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The kinetics and warm flame chemistry associated with radiative extinction of spherical diffusion flames Combust. Theory Model. (IF 1.3) Pub Date : 2024-03-17 Kendyl A. Waddell, Gregory Yablonsky, Denis Constales, Peter B. Sunderland, Richard L. Axelbaum
Several studies have found that microgravity diffusion flames with sufficient heat loss cool until they extinguish at a critical temperature near 1130 K. In this work, the associated chemical kinet...
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A fast uncertainty quantification methodology and sampling technique for joint probability distribution of the Arrhenius rate expression: a case study applied to H2/CO kinetic mechanism Combust. Theory Model. (IF 1.3) Pub Date : 2024-03-12 Krunal Panchal, Vaisakh Vasudevan, Sivaram Ambikasaran, Krithika Narayanaswamy
This work proposes a fast, novel, mathematically robust, and elegant unconstrained Method of Uncertainty Quantification (MUQ) for the temperature-dependent Arrhenius rate constant using Cholesky De...
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Exploring the chemical kinetic effects on the direct detonation initiation in H2-O2-Ar mixtures Combust. Theory Model. (IF 1.3) Pub Date : 2024-01-31 Yuen Liu, Yuxuan Chen, Qing Xie, Xingyu Su, Zhuyin Ren, Hao Zeng
Chemical kinetics plays an important role in the direct detonation initiation (DDI) of various combustible mixtures. However, its impact on detonation dynamics has rarely been studied with detailed...
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Evolutionary equations for the disturbed flame stabilised at the flat burner Combust. Theory Model. (IF 1.3) Pub Date : 2024-02-02 Sergey Minaev, Evgeniy Sereshchenko, Vladimir Gubernov
The dynamics of the burner-stabilised flame is investigated theoretically in the frame of diffusive-thermal model. The nonlinear system of equations describing dynamics of curved flame front and th...
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An iterative methodology for REDIM reduced chemistry generation and its validation for partially-premixed combustion Combust. Theory Model. (IF 1.3) Pub Date : 2023-12-27 Prashant Shrotriya, Robert Schießl, Chunkan Yu, Viatcheslav Bykov, Thorsten Zirwes, Ulrich Maas
Partially-premixed flames (PPFs) incorporate effects of both premixed and non-premixed types of reaction zones. The modelling of PPFs using manifold-based model reduction methods faces some inheren...
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Numerical modeling and parametric analysis of performance of a monopropellant thruster using a single-part catalyst bed model Combust. Theory Model. (IF 1.3) Pub Date : 2023-12-27 Mohammad Reza Salimi, Hadiseh Karimaei, Mostafa Gholampour Yazdi
Monopropellant hydrazine thruster, depending on their thrust level, specific impulse, and unique functional regime, are widely used in situation control, orbital transmission, and position correcti...
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Diffusive-thermal instabilities of a planar premixed flame aligned with a shear flow Combust. Theory Model. (IF 1.3) Pub Date : 2023-12-27 Joel Daou, Prabakaran Rajamanickam
The stability of a thick planar premixed flame, propagating steadily in a direction transverse to that of unidirectional shear flow, is studied. A linear stability analysis is carried out in the as...
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A super-grid approach for LES combustion closure using the Linear Eddy Model Combust. Theory Model. (IF 1.3) Pub Date : 2023-12-27 Abhilash M. Menon, Michael Oevermann, Alan R. Kerstein
LES–LEM is a simulation approach for turbulent combustion in which the stochastic Linear Eddy Model (LEM) is used for sub-grid mixing and combustion closure in Large-Eddy Simulation (LES). LEM reso...
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Large eddy simulations of a buoyant turbulent line flame using conditional source-term estimation (CSE) Combust. Theory Model. (IF 1.3) Pub Date : 2023-12-13 Ahmed M.K. Abdalhamid, Cecile Devaud
The objective of this paper is to assess the capabilities of the Conditional Source-term Estimation (CSE) approach applied to a laboratory scaled turbulent buoyant flame without extinction. CSE is ...
