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Experimental and numerical simulation of launcher base flows are crucial for future launcher design. In experiments, exhaust plume simulation is often limited to cold or slightly heated gases. In numerical simulations, multi-species reactive flow is often neglected due to limited resources. The impact of these simplifications on the relevant flow features, compared to real flight scenarios, needs to be characterized in order to enhance the design process. Experimental and numerical investigations were carried out within the framework of the SFB/TRR 40 Collaborative Research Centre to study the impact of plume and wall temperature on the base flow of a generic small-scale launcher configuration. Wind tunnel tests were performed in the Hot Plume Testing Facility (HPTF) at DLR, Cologne, using subsonic ambient flow and pressurized air or hydrogen–oxygen combustion as exhaust gases. The tests were numerically rebuilt using the DLR TAU code employing a scale-resolved IDDES approach, including thermal coupling and detailed chemistry. The paper combines the experimental and numerical findings from the SFB/TRR 40 base flow studies and highlights the most prominent influences on the mean flow field, the pressure field, the dynamic wake flow motion, and the resulting aerodynamic forces on the nozzle. High-frequency pressure measurements, high-speed schlieren recordings, and time-resolved CFD results are evaluated using spectral and modal analysis of the one- and two-dimensional flow field data. [ABSTRACT FROM AUTHOR]

A novel technique is presented to improve the initialization of compressible combustion LES, DNS or URANS by numerically turning the flame into a damper to quickly remove (artificial) pressure fluctuations and acoustic energy from the system. This is achieved by modifying the pressure dependency of the heat release rate, effectively modifying the Rayleigh Integral to achieve negative values, so that the acoustic energy is quickly removed from the system. The technique can (a) reduce the cost of simulations (by shortening the initialization), (b) contribute to stabilize the simulation, (c) help to avoid unrealistic thermoacoustic modes and, (d) potentially, be modified to compensate for excessive numerical dissipation of acoustic energy. Examples from LES of a thermoacoustic test case are presented to demonstrate the effective stabilization achieved. [ABSTRACT FROM AUTHOR]

Geological carbon sequestration in jointed reservoirs will require the use of fracture network for the flow of CO2 plumes. However, acidic solution formed at the interface between brine and CO2 can cause chemical erosion of the local rock mass, especially in rocks with high carbonate content. The use of the water alternating gas technique for injection stimulation can exacerbate this issue, as the water–CO2 interface occurs in areas near the injection point. As a result, acidic flow can impact the surrounding rock mass, particularly around the main flow paths where fracture network conductivity is much higher than matrix permeability. To investigate the impact of acidic flow on fracture conductivity, we conducted an experiment on a fractured sandstone sample that was exposed to CO2-saturated water. Our findings revealed a nearly ten-fold increase in post-experimental water-relative permeability, and restriction of flow within established flow channels, which consist one third of the fracture surface. In conclusion, our study sheds light on the dynamic behavior of fractured sandstone under the influence of CO2–H2O flow, revealing significant changes in transmissivity and fracture geometry. These findings contribute to a better understanding of the hydraulic performance of fractures in the context of geological carbon sequestration. [ABSTRACT FROM AUTHOR]

Reservoir modeling consists of two key components: the reproduction of the historical performance and the prediction of the future reservoir performance. Industry-standard reservoir simulators must run fast on enormous and possibly unstructured grids while yet guaranteeing a reasonable representation of physical and chemical processes. However, computational demands limit simulators in capturing involved physical and geochemical mechanisms, especially when chemical reactions interfere with reservoir flow. This paper presents a mathematical workflow, implemented in IORSim, that makes it possible to add geochemical calculations to porous media flow simulators without access to the source code of the original host simulator. An industry-standard reservoir simulator calculates velocity fields of the fluid phases (e.g., water, oil, and gas), while IORSim calculates the transport and reaction of geochemical components. Depending on the simulation mode, the geochemical solver estimates updated relative and/or capillary pressure curves to modify the global fluid flow. As one of the key innovations of the coupling mechanism, IORSim uses a sorting algorithm to permute the grid cells along flow directions. Instead of solving an over-dimensionalized global matrix calling a Newton–Raphson solver, the geochemical software tool treats the species balance as a set of local nonlinear problems. Moreover, IORSim applies basis swapping and splay tree techniques to accelerate geochemical computations in complex full-field reservoir models. The presented work introduces the mathematical IORSim concept, verifies the chemical species advection, and demonstrates the IORSim computation efficiency. After validating the geochemical solver against reference software, IORSim is used to investigate the impact of seawater injection on the NCS Ekofisk reservoir chemistry. Article Highlights: The IORSim sorting algorithm decouples the nonlinear geochemical reaction calculations into recurring one-dimensional problems to assure numerical stability and computation efficiency. To the best of our knowledge, this work presents the mathematical concept, implementation, and application of topological sorting for the first time on (industry) field-scale problems. IORSim combines topological sorting with basis swapping and splay trees to significantly reduce computation times. Moreover, a high-speed forward simulation mode was developed to allow the post-advection of chemical components to visualize species distribution, water chemistry, and mineral interactions. If the geochemical reactions interfere with the fluid flow, the IORSim backward mode uses relative permeability curves to update the global fluid flow at each time step. We validate the implemented topological scheme on a reservoir grid, show the computation efficiency, and compare the impact of explicit, implicit, and grid refinement on numerical dispersion. The decoupled flow simulator and geochemical reaction calculations allow seamless integration of full-field reservoir models that contain complex geological structures, a large number of wells, and long production histories. The computation capabilities of IORSim are demonstrated by simulating and reproducing the impact of seawater injection in the southern segment of the giant Ekofisk field (more than 50 years of injection and production history). IORSim shows that seawater injection changed the Ekofisk mineralogy and impacted the produced water chemistry. In the investigated Ekofisk case, seawater promoted calcite dissolution and led to the precipitation of magnesite and anhydrite. Moreover, surface complexation modeling revealed that sulfate is adsorbed on the calcite surface. [ABSTRACT FROM AUTHOR]

A novel volume of fluid method is presented for mineral precipitation coupled with fluid flow and reactive transport. The approach describes the fluid-solid interface as a smooth transitional region, which is designed to provide the same precipitation rate and viscous drag force as a sharp interface. Specifically, the governing equation of mineral precipitation is discretized by an upwind scheme, and a rigorous effective viscosity model is derived around the interface. The model is validated against analytical solutions for mineral precipitation in channel and ring-shaped structures. It also compares well with interface tracking simulations of advection-diffusion-reaction problems. The methodology is finally employed to model mineral precipitation in fracture networks, which is challenging due to the low porosity and complex geometry. Compared to other approaches, the proposed model has a concise algorithm and contains no free parameters. In the modeling, only the pore space requires meshing, which improves the computational efficiency especially for low-porosity media. [ABSTRACT FROM AUTHOR]

