected from Jharia coalfield were blended with thermal coal (28% ash and 5650 kcal/kg GCV) in different ratios of 90:10, 80:20, 70:30 and 60:40 to identify the desirable blend ratio for burning of blended coal in thermal utilities. Burning characteristics of all the coals were carried out using TGA. Various combustion parameters such as ignition temperature, peak temperature, burnout temperature, ignition index, burnout index, combustion performance index, rate and heat intensity index of the combustion process and activation energy were evaluated to analyse the combustion process. Experimental and theoretical analysis shows the blend ratio of 90:10 can be used in place of only thermal coal in utilities to reduce the fuel cost.

The paper presents the method of studying the fuel combustion and typical characteristics of biogas combustion process obtained in experiments. The main factors influencing the flame stability and the laminar combustion velocity in the biogas flow are investigated. The effect of combustion temperature, pressure, and other parameters on the formation of pollutants in the combustion chamber is analyzed.

Exergy analysis is achieved by assessing exergies related to the inlet fuel and air, output power, heat loss, gas exhaust loss and destruction or system irreversibility. The exergy fraction of each component is considered for all mixtures by dividing the individual exergy quantity into the exergy of the fuel. In the present investigation, the combustion process has been simulated in a DI diesel engine (OM314) with biodiesel fuel different Blends (B20, B40, B100) of soybean at full load and 1200 rpm by a thermodynamic model using both thermodynamics first and second laws of thermodynamics. The results showed good agreement with the experimental pressure. The results of the analysis of energy and availability balance show that the first and second laws efficiency for pure biodiesel fuel is more than the other two fuel and total availability. indicated work availability, the heat loss availability, burned fuel availability and irreversibility for 20% biodiesel fuel are more than two other fuels.

The development of a mobile waste incineration plant designed for the recovery of garbage dumps located near towns and villages, from where the removal of garbage to the city to the incineration plant is not profitable due to the large remoteness of small settlements from the city. The installation has two combustion zones: in the 1st zone, the combustion process of solid municipal waste (MSW) is achieved at temperatures up to 600 °C, and in the second zone – up to 1200 °C. Afterburning of flue gas to reduce the formation of dioxins, furans and soot is provided.

A computational and experimental study of the passage of a gasless combustion wave through a wedge-shaped inert obstacle was performed. The stability of the transient combustion process to a change in the thermophysical and geometric parameters of the obstacle and the energy-kinetic parameters of chemically active layers was studied. By the region of stable transient combustion process is meant the range of parameters in which the passage of the combustion wave through the contact boundary ends with the establishment of its steady-state propagation regime in the ignited composition. The dynamics of transient combustion under near-critical conditions of its existence was investigated.

Phenomena accompanying the self-ignition period have been and are the subject of extensive research in this area. They are usually carried out in constant volume pressure chambers or in reactors with constant air flow. Such tests are considered to be basic tests. The conditions in these tests are definitely different from those in compression-ignition engines. Therefore, the comparison of the auto-ignition delay periods from test stands to those obtained from real engines raises a number of doubts. Because the self-ignition delay period determines the combustion process, I made a theoretical analysis of a number of factors that have an impact on this process which determines the operational aspects of the engine, and thus its economics and ecology. The research object was a single-cylinder engine from the AVL LIST GmbH in Graz, Austria. The engine is equipped with Common Rail injection system. The test stand meets the standards: Directive 1999/96/EC of the European Parliament and the Council of 13th December 1999, Regulation (EC) No 715/2007 of the European Parliament and the Council of 20th June 2007, as well as Commission Regulation (EC) No692 /2008 of 18th July 2008. The analysis of the operational aspects of the self-ignition delay period was based on the results of tests on the AVL 5402 engine when fed with hydrocarbon fuels: diesel and synthetic oil. The engine was also fed with vegetable fuel - rapeseed oil. The obtained material from the tests warns the user of CI engines against the effects of their failure if the engine control parameters and the quality of fuel for its supply are not maintained as recommended by the manufacturers. The material contained in the publication is used for scientific analysis, and, which is worth emphasizing, is of a utilitarian nature.

