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

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 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 ( Rp) of low-smoke (non-aluminised) multi-modal AP–HTPB propellants. The Rp 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 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

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

In the current work, the auto-ignition of a turbulent round methane jet is studied numerically by means of a transported probability density function (PDF) method. The methane jet is issued into a hot, vitiated coflow, where it ignites to form a steady lifted flame. For this flame, experimental data of hydroxyl, temperature and mixture fraction are provided in the area where the fuel auto-ignites.

Due to recent interest in methanol economy, it is seen that a numerical study of combustion of methanol in a comprehensive manner is necessary. Motivated from this interest and based on the studies from literature, a numerical study on prediction of structures of non-premixed methanol-air flames in laminar forced convective environment is reported. Two-dimensional, planar and axisymmetric, computational

In this work, we propose a physics-based scaling theory for the evolution of small-scale turbulence eddies in the unburnt mixture when they travel across the preheat zone of a premixed flame. This scaling theory is developed to explicitly account for the effects of viscous diffusion on the length and velocity scales of turbulence eddies that are smaller than the inner reaction zone thickness of a premixed

This paper introduces a new method to formulate reaction progress variables for the application of FGM in combustion systems. The method involves a multiobjective optimisation to find a reaction progress variable that accurately reproduces complex reactive phenomenon of interest. In our current research, the method is applied to igniting non-premixed flames. The optimised progress variable combinations

A simple model with detailed chemistry for predictions of NO x and CO emission from cylindrical porous burners is proposed on the basis of chemical reactor network concept. Combustion in the inner hollow of the burner is modelled by laminar premixed flame while the processes inside the porous shell are described by zero-dimensional constant pressure perfect stirred reactor. Numerical results on NO

Detonation development inside spark ignition engines can result in the so called super-knock with extremely high pressure oscillation above 200 atm. In this study, numerical simulations of autoignitive reaction front propagation in hydrogen/air mixtures are conducted and the detonation development regime is investigated. A hot spot with linear temperature distribution is used to induce autoignitive

This paper presents a combustion model of a nano-aluminum-air (nAl-air) suspension. The special feature of the model is performing a local mathematical model of the oxidant diffusion through an aluminum oxide layer on the particle surface taking into account the aluminum-oxidant reaction to simulate the combustion of nano-size aluminum (nAl) particles. The oxidation rate of the aluminum particles and

We propose an algorithm for low Mach number reacting flows subjected to electric field that includes the chemical production and transport of charged species. This work is an extension of a multi-implicit spectral deferred correction (MISDC) algorithm designed to advance the conservation equations in time at scales associated with advective transport. The fast and nontrivial interactions of electrons

In this paper, the porous flow effects (tortuosity and dispersion) on the characteristics of porous combustion are numerically studied. The effects of tortuosity and dispersion are introduced in the porous diffusion coefficients to investigate the influences on the flame propagation speed and the operating range of inlet flow velocity. It is found that the ratio of thermal to mass diffusion coefficients