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Stochastic characterisation of unstable lean hydrogen–air annular premixed flames Combust. Theory Model. (IF 1.3) Pub Date : 2023-11-29 Luis Fernando Figueira da Silva
This study is devoted to the characterisation of lean premixed hydrogen–air laminar flames stabilised on an annular burner. The flames studied are chosen to lie close to the lean flammability limit...
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Asymptotic analysis of detonation development at SI engine conditions using computational singular perturbation Combust. Theory Model. (IF 1.3) Pub Date : 2023-11-20 Iliana D. Dimitrova, Minh-Bau Luong, Sangeeth Sanal, Efstathios-Al. Tingas, Hong G. Im
The occurrence and intensity of the detonation phenomenon at spark-ignition (SI) engine conditions is investigated, with the objective to successfully predict super-knock and to elucidate the effec...
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A combustion mechanism reduction method based on entropy production analysis in fuel auto-ignition and laminar flames Combust. Theory Model. (IF 1.3) Pub Date : 2023-11-02 Yusen Liu, Jiabo Zhang, Dong Han
This study provides a chemical mechanism reduction strategy based on entropy production analyses in both auto-ignition and laminar flames, which enhances the predictive accuracy for laminar burning...
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Different conditional source-term estimation formulations applied to turbulent nonpremixed jet flames with varying levels of extinction Combust. Theory Model. (IF 1.3) Pub Date : 2023-10-20 Amir H. Mahdipour, Cecile Devaud
The objective of the present study is to investigate two new formulations of the Conditional Source-term Estimation (CSE) model using Reynolds Averaged Navier Stokes (RANS) calculations applied to ...
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Prediction of lower explosion limit of liquid fuel aerosol Combust. Theory Model. (IF 1.3) Pub Date : 2023-10-20 Yongsheng Jia, Yingkang Yao, Qi Zhang
Unlike the explosion limit of liquid fuel vapour, the explosion limit of aerosol is a function of the aerosol state. In this study, a prediction model of the lower explosion limit (LEL) of liquid f...
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Grid resolution requirement of chemical explosive mode analysis for large eddy simulations of premixed turbulent combustion Combust. Theory Model. (IF 1.3) Pub Date : 2023-10-17 Haochen Liu, Chao Xu, Zifei Yin, Hong Liu
The grid resolution requirement for trustworthy Chemical Explosive Mode Analysis (CEMA) in Large Eddy Simulation (LES) of premixed turbulent combustion is proposed. Explicit filtering, to emulate t...
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A laminar smoke point-based soot model considering surface growth and soot reactions Combust. Theory Model. (IF 1.3) Pub Date : 2023-10-09 Shahrooz Motaghian, Tarek Beji
This paper proposes a Laminar Smoke Point (LSP)-based soot model, incorporating (as opposed to previously developed LSP-based models) soot surface growth. The latter is indeed believed to be domina...
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Numerical study on three-stage ignition of dimethyl ether by hot air under engine-relevant conditions Combust. Theory Model. (IF 1.3) Pub Date : 2023-09-25 Xinyi Chen, Zisen Li, Yiqing Wang, Wang Han, Arne Scholtissek, Peng Dai, Christian Hasse, Zheng Chen
Non-premixed combustion often occurs in practical engines, and it is affected by the coupling effects of chemical kinetics and transport. This study aims to elucidate the individual effect of chemi...
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Numerical simulation of turbulent premixed flames with the conditional source-term estimation model using Bernstein polynomial expansion Combust. Theory Model. (IF 1.3) Pub Date : 2023-09-25 Mojtaba Latifi, Mohammad Mahdi Salehi
Conditional Source-term Estimation (CSE) is a turbulence-chemistry interaction model similar to CMC, except that the conditional scalars are calculated from unconditional ones using an integral equ...
