-
Molecular level simulations of combustion processes using the DSMC method Combust. Theory Model. (IF 2.076) Pub Date : 2021-01-07 Shrey Trivedi; R. S. Cant; John K. Harvey
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
-
Development of a mechanism-dynamic-selection turbulent premixed combustion model with application to gasoline engine combustion and emissions simulation Combust. Theory Model. (IF 2.076) Pub Date : 2021-01-07 Shiyou Yang
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
-
A generalised spray-flamelet formulation by means of a monotonic variable Combust. Theory Model. (IF 2.076) Pub Date : 2021-01-05 D. O. Maionchi; F. P. Santos; J. Melguizo-Gavilanes; M. A. Endo Kokubun
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
-
Simulations of turbulent acetone spray flames using the conditional source term estimation (CSE) approach Combust. Theory Model. (IF 2.076) Pub Date : 2020-12-24 A. Hussien; C.B. Devaud
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
-
Diffusion-controlled premixed flames Combust. Theory Model. (IF 2.076) Pub Date : 2020-12-24 William A. Sirignano
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
-
A comprehensive assessment of fractal wrinkling/eddy dissipation based combustion model for simulating conventional turbulent premixed and non-premixed flames Combust. Theory Model. (IF 2.076) Pub Date : 2020-12-17 Mohammadreza Farokhi; Madjid Birouk
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
-
Numerical study on the effect of injection pressure on high-pressure diesel spray Combust. Theory Model. (IF 2.076) Pub Date : 2020-12-03 Yong Liang Ong; Fatemeh Salehi; Mohammadmahdi Ghiji; Vikram Garaniya
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
-
Micro-explosion effects in a laminar water-in fuel spray diffusion flame Combust. Theory Model. (IF 2.076) Pub Date : 2020-11-23 J. Barry Greenberg; Sahar Shpitz
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
-
The velocity and viscosity impact on the annular spray atomisation of different fuels Combust. Theory Model. (IF 2.076) Pub Date : 2020-11-23 Elyas Rostami; Hossein Mahdavy Moghaddam
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
-
Improved path flux analysis mechanism reduction method for high and low temperature oxidation of hydrocarbon fuels Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-16 Wei Han; Xiaolong Gou
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
-
Numerical and theoretical investigation of ethanol/air flame instability Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-17 Ning Zhang; Fan Zhang; Shenghui Zhong; Zhijun Peng; Jiangfei Yu; Haifeng Liu; Cangsu Xu
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
-
Flammability dynamics and oscillation-induced extinction mechanism of dimethyl ether spherical diffusion flame in microgravity Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-17 Pengyuan Zhang; Yinhu Kang; Yi Zhang; Xiaofeng Lu; Quanhai Wang
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
-
Burning characteristics and soot formation in laminar methyl methacrylate pool flames Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-23 Dakshnamurthy Shanmugasundaram; Selvaraj Muthu Kumaran; Stanislav A. Trubachev; Anna Bespalova; Oleg P. Korobeinichev; Andrey G. Shmakov; Vasudevan Raghavan
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
-
Assessment of disparities in estimating filtered chemical reaction rates in LES using DNS of turbulent premixed flames Combust. Theory Model. (IF 2.076) Pub Date : 2020-10-16 Yash G. Shah; James G. Brasseur; Yuan Xuan
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
-
Adjoint-based sensitivity analysis of steady char burnout Combust. Theory Model. (IF 2.076) Pub Date : 2020-11-12 Ahmed Hassan; Taraneh Sayadi; Vincent Le Chenadec; Heinz Pitsch; Antonio Attili
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
-
An extended flame index partitioning for partially premixed combustion Combust. Theory Model. (IF 2.076) Pub Date : 2020-11-12 Enric Illana; Daniel Mira; Arnaud Mura