Purpose The epoxy resins need to be added with flame retardant to ensure safety in practical applications. There were a lot of highly toxic substances in the flame retardant used in the past, which caused greater harm to human body and the environment. Therefore, this study aims to propose a research on the synthesis of new phosphorous-containing flame retardant and the properties of flame retardant epoxy resins. Design/methodology/approach The flame retardant intermediate DOPO was synthesized using o-phenylphenol as the substrate. The intermediate was mixed with D4Vi under certain conditions to synthesize a new phosphorous-containing flame retardant. The flame retardant was added to the epoxy resins to prepare the flame retardant epoxy resins. Findings The experimental results show that the synthetic new phosphorous-containing flame retardant is far less harmful than the flame retardant used in the past and has extremely low toxicity, which is suitable for use in practical projects. Originality/value The new phosphorus-containing flame retardant synthesized by forms a more uniform and dense carbon layer in the combustion process, which well protects the underlying materials, thus improving the flame retardancy of epoxy resin materials. The harm of the new phosphorus-containing flame retardant is far less than that of ordinary flame retardant. The flame retardant used in the past has very low toxicity and is suitable for practical engineering.

As requirements for continuously improving internal combustion engine fuel economy with satisfactory emissions, model-based control strategies are often used to optimize the combustion process. To apply advanced control techniques for closed-loop engine combustion control, control-oriented engine combustion models are necessary and they are physics-based, accurate enough for model-based control, computationally low cost, and capable of real-time simulations. In addition, control-oriented combustion model with adequate fidelity may need to adapt to physical system and environment changes over time to maintain model-based control performance, such as model-reference (guided) control, where the control-oriented combustion model runs in real-time to generate an error signal between physical system and reference-model output for feedback control. This paper provides a review of existing control-oriented engine combustion models, along with their associated applications. Three main groups of control-oriented combustion models are reviewed from simple to sophisticated physics-based dynamic models, including mean-value, Wiebe function-based, and reaction-based models. The fundamental principle of each model group is reviewed briefly and its applications are also addressed. At the macro level, a control-oriented engine model can be used for crank angle-based and/or cycle-based control. As the engine control hardware performance continuous improving with reduced cost, model-reference (guided) combustion control shall become reality since now it is feasible to run a physics-based control-oriented engine combustion model inside an engine control module. On the other hand, each model group, even for the simple mean-value model, has its own applicable scenarios.

This paper presents numerical modeling to determine characteristics of producer gas combustion in a cyclone combustor under different air–fuel mixing patterns. The burner was configured by varying in premixed, non-premixed, and co-flow modes. The combustion process was operated at a thermal power input of about 50 kW with respect to ambient conditions of air–fuel injections. The numerical modeling was carried out using the eddy dissipation concept combustion model integrated with a 17 species skeletal (SK17) reaction mechanism. The numerical result was validated with the existing experimental data before implementing the studied cases. Swirling flow field and combustion characteristics were compared for all three cases. It could be concluded that the premixed combustion mode was a better option in comparison with two other cases, considering that it gives higher swirling flow field characteristics, leading to a good result in combustion efficiency and lower both CO and NO emissions.

Reactivity controlled compression ignition (RCCI) engine give advantages over conventional diesel engine with the promising engine power and good control on NOx and soot emission. The trend of the RCCI concept is still new and Is very important to control the ignition in order to control the combustion progress and emission. The objective of this study is to provide data on the combustion characteristics and emission of diesel as high reactive, and ethanol as the low reactive fuel in the RCCI engine. The engine speed and injection timing were varied. Simulation work was conducted by using the Converge CFD software based on the Yanmar TF90 diesel engine parameter. Results show that operating the engine at low speed resulting in better engine performance and low carbon emissions due to the sufficient oxygen contents. For the high-speed engine, advancing the injection timing improves the fuel and air reactivity and steeper the equivalence ratio gradient, which result in a complete combustion process.