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LES of premixed jet flames subjected to extreme turbulence using flamelet-generated manifolds: a comparison of unstrained and strained flamelets Combust. Theory Model. (IF 1.3) Pub Date : 2023-08-23 Weijie Zhang, Deli Li, Guangya Hu, Jinhua Wang
Two piloted premixed CH 4/air jet flames with extreme turbulence are modelled using the Flamelet-Generated Manifold (FGM) method in the context of Large Eddy Simulation (LES). Free-propagating and ...
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Effect of ethanol enrichment and engine parameters on the performance of an HCCI engine fuelled with biodiesel/ethanol mixtures Combust. Theory Model. (IF 1.3) Pub Date : 2023-08-21 Massouda Mosbah, Zina Boutera, Yacine Rezgui, Miloud Guemini, Ammar Tighezza
Based on models resulting from the merging of validated kinetic schemes, four reaction mechanisms were developed to describe the combustion of biodiesel-surrogate/ethanol blends in an HCCI engine. ...
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Determining the global activation energy of methane–air premixed flames Combust. Theory Model. (IF 1.3) Pub Date : 2023-08-10 Anastasia D. Moroshkina, Alina A. Ponomareva, Vladimir V. Mislavskii, Evgeniy V. Sereshchenko, Vladimir V. Gubernov, Viatcheslav V. Bykov, Sergey S. Minaev
In this work, the determination of the apparent activation energy of a global chemical reaction mechanism of the methane–air flames is revisited. The one-step formulation allows to derive the theor...
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Simulation of reaction initiation in powder compacting from the surface with composite formation in equivalent reaction cell Combust. Theory Model. (IF 1.3) Pub Date : 2023-08-02 Anna Georgievna Knyazeva, Natalia Valerievna Bukrina
In the present work, we propose a new variant of the model of the composite synthesis under surface heating. We believe that the formation of the composition occurs at the level of reaction cell. T...
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Updated asymptotic structure of cool diffusion flames Combust. Theory Model. (IF 1.3) Pub Date : 2023-07-07 Forman A. Williams, Vedha Nayagam
The influence of adding a seventh important elementary step to a six-step mechanism, previously employed for describing the asymptotic structure of normal-alkane droplet combustion supported by coo...
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Flamelet/transported PDF simulations of ethylene/air jet turbulent non-premixed flame using a three-equation PAH-based soot production model Combust. Theory Model. (IF 1.3) Pub Date : 2023-06-20 Fatiha Nmira, Antoine Bouffard, Jean-Louis Consalvi
This article reports flamelet/transported PDF (TPDF) simulations of the well-documented ethylene/air turbulent non-premixed jet flame investigated experimentally at Sandia. The transported PDF equation is solved with the Stochastic Eulerian Field method. The soot production is modelled by a validated three equation PAH-based soot model that predicts the mean soot aggregate properties at low computational
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Coflow filtration combustion waves Combust. Theory Model. (IF 1.3) Pub Date : 2023-06-20 Alvin Bayliss, Evgeny Shafirovich, Vladimir A. Volpert
Recently, it has been proposed to develop space power systems based on filtration combustion of metal powders with oxygen supplied by a chemical oxygen generator. The experiments with lithium and m...