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
-
Stabilisation and extinction mechanisms of flames in cavity flameholder scramjets Combust. Theory Model. (IF 2.076) Pub Date : 2020-11-12 Jiangheng L. Ruan; Guillaume Ribert; Pascale Domingo
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
-
Explosion characteristics and energy utilisation of coal mine ultra-lean methane Combust. Theory Model. (IF 2.076) Pub Date : 2020-10-22 Baisheng Nie; Chao Peng; Jie Gong; Feifei Yin; Kedi Wang
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
-
Exploring subgrid-scale variance models in LES of lab-scale methane fire plumes Combust. Theory Model. (IF 2.076) Pub Date : 2020-10-16 L. Ma; F. Nmira; J. L. Consalvi
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
-
A one-dimensional model for ion transport in a flame with two absorbing surfaces Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-30 Christopher Martin; Alexandrina Untaroiu; Kemu Xu
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 unsteady response of radiating laminar diffusion flames exposed to decreasing mixing rate conditions representative of fires Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-23 Rui Xu; Van Minh Le; Alexis Marchand; Thomas Rogaume; Franck Richard; Jocelyn Luche; Arnaud Trouvé
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
-
Temperature uniformity evaluation of a shuttle kiln for the sanitary ware industry using CFD Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-08 Michel Romero-Flores; Alejandro D. Tapia-Martínez; Karlo Mariella-González; Alberto Cantú-Pérez; Alejandro Montesinos-Castellanos
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
-
DNS-studies on flame front markers for turbulent premixed combustion Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-02 Robert Schießl; Jordan A. Denev
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
-
Taylor-diffusion-controlled combustion in ducts Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-01 Amable Liñán; Prabakaran Rajamanickam; Adam D. Weiss; Antonio L. Sánchez
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
-
Stability of combustion waves propagating in two thermally coupled thin solid fuel layers Combust. Theory Model. (IF 2.076) Pub Date : 2020-09-01 Taisia P. Miroshnichenko; Vladimir V. Gubernov; Vadim N. Kurdyumov
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
-
The role of composition in the combustion of n-heptane/iso-butanol mixtures: experiments and detailed modelling Combust. Theory Model. (IF 2.076) Pub Date : 2020-08-17 A. Dalili; J. D. Brunson; S. Guo; M. Turello; F. Pizzetti; L. Badiali; C. T. Avedisian; K. Seshadri; A. Cuoci; F. A. Williams; A. Frassoldati; M. C. Hicks
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
-
The role of composition in the combustion of n-heptane/iso-butanol mixtures: experiments and detailed modelling Combust. Theory Model. (IF 2.076) Pub Date : 2020-08-17 Alireza Dalili; Jordan D. Brunson; Songtao Guo; Massimiliano Turello; Fabio Pizzetti; Lucia Badiali; Charles T. Avedisian; Kalyanasundaram Seshadri; Alberto Cuoci; Forman A. Williams; Alessio Frassoldati; Michael C. Hicks
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
-
Applicability of extrapolation relations for curvature and stretch rate dependences of displacement speed for statistically planar turbulent premixed flames Combust. Theory Model. (IF 2.076) Pub Date : 2020-08-06 Alexander Herbert; Umair Ahmed; Nilanjan Chakraborty; Markus Klein
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
-
Analysis of flame characteristics of low calorific value gas diffusion combustion under the action of thermal dynamics Combust. Theory Model. (IF 2.076) Pub Date : 2020-07-16 Jinqiao He; Chun Leng; Bo Liu; Zhengchun Chen; Zhenlin Li
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
-
Flamelet chemistry model for efficient axisymmetric counterflow flame simulations with realistic nozzle geometries and gravitational body force Combust. Theory Model. (IF 2.076) Pub Date : 2020-06-26 Evrim Solmaz; Fabrizio Bisetti