Because diesel combustion processes produce harmful detrimental nitrous oxides, the selective catalytic reduction, an after-treatment method using diesel exhaust fluid (AdBlue) to reduce these emissions, is an important part in the cycle of the combustion process. Therefore, it is crucial to continuously monitor the quality of the diesel exhaust fluid to secure the ideal selective catalytic reduction. This article presents a platinum thin-film sensor using the 3ω method which is able to characterize the diesel exhaust fluid. By means of the 3ω method, information about the concentration of urea in water can be extracted. In this investigation, a digital lock-in amplification technique is used to execute the measurements. The results show that this sensor can determine the urea content within 1 % by weight. Moreover, besides the analysis of the 3ω signal, the 1ω signal is analyzed in depth to receive additional information about the temperature. Because the same structure can measure multiple parameters, such as concentration, temperature, and flow, the sensor might be a good alternative to the state-of-the-art diesel exhaust fluid sensor.

The main objective of this thesis is to propose a method to overcome a limitation of combustion in lean-burn condition by applying the Amplified Ignition Source (AIS). In order to analyze the combustion efficiency, Constant volume combustion chamber (CVCC) was designed to conduct experiments such as flame visualization, combustion pressure and flame kernel. As the experimental and analysis conditions, Ignition device were applied to two models, C_type plug and J_type plug, and conducted the analysis and experiment with parameters of compressed pressure and air/fuel ratio. Experimental results showed that as the air/fuel ratio increased, the efficiency of C_type decreased, resulting in large combustion delay in the air/fuel ratio 1.4 area, and a misfire occurred without burning in the 1.6 area. However, in case of J_type, combustion occurred smoothly up to air/fuel ratio 1.6, and the combustion pressure was also higher than that of C_Type. In addition, In the case of coldflame expansion, J_Type was doubled at air/fuel ratio 1.0. air/fuel ratio, and the expansion of the coldflame increased as the air/fuel ratio increased. As the combustion process in the lean combustion area proceed the combustion efficiency of J-type improves.

Pressurized oxy-combustion is one of the most efficient emerging combustion systems for coal-based power generation with CO2 capture. Mercury reemission and the fate of mercury, arsenic, and seleni...

Benzene is a very important molecule in a variety of industrial, environmental, and chemical systems. In combustion, benzene plays an essential role in the formation and growth of polycyclic aromatic hydrocarbons and soot. In this work, a new laser-based diagnostic is presented to make quantitative, interference-free, and sensitive measurements of benzene in the mid-infrared (MIR) region. The diagnostic is based on a widely tunable difference-frequency-generation (DFG) laser system. We developed this laser source to emit in the MIR between 666.54 cm−1 and 790.76 cm−1 as a result of the DFG process between an external-cavity quantum-cascade-laser and a CO2 gas laser in a nonlinear, orientation-patterned GaAs crystal. Benzene measurements were carried out at the peak (673.94 cm−1) of the Q-branch of the ν11 vibrational band of benzene. The absorption cross-section of benzene was measured over a range of pressures (4.44 mbar to 1.158 bar) at room temperature. The temperature dependence of the absorption cross-section was studied behind reflected shock waves over 553–1473 K. The diagnostic was demonstrated in a high-temperature reactive experiment of benzene formation from propargyl radicals. The new diagnostic will prove highly beneficial for high-temperature studies of benzene formation and consumption kinetics.

The cotton fire often occurs during storage, and it is valuable to reveal the combustion characteristics of cotton bales. However, most of the previous studies only focused on the combustion phenomenon of cotton bales after ignited externally. In fact, during the storage of cotton, the fire often originated from inside of a cotton bale, resulted from the sparks introduced into the cotton bale by the ginning machinery and the heat generated due to hygroscopic property. Therefore, an experimental study was conducted to investigate the effect of density on the smoldering characteristics of cotton bales ignited internally. In this study, the cotton densities of experimental study were 50, 60, 70, 80, 90, 100, 110 and 120 kg/m3. The change rules of the smoldering spread rate in external horizontal, internal horizontal, and internal vertical during the combustion process as well as the mass loss of the cotton bales with these densities were studied, and the spreading processes of the smoldering in these cotton bales were also determined. The experimental results show that due to differences in the amount of oxygen and heat flux, an increase in density leads to a decrease in the spread rates in external horizontal, internal horizontal and internal vertical. With the increase in density, the porosity decreases and the amount of air is reduced, so the spread rate gradually decreases. However, the mass loss rate, i.e. the amount of burning cotton per unit time, increases with density. And, as the overall amount of cotton increases with density, the burning time also increases.