This paper presents and discusses the results obtained by the participants to the benchmark described in de Hoop et al, Comput. Geosci. (2024). The benchmark uses a model for CO2 geological storage and focuses on the coupling between two-phase flow and geochemistry. Several test cases of various levels of difficulty are proposed, both in one and two spatial dimensions. Six teams participated in the benchmark, each with their own simulation code, though not all teams attempted all the cases. The codes used by the participants are described, and the results obtained on the various test cases are compared, as well as the performance of the codes. It is shown that the results obtained are widely consistent, giving a good level of confidence in the outcome of the benchmark. The general complexity of two-phase flow coupled with chemical reactions altering porous media means that some differences between the codes remain. Besides, from the convergence study, it is clear that the two-dimensional problem has a relatively high sensitivity to a spatial resolution which adds to the complexity. [ABSTRACT FROM AUTHOR]

In today's context of power generation from wind, the demand for reliable and high-performing inverters is on the rise. The quasi-Z-source inverters (q-ZSI) are gaining attention in grid-tied wind power generation systems (WPGS) when compared to conventional inverters for their inherent capability of single-stage power conversion and maximum power point tracking (MPPT) performance. However, the erratic nature of wind speed creates a constant challenge for engineers seeking to optimize the performance of wind turbines (WT). Therefore, this paper suggests a new grey wolf-optimized MPPT (GWO-MPPT) controller for q-ZSI-based grid-tied WPGS, which holds great potential for maximizing the power output of WTs. The conventional MPPT controller used in q-ZSI-based WPGS cannot guarantee stable operation during large variations in wind speed. The GWO-MPPT controller can immediately respond during wind speed variations and trace the maximum power point (MPP) without fluctuations around it, thus improving the MPPT performance. The GWO algorithm estimates the optimum rectifier DC voltage for each wind speed to locate the MPP and subsequently determines the shoot-through duty ratio for the q-ZSI. In addition, this work introduces a decoupling current control strategy supported by dual frequency modulation (DFM) for managing the grid's active and reactive power flows. The functionality of the proposed controllers is rigorously examined using the MATLAB/Simulink tool through extensive simulations. Finally, their practicality is evaluated through an experimental hardware setup. This integrated approach thoroughly investigates the controllers' effectiveness and suitability for practical implementation in WPGS. [ABSTRACT FROM AUTHOR]

In this article we explore (a) optical and (b) thermochemical properties of reactive hypersonic flows, with an emphasis on oxygen dynamics and time resolved measurement capabilities. First, we discuss experimental and numerical analysis of reactive hypersonic flows of an argon–oxygen mixture over a blunt wedge geometry. The experimental campaign for that geometry uses Michelson interferometry to determine the refractive index of the shock layer. Numerical analysis of these cases reveals that there is dissociation of molecular oxygen in the shock layer. Excellent comparison between numerically predicted and nanosecond sampled experimentally observed refractive index serve as verification of non-equilibrium refractive index theory and the thermochemistry models used in the simulation. Uncertainties and limitations of the interferometry technique are discussed. In addition, we perform subnanosecond sampled femtosecond/picosecond hybrid Coherent anti-Stokes Raman scattering (CARS) spectroscopy behind a hypersonic Mach stem configuration in a pure oxygen flow to demonstrate capabilities to enhance understanding of nonequilibrium vibrational mode contributions to the refractive index. Hybrid CARS gives instantaneous vibrational populations and relevant vibrational temperatures at specific locations downstream of the shock. [ABSTRACT FROM AUTHOR]

Background: The mixed convection flow of viscous fluid due to an oscillating plate is inspected. The external heating effects and chemical reaction assessment are predicted. Moreover, the flow applications of the entropy generation phenomenon are claimed. Results: The dimensionless system is expressed in partial differential forms, which are analytically treated with the Laplace scheme. The physical aspects of the flow model are graphically observed. The optimized phenomenon is focused on flow parameters. The results for the Bejan number are also presented. The dynamic of heat transfer and entropy generation phenomenon is observed with applications of Bejan number. Conclusions: It is claimed that an enhancement of entropy generation phenomenon is noticed due to heat and mass Grashof coefficients. The Bejan number declined due to mass Grashof number. Furthermore, the velocity profile boosted due to Grashof constant. [ABSTRACT FROM AUTHOR]

In a DFIG grid interconnected system, the control of real and reactive power relies on various factors. This paper presents an approach to regulate the flow of real and reactive power using a Neural Tuning Machine (NTM) based on a recurrent neural network. The focus is on controlling the flow of reactive power from the rotor-side converter, which is proportional to the grid-side controller through a coupling voltage. The proposed NTM method leverages neural networks to fine-tune the parameters of the PI controller, optimizing performance for DFIG grid integration. By integrating dense plexus terminals, also known as dense connections, within the neural network, the control system achieves enhanced adaptability, robustness, and nonlinear dynamics, addressing the challenges of the grid. Grid control actions are based on the voltage profile at different bus locations, thereby regulating voltage. This article meticulously examines the analysis in terms of DFIG configuration and highlights the advantages of the neural tuning machine in controlling inner current loop parameters compared to conventional PI controllers. To demonstrate the robustness of the control algorithm, a MATLAB Simulink model is designed, and validation is conducted with three different benchmarking models. All calculations and results presented in the article strictly adhere to IEEE and IEC standards. This research contributes to advancing control methodologies for DFIG grid integration and lays the groundwork for further exploration of neural tuning methods in power system control. [ABSTRACT FROM AUTHOR]

The authors have presented experimental data and theoretical investigations of turbulence induced by the chemical processes in the compression zone ahead of the blunt body flying in a multiatomic gas medium. The possibility of the flow instability just due to the physicochemical processes in the gas and to the flow curvature irrespective of the boundary conditions on the body′s surface has been substantiated theoretically. Conditions for the flow instability have been found analytically. The found conditions for the occurrence of instability are in good agreement with experimental investigations not only quantitatively, but also qualitatively. [ABSTRACT FROM AUTHOR]

Non-thermal plasma (NTP) efficiently regenerates diesel particulate filters by oxidizing carbon soot (CS) at low temperatures. However, numerical studies on the spatial characteristics of CS oxidation by NTP are scarce. In addition, the influence of background gas heating on the CS-oxidizing performance by NTP remains inadequately understood. This research investigates the impact of gas temperature (323–573 K) on heterogeneous CS oxidation using NTP in a two-dimensional configuration. The results indicate that CS is mainly oxidized by O 3 , NO 2 , and O 2 during NTP treatment. The energy efficiency of CS removal by NTP ranges from 0.1 to 2.6 g kWh–1 for varying gas temperature and applied voltage, consistent with previous research. Higher gas temperatures enhance both CS removal rate and efficiency, whereas higher applied voltages enhance rate at the expense of efficiency. The study also assesses energy conversion efficiency from electrical power input to chemical bonding energy during CS oxidation by NTP, yielding 0.03 to 0.23% efficiency for the considered gas temperature and voltage ranges, with higher temperatures leading to better efficiency. [ABSTRACT FROM AUTHOR]