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High-order methods for the simulation of unsteady counterflow flames subject to stochastic forcing of large amplitude Combust. Theory Model. (IF 1.3) Pub Date : 2023-06-14 Fabrizio Bisetti
Unsteady counterflows are employed to understand and model the effect of turbulence on flames. We present a novel numerical approach for the simulation of one-dimensional unsteady counterflow flames with fourth order spatial discretization and up to fourth order time discretization. The approach couples a three-stage Lobatto IIIa formula for boundary value problems and variable-order, variable time
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Structure and similarity properties of the laminar counterflow spray flame Combust. Theory Model. (IF 1.3) Pub Date : 2023-05-18 Qun Hu, Lipo Wang
The spray flame in a laminar counterflow is influenced by various setup conditions, for instance the strain rate and liquid droplet parameters, including the initial temperature, size distribution, hydrodynamics and the vaporisation history. With some reasonable simplification, the two phase governing equations can be reformulated as equations in the single gas phase with reconstructed spray-related
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Conditional space evaluation of progress variable definitions for Cambridge/Sandia swirl flames Combust. Theory Model. (IF 1.3) Pub Date : 2023-05-12 Nikola Sekularac, XiaoHang Fang, W. Kendal Bushe, Martin H. Davy
Data from all spatial locations of nine turbulent flames in the Cambridge/Sandia swirl database are combined to study how the choice of scalar variables in conditional moment closure (CMC) type approaches affect the conditional spatial fluctuations of reactive scalars. In order to investigate the influence of swirl and stratification, two additional data-sets have been constructed. Principal component
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Quenching modes of local flame–wall interaction for turbulent premixed methane combustion in a constant volume vessel Combust. Theory Model. (IF 1.3) Pub Date : 2023-05-11 Ye Wang, Yuki Minamoto, Masayasu Shimura, Mamoru Tanahashi
The quenching mode of local flame–wall interaction (FWI) is investigated for its response to different levels of turbulence intensity as well as its effect on quenching distance, wall heat flux, and near-wall reaction. For that, direct numerical simulations of turbulent premixed methane combustion in a constant volume vessel are carried with initial Karlovitz numbers (Ka) of 1.0, 10.0, and 30.0. Local
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Hydrodynamic instability of premixed tubular flame stabilized in stretched rotating flow Combust. Theory Model. (IF 1.3) Pub Date : 2023-05-02 Sergey Minaev, Evgeniy Dats, Konstantin Shtym
The paper analyzes the hydrodynamic instability of a cylindrical flame stabilized in a converging rotating gas flow simulating the flow in a cyclone combustion chamber. The analysis was carried out within the framework of a two-dimensional model describing the gas flow with radial and tangential supply of combustible gas through the walls of a cylindrical chamber. In the stationary case, the gas flow
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How random fluctuations can generate and suppress complex oscillatory regimes in continuous stirred tank reactors Combust. Theory Model. (IF 1.3) Pub Date : 2023-04-27 Irina Bashkirtseva, Lev Ryashko
Motivated by important chemical engineering applications, we study probabilistic mechanisms of stochastic effects in a randomly forced model of the continuous stirred tank reactor. The bifurcation analysis of the deterministic model reveals the parameter zone of bistability with coexistence of the equilibrium and oscillatory regimes. It is shown that the boundary between basins of these regimes is
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Sliding mode control for longitudinal oscillating combustion Combust. Theory Model. (IF 1.3) Pub Date : 2023-04-05 Long Zhang, Xingyu Su, Hua Zhou, Zhuyin Ren
Considerable research has been reported on developing effective active control means to suppress oscillating combustion. The typical pressure oscillation can be divided into linear growth, transition and saturation stages. In this study, a sliding mode control strategy, consisting of a state estimate model, disturbance observers and a sliding mode controller, is proposed to suppress the longitudinal
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Effects of artificial flame front thickening on intermediate minor species prediction using the LES–FGM method Combust. Theory Model. (IF 1.3) Pub Date : 2023-04-05 Weijie Zhang, Quan Zhou, Jinhua Wang, Zuohua Huang