The present paper reports the results of the design optimization of an air manifold utilized for delivering the air necessary for the combustion process in a biomass-fired batch boiler. A CFD model is built and validated by using experimental data. The numerical model is used to improve the device performances by reducing the entropy generation, considered as a measure of the effectiveness of the design. Other parameters, namely outlet velocities, are also monitored in order to guarantee an efficient combustion process. Four different designs of the manifold, characterized by a progressive reduction in entropy generation, are proposed and then compared with the base case. In each design step possible sources of irreversibility, such as corners, sharp variation of the flow direction, etc. are smoothed, for example by rounding the corners or by accompanying the flow in its directional changes. For all the cases, entropy generation is monitored and a reduction in its value of ∼10 times is observed if the first and last designs are compared. Values of velocities and pressure drops are monitored to confirm the acceptability of the improved designs. Finally, entropy generation and pressure drops are analysed for varied air flow controlled by the fan power.

The combustion characteristics of blended fuels pool fire were experimentally studied. Six square pools with length ranging from 5 cm to 20 cm were adopted, and mutually insoluble n-heptane-methanol blended fuels were used with different mixing proportions. In the experiments, burning rate and fuel temperature were measured and recorded during the whole combustion process. Results show that the special effect of azeotropism can influence the burning characteristics of n-heptane-methanol blended fuels to a large extent. For the cases with n-heptane fraction larger than the azeotropic proportion (0.485), there exists two burning stages of blended fuels and n-heptane, respectively; while if n-heptane fraction is smaller than 0.485, the two burning stages turn into blended fuels and methanol, respectively. In the steady burning stage of blended fuels, the fuels will burn together at the constant azeotropic proportion (0.485) regardless of the initial mixing proportions of liquid fuels. Due to the effect of azeotropism, the blended fuels are boiling at the azeotropic point (59.1 °C) lower than either boiling point of n-heptane and methanol, which leads to smaller mass loss rates compared to the pure fuel pool fires. That is, the azeotropism between n-heptane and methanol weakens the burning intensity of blended fuels compared to the pure fuel.

Propagation of combustion wave in a two-layer system was numerically modelled with account for melting, interdiffusion, and heat losses. Combustion wave propagation in between two reactive layers of a bilayer structure was found capable of steady propagating until some critical bilayer thickness (lcr). An oscillation combustion mode arising above lcr was found to yield a product with periodic inhomogeneities in its structure. Strong heat losses led to encapsulation of combustion process into a shell of unreacted mixtures.

Presented study deals with the final structure and radiological properties of different fly-ash based geopolymers. Lignite fly-ash (lignite Kolubara ? Serbia) and wood fly ash were obtained in combustion process together with commercial fly-ash. Synthesis of the geopolymers was conducted by mixing fly-ash, sodium silicate solution, NaOH and water. The samples were strengthened 60 ?C for 48 hours after staying at room temperature in covering mold for 24 hours. The X-ray diffraction, Fourier transform infrared and SAM measurements were conducted on the samples after 28 days of geopolymerization process. The X-ray diffraction measurements of lignite fly-ash samples show anhydrite as the main constituent, while wood fly-ash samples consist of calcite, albite and gypsum minerals. Besides determination of physicochemical properties, the aim of this study was radiological characterization of lignite fly-ash, wood fly-ash and the obtained geopolymer products. Activity concentration of 40K and radionuclides from the 238U and 232Th decay series, in ash samples and fly-ash based geopolymers, were determined by means of gamma-ray spectrometry, and the absorbed dose rate, D, and the annual effective dose rate, E, were calculated in accordance with the UNSCEAR 2000 report.