Microfluidic systems with integrated sensors are ideal platforms to study and emulate processes such as complex multiphase flow and reactive transport in porous media, numerical modeling of bulk systems in medicine, and in engineering. Existing commercial optical fibre sensing systems used in integrated microfluidic devices are based on single-core fibres, limiting the spatial resolution in parameter measurements in such application scenarios. Here, we propose a multicore fibre-based pH system for in-situ pH mapping with tens of micrometer spatial resolution in microfluidic devices. The demonstration uses custom laser-manufactured glass microfluidic devices (called further micromodels) consisting of two round ports. The micromodels comprise two lintels for the injection of various pH buffers and an outlet. The two-port system facilitates the injection of various pH solutions using independent pressure pumps. The multicore fibre imaging system provides spatial information about the pH environment from the intensity distribution of fluorescence emission from the sensor attached to the fibre end facet, making use of the cores in the fibre as independent measurement channels. As proof-of-concept, we performed pH measurements in micromodels through obstacles (glass and rock beads), showing that the particle features can be clearly distinguishable from the intensity distribution from the fibre sensor. [ABSTRACT FROM AUTHOR]

This paper proposes a benchmark study for reactive multiphase multicomponent flow in porous media. Modeling such problem leads to a highly nonlinear coupled system of partial differential equations, ordinary differential equations and algebraic constraints, which requires special numerical treatment. The benchmark consists of five test problems in total (both in 1D and in 2D), with varying degrees of difficulty, designed to verify the algorithms and the codes dedicated to simulating coupled isothermal Hydro-Chemical processes during injection and storage of CO2 in the subsurface. It is intended to be used as a basis for comparing codes in order to better understand different couplings such as chemical reactions with two-phase flow, phase behavior with equilibrium reactions, dissolution and precipitation. [ABSTRACT FROM AUTHOR]

A study has been made of the flow of a non-Newtonian polymer medium in a plane channel and of heat transfer in it with boundary conditions of the first kind for small Reynolds numbers and a large Péclet number with the Ellis rheological model with a viscosity dependent on the temperature, pressure, and degree of chemical conversion of the medium. Consideration was given to the flow of a high-viscosity medium with chemical reactions leading to an abrupt increase in its viscosity for whose mathematical description the authors used a model that included the kinetic chemical-reaction equation and the energy equation with a dissipative term. Significant influence of various factors on the formation and rate of growth of the solidified wall layer in such flow has been shown. The problem has been solved numerically by the finite-diff erence method according to the iterative scheme. [ABSTRACT FROM AUTHOR]

This study presents a new single-phase transformer-less grid-connected inverter based on a six-phase interleaved dc/dc converter as a suitable topology for PV applications. The proposed topology consists of a dc input and multi-output in the dc-link side which results in production of six levels per half cycle. The voltage of the inverter at output side is 7-level that is injected into the network. The voltage of PV panels is low and this problem is solved by increasing the voltage level in the interleaved converter. Besides, the input current ripple of the interleaved dc/dc converter is very low which causes to improve the quality of the injected current into the grid through a PV panel. For control of the power switches and active/reactive power flows, the model predictive control (MPC) method is applied. The proposed system is capable of creating different voltage levels in step-up/down at the dc-link side and this will make it suitable for working in a wide range of power in the grid-tied. Besides, the total voltage blocking (TVB) of the power switches at the inverter side is greatly decreased. Consequently, the efficiency of the proposed system is high. To prove the accuracy of theoretical calculations, the proposed topology for a 900 W prototype at an operation of 50 Hz is built and tested in the laboratory. [ABSTRACT FROM AUTHOR]

The occurrence of buoyancy-driven flow and reactive solute transport in a fluid-saturated porous medium can be induced by either natural processes or human activities. Typical examples include the groundwater salinization in carbonate-rock aquifers and the acid treatment of oil wells in petroleum drilling industry. In this paper, the classical Elder problem of buoyancy-driven convection in two-dimensional porous media is extended to include the local chemical interactions between the solute in the pore liquid (e.g. salt such as NaCl or acids such as HCl and HCl/HF mixtures) and the solid space of the porous medium (e.g. minerals such as calcite and dolomite). Effects of the geochemical processes on the flow and mass transport are investigated. For the reactive, strongly solute-driven case in the regime dominated by the diffusive mass transport, a decrease in the net solute concentration is found as compared to the non-reactive case. This decrease is pronounced at higher values of the Damköhler number when the solute reaction rate becomes larger than the solute diffusion rate. Furthermore, the flow structure is affected by products generated by the chemical reaction when the Rayleigh number for the products is sufficiently high. In that case, numerical simulations show the formation of diluted fluid tongues exhibiting damped periodic oscillations about a nonzero mean. The results are obtained using the pseudospectral numerical method, verified against the analytical solution for the non-reactive, purely diffusive case. [ABSTRACT FROM AUTHOR]

In this article, the magnetohydrodynamic flow of a chemically reactive blood-gold nanofluid between two rotating disks is examined. At the lower disk surface, the thermal convective and zero mass flux conditions are considered, while the upper disk is kept at a constant temperature and concentration. The mathematical formulation of this analysis is presented in the form of PDEs. By means of proper similarity variables, PDEs are transformed into ODEs. The perseverance of this research is to investigate the influences of different entrenched factors, which are established during the transformation procedure, on the blood-gold nanofluid flow. The numerical solution of the modeled problem is established using the bvp4c MATLAB function. The correctness of the present model is confirmed by a comparison between the outcomes of the current numerical solution and those from previously published studies. The outcomes exhibit that the solid volume fraction increases both the axial and tangential velocities of the blood-gold nanofluid flow while decreasing its temperature. It is originated that the solid volume fraction has a dual effect on radial velocity of the blood-gold nanofluid flow. Also, we have seen that the axial velocity of the lower disk is greater for blood-gold nanofluid flow, while at the upper disk the axial velocity is lesser for blood-gold nanofluid flow. In addition, the pure blood has maximum temperature. It is observed that the axial, radial, and tangential velocities of the blood-gold nanofluid flow increase while the thermal profile reduces with the increasing Casson factor. [ABSTRACT FROM AUTHOR]

