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This paper aims to introduce a two-dimensional smoothed particle hydrodynamics (SPH) framework for simulating the evaporation and combustion process of fuel droplets.

To solve the gas–liquid two-phase flow problem, a multiphase SPH method capable of handling high density-ratio problems is established. Based on the Fourier heat conduction equation and Fick’s law of diffusion, the SPH discrete equations are derived. To effectively characterize the phase transition problem, inspired by volume of fluid method, the concept of liquid phase mass fraction of the SPH particles is proposed. The one-step global reaction model of n-hexane is used for the vapor combustion.

The evaporation and combustion process of single droplet conforms to the law. The framework works out well when the evaporation of multiple droplets involves coalescence process. Three different kinds of flames are observed in succession in the combustion process of a single droplet at different inflow velocity, which agree well with the results of the experiment.

To the best of the authors’ knowledge, this is the first computational framework that has the capability to simulate evaporation and combustion with SPH method. Based on the particle nature of SPH method, the framework has natural advantages in interface tracking.

The purpose of this paper is to study the soot formation and evolution by using this newly developed Lagrangian particle tracking with weighted fraction Monte Carlo (LPT-WFMC) method.

The weighted soot particles are used in this MC framework and is tracked using Lagrangian approach. A detailed soot model based on the LPT-WFMC method is used to study the soot formation and evolution in ethylene laminar premixed flames.

The LPT-WFMC method is validated by both experimental and numerical results of the direct simulation Monte Carlo (DSMC) and Multi-Monte Carlo (MMC) methods. Compared with DSMC and MMC methods, the stochastic error analysis shows this new LPT-WFMC method could further extend the particle size distributions (PSDs) and improve the accuracy for predicting soot PSDs at larger particle size regime.

Compared with conventional weighted particle schemes, the weight distributions in LPT-WFMC method are adjustable by adopting different fraction functions. As a result, the number of numerical soot particles in each size interval could be also adjustable. The stochastic error of PSDs in larger particle size regime can also be minimized by increasing the number of numerical soot particles at larger size interval.

Gas explosion is one of the most major types of accident in mining projects, and the flame front with high temperature is major hazardous factor induced by this kind of accident. Support engineering provides an available way to solve problems related to ground movements, but very likely has a great influence on the gas explosion accident process, especially the flame propagation, and then aggravates mining risk. However, until now it has not been received much attention from scientific works. The paper aims to discuss these issues.

A commercial CFD software package AutoReaGas suitable for gas explosion is used to carry out the numerical investigation of gas explosion process in a straight coal tunnel with typical support engineering, especially the unsteady explosion field and the flame propagation process in it.

Support engineering composed by multiple bars take positive influence on flame acceleration: the flame speed is much faster than that under no support bars, and the smaller support spacing induces greater flame speed near the ignition. The support bars also exert negative influence on flame acceleration: the larger support spacing induces greater flame speed in most region of the tunnel. Furthermore, a traditional viewpoint that denser obstacles induce greater explosion effects is one-sided according to this study.

At present, no one concerns the aggravating influence of support engineering on accident risk in practical mining projects because of small geometric dimension. This work examines the effect of steel support system on evolution processes of gas explosion accidents, especially the flame propagation. The conclusions provide quantitative scientific basis for this kind of the accidents in risk evolution and accident investigation of mining engineering.

This study aims to investigate the insights of soot formation such as rate of soot coagulation, rate of soot nucleation, rate of soot surface growth and soot surface oxidation in ethylene/hydrogen/nitrogen diffusion jet flame at standard atmospheric conditions, which is very challenging to capture even with highly sophisticated measuring systems such as Laser Induced Incandescence and Planar laser-induced fluorescence. The study also aims to investigate the volume of soot in the flame using soot volume fraction and to understand the global correlation effect in the formation of soot in ethylene/hydrogen/nitrogen diffusion jet flame.

A large eddy simulation (LES) was performed using box filtered subgrid-scale tensor. A filtered and residual component of the governing equations such as continuity, momentum, energy and species are resolved and modeled, respectively. All the filtered and residual components are numerically solved using the ILU method by considering PISO pressure–velocity solver. All the hyperbolic flux uses the QUICK algorithm, and an elliptic flux uses SOU to evaluate face values. In all the cases, Courant–Friedrichs–Lewy (CFL) conditions are maintained unity.

The findings are as follows: soot volume fraction (SVF) as a function of a flame-normalized length for three different Reynolds number configurations (Re = 15,000, Re = 8,000 and Re = 5,000) using LES; soot gas phase and particulate phase insights such as rate of soot nucleation, rate of soot coagulation, rate of soot surface growth and soot surface oxidation for three different Reynolds number configurations (Re = 15,000, Re = 8,000 and Re = 5,000); and soot global correction using total soot volume in the flame volume as a function of Reynolds number and Froude number.

The originality of this study includes the following: coupling LES turbulent model with chemical equilibrium diffusion combustion conjunction with semi-empirical Brookes Moss Hall (BMH) soot model by choosing C6H6 as a soot precursor kinetic pathway; insights of soot formations such as rate of soot nucleation, soot coagulation rate, soot surface growth rate and soot oxidation rate for ethylene/hydrogen/nitrogen co-flow flame; and SVF and its insights study for three inlet fuel port configurations having the three different Reynolds number (Re = 15,000, Re = 8,000 and Re = 5,000).