Two stratified premixed Cambridge/Sandia flames SwB1 and SwB9 are modelled using the Flamelet-Generated Manifold in the context of Large-eddy Simulation. Two kinds of sub-grid closure models are adopted and systematically compared, that is, the Dynamically Thickened Flame (DTF) and the Presumed Probable Density Function (PPDF) models, in order to study the effects of artificial flame front thickening
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On the numerical approach to the prediction of flame spread over non-planar surface of solid combustibles Combust. Theory Model. (IF 1.3) Pub Date : 2023-04-05 Artem A. Shaklein, Alexander I. Karpov
The flame spread over a non-planar surface of solid fuel has been studied numerically by the coupled model of heat transfer using the proposed approach for the evaluation of burning surface regression. The boundary conditions for the surface regression rate are formulated by the combination of flame spread modes over the vertical and horizontal surfaces resulted from the staircase shape of the burning
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A theoretical study on the relationship between pressure rise and the Damköhler number of end-gas auto-ignition in spark-ignited engines Combust. Theory Model. (IF 1.3) Pub Date : 2023-03-16 Shinji Hayashi, Yasuyuki Sakai, Kotaro Tanaka
The pressure rise caused by end-gas auto-ignition in spark-ignited engines is discussed using numerical simulation and theoretical approaches. The main objective of this study is to explain the mechanism by which the end-gas expansion during auto-ignition suppresses the pressure rise in spark-ignited engines, and theoretically to demonstrate using asymptotic analysis that the pressure rise depends
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Effect of hydrogen addition on the consumption speed of lean premixed laminar methane flames exposed to combined strain and heat loss Combust. Theory Model. (IF 1.3) Pub Date : 2023-02-28 Alex M. Garcia, Sophie Le Bras, Wolfgang Polifke
This study presents a numerical analysis of the impact of hydrogen addition on the consumption speed of premixed lean methane-air laminar flames exposed to combined strain and heat loss. Equivalence ratios of 0.9, 0.7, and 0.5 with fuel mixture composition ranging from pure methane to pure hydrogen are considered to cover a wide range of conditions in the lean region. The 1-D asymmetric counter-flow
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Modelling of acetaldehyde and acetic acid combustion Combust. Theory Model. (IF 1.3) Pub Date : 2023-02-22 Fekadu Mosisa Wako, Gianmaria Pio, Ernesto Salzano
Despite the beneficial impact of biofuels on most regulated pollutants and carbon dioxide emissions, their combustion results in the generation of undesired pollutants, such as acetaldehyde and acetic acid. To better understand the chemistry of these species, detailed chemical kinetic models deriving from two alternative strategies for mechanism generation were developed and validated against available
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Efficient two-dimension particle element method of interior ballistic two-phase flow Combust. Theory Model. (IF 1.3) Pub Date : 2023-02-22 Cheng Shenshen, Tao Ruyi, Lu Xinggan, Xue Shao, Jiang Kun
Reducing the calculation cost is of great importance as the demand for interior ballistic calculation is increasing. The key factor of interior ballistic simulation is the quest to develop a more efficient method. In this paper, an efficient two-dimension particle element method (PEM) is proposed to simulate the detailed multidimensional flow of the gas and propellant particle in the chamber. Firstly
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A thick reaction zone model for premixed flames in two-dimensional channels Combust. Theory Model. (IF 1.3) Pub Date : 2023-02-10 Prabakaran Rajamanickam, Joel Daou
Direct interactions between the flow field and the chemical reaction in premixed flames occur when the reaction zone thickness is comparable to, or greater than flow length scales. To study such interactions, a laminar model is considered that has direct bearings to steadily propagating deflagrations in a Hele-Shaw channel with a background plane Poiseuille flow. The study employs asymptotic analyses
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Analysis of an innovative sampling strategy based on k-means clustering algorithm for POD and POD-DEIM reduced order models of a 2-D reaction-diffusion system Combust. Theory Model. (IF 1.3) Pub Date : 2023-02-08 Enrico Alberto Cutillo, Gianmarco Petito, Katarzyna Bizon, Gaetano Continillo