Nanolubricants fall among the newly evolved and emerged technologies used in lubrication and heat transfer systems due to their unique thermo-physical properties. They are crucial to the industry because they enhance surface performance, reduce maintenance and fuel costs and boost engine efficiency. They are also used in mechanical systems to efficiently minimize friction and surplus heat. The present investigation focuses to analyze Darcy–Forchheimer flow of magnetized ZnO-SAE50 nanolubricant across Riga plate. Riga plate is poised of an electromagnetic equator that consists of an everlasting magnet and a span-wise collection of irregular electrodes mounted over a planner surface and is utilized in achieving proficient flow. The flow takes place in the presence of viscous dissipation, heat source–sink and chemical reaction of higher order. Newtonian heating and thermophoretic particle deposition effects are also investigated in this study. The role of viscosity is quite important and dynamical in various engineering and industrial fields. The viscosity variation highly fluctuates the thermal systems. The present work also highlights the role of variable viscosity, owing to its importance. A novel micro-nano-convection model called the Patel model is invoked in perspective of the enhancement in thermal conductivity of nanolubricant. The use of ZnO-SAE50 nanolubricant (a brand-new form of nanolubricant) over Riga plate, variable viscosity effects and the application of Patel model are novel features of this study. The application of selected transformations causes the modeled PDEs to change into ODEs. The modeled problem is executed numerically with MATLAB bvp-4c solver. The alterations in the concerned profiles corresponding to various emerging parameters of interest are presented graphically in order to develop better understanding and make analysis. The outcomes reveal that larger modified Hartmann number significantly favors the velocity of nanolubricant ZnO-SAE50, while solid volume fraction, magnetic parameter and variable viscosity parameter halt it. The heat source–sink parameter, Eckert number and solid volume fraction are found to be helpful agents in improving temperature of nanolubricant ZnO-SAE50. In comparison with Newtonian heating (NH), common wall temperature condition (CWT) yields better thermal enhancement. The enhancing chemical reaction order ameliorates the concentration profile but it gets minified for chemical reaction parameter and thermophoresis parameter. The increasing values of magnetic parameter, variable viscosity parameter and inertial parameter tend to enhance the skin friction, while the modified Hartman number reduces it. The enhancing values of Eckert number, magnetic parameter and heat source–sink parameter increase the value of Nusselt number. [ABSTRACT FROM AUTHOR]

Matrix acidizing is one of carbonate reservoirs' most efficient and widely implemented stimulation techniques. It improves productivity and flow capacity by creating new conductive flow channels called wormholes. The propagation of these channels has been a topic of interest as many researchers tried to investigate this phenomenon experimentally, theoretically, and numerically. Among various models, the two-scale continuum (TSC) model is the most common and reliable model due to its ability to predict better results as it combines Darcy and pore scales to capture the phenomenon. However, the main disadvantage of using the TSC model is its high computational cost. This highlights the need for a computationally efficient model that reduces that cost while maintaining solution accuracy. Also, examining wormhole propagation in 3D perforation is untouched yet. In this paper, we developed a numerical model in-house using MATLAB® software to simulate the wormhole generation considering the perforation in three-dimensional space based on the two-scale continuum mathematical model. The model performance is optimized to be a time-efficient simulation model that considers thermal energy transfer beside flowing and reactive mass transfer. Computation efficiency is achieved using the Darcy equation, vectorizing code operations, and implementing a proposed iterative algorithm that is based on the GMRES method. The associated tuning parameters and a proper preconditioner are obtained, which improved the model efficiency by more than 90%. The model used typical data reported in experimental acidizing work. [ABSTRACT FROM AUTHOR]

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Physical barrier has been proven to be one of the most effective measures to prevent and control seawater intrusion (SWI) in coastal areas. Mixed physical barrier (MPB), a new type of physical barrier, has been shown to have higher efficiency in SWI control. As with conventional subsurface dam and cutoff wall, the construction of MPB may lead to the accumulation of nitrate contaminants in coastal aquifers. We investigated the SWI control capacity and nitrate accumulation in the MPB using a numerical model of variable density flow coupling with reactive transport, and performed sensitivity analysis on the subsurface dam height, cutoff wall depth and opening spacing in the MPB. The differences in SWI control and nitrate accumulation between MPB and conventional subsurface dam and cutoff wall were compared to assess the applicability of different physical barrier. The numerical results show that the construction of MPB will increase the nitrate concentration and contaminated area in the aquifer. The prevention and control efficiency of MPB against SWI is positively correlated with the depth of the cutoff wall, reaching the highest efficiency at the minimum effective dam height, and the retreat distance of the saltwater wedge is positively correlated with the opening spacing. We found a non-monotonic relationship between the change in subsurface dam height and the extent of nitrate accumulation, with total nitrate mass and contaminated area increasing and then decreasing as the height of the subsurface dam increased. The degree of nitrate accumulation increased linearly with increasing the height of the cutoff wall and the opening spacing. Under certain conditions, MPB is 46–53% and 16–57% more efficient in preventing and controlling SWI than conventional subsurface dam and cutoff wall, respectively. However, MPB caused 14–27% and 2–12% more nitrate accumulation than subsurface dam and cutoff wall, respectively. The findings of this study are of great value for the protection of coastal groundwater resources and will help decision makers to select appropriate engineering measures and designs to reduce the accumulation of nitrate pollutants while improving the efficiency of SWI control. [ABSTRACT FROM AUTHOR]

Restricted by the development of the transient flow and solute reactive transport models for unsaturated soil, empirical functions have been used previously to calculate the mass of dissolved or precipitated salt when they have to be taken into account. Besides, the solute reactive transport process has often been inferred based on measurements that cost lots of time and manpower. HP1 model coupled with PHREEQC provides a suitable tool to improve the estimation of salt distribution during evaporation in saline soil, where the salt dissolution and precipitation cannot be ignored. In this study, we compare the performance of a standard solute transport (SST) model and the HP1 model to examine the improvement of salt distribution estimation. Model results are compared with experimental data sets from four field lysimeters. These columns were exposed to NaCl solution with different concentrations (3, 30, 100, and 250 g/L) and were undergoing the same strong evaporation boundary condition. The pre-existing CaSO4, NaCl and Na2SO4 loads were 1.15, 0.47 and 0.23 g/(100 g of soil), respectively. Simulation results show that HP1 ameliorates the overestimation of salt content by SST in deeper soil due to the absence of dissolution of pre-existing soluble salts, and prevents the concentration of the solute from exceeding the solubilities which would occur in SST-result. Additionally, HP1-predicted results can help trace the transport process of each solute. Based on the results, we strongly suggest that the management of fields sensitive to salt content should make use of a coupled flow and chemical reaction model. [ABSTRACT FROM AUTHOR]

Optimal reactive power flow (ORPF) is of great importance for the electrical reliability and economic operation of modern power systems. The integration of distributed generations (DGs) and two-terminal high voltage direct current (HVDC) systems into electrical networks has further complicated the ORPF problem. Due to the high computational complexity of the ORPF problem, a powerful and robust optimization algorithm is required to solve it. This paper proposes a powerful metaheuristic algorithm namely fitness-distance balance-based adaptive gaining-sharing knowledge (FDBAGSK). In the performance evaluation, 39 IEEE CEC benchmark functions are used to compare FDBAGSK with the original AGSK algorithm. Moreover, the proposed algorithm is applied to perform the ORPF task in modified IEEE 30- and IEEE 57-bus test systems. The effectiveness of the FDBAGSK method was tested for the optimization of three non-convex objectives: active power loss, voltage deviation and voltage stability index. The ORPF results obtained from the FDBAGSK algorithm are compared with other optimization algorithms in the literature. Given that all results are together, it has been observed that FDBAGSK is an effective method that can be used in solving global optimization and constrained real-world engineering problems. [ABSTRACT FROM AUTHOR]

