A technique called the Direct Simulation Monte Carlo (DSMC) method is used for simulating laminar one-dimensional hydrogen-air flames with an aim to establish the feasibility of molecular-level simulations for combustion using the Quantum-Kinetic (QK) reaction model. In DSMC, simulation particles are employed which represent many molecules with similar properties. The DSMC method effectively solves

In order to overcome the drawback (tuning reaction rate coefficients) of using a single mechanism in the chemical-kinetics-based turbulent premixed combustion modelling approach, a mechanism-dynamic-selection turbulent premixed combustion model has been developed, validated, and successfully applied to the combustion and emissions simulation of spark ignition gasoline engines. In this new model, based

The external structure of the spray-flamelet can be described using the Schvab–Zel'dovich–Liñan formulation. The gaseous mixture-fraction variable as function of the physical space, Z ( x i ) , typically employed for the description of gaseous diffusion flames leads to non-monotonicity behaviour for spray flames due to the extra fuel supplied by vaporisation of droplets distributed into the flow. As

Turbulent dilute acetone spray flames are simulated in an Eulerian–Lagrangian framework using Conditional Source-term Estimation (CSE) for closure of the mean reaction rate. The objective of this work is to assess the performance of the coupled CSE-spray approach, investigated for the first time for the selected configuration. One non-reacting case and four non-premixed flames, AcF1–AcF3 and AcF5 are

Steady laminar flow structures with mixing, chemical reaction, and normal strain qualitatively representative of turbulent combustion at the small scales are analysed. A contrived counterflow configuration is examined to focus more easily on the premixed flames that are known to occur in multiple-flame structures; the premixed flame can be driven by a controlled heat source which is a surrogate for

This paper presents a step-forward extension of the well-known chemistry/flow interaction Eddy Dissipation Concept approach for modelling both, non-premixed and premixed, combustion regimes in a Reynolds-Averaged Navier Stokes framework. The Eddy Dissipation Concept approach and its extended versions (e.g. Partially Stirred reactors, PaSR) are widely used for CFD modelling of a variety of combustion

This paper analyses the effect of injection pressures on spray and flame structures under high-pressure diesel spray conditions using a three-dimensional Reynolds-Average Navier-Stokes (RANS) model. The simulations are conducted using three kinetic mechanisms known as Luo (106 species), Cai (57 species) and Yao (54 species). Tabulation and Dynamic Adaptive Chemistry (TDAC) solver is adopted to reduce

In this work, we formulate a simple one-dimensional model as a framework for studying the influence of water-in-fuel emulsions on spray diffusion flames. The special contribution of these emulsions to combustion is examined via the relevant steady state equations, which are solved both analytically, when the chemical Damköhler number becomes infinitely large, and numerically when it is finite. Two

Numerical methods for predicting the primary breakup length, the ligament and droplet diameter of fuels are a suitable substitute for experimental work. Mazut, diesel, biodiesel and water fluids are selected for the study. A linear instability model has been applied for the analysis of various liquid sprays. The effects of velocity (axial and swirl), viscosity and temperature on the atomisation of

Due to the increasing attention of low temperature combustion, more precise and convenient low temperature chemical reaction mechanism is needed in the combustion reaction flow modelling. However, most of the conventional mechanism reduction methods are difficult to deal with the low temperature mechanism. In order to reduce the low temperature combustion mechanisms of hydrocarbon fuel efficiently

A series of two dimensional (2D) detailed numerical simulations of premixed cylindrical expanding ethanol/air flames in a constant volume encloser under elevated pressures and equivalence ratios are performed to investigate cellular flame instability. The results demonstrate that at pressure of 10 atm and temperature of 358 K, ethanol/air flame cellular instability increases non-monotonically with

Continuation computations were performed to generate the S-curve as well as the flammability limit. Transient simulations using detailed fuel chemistry and transport models were conducted to reproduce the oscillatory extinction process. It was found that the cool spherical diffusion flame (SDF) had a much extended extinction limit than the hot SDF. The cool SDF with double-reaction-zone structure had

This study presents careful measurements from lab-scale experiments and predictions from comprehensive numerical model for the burning characteristics of laminar flames over MMA pools of different diameters with varying ullages or lip heights. Lab-scale experiments for steady burning of MMA pool are conducted, and temperature and concentrations of major species, have been measured for 3 mm ullage case

An a priori assessment of the disparities in estimating the filtered chemical reaction rates in Large-Eddy Simulations (LES) is performed using two Direct Numerical Simulations (DNS) of turbulent premixed flames. DNS of turbulent premixed flames with the same turbulent Reynolds number but different Karlovitz numbers are carried out using semi-detailed finite-rate chemistry to represent different flame