AS was announced in the June 1955 issue of Aircraft Engineering, this conference was held in Boston, Massachusetts in June, and again in London in October.

Explosions are the main type of accident causing casualties in underground coal mines. Little attention has been devoted to investigating the flame propagations for methane‐air explosion in a tunnel with full scale. This paper seeks to address this topic.

Based on the numerical simulation and the analysis, the propagation rule of flame and temperature waves inside and outside the space occupied by methane/air mixture at the various concentrations in a tunnel were obtained in this work.

The original interface of methane‐air mixture and air moves forward in the explosion and the original mixture area extends. For the methane‐air mixture with rich fuel concentration, the flame speed increases with distance within a range beyond the original position of the interface between the mixture and air. The flame speed reaches maximum value outside the original area of methane‐air mixture with rich fuel concentration.

Based on the numerical simulation and the analysis, the propagation rule of flame and temperature wave inside and outside the space occupied by methane/air mixture at the various concentrations in a tunnel were obtained.

Text books on gas turbines, and aircraft gas turbines in particular, are now so common that the student is beginning to find difficulty in selecting the most suitable for his purpose. Books have appeared which range from little more than elementary descriptions of turbine engines to highly detailed theoretical and mathematical analysis of the thermodynamic cycles and performance. The present volume tends towards the theoretical treatment, but this should not deter practical engineers, who will find the material presented in a refreshingly clear and concise manner.

The purpose of this paper is to investigate the problem of entropy generation around a spinning/non‐spinning solid sphere subjected to uniform heat flux boundary condition in the forced‐convection regime.

The governing continuity, momentum, energy and entropy generation equations are numerically solved for a wide range of the controlling parameters; Reynolds number and the dimensionless spin number.

The dimensionless overall total entropy generation increases with the dimensionless spin number. The effect of increasing the spin number on the fluid‐friction component of entropy generation is more significant compared to its effect on heat transfer entropy generation.

Since the boundary‐layer analysis is used, the flow is presented up to only the point of external flow separation.

Entropy generation analysis can be used to evaluate the design of many heat transfer systems and suggest design improvements.

A review in the open literature indicated that no study is available for the entropy generation in the unconfined flow case about a spinning sphere.

The aim of this paper is to find the optimal values of the reaction rates coefficients for the combustion of a methane/air mixture for a given reduced reaction mechanism which has a high appropriateness with full reaction mechanism.

A multi‐objective genetic algorithm (GA) was used to determine new reaction rate parameters (A's, β's, and E_a's in the non‐Arrhenius expressions). The employed multi‐objective structure of the GA allows for the incorporation of perfectly stirred reactor (PSR), laminar premixed flames, opposed flow diffusion flames, and homogeneous charge compression ignition (HCCI) engine data in the inversion process, thus enabling a greater confidence in the predictive capabilities of the reaction mechanisms obtained.

The results of this study demonstrate that the GA inversion process promises the ability to assess combustion behaviour for methane, where the reaction rate coefficients are not known. Moreover it is shown that GA can consider a confident method to be applied, straightforwardly, to the combustion chambers, in which complex reactions are occurred.

In this paper, GA is used in more complicated combustion models with fewer assumptions. Another consequence of this study is less CPU time in converging to final solutions.

The purpose of this paper is to assess the validity of Weller's b-ω flamelet model for practical swirl-stabilized combustion applications.

Swirl-stabilized premixed flame behavior is investigated utilizing an atmospheric combustor test rig. Swirl number of the flow is 0.74 with a cold flow Reynolds number of 19,400 based on the hydraulic diameter at the inlet pipe. Operating condition corresponds to an equivalence ratio of 0.7 at a thermal load of 20.4 kW. Reacting flow was seeded with TiO₂ particles, and velocity distribution at the center plane was measured utilizing particle image velocimetry. These results serve as a validation dataset for numerical simulations. An open-source computational fluid dynamics (CFD) code library (OpenFOAM) is used for numerical computations. These unsteady Reynolds averaged Navier Stokes (RANS) computations were performed at the same load condition corresponding to experimental data. Parallel numerical simulations were carried out on 128 processor cores. To resolve turbulence, Menter's k-ω shear stress transport model was utilized; flame behavior, on the other hand, was described by Weller's b-ω flamelet model. A block-structured all-hexahedral mesh was used.

It is observed that two counter-rotating vortices in the main recirculation zone are responsible for flame stabilization. Weak secondary recirculation zones are also present at the sides above the dump plane. Flame front location was inferred from Mie scattering images. Experimental findings show that the flame anchors both on the tip of the center body and also at the rim of the outlet pipe. Numerical simulations capture the complex interactions between the flame and the turbulent flow. These results qualitatively agree with the flame structure observed experimentally.

Swirl-stabilized combustion systems are used in many practical applications ranging from aeroengines to land-based power generation systems. There are implications regarding the understanding of these combustion systems.

Better understanding of combustion systems contributes to better performing turbine engines and reduced emissions with implications for the entire society.

The paper provides experimental insight into the application of a combustion model for a flame configuration of practical interest.