In this work, a model-order reduction methodology based on proper orthogonal decomposition (POD) and Galërkin projection is presented and applied to the simulation of the self-ignition of a stockpile of solid fuel. Self-ignition is a phenomenon associated with steep changes in space and time, yielding high gradients of state variables which demand grid refinement and, thus, increase of the computational
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Simulation and performance improvement of an industrial steam methane reformer: depreciation and ceramic coating effects Combust. Theory Model. (IF 1.3) Pub Date : 2023-02-02 Saeedeh Hamoudi, Azadeh Mirvakili, Ahmad Jamekhorshid, Mohamad Gholipour
In this work, Computational Fluid Dynamic (CFD) is applied to compare the performance of an industrial reformer furnace in four cases. The first and tenth years of operation are two cases with different emissivity factors and fuel components. The results are validated with industrial data and with other CFD simulation typical plants reported in the SMR literature. The results show that a 10% increase
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Comprehensive influence of uncertainty propagation of chemical kinetic parameters on laminar flame speed prediction: a case study of dimethyl ether Combust. Theory Model. (IF 1.3) Pub Date : 2023-02-01 Yachao Chang, Pengzhi Wang, Shuai Huang, Xu Han, Ming Jia
The uncertainties existing in the parameters of chemical kinetic models have a non-negligible influence on the model predictions. It is necessary to conduct a quantitative uncertainty analysis to explore the influence of each parameter on chemical mechanism predictions. To comprehensively consider the effect of the uncertainties of reaction rate parameters, thermodynamic parameters, and transport parameters
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Dynamics of hydrodynamically unstable premixed flames in a gravitational field – local and global bifurcation structures Combust. Theory Model. (IF 1.3) Pub Date : 2023-01-30 Kaname Matsue, Moshe Matalon
The dynamics of hydrodynamically unstable premixed flames are studied using the nonlinear Michelson–Sivashinsky (MS) equation, modified appropriately to incorporate effects due to gravity. The problem depends on two parameters: the Markstein number that characterises the combustible mixture and its diffusion properties, and the gravitational parameter that represents the ratio of buoyancy to inertial
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Reduced kinetic mechanism for methane/oxygen rocket engine applications: a reliable and numerically efficient methodology Combust. Theory Model. (IF 1.3) Pub Date : 2023-01-30 Guido Saccone, Paola Breda, Pasquale Natale, Francesco Battista
CFD simulations of turbulent reacting flows based on finite rate chemistry often employ reduced kinetic mechanisms to decrease the computational cost, especially if the combustion of hydrocarbons is involved. This work presents a chemical-kinetic methodology, consisting of the formulation, development, testing and validation of a reduced, skeletal mechanism targeted to the Liquid Rocket Engines (LRE)
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Experimental and numerical study of flame acceleration and DDT in a channel with continuous obstacles Combust. Theory Model. (IF 1.3) Pub Date : 2023-01-31 Huahua Xiao, Xiaoxi Li
Flame acceleration and deflagration-to-detonation transition (DDT) in obstructed channels is an important subject of research for propulsion and explosion safety. Experiment and numerical simulation of DDT in a stoichiometric hydrogen–oxygen mixture in a channel equipped with continuous triangular obstacles were conducted in this work. In the experiment, high-speed schlieren photography was used to
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Flame front reconstruction and volume estimation through computational geometry: a case study on machine vision applied to combustion systems Combust. Theory Model. (IF 1.3) Pub Date : 2023-01-18 Jorge E. De León-Ruiz, Ignacio Carvajal-Mariscal, Mauricio De La Cruz-Ávila, Ricardo Beltrán-Chacón
A computationally-supported experimental procedure to estimate the primary dimensions of diffusion flames, using volume reconstruction from thermal imagery, is presented. The experimental setup uses a 4 × 16.94 mm radial distribution gas-burner, with a 0.8 mm nozzle diameter, a thermal imaging camera and a proprietary image processing algorithm. Flame thermal imagery was captured, using four different