Simulations of pulverised coal combustion rely on various models, required in order to correctly approximate the flow, chemical reactions, and behaviour of solid particles. These models, in turn, rely on multiple model parameters, which are determined through experiments or small-scale simulations and contain a certain level of uncertainty. The competing effects of transport, particle physics, and

Compared to partially premixed combustion (or combustion of non-homogeneous reactants in general), fully premixed and diffusion flames represent only two asymptotic limits of combustion modes. However, the deep knowledge accumulated over the years on these two elementary and archetypal flame prototypes is such that they remain the cornerstone and reference building blocks of most combustion modelling

Stabilising a flame in scramjet engines is a current technological challenge. Indeed, the residence time in the combustion chamber is very short, thus limiting the mixing efficiency and consequently, the combustion. This problem is presently addressed by simulating the scramjet combustor of the U.S. Air Force Research Laboratory in which ethylene is injected from the back of a slanted cavity to react

Reasonable recycling low concentration methane, especially the ultra-lean methane (the concentration lower than 5%), is significant to resource saving and environment protection. Nowadays, low concentration gas power generation technology is well developed. Notwithstanding this, ultra-lean methane has not been applied in large scale mainly due to the high utilisation costs. Therefore, to address this

Large Eddy Simulation (LES) of the lab-scale methane fire plumes investigated experimentally by McCaffrey is performed using the steady laminar flamelet/presumed beta filtered density function model on grids of different resolution ranging from the Taylor length scale to about six times the Kolmogorov length scale. This work focuses on investigating existing subgrid (SGS) mixing models for mixture

This paper presents numerical and asymptotic analytical solutions for the current–voltage characteristic of a flame using a one-dimensional ion transport model with boundary conditions that include detailed treatment of sheath formation. Non-dimensional conservation equations are presented for the free electron, the hydronium ion, and the electrical potential in a one-dimensional flow field with uniform

The objective of this study is to bring fundamental information on the coupling between combustion and thermal radiation occurring at flame scale. The study considers a simplified configuration corresponding to one-dimensional counterflow planar laminar diffusion flames subjected to time-evolving moderate-to-slow mixing conditions that are representative of fires. The flame simulations are performed

Shuttle kilns are widely used in the sanitary ware industry. A key parameter to reduce energy consumption and increase their overall performance is temperature uniformity. Therefore, in this paper a systematic and statistical study of the effect of the position of burners and their interactions on the temperature uniformity of a shuttle kiln is performed. CFD simulations and a 4k factorial analysis

Flame front identification and analysis in premixed turbulent combustion often relies on some scalar iso-surface as a flame marker, and the quest for a suitable scalar, and an appropriate flame-identifying iso-value, then becomes important. In an effort to contribute to this field, we study the suitability of various flame front identification approaches using the concept of ridge analysis. This serves

An analysis is presented for the Burke–Schumann flame established when a fuel tank discharges with mean velocity U along a circular duct of radius a filled initially with air. Attention is focused on effects of interactions of shear with transverse diffusion resulting in enhanced longitudinal dispersion. The analysis accounts for preferential-diffusion effects arising for non-unity values of the fuel

In this work we investigate the linear stability of combustion waves propagating in a system of two layers of different exothermic reacting materials under conditions of thermal contact between them through the common interface using the reaction sheet approximation. The dispersion relations are found and the dependence of the stability boundary on the parameters of the model is studied. It is demonstrated

Experimental data and detailed numerical modelling are presented on the burning characteristics of a model gasoline/biofuel mixture consisting of n-heptane and iso-butanol. A droplet burning in an environment that minimises the influence of buoyant and forced convective flows in the standard atmosphere is used to promote one-dimensional gas transport to facilitate numerical modelling of the droplet

Experimental data and detailed numerical modelling are presented on the burning characteristics of a model gasoline/biofuel mixture consisting of n-heptane and iso-butanol. A droplet burning in an environment that minimises the influence of buoyant and forced convective flows in the standard atmosphere is used to promote one-dimensional gas transport to facilitate numerical modelling of the droplet

A three-dimensional Direct Numerical Simulation (DNS) database of statistically planar turbulent premixed flames covering the wrinkled/corrugated flamelets and the thin reaction zones regimes of premixed turbulent combustion has been utilised to assess the performances of the extrapolation relations, which approximate the stretch rate and curvature dependences of density-weighted displacement speed

In this paper, the flame characteristics of co-axial concomitant flow diffusion combustion of low calorific value gas under the action of thermal dynamics are studied. Based on Fluent software, the combustion process of low calorific value gas is simulated by a finite element volume method. According to different air preheating temperatures T a i n , by analyzing the changes of temperature field, velocity

A flamelet model is applied to the simulation of axisymmetric counterflow laminar flames including gravitational acceleration and the geometrical details of main nozzles and annular shrouds. The flamelet chemistry model consists of two mixture fractions and is found to be very accurate when compared to results obtained with finite rate chemistry and mixture-average transport. Steady and unsteady solvers