The Bisciarelle fault is a brittle thrust crosscutting lherzolite of the Voltri Massif (Italy) and is similar to the historical gold veins of the area. This is a 16-m-thick fault showing a large damage zone and a 4-m-wide hydrothermal alteration halo. Its fault rocks interacted with a hydrothermal fluid and host peculiar Au-bearing zones made of concentric and circular dolomite aggregates, which we call spherulites, and chalcedony. To constrain spherulite genesis, we quantify fluid-fault interactions at Bisciarelle combining field and microtextural data, mass transfer calculations, and a multi-technique analytical dataset including element imaging by laser ablation-inductively coupled plasma-time-of-flight mass spectrometry. We show that faulting was coupled with significant transfer of H2O, CO2, Ca, Sb, and W from the fault fluid to the protolith, and variable transfers of SiO2 and some trace elements from the protolith to the fluid. This process deposited Au within the spherulites, caused serpentinization and carbonation of the protolith, and weakened the fault localizing subsequent shearing events and providing components for the growth of spherulites and the other fault rocks. We interpret Bisciarelle as a permeable epizonal orogenic vein, which formed fast as a result of dilation and top-to-NE shearing. This fault developed via cycles of fluid pressure build-up, opening, fluid effervescence, and mineral precipitation from a H2O-CO2 hydrothermal fluid. The fluid transported and deposited a suite of metals including Au and interacted with the protolith. A similar mechanism of faulting and reactive fluid flow could have generated the other Au deposits of the area. [ABSTRACT FROM AUTHOR]

The forecasted need for diesel fuel continues to rise, and likewise, the competitive biodiesel demand in the middle- to long-term future remains promising. Unfortunately, biodiesel production generates a significant amount of crude glycerol with the byproduct typically exceeding 10% of the biodiesel produced. The current glycerol market cannot accommodate the use of waste crude glycerol; therefore, an alternative solution is needed for the utilization of the crude glycerol and gasification is a potential pathway. In this work, the technical feasibility of gasification of crude glycerol is assessed at two levels: equilibrium modeling which was conducted under ideal conditions and high-fidelity reactive flow modeling in a tubular reactor. Results revealed that elevated steam ratios are required for the gasification of glycerol to reach high conversion rates of 99% and an acceptable cold gasification efficiency of 40%. Although this value is far off from the conventional coal gasification that hovers around 60%, the analysis suggests that gasification of crude glycerol can be accepted as an intermediate solution to the expected flood of glycerol generated by the biodiesel transesterification industry before becoming a waste burden. [ABSTRACT FROM AUTHOR]

The emergence of the "mush paradigm" has raised several questions for conventional models of magma storage and extraction: how are melts extracted to form eruptible liquid-rich domains? What mechanism controls melt transport in mush-rich systems? Recently, reactive flow has been proposed as a major contributing factor in the formation of high porosity, melt-rich regions. Yet, owing to the absence of accurate geochemical simulations, the influence of reactive flow on the porosity of natural mush systems remains under-constrained. Here, we use a thermodynamically constrained model of melt-mush reaction to simulate the chemical, mineralogical, and physical consequences of reactive flow in a multi-component mush system. Our results demonstrate that reactive flow within troctolitic to gabbroic mushes can drive large changes in mush porosity. For example, primitive magma recharge causes an increase in the system porosity and could trigger melt channelization or mush destabilization, aiding rapid melt transfer through low-porosity mush reservoirs. In this study, the authors use a thermodynamically constrained model of melt-mush reaction to simulate the chemical, mineralogical, and physical consequences of reactive flow in a multi-component mush system. [ABSTRACT FROM AUTHOR]

N:TiO2 thin films were sputtered on glass, Si(100) and FTO substrates at various nitrogen to total reactive gas flow ratio (η). Tetragonal anatase phase were indexed for all prepared films. The incorporation of nitrogen into the TiO2 film did not have significant influence on the crystal structure. Slight decrease in the peak intensities and grain sizes was observed with increasing nitrogen ratio. The reduction of the UV–Vis–NIR transmittance and the elevation of reflectance coincided with the nitrogen content. The optical band gap (Eg) of the indirect transition was reduced from 3.35 to 3.04 eV with rising η from 0 to 0.95. Nitrogen incorporation also had a great effect on the refractive index (n) and extinction coefficient (k). The results of measuring the chopped and continuous photocurrent densities under light irradiation leaded to examine the photoelectrochemical process for sewage water splitting of N:TiO2 films. The photocurrent density enhances with increasing nitrogen content up to η = 0.75, above which a decrease in photocurrent is observed. [ABSTRACT FROM AUTHOR]

This paper presents the parameter design of a new topology of hybrid active power filter (HAPF), which makes the system capacity smaller. Based on the main topological circuit, the passive LC single-tuned circuit shunted into the HAPF effectively reduces the capacity of the system. By introducing the grid voltage feedforward method, the DC-side voltage control becomes relatively stable, and the fundamental reactive current flowing through the converter is effectively reduced. Meanwhile, to suppress the resonance of the HAPF, the state variable feedback method is adopted. According to theoretical analysis, a simulation model of the system is built in the MATLAB environment. Then a low-voltage experimental HAPF platform is built to validate the result of the simulations. [ABSTRACT FROM AUTHOR]

Silver oxide nano layers were deposited on SiO2 ‎amorphous substrates by RF reactive magnetron of a silver target (99.999%) in different oxygen gas flow (1, 2 to 3 SCCM) in Ar–O2 reactive gas mixtures. Their crystallography, phase transitions and nanostructures were investigated by X-ray diffraction, SEM, EDAX and AFM analysis. Optical properties ‎were calculated using Kramers-Kronig relations by reflectance spectra. According to X-ray diffraction measurements, at low oxygen flow rate, in addition to cubic phase of Ag, Ag2O phase of silver oxide was observed while, at higher oxygen flow rate only Ag2O crystalline phase was occurred. However, by increasing the oxygen flow to 3 SCCM, target poisoning happened and deposition rate decreased. The SEM images showed that by increasing oxygen flow, dense texture with non-homogenous grains changed to porous morphology. Optical results revealed that the highest optical band gap of 2.7 eV was achieved at highest oxygen flow (3 SCCM) and the highest transmittance of ~ 60% was obtained at same flow. [ABSTRACT FROM AUTHOR]