Currently, the use of secondary agricultural raw material is a topical issue. There are various applications of agricultural crop residues possible, but they are finance- and energy-consuming. Burning crop residues is very harmful for the environment. One of the ways to solve the problem is the production of solid biofuel that can be used to heat buildings. The authors suggest producing solid biofuel in the form of small-sized fuel rolls / pellets (SFR), which are made of oleaginous flax residues. As a result of the conducted experimental investigations, the authors have proved the efficiency and the environmental safety of SFR consumption. The new fuel can be recommended if the requirement of efficient and ecologically safe combustion is met. Thus, the influence of small-sized fuel rolls’ properties on the process of their combustion as well as quantitative and qualitative analysis of the combustion gases from burning solid fuel made of oleaginous flax residues have been investigated. The paper presents the results proving that SFR combustion is the most efficient on condition of providing reduced moisture (10-12%) and reasonable density (80 kg/m3) in the process of pellet production. In addition, it has been determined that there is a significant reduction of harmful CO emissions and normalization of СО2 concentration. The application of the suggested solid biofuel can make it possible to solve the problem of using oleaginous flax residues and provide cheap fuel for household purposes.

The article considers the influence of electro-hydraulic pulses on the combustion of phosphorus sludge. Electric discharges in the environment of phosphorus sludge are sources of shock waves, which destroying the structure of phosphorus sludge and contribute to the intensification of the combustion process. A distinctive feature of the electro-hydraulic effect is the ability to control the parameters of pressure waves over a fairly wide range using the characteristics of the electric discharge circuit. For determine the optimal productivity and purity of the final product of the electric discharge unit’s operation mode, experiments were conducted on the effect of the discharge energy on the efficiency of the electric discharge method for extracting phosphorus from phosphorus sludge. The efficiency of the electric discharge process was estimated by the amount of phosphorus that was released after settling and expressed as a percentage of the total amount of phosphorus in a phosphorus sludge’s portion. The experiments were conducted out for sludges of different structures, with different phosphorus content and were conditionally divided into three groups: “rich” with phosphorus content — 70 %, “medium” — 50 % and “poor” — phosphorus content — 30 %.

In order to develop the scientific and technical foundations of creating an artificial intelligence system for monitoring terrorist acts, the paper presents the results of a study of the amplitude-frequency spectra of acoustic emission (AE) of the combustion process of cellulose-containing materials (as one of the main materials used to carry out arson and attacks in organizing terrorist actions in the form of law and order violations in the local territory) of various physicochemical composition. The technical implementation of this effect in the development of automated devices for monitoring acoustic space as part of an operational monitoring system for the terrorist zone, aimed at early identification of the sources of terrorist threats to the normal functioning of the local territory of the state.

New methods have been studied in the past few decades to decrease exhaust emissions and fuel consumption of diesel engines. Using new combustion methods as low-temperature combustion (LTC) strategies and also utilizing new fuels as bio-diesel are beneficial ways to overcome diesel engine issues. This numerical study focused on the effect of split injection strategies as well as swirl ratio (SR) on the biodiesel premixed charge compression ignition (PCCI) combustion process and the related emissions. In this regard, KIVA-3V code as a CFD tool has been utilized to analyze the combustion and emission characteristics of the diesel engine. Single and split injection strategies have been executed on biodiesel PCCI combustion and have been compared in order to probe and examine the injection strategies. The results show that in both strategies, advancing the injection timing can lower the combustion emission and improve the engine performance by optimizing the start of injection (SOI) as sweet spot value. Utilizing a high swirl ratio with the split injection strategy has a negative effect on overall combustion, emission, and performance in comparison with the single injection strategy. For multi-injection scheme, SOI = −35 ATDC, SR = 1.1, and for single injection scheme, SOI = −40 ATDC, SR = 1.1 are considered as optimum cases regarding minimum total exhaust emissions and highest performance.

The process of making pellets at PT. Estren Pear flour Millss require hot steam generated from the Indomarine boiler. This study aims to determine the performance of Boier Indomrine. The research method used is to collect measured data on instruments and stored in the control documents of PT. Eastern Pearl Flour Mills. The results of the calculation show that the heat energy loss in the distribution pipe installation is 32.5 kW, while the available fuel energy from the combustion process is 2334311 kJ / hour. mass balance of the working fluid that occurs is the mass rate of feed water used is 1126.35 kg / hour, the mass rate of steam produced is 934.35 kg / hour. While the rest came out through the blow down process of 192 kg / hour.

A liquid bipropellant rotating detonation rocket engine was successfully test fired. The 6.5-in.-diam engine operates on a mixture of rocket-grade hydrogen peroxide and triglyme. Ignition is accomp...