A flamelet model is applied to the simulation of axisymmetric counterflow laminar flames including gravitational acceleration and the geometrical details of main nozzles and annular shrouds. The flamelet chemistry model consists of two mixture fractions and is found to be very accurate when compared to results obtained with finite rate chemistry and mixture-average transport. Steady and unsteady solvers

Laminar flame speed (LFS) is one of the most important physicochemical properties of a combustible mixture. At normal and elevated temperatures and pressures, LFS can be measured using propagating spherical flames in a closed chamber. LFS is also used in certain turbulent premixed flame modelling for combustion in spark ignition engines. Inside the closed chamber or engine, transient pressure rise

A reduced order kinetic model for NO (nitric oxide) prediction, based on the virtual chemistry methodology [M. Cailler, N. Darabiha, and B. Fiorina, Development of a virtual optimized chemistry method. Application to hydrocarbon/air combustion, Combust. Flame 211 (2020), pp. 281–302], is developed and applied. Virtual chemistry aims to optimise thermochemical properties and kinetic rate parameters

A model is developed for the formation and propagation of cracks in a material sample that is heated at its top surface, pyrolyses, and then thermally degrades to form char. In this work the sample is heated uniformly over its entire top surface by a hypothetical flame (a heat source). The pyrolysis mechanism is described by a one-step overall reaction that is dependent nonlinearly on the temperature

A reduced order kinetic model for NO (nitric oxide) prediction, based on the virtual chemistry methodology [M. Cailler, N. Darabiha, and B. Fiorina, Development of a virtual optimized chemistry method. Application to hydrocarbon/air combustion, Combust. Flame 211 (2020), pp. 281–302], is developed and applied. Virtual chemistry aims to optimise thermochemical properties and kinetic rate parameters

In this paper, the Heterogeneous Quasi 1-D model for steady combustion of AP–HTPB propellants is extended to the unsteady regime. The extended model is used to calculate the pressure-coupled frequency response ( R p ) of low-smoke (non-aluminised) multi-modal AP–HTPB propellants. The R p of a multi-modal propellant is expressed in terms of that of the individual binder-matrix coated AP particles constituting

Radiative heat transfer plays an important role in the chemical reactions in the combustor. The widely used WSGG model proposed by Smith is established for normal pressure, which shows inevitable computational errors when dealing with radiative heat transfer problems at reduced or elevated pressures. In this paper, an improved global model is established to calculate the radiant energy exchanges between

In this study, mixed fuel droplets of ethyl alcohol and biodiesel with different volumes or ratios were prepared and the related expansion, injection and micro-explosion phenomena were investigated. During the tests, a mixed-fuel droplet was hung on a high-temperature-resistant Cr-Ni wire, which was transported to the preheating piston for heating and then was ignited automatically. Micro-needles and

In this study, mixed fuel droplets of ethyl alcohol and biodiesel with different volumes or ratios were prepared and the related expansion, injection and micro-explosion phenomena were investigated. During the tests, a mixed-fuel droplet was hung on a high-temperature-resistant Cr-Ni wire, which was transported to the preheating piston for heating and then was ignited automatically. Micro-needles and

In this work, a quasi-one-dimensional ZND model of detonation considering the expansion process perpendicular to the detonation propagation direction is extended to the rotating detonation engine (RDE) to investigate the influence of expansion on the detonation waves in RDEs. This model is first used in more general cases of one-dimensional detonation waves, coupled with the one- and two-step kinetic

We investigate a model of solid propellant combustion involving surface pyrolysis coupled to finite activation energy gas-phase combustion. Existence and uniqueness of a travelling wave solution are established by extending dynamical system tools classically used for premixed flames, dealing with the additional difficulty arising from the surface regression and pyrolysis. An efficient shooting method

A novel combustion modelling approach is proposed here to study the transient effects of diesel spray. Conditional Source-term Estimation (CSE) is a combustion model which invokes the Conditional Moment Closure (CMC) hypothesis to provide an approximation of the mean chemical source term in an averaged transport equation. Unlike CMC, where transport equations are solved for conditional moments, CSE

The Sydney piloted partially premixed flames with both homogeneous and inhomogeneous fuel/air inlets are studied using a dynamic second-order moment closure model in the framework of large eddy simulation with a four-step global reaction mechanism. The filtered reaction rates are directly closed using the second-order correlation moments of reactive scalars. Good agreements between LES and experimental

In this paper, the effect of geometry on the dynamics of the hydrogen–air flame stabilised on the surface of a burner is investigated numerically. Two main regimes of combustion front stabilisation near the cylindrical burner: attached and detached flames are investigated and compared to the planar case. The neutral stability boundary for diffusive-thermal instability is studied in detail. The attached