Mind-wandering assessment relies heavily on the thought probe technique as a reliable and valid method to assess momentary task-unrelated thought (TUT), but there is little guidance available to help researchers decide how many probes to include within a task. Too few probes may lead to unreliable measurement, but too many probes might artificially disrupt normal thought flow and produce reactive effects. Is there a "Goldilocks zone" for how few thought probes can be used to reliably and validly assess individual differences in mind-wandering propensity? We address this question by reanalyzing two published datasets (Study 1, n = 541; Study 2, ns ≈ 260 per condition) in which thought probes were presented in multiple tasks. Our primary analyses randomly sampled probes in increments of two for each subject in each task. A series of confirmatory factor analyses for each probe "bin" size tested whether the latent correlations between TUT rate and theoretically relevant constructs like working memory capacity, attention-control ability, disorganized schizotypy, and retrospective self-reported mind wandering changed as more probes assessed the TUT rate. TUT rates were remarkably similar across increasing probe-bin sizes and zero-order correlations within and between tasks stabilized at 8–10 probes; moreover, TUT-rate correlations with other latent variables stabilized at about 8 thought probes. Our provisional recommendation (with caveats) is that researchers may use as few as 8 thought probes in prototypical cognitive tasks to gain reliable and valid information about individual differences in TUT rate. [ABSTRACT FROM AUTHOR]

We study mixing-controlled chemical reactions in unsaturated porous media from a pore-scale perspective. The spatial heterogeneity induced by the presence of two immiscible phases, here water and air, in the pore space generates complex flow patterns that dominate reactive mixing across scales. To assess the impact of different macroscopic saturation states (the fraction of pore volume occupied by water) on mixing-controlled chemical reactions, we consider a fast irreversible reaction between two initially segregated dissolved species that mix as one solution displaces the other in the heterogeneous flow field of the water phase. We use the pore-scale geometry and water distributions from the laboratory experiments reported by Jiménez-Martínez et al. (Geophys. Res. Lett. 42: 5316–5324, 2015). We analyze reactive mixing in three complementary ways. Firstly, we post-process experimentally observed spatially distributed concentration data; secondly, we perform numerical simulations of flow and reactive transport in the heterogeneous water phase, and thirdly, we use an upscaled mixing model. The first approach relies on an exact algebraic map between conservative and reactive species for an instantaneous irreversible bimolecular reaction that allows to estimate reactive mixing based on experimental conservative transport data. The second approach is based on reactive random walk particle tracking simulations in the numerically determined flow field in the water phase. The third approach uses a dispersive lamella approach that accounts for the impact of flow heterogeneity on mixing in terms of effective dispersion coefficients, which are estimated from both experimental data and numerical random walk particle tracking simulations. We observe a significant increase in reactive mixing for decreasing saturation, which is caused by the stronger heterogeneity of the water phase and thus of the flow field. This is consistently observed in the experimental data and the direct numerical simulations. The dispersive lamella model, parameterized by the effective interface width, provides robust estimates of the evolution of the product mass obtained from the experimental and numerical data. [ABSTRACT FROM AUTHOR]

The use of extendible nozzles in propulsion systems is one potential way to increase the nozzle expansion ratio and the specific thrust. Numerical simulation of the supersonic turbulent flow of a viscous compressible gas in a dual-bell nozzle is considered. The displacement of the extendible section of the nozzle from the initial to the working position is taken into account. Numerical calculations are based on the Reynolds-averaged Navier –Stokes equations and equations of the SST turbulence model and sliding meshes. The unsteady structure of the flow formed when the nozzle is restored to service, and the topological features of the flow and relationships between flow quantities are studied. A variation of the force applied to the nozzle walls when the reactive jet flows out is discussed. [ABSTRACT FROM AUTHOR]

The transition of filtration reactive flow in a double-porosity medium into a self-oscillating mode is studied. Flow stability is analyzed using numerical methods for solving multiphase filtration equations in a double-porosity medium. The region of development of self-oscillations is investigated depending on the external parameters of the system and the properties of the reactants. [ABSTRACT FROM AUTHOR]

During tapping of metal from silicon furnaces, a significant amount of gas is often released through the tap-hole. The gas is combustible, and a flame jet is created which poses a safety threat to operators. Due to the high temperatures involved, thermal NOx is also produced. This is a threat to the environment and the health of the operators. These phenomena, known as gassing, have been studied here by a mathematical model for reactive turbulent flows. The results show that the flame jet can extend several meters out from the tap-hole, and that the strength of the flame jet increases with the amount of gassing. The simulations also show that the NOx production increases with the amount of gas exiting the tap-hole, and that the thermal NOx formation does not substantially impact the length of the gas jet. [ABSTRACT FROM AUTHOR]

Numerical simulations of reactive flows are still a challenge when using full detailed kinetic mechanisms, which are becoming larger and larger to incorporate most of the combustion phenomena. One strategy to overcome this issue and simplify the treatment of the chemical kinetics is to use manifold-based methods, and one representative of this class is the Reaction–Diffusion Manifolds (REDIM). In the present work, the REDIM is applied for the first time to study soot formation in ethylene/air counterflow non-premixed flames. A simplified semi-empirical model for soot formation based on acetylene that describes nucleation, surface growth, and oxidation is used, and an uncoupled framework between gas phase and the formation of particulate matter is presented. Validation is carried out for laminar flames, and the results show that REDIM can predict with good accuracy the slow process of soot formation. [ABSTRACT FROM AUTHOR]

In the context of a deregulated electricity market, this paper presents a new method for the distribution of electrical losses in distribution systems with local generators, incorporating variations in consumer power factor. Additionally, the paper examines how local generators may gain the utmost possible advantage from their contributions to system performance enhancement. The proposed approach initially analyzes dynamic changes in active and reactive power flow caused by a change in consumer power factor, followed by a loss allocation mechanism. This method is developed based on Kirchhoff’s law and the natural decomposition of injected bundled power flow at a bus. To completely eliminate cross-subsidies, the proposed mechanism follows a two-stage power flow: first, consumer-controlled power flows, and second, determining variations in power flow as compared to the first stage due to interactions with local generators. Consumer load modeling is being considered to improve the proposed method’s adaptability and efficiency across different distribution systems. The effectiveness of the proposed method is validated through testing on 30-bus and 69-bus distribution systems, and the results obtained are compared with those of other methods found in the literature. [ABSTRACT FROM AUTHOR]