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A dynamic load balancing model coupled with DAC and ISAT for a stochastic turbulent combustion model Combust. Theory Model. (IF 1.3) Pub Date : 2023-01-17 Zhijie Huo, Matthew J. Cleary, Kun Wu, Assaad R. Masri, Xuejun Fan
Due to the composition-dependent stiffness of chemistry, simulations of reactive turbulent flows may present computational load imbalance among parallel processes when spatial decomposition is used for parallelisation, causing high CPU idle time and waste of computational resources. To increase computational efficiency, a dynamic load balancing (DLB) model is proposed to redistribute computational
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Synchronisation behaviour between two candle flame oscillators with similar and dissimilar amplitudes of oscillations Combust. Theory Model. (IF 1.3) Pub Date : 2023-01-17 Arijit Bhattacharya, Sirshendu Mondal, Somnath De, Achintya Mukhopadhyay, Swarnendu Sen
Interactions between a couple of flames often lead to their synchronisation. Flame–flame interaction has recently been linked with thermoacoustic instability in combustors. However, synchronisation caused by the interaction of coupled flames is still not fully understood. Furthermore, the interacting flame oscillators in practical situations often have a slight dissimilarity between them. Here, we
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Response of one-dimensional ionised layer to oscillatory electric fields Combust. Theory Model. (IF 1.3) Pub Date : 2023-01-17 Narjisse Kabbaj, Hong G. Im
To provide fundamental insights into the response of laminar flames to alternating current (AC) electric fields, a simplified one-dimensional model using an ionised layer model is formulated with the conservation equations for the ion species with ionisation, recombination, and transport due to molecular diffusion and electric mobility. A parametric study is conducted to investigate the response of
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Impact of a discretisation method and chemical kinetics on the accuracy of simulation of a lifted hydrogen flame Combust. Theory Model. (IF 1.3) Pub Date : 2023-01-12 Artur Tyliszczak, Agnieszka Wawrzak, Karol Wawrzak
This paper presents an analysis of numerical and modelling issues based on a simulation of nitrogen-diluted hydrogen lifted flame evolving in a hot co-flow. We apply the large-eddy simulations (LES) method with the so-called ‘no combustion model’ and concentrate on the impact of chemical mechanisms and various discretisation schemes on the obtained results. The main attention is put to the latter issue
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Effect of slit pattern on the structure of premixed flames issuing from perforated burners in domestic condensing boilers Combust. Theory Model. (IF 1.3) Pub Date : 2022-12-28 Rachele Lamioni, Cristiana Bronzoni, Marco Folli, Leonardo Tognotti, Chiara Galletti
Domestic condensing boilers are equipped with perforated burners ensuring short-length premixed flames issues from a series of circular holes and slits. Despite some efforts that have been devoted to understanding the effect of hole diameter, pattern, and hole-to-hole distance on the resulting flames, very little is known about the flames from a series of slits. In this work 3-dimensional numerical
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Insights into and the evolution of a novel predictive model for free burning wooden cribs Combust. Theory Model. (IF 1.3) Pub Date : 2022-12-22 Hanasoge Suryanarayana Avadhany Mukunda, Annaiappa Shiva Kumar, Sachin Payannad, Chitradurga Subrahmanya Bhaskar Dixit
The extensive work on wood crib fires, both experimental and model development over the last six decades is examined in some detail. The wide range of parameters of crib tests and the theories have been reviewed in the literature and a satisfactory correlation has still to emerge from these studies. From early times, the burn flux (g/m 2s) has been considered the most appropriate parameter to characterise
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Distributed transfer function approach for one-dimensional thermoacoustic combustor models Combust. Theory Model. (IF 1.3) Pub Date : 2022-12-14 Myunggon Yoon
This paper proposes a new approach for one-dimensional thermoacoustic combustor models. Our new model is a transfer function estimated from the frequency response of the linearised Euler equation to a spatially normalised and temporally impulsive input. The proposed approach can deal with combustors with varying cross-sectional areas under a non-zero mean flow, distributed heating/cooling, and outlet