Olive stones are being widely used as a fuel in Southern Europe, especially in Spain, where a standard that grades their quality for combustion has been developed. Oil content is one of the parameters considered, although no studies about its influence on the combustion process have been found in literature. In order to determine the quality of the olive stones marketed in Spain, a sampling plan was designed and the collected samples were characterised. Most of the samples showed good characteristics for being used as a fuel. It can be noticed that higher fractions of impurities (pulp, skin and stalks) caused lower bulk densities and higher net calorific values, ash, fines below 1 mm, oil and nitrogen contents. With the aim of studying the influence of oil content in the combustion of olive stones, samples with four different oil contents (between 0.16 and 2.0%) were used in combustion tests in two domestic devices (boiler and stove). Oil contents above 1% resulted in an increase in CO, TOC, TSP, PM1 and PM0.1 emissions, which was noticeable when using olive stones with 2% oil content. NOx emissions increased as the oil content raised, due to the higher N content in the fuel.

The pulverised coal and its mixture with biomass are one of the most popular fuels in industrial energy. To ensure, on one hand, minimal greenhouse gas emission and, on the other hand, maximum energy production efficiency, it is necessary to monitor the combustion process of these fuels. One way to do this is to monitor the flame intensity. This is an optical, non-invasive solution, and information on the status of the process is obtained with minimal delay. The article proposes a method for identifying undesired combustion states for which the excess air coefficient is greater or smaller than the value ensuring total combustion. Three deep recurrent neural network architectures for classifying the flame intensity time series were explored. The best results were obtained using the convolutional long short-term memory model, which offered the accuracy of 86.5%–99.8%, depending on the current thermal power. The prediction time of a single data sequence was about 0.6 ms. High accuracy and low time consumption of the proposed method create an opportunity for its use in industrial combustion systems of pulverised coal and its mixture with biomass.

The pre-chamber ignition system scavenged with natural gas can effectively improve the in-cylinder combustion process and extend the lean-burn limit of natural gas engines. The scavenging process affects the flow field and fuel-air mixture concentration distribution in the pre-chamber and affects the combustion process in the pre-chamber as well as the ignition process in the main chamber. This has a significant influence on the performance of natural gas engines. It is supposed that the ratio of natural gas remaining in the mixture inside the pre-chamber at the ignition timing affects the combustion process in the pre-chamber. To verify this suppose, an independent injection system for injecting natural gas into the pre-chamber is designed and experiments are carried out on a single-cylinder natural gas engine. The ratio of natural gas remaining in the mixture inside the pre-chamber at the ignition timing is adjusted by changing the injection start angle of the scavenging process. The combustion process in the pre-chamber and the main chamber are analyzed using the in-cylinder pressures. The results indicate that, with the delay of the injection start angle, the ratio of natural gas remaining in the mixture inside the pre-chamber at the ignition timing increases, the combustion process in the pre-chamber is enhanced, the maximum pressure difference between two chambers increases and appears earlier. The energy of the hot jets and the penetration of the jets increase, which enhances the combustion process in the main chamber.

An analysis of the combustion process along gradient trajectories is presented for a set of Direct Numerical Simulations of turbulent premixed jet flames at different Reynolds numbers and approxima...

In this study, a numerical study based on Euler equations and coupled with detail chemistry model is used to improve the propulsion performance and stability of the rotating detonation engine. The proposed fuel injection called stratified injection functions by suppressing the isobaric combustion process occurring on the contact surface between fuel and detonation products, and thus the proportion of fuel consumed by detonation wave increases from 67% to 95%, leading to more self-pressure gain and lower entropy generation. A pre-mixed hydrogen-oxygen-nitrogen mixture is used as a reactive mixture. The computational results show that the propulsion performance and the operation stability of the engine with stratified injection are both improved, the temperature of the flow field is notably decreased, the specific impulse of the engine is improved by 16.3%, and the average temperature of the engine with stratified injection is reduced by 19.1%.

Rotating detonation engines (RDEs) are gaining significant interest as a practical approach to increasing the operating efficiency of propulsion systems through pressure gain combustion. To use RDE...