In recent years, attention has been focused on the use of porous materials to enhance the efficiency of combustion systems and reduce the pollutants emission. However, the porous media burners have the problem of inclined flame when used for surface heat treatments. In order to solve this problem, a new structure of porous media burner with pores step distribution in radial direction is proposed in

The dynamic behaviour and structures of laminar counterflow diffusion methane flames under oscillatory strain rates are investigated based on both detailed and reduced chemistry. It is known both from experiment and numerical studies that flame can deviate from its quasi-steady manner for high frequencies, which makes the well-known steady laminar flamelet model questionable. In this work, the Reaction-diffusion

Spherical flame initiation and propagation in particle-laden mixtures are investigated theoretically in this work. Within the framework of constant density, large activation energy and quasi-steady assumptions, a correlation describing spherical flame propagation speed as a function of flame radius is derived. This correlation is used to assess the influence of gas and particle properties on initiation

Turbulence-radiation interactions are studied in this work for large-eddy simulations (LES) of an artificially scaled configuration based on the Sydney bluff-body burner. This investigation is performed by applying the combustion model flamelet generated manifolds, and the transported PDF Eulerian stochastic field method is employed to account for turbulence-chemistry interaction. The radiative transfer

This study investigates the formation and evolution of soot and NO X in a high-pressure constant-volume combustion chamber. This work focuses on the effect of multiphase thermal radiation and O2 dilution in ambient/exhaust gases, sometimes also referred to as exhaust gas recirculation (EGR), qualitatively and quantitatively. The spray-A case (n-dodecane as fuel) from Engine Combustion Network (ECN)

This paper presents CFD modelling of hydrogen-air deflagrations. The proposed mathematical models are validated with the experiments provided to SARNET2 (Severe Accident Research NETwork of Excellence 2) project [A. Bentaib, A. Bleyer, N. Chaumeix, B. Schramm, P. Kostka, M. Movahed, H.S. Kang and M. Povilaitis, Final results of the SARNET Hydrogen deflagration Benchmark Effect of turbulence on flame

Freely propagating, one-dimensional, laminar, premixed flames of ethylene–air are analysed at standard temperature and pressure (STP) and at elevated temperature and pressure conditions to reveal the differences in flame structure. For high-temperature and low-pressure conditions, there is a significant contribution to the total heat release in the post-flame region leading to an ambiguity in the definition

The paper analyses the hydrodynamic instability of a flame propagating in the space between two parallel plates in the presence of gas flow. The linear analysis was performed in the framework of a two-dimensional model that describes the averaged gas flow in the space between the plates and the perturbations development of two-dimensional combustion wave. The model includes the parametric dependences

The topic of thermoacoustic instabilities in combustors is well-investigated, as it is important in the field of combustion, primarily in gas-turbine engines. In recent years, much attention has been focused on monitoring, diagnosis, prognosis, and control of high-amplitude pressure oscillations in confined combustion chambers. The Rijke tube is one of the most simple, yet very commonly used, laboratory

In this work, the mathematical modelling of a internal combustion (IC) engine fed with multiple fuels, and a control scheme for controlling the spark timing of the IC engine are presented. The goal of this work is controlling the IC engine spark timing when it is feed with a hydrogen-enriched E10 blend as fuel, without efficiency and torque losses, at different operating points. The importance of controlling

The critical dimension necessary for a flame to propagate in suspensions of fuel particles in oxidiser is studied analytically and numerically. Two types of models are considered: First, a continuum model, wherein the individual particulate sources are not resolved and the heat release is assumed spatially uniform, is solved via conventional finite difference techniques. Second, a discrete source model

The study investigates detonations with multiple quasi-steady velocities that have been observed in the past in systems with multi-peaked thermicity, using Fickett's detonation analogue. A steady-state analysis of the travelling wave predicts multiple states, however, all but the one with the highest velocity develop a singularity after the sonic point. Simulations show singularities are associated

Combustion research still needs more advanced fundamental understanding of combustion chemistry and dynamics from molecule scale to particle. The latter is also needed for soot and nanoparticles formation and combustion system control such as homogeneous charge compression ignition engine, and flame regimes and instability. The complex interactions between hundreds of species linked within thousands

In this paper, we present a systematic roadmap for developing a robust and parallel multi-material reactive hydrodynamic solver that integrates historically stable algorithms with new and current modern methods to solve explosive system design problems. The Ghost Fluid Method and Riemann solvers were used to enforce appropriate interface boundary conditions. Improved performance in terms of computational

(2019). Correction. Combustion Theory and Modelling: Vol. 23, No. 6, pp. 1191-1192.

During the last decades, tabulated chemistry approaches, like manifold-based concepts to implement model reduction, have become a widespread, promising and accurate method to take chemical reactions into account in computing reacting flows. However, there is a number of crucial issues concerning the generation and implementation of the tabulated chemistry approaches. These concern the way manifolds