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An improved stiff-ODE solving framework for reacting flow simulations with detailed chemistry in OpenFOAM Combust. Theory Model. (IF 1.3) Pub Date : 2022-12-12 Kun Wu, Yuting Jiang, Zhijie Huo, Di Cheng, Xuejun Fan
The integration of stiff ordinary differential equation (ODE) systems associated with detailed chemical kinetics is computationally demanding in practical combustion simulations. Despite the various approaches in expediting the computational efficiency, it is still necessary to optimise the cell-wise calculation in operator-splitting type simulations of reactive flow. In this work, we proposed an improved
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Experimental study and thermodynamic analysis of coal spontaneous combustion characteristics Combust. Theory Model. (IF 1.3) Pub Date : 2022-12-09 Minbo Zhang, Zichao Wang, LongKang Wang, Zhen Zhang, Dangyu Zhang, Chunxin Li
Spontaneous coal combustion is one of the most common disasters in coal mine production. In order to explore the mechanism of coal spontaneous combustion more deeply, coal samples from the Yangdong wellfield of Jizhong Energy were selected for oxidative heat energy analysis experiments. A temperature-programmed experiment was selected to study the changes in characteristic parameters during the low-temperature
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Comparison of combustion duration and end-gas autoignition in inwardly and outwardly propagating flames induced by different ignition configurations Combust. Theory Model. (IF 1.3) Pub Date : 2022-12-09 Linlin Yang, Yiqing Wang, Zheng Chen
Recently, multiple spark ignition has received great attention since it helps to increase thermal efficiency and to reduce misfire in engines. Multiple spark ignition also affects the combustion duration and thereby it can be used for knock control. However, previous studies reported opposite trends in terms of how multiple spark ignition affects engine knock. This work aims to assess and interpret
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Application of machine learning in low-order manifold representation of chemistry in turbulent flames Combust. Theory Model. (IF 1.3) Pub Date : 2022-12-08 Arash Mousemi, Mehdi Jadidi, Seth B. Dworkin, W. Kendal Bushe
The Uniform Conditional State (UCS) and the Multidimensional Flamelet Manifold (MFM) models are methods for the tabulation of chemistry in simulations of turbulent flames. The high-dimensionality of the tables these models generate and many possible combinations of the values for the input variables necessitate the allocation of a considerable size of memory during CFD calculations. This issue becomes
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Optimisation method for automatic selection of rate constants of global reaction mechanisms Combust. Theory Model. (IF 1.3) Pub Date : 2022-12-08 Aleksander D. Zakharov, Roman V. Fursenko, Sergey S. Minaev
Optimisation approach to automate selection of global reaction mechanisms rate constants is proposed and studied. The objective of optimisation is to find reaction rate constants minimising deviation of some flame characteristics (e.g. laminar burning velocity, ignition delay time, etc.) calculated by global mechanism from their reference values known from experiments or computed by detailed mechanisms
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PeleLM-FDF large eddy simulator of turbulent reacting flows Combust. Theory Model. (IF 1.3) Pub Date : 2022-11-14 Aidyn Aitzhan, Shervin Sammak, Peyman Givi, Arash G. Nouri
A new computational methodology, termed ‘PeleLM-FDF’ is developed and utilised for high fidelity large eddy simulation (LES) of complex turbulent combustion systems. This methodology is constructed via a hybrid scheme combining the Eulerian PeleLM base flow solver with the Lagrangian Monte Carlo simulator of the filtered density function (FDF) for the subgrid scale reactive scalars. The resulting methodology
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Flame speed in diffusion dominated premixed flames Combust. Theory Model. (IF 1.3) Pub Date : 2022-11-12 Faizan Habib Vance, Jeroen A. van Oijen, L.P.H. de Goey
Development of a premixed flame theory that includes the effects of flame stretch and curvature has been at the forefront of combustion research. Diffusion dominated flames such as highly curved flame balls present a challenging flame structure that has not been included in current flame stretch theory so far. In such flames, the relationship between consumption speed and negative displacement speed