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
-
Flamelet chemistry model for efficient axisymmetric counterflow flame simulations with realistic nozzle geometries and gravitational body force Combust. Theory Model. (IF 2.076) Pub Date : 2020-06-26 Evrim Solmaz; Fabrizio Bisetti
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
-
Effects of pressure rise rate on laminar flame speed under normal and engine-relevant conditions Combust. Theory Model. (IF 2.076) Pub Date : 2020-06-18 Yiqing Wang; Jagannath Jayachandran; Zheng Chen
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 virtual chemical mechanism for prediction of NO emissions from flames Combust. Theory Model. (IF 2.076) Pub Date : 2020-06-01 Giampaolo Maio; Mélody Cailler; Alberto Cuoci; Benoît Fiorina
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 for crack formation during active solid pyrolysis of a char-forming solid: crack patterns; surface area generation; volatile mass efflux Combust. Theory Model. (IF 2.076) Pub Date : 2020-06-01 Indrek S. Wichman; Yen T. Nguyen; Thomas J. Pence
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 virtual chemical mechanism for prediction of NO emissions from flames Combust. Theory Model. (IF 2.076) Pub Date : 2020-06-01 G. Maio; M. Cailler; A. Cuoci; B. Fiorina
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
-
Perturbation analysis of the Heterogeneous Quasi 1-D model – a theoretical framework for predicting frequency response of AP–HTPB composite solid propellants Combust. Theory Model. (IF 2.076) Pub Date : 2020-05-28 Vishal Wadhai; S. Varunkumar
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
-
An improved model to calculate radiative heat transfer in hot combustion gases Combust. Theory Model. (IF 2.076) Pub Date : 2020-05-27 Yue Zhou; Ran Duan; Xijuan Zhu; Jie Wu; Jing Ma; Xia Li; Qiang Wang
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
-
Expansion, injection and micro-explosion phenomena during the full combustion cycle of mixed fuel droplets of ethyl alcohol and biodiesel Combust. Theory Model. (IF 2.076) Pub Date : 2020-05-13 Kesheng Meng; Wei Fu; Fengyu Li; Yanyan Lei; Qizhao Lin
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
-
Expansion, injection and micro-explosion phenomena during the full combustion cycle of mixed fuel droplets of ethyl alcohol and biodiesel Combust. Theory Model. (IF 2.076) Pub Date : 2020-05-13 Kesheng Meng; Wei Fu; Fengyu Li; Yanyan Lei; Qizhao Lin
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
-
Analytical and numerical study of the expansion effect on the velocity deficit of rotating detonation waves Combust. Theory Model. (IF 2.076) Pub Date : 2020-05-07 Mingyi Luan; Shujie Zhang; Zhijie Xia; Songbai Yao; J.-P. Wang
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
-
Travelling wave mathematical analysis and efficient numerical resolution for a one-dimensional model of solid propellant combustion Combust. Theory Model. (IF 2.076) Pub Date : 2020-04-22 Laurent François; Joël Dupays; Dmitry Davidenko; Marc Massot
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
-
Simulation of ECN diesel spray A using conditional source-term estimation Combust. Theory Model. (IF 2.076) Pub Date : 2020-04-17 Xiao Hang Fang; Riyaz Ismail; Kendal Bushe; Martin Davy
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
-
Large eddy simulation of turbulent partially premixed flames with inhomogeneous inlets using the dynamic second-order moment closure model Combust. Theory Model. (IF 2.076) Pub Date : 2020-04-11 Kun Luo; Runzhi Liu; Yun Bai; Wenjian Bi; Jianren Fan
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
-
Combustion of rich hydrogen–air mixture stabilised near a cylindrical porous burner Combust. Theory Model. (IF 2.076) Pub Date : 2020-03-31 B. Kichatov; A. Kolobov; V. Gubernov; V. Bykov; U. Maas
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
-