In this article, we present a novel data assimilation strategy in pore-scale imaging and demonstrate that this makes it possible to robustly address reactive inverse problems incorporating Uncertainty Quantification (UQ). Pore-scale modeling of reactive flow offers a valuable opportunity to investigate the evolution of macro-scale properties subject to dynamic processes in the context of Carbon Capture and Storage (CCS). Yet, they suffer from imaging limitations arising from the associated X-ray microtomography (X-ray μ\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mu $$\end{document}CT) process, which induces discrepancies in the properties estimates. Assessment of the kinetic parameters also raises challenges, as reactive coefficients are critical parameters that can cover a wide range of values. We account for these two issues and ensure reliable calibration of pore-scale modeling, based on dynamical μ\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mu $$\end{document}CT images, by integrating uncertainty quantification in the workflow. The present method is based on a multitasking formulation of reactive inverse problems combining data-driven and physics-informed techniques in calcite dissolution. This allows quantifying morphological uncertainties on the porosity field and estimating reactive parameter ranges through prescribed PDE models, with a latent concentration field, and dynamical μ\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mu $$\end{document}CT observations. The data assimilation strategy relies on sequential reinforcement incorporating successively additional PDE constraints and suitable formulation of the heterogeneous diffusion differential operator leading to enhanced computational efficiency. We provide a robust and unbiased uncertainty quantification by straightforward adaptive weighting of Bayesian Physics-Informed Neural Networks (BPINNs), ensuring reliable micro-porosity changes during geochemical transformations. We demonstrate successful Bayesian Inference in 1D+Time calcite dissolution based on synthetic μ\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mu $$\end{document}CT images with meaningful posterior distribution on the reactive parameters and dimensionless numbers. We eventually apply this framework to a more realistic 2D+Time data assimilation problem involving heterogeneous porosity levels and synthetic μ\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\mu $$\end{document}CT dynamical observations. [ABSTRACT FROM AUTHOR]

This correction notice is for an article titled "Efficient handling of ACL policy change in SDN using reactive and proactive flow rule installation" published in Scientific Reports. The original version of the article contained errors in the Funding section, which have now been corrected. The research was co-funded by the Ministry of Education, Youth and Sports of the Czech Republic within a Student Grant Competition in the VSB – Technical University of Ostrava. The authors of the article are Mudassar Hussain, Rashid Amin, Rahma Gantassi, Asma Hassan Alshehri, Jaroslav Frnda, and Syed Mohsan Raza. [Extracted from the article]

The aim of the current article is to study the combustion characteristics of the liquid fuel (Jet-A) inside a gas turbine model combustor under different conditions of the inlet air and fuel. The two-phase flow of the air and liquid droplets is modeled with the two-way coupling in the Eulerian–Lagrangian approach. The steady flamelet and discrete ordinates models are implemented to model the combustion and radiative heat transfer, successively. The NOx\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\text{NO}}_{\text{x}}$$\end{document} modeling is done as a post-process using the finite rate model. The outcomes indicate that increasing the fuel spray velocity leads to an improvement in the combustion phenomenon in the primary region, a rise in the flame temperature, and finally, a growth in the amount of NOx\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\text{NO}}_{\text{x}}$$\end{document} produced. By decreasing the half angle of fuel injection by 10°, the maximum temperature inside the combustion chamber decreases by 43 K. An increase of 26\%\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$26\text{\%}$$\end{document} in the inlet air temperature (from 373\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$373$$\end{document} to 473K\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$473\text{ K}$$\end{document}) does not have a considerable effect on the species’ concentration distribution. However, with a 54\%\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$54\text{\%}$$\end{document} growth in the inlet air temperature, changes in the concentration distributions particularly in the concentration of CO2\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$${\text{CO}}_{2}$$\end{document} become noticeable. Enhancing the temperature of the inlet air causes a rise in the concentration of NO\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\text{NO}$$\end{document}. The concentration of NO\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\text{NO}$$\end{document} is highly dependent on the inlet air pressure, and a direct relationship has been observed between increasing the inlet air pressure and the amount of the NO\documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\text{NO}$$\end{document} produced. [ABSTRACT FROM AUTHOR]

This report presents the three-dimensional electromagnetohydrodynamic flow of a zinc-oxide–water nanofluid past a bidirectional Riga plate with velocity slips and thermal and mass convection conditions. The Cattaneo–Christov heat and mas flux model, thermal radiation, chemical reaction and activation energy are considered to analyze the flow problem. The volume fraction of the ZnO nanoparticles is taken 6% in this analysis. An appropriate set of similarity variables is used to transform the partial differential equations into ordinary differential equations. During this process, some parameters are found and influences of these factors on the flow profiles are shown and discussed in detail. A numerical technique called NDSolve is considered for the solution of the nanofluid flow problem. The results showed that higher solid volume fraction and slip parameter have reduced velocities profiles and the increasing solid volume fraction and thermal Biot number have increased the temperature profile. Additionally, the concentration Biot number has increased the concentration profile. The modified Hartmann number has significantly increased the velocity profile. Dual impacts in velocity profiles along primary and secondary direction has been observed due to stretching ratio parameter. A comparison of current results has been carried with a fine agreement amongst current and established results. [ABSTRACT FROM AUTHOR]

Mid-infrared laser polarization spectroscopy (IRPS) is a powerful diagnostic technique suitable for the quantitative measurement of species concentration and temperature. IRPS is well suited to reactive multiphase flows and is not affected by the presence of particles and other nanostructures. It has the potential to detect species that have no accessible single-photon electronic transition in the UV/Visible range. In this review, an overview of the various contributions that have been devoted to the development and application of IRPS are summarized and discussed. The basic theoretical framework is presented and the nature of the IRPS experiments is described. Then, several types of IRPS applications are reviewed, including the measurement of the concentration of minor species and the temperature, the study of molecular dynamics and collision energy transfer, and the feasibility of 2D imaging with high spatial resolution. Finally, future prospects, required improvements, and potential application fields of IRPS are provided. [ABSTRACT FROM AUTHOR]

The authors have performed numerical modeling and have analyzed, from the results of calculation, distinctive features of two-phase flow in a channel of constant cross section upon traverse injection of a reactive liquid through spray injectors. A model hydrocarbon fuel with thermophysical properties similar to TS-1 kerosene has been considered as the reactive liquid. The characteristics of spraying and evaporation of liquid droplets in a high-enthalpy subsonic air flow have been obtained by mathematical modeling, and an analysis has been made of the quality of mixing and the intensity of combustion of a two-phase mixture. Also, the regularities of the influence of the number of injectors and the pressure difference in them and of the mass flow rate of the reactive liquid on the intensity of processes occurring in the channel have been obtained. [ABSTRACT FROM AUTHOR]

Modeling of the chemistry and thermodynamics is crucial in numerical simulations that attempt to accurately simulate reactive flows such as flame acceleration and detonation phenomena. The current study explores how a four-species, four-step combustion mechanism performs to predict ignition processes in various premixed hydrocarbon fuel mixtures when compared to detailed chemical kinetic mechanisms. A key objective of this research is to determine how well this model, which has been modified to include only three species transport equations, performs at predicting fundamental combustion properties that are important for flame acceleration and detonation applications. On comparison with full chemistry mechanisms, the four-step model demonstrates an ability to predict the ignition time, reaction stiffness, thermodynamic state, and detonation stability-parameter to a high level of accuracy, for ignition processes over a wide range of initial temperatures and densities. With the ignition structures and key detonation stability parameters correctly predicted, we conclude that the four-step model is an effective and economic tool for studying complex explosion phenomena in situations where pre-combustion temperature and density are constantly changing, such as deflagration-to-detonation transition by flame acceleration or shock–flame interaction. [ABSTRACT FROM AUTHOR]

This work comprehensively reviews the equations governing multicomponent flow and reactive transport in porous media on the pore-scale, mesoscale and continuum scale. For each of these approaches, the different numerical schemes for solving the coupled advection–diffusion-reactions equations are presented. The parameters influenced by coupled biological and chemical reactions in evolving porous media are emphasised and defined from a pore-scale perspective. Recent pore-scale studies, which have enhanced the basic understanding of processes that affect and control porous media parameters, are discussed. Subsequently, a summary of the common methods used to describe the transport process, fluid flow, reactive surface area and reaction parameters such as porosity, permeability and tortuosity are reviewed. [ABSTRACT FROM AUTHOR]

The solar thermal system can address a large amount of heating and cooling load required by buildings and industry. To enhance the absorption efficiency in solar thermal systems, nanofluids are considered as promising heat transfer medium. The study presents a numerical study to investigate physical feature of the entropy production in hydro-magnetic reactive unsteady flow of Prandtl nanoliquid over an infinite plate. The heat expression is modeled subject to thermal radiation and magnetic field. Innovative characteristics slip mechanisms i.e., thermophoresis diffusion and Brownian motion are also accounted. Mathematical modeling of entropy production is described by employing thermodynamics law (second law). Furthermore chemical reactions takes place at surface of plate are implemented. Nonlinear system are converted to dimensionless form via suitable transformation. The resultant system is solved by numerical approach (finite difference method). Characteristics of thermal field, entropy rate, fluid flow and concentration are physical discussed through sundry parameters. The outcomes display that the maximum velocity field exists near the center of the surface, whereas the average time flow enhances the velocity distribution. An augmentation in thermal field is distinguished versus magnetic parameter, while reverse behavior holds for fluid flow. An increase in the thermal field with respect to the magnetic variable is noted, while the opposite effect is observed for the fluid flow. A larger approximation of radiation rises entropy rate and thermal field. Increasing the Brownian motion variable increases concentration, while reverse impact is observed for Schmidt number. [ABSTRACT FROM AUTHOR]

Carbonated serpentinites (listvenites) in the Samail Ophiolite, Oman, record mineralization of 1–2 Gt of CO2, but the mechanisms providing permeability for continued reactive fluid flow are unclear. Based on samples of the Oman Drilling Project, here we show that listvenites with a penetrative foliation have abundant microstructures indicating that the carbonation reaction occurred during deformation. Folded magnesite veins mark the onset of carbonation, followed by deformation during carbonate growth. Undeformed magnesite and quartz overgrowths indicate that deformation stopped before the reaction was completed. We propose deformation by dilatant granular flow and dissolution-precipitation assisted the reaction, while deformation in turn was localized in the weak reacting mass. Lithostatic pore pressures promoted this process, creating dilatant porosity for CO2 transport and solid volume increase. This feedback mechanism may be common in serpentinite-bearing fault zones and the mantle wedge overlying subduction zones, allowing massive carbonation of mantle rocks. Mantle rocks can efficiently bind carbon by reaction with CO2 if fluid pathways remain open. This study of samples from Oman demonstrates that coupling of synchronous reaction and deformation facilitates fluid flow and massive carbon sequestration. [ABSTRACT FROM AUTHOR]

We investigate reactive flow and transport in evolving porous media. Solute species that are transported within the fluid phase are taking part in mineral precipitation and dissolution reactions for two competing mineral phases. The evolution of the three phases is not known a-priori but depends on the concentration of the dissolved solute species. To model the coupled behavior, phase-field and level-set models are formulated. These formulations are compared in three increasingly challenging setups including significant mineral overgrowth. Simulation outcomes are examined with respect to mineral volumes and surface areas as well as derived effective quantities such as diffusion and permeability tensors. In doing so, we extend the results of current benchmarks for mineral dissolution/precipitation at the pore-scale to the multiphasic solid case. Both approaches are found to be able to simulate the evolution of the three-phase system, but the phase-field model is influenced by curvature-driven motion. [ABSTRACT FROM AUTHOR]

With high access of wind energy conversion system (WECS) into the grid, it is essential that the wind energy producing companies have to conform the grid code standards laid down by the country. The low voltage-ride through (LVRT) capability is one among the obligations of all grid code standards. The LVRT capability can be enhanced by controlling the power electronic converters without any additional cost. This work proposes a novel adaptive hysteresis controller (AHC) for the LVRT capability enhancement of grid connected double-feed induction generator (DFIG)-driven WEC system. The active and reactive power flow at the DFIG is managed by modified PQ controller, and the results are compared with PQ controller. The DC link voltage (Vdc) under normal and fault conditions is controlled by fuzzy logic control (FLC). The proposed AHC controller is tested with 9 MW grid connected WEC system on Matlab/Simulink platform, and a detailed simulation was carried out under normal and fault conditions. The test results disclose the efficiency of the proposed approach. [ABSTRACT FROM AUTHOR]

Fluid flow in crystalline rocks in the absence of fractures or ductile shear zones dominantly occurs by grain boundary diffusion, as it is faster than volume diffusion. It is, however, unclear how reactive fluid flow is guided through such pathways. We present a microstructural, mineral chemical, and thermodynamic analysis of a static fluid-driven reaction from dry granulite to 'wet' eclogite. Fluid infiltration resulted in re-equilibration at eclogite-facies conditions, indicating that the granulitic protolith was out of equilibrium, but unable to adjust to changing P–T conditions. The transformation occurred in three steps: (1) initial hydration along plagioclase grain boundaries, (2) complete breakdown of plagioclase and hydration along phase boundaries between plagioclase and garnet/clinopyroxene, and (3) re-equilibration of the rock to an eclogite-facies mineral assemblage. Thermodynamic modelling of local compositions reveals that this reaction sequence is proportional to the local decrease of the Gibbs free energy calculated for 'dry' and 'wet' cases. These energy differences result in increased net reaction rates and the reactions that result in the largest decrease of the Gibbs free energy occur first. In addition, these reactions result in a local volume decrease leading to porosity formation; i.e., pathways for new fluid to enter the reaction site thus controlling net fluid flow. Element transport to and from the reaction sites only occurs if it is energetically beneficial, and enough transport agent is available. Reactive fluid flow during static re-equilibration of nominally impermeable rocks is thus guided by differences in the energy budget of the local equilibrium domains. [ABSTRACT FROM AUTHOR]