Investigation of flame characteristic in porous media burner with pores step distribution in radial direction Combust. Theory Model. (IF 2.076) Pub Date : 2020-03-16 Liu Hui; Kang Liusheng; Yi Zhi; Yang Xiaoxi; Wang Duo
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
-
REDIM reduced chemistry for the simulation of counterflow diffusion flames with oscillating strain rates Combust. Theory Model. (IF 2.076) Pub Date : 2020-03-09 Chunkan Yu; Felipe Minuzzi; Ulrich Maas
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
-
Initiation and propagation of spherical premixed flames with inert solid particles Combust. Theory Model. (IF 2.076) Pub Date : 2020-02-20 Qiang Li; Chaoyi Liu; Huangwei Zhang; Mengze Wang; Zheng Chen
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
-
Large-eddy simulation of a bluff-body stabilised nonpremixed flame with radiation heat transfer Combust. Theory Model. (IF 2.076) Pub Date : 2020-02-14 F. C. Miranda; P. J. Coelho; J. Ströhle; J. Janicka
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
-
Effect of O2 concentration in ambient mixture and multiphase radiation on pollutant formation in ECN spray-A Combust. Theory Model. (IF 2.076) Pub Date : 2020-02-12 Khaled Mosharraf Mukut; Somesh P. Roy
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)
-
CFD simulations of hydrogen deflagration in slow and fast combustion regime Combust. Theory Model. (IF 2.076) Pub Date : 2020-02-12 Robert Cherbański; Eugeniusz Molga
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
-
On the ambiguity of premixed flame thickness definition of highly pre-heated mixtures and its implication on turbulent combustion regimes Combust. Theory Model. (IF 2.076) Pub Date : 2020-02-06 Andreas H. Rauch; Harsha K. Chelliah
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
-
Hydrodynamic instability of premixed flame propagating in narrow planar channel in the presence of gas flow Combust. Theory Model. (IF 2.076) Pub Date : 2020-01-27 Taisia Miroshnichenko; Vladimir Gubernov; Sergey Minaev
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
-
Reduced-order modelling of thermoacoustic instabilities in a two-heater Rijke tube Combust. Theory Model. (IF 2.076) Pub Date : 2020-01-17 Chandrachur Bhattacharya; Sudeepta Mondal; Asok Ray; Achintya Mukhopadhyay
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
-
Modelling and control of the spark timing of an internal combustion engine based on an ANN Combust. Theory Model. (IF 2.076) Pub Date : 2019-12-20 D. A. Carbot-Rojas; Ricardo F. Escobar-Jiménez; J. F. Gómez-Aguilar; J. García-Morales; A. C. Téllez-Anguiano
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
-
Dimensional scaling of flame propagation in discrete particulate clouds Combust. Theory Model. (IF 2.076) Pub Date : 2019-12-18 Fredric Y.K. Lam; XiaoCheng Mi; Andrew J. Higgins
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
-
Multiplicity of detonation regimes in systems with a multi-peaked thermicity Combust. Theory Model. (IF 2.076) Pub Date : 2019-12-10 S.S.M. Lau-Chapdelaine; Fan Zhang; Matei I. Radulescu
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
-
Degree centrality of combustion reaction networks for analysing and modelling combustion processes Combust. Theory Model. (IF 2.076) Pub Date : 2019-12-06 Ahmad Saylam; Kamal Hadj Ali; Mustapha Fikri
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
-
Computational modelling of multi-material energetic materials and systems Combust. Theory Model. (IF 2.076) Pub Date : 2019-11-15 Alberto M. Hernández; D. Scott Stewart
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
-
Correction Combust. Theory Model. (IF 2.076) Pub Date : 2019-11-04
(2019). Correction. Combustion Theory and Modelling: Vol. 23, No. 6, pp. 1191-1192.
-
Implementation problems of manifolds-based model reduction and their generic solution Combust. Theory Model. (IF 2.076) Pub Date : 2019-10-23 Philipp Golda; Andreas Blattmann; Alexander Neagos; Viatcheslav Bykov; Ulrich Maas
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
Contents have been reproduced by permission of the publishers.