A computational study of spherical diffusion flames in microgravity with gas radiation. Part II: Parametric studies of the diluent effects on flame extinction

Tang, Szu-Yu; Im, Hong G.

doi:10.1016/j.combustflame.2009.09.011

Cited by 21 publications

(6 citation statements)

References 10 publications

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“…Such gases may be essential, for example, for extinguishing fires in confined environments such as spacecraft. The extinguishing mechanisms of these diluents have been studied experimentally and computationally for various flame configurations at terrestrial or microgravity conditions [1][2][3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Extinction of premixed methane/air flames in microgravity by diluents: Effects of radiation and Lewis number

Qiao

Gan

Nishiie

et al. 2010

Combustion and Flame

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Section: Introductionmentioning

confidence: 99%

Extinction of premixed methane/air flames in microgravity by diluents: Effects of radiation and Lewis number

Qiao

Gan

Nishiie

et al. 2010

Combustion and Flame

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“…At the ambient side, mass fractions of the ambient species (including He and O 2 for the NDFs, or DME and Ar for the IDFs) were constrained; while that of the other species were relaxed with zero gradient, as eq () shows. The applicability and accuracy of the present models in the simulations of spherical diffusion flame were extensively verified in the literature. − …”

Section: Details Of the Numerical Simulationmentioning

confidence: 59%

“…The applicability and accuracy of the present models in the simulations of spherical diffusion flame were extensively verified in the literature. 29 − 34 …”

Section: Details Of the Numerical Simulationmentioning

confidence: 99%

Comparative Study on the Dimethyl Ether Combustion Characteristics in Normal and Inverse Diffusion Spherical Flame Geometries

et al. 2020

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This paper makes a comparative study on the normal diffusion flame (NDF) and inverse diffusion flame (IDF) characteristics of dimethyl ether (DME) in microgravitational spherical diffusion flame geometry by simulations with detailed fuel chemistry and a transport model. It is found that there always existed two combustion modes (i.e., hot flame and cool flame) in either NDF or IDF condition. The combustion progress of hot flames was controlled by diffusive mixing, while that of cool flames was controlled by low-temperature competing kinetics. The cool-flame structure dynamics were far away from the chemical equilibrium. The low-temperature branching rate of DME was positively dependent on the oxygen level, while its termination rate was enhanced with the increasing temperature. Being rather distinct from the NDF counterpart, DME IDFs had the oxygen-enriched combustion feature in either hot- or cool-flame condition. Furthermore, DME hot-flame extinction was induced by thermal radiative loss, while the cool-flame extinction was induced especially by the decrease of the low-temperature branching rate. Compared with hot NDFs, it would be of less effectiveness to control the hot IDF combustion process by positive measures. However, combustion in the latter configuration was much more stable than the former. In either NDF or IDF geometry, the cool-flame chemistry could help to extend the fuel flammability range considerably, and the two-reaction-zone structure of cool flame was responsible for cool-flame stability. In addition, the IDFs had much better ignition performance than the NDF counterpart.

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“…Mills and Matalon [202] and Wang and Chao [203] have identified the kinetic and radiative extinction limits of steady diffusion flames. Propagation and radiative extinction of transient flames were also studied experimentally and numerically by Tse et al [204], Santa et al [205], [206] and Tang et al [208], [209], where they observed that the extinction behaviour is different from steady flames.…”

Section: Radiation-induced Extinction Of Diffusion Flamesmentioning

confidence: 98%

The impact of radiative heat transfer in combustion processes and its modeling – with a focus on turbulent flames

Liu

Consalvi

Coelho

et al. 2020

Fuel

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Radiative heat transfer (RHT) is often the dominant mode of heat transfer in flames, fires, and combustion systems and affects significantly temperature distributions directly and kinetically controlled chemical processes indirectly. Modeling RHT accurately in multidimensional flames and combustion systems is challenging mainly due to the highly spectral dependence of radiative properties of combustion products, the high computational cost of solving the radiative transfer equation (RTE), and the strong turbulence and radiation interactions (TRI). Significant progress has been made in all the three aspects in the last three decades and the state-of-the-art models and methods have been incorporated into CFD practice for modeling fires, turbulent jet flames, and turbulent combustion in combustion systems. In this article, we first discuss the coupling between RHT and combustion and the important role played by RHT in some fundamental flame phenomena. Then we discuss the state-of-the-art radiation models with a focus on RTE solvers, radiative property models and TRI. Next, we review the recent simulations of turbulent combustion systems involving these state-of-the-art radiation models. Finally, we provide concluding remarks and some potential research areas to advance RHT modeling in multiphase reacting flows. Nomenclature, , area normal to directions x, y and z [m 2 ] non-grey stretching factor for WSGG, SLW, and FSK methods absorption cross-section of a soot primary particle [m 2 ] absorption cross-section of a soot aggregate [m 2 ] diameter [m] , , integral over a control angle of the direction cosines relative to x, y and z-axis particle size parameter [-] radiant fraction [-] array of variables defining the absorption coefficient, = { , , , } Ω solid angle [sr] Subscript Fuel direction j spectral line S soot at a given wavenumber Superscript aggregate lth direction (DOM) or lth control angle (FVM) mth direction (DOM) or mth control angle (FVM) primary particle Operators 〈 〉 Reynolds averaged quantity ′ Reynolds fluctuating quantity ̅ filtered (or resolved) quantity ′′ subgrid-scale (or residual) fluctuation Recently, quasi-MC methods [43], [44] were employed to solve RHT problems in 3D participating media, aimed at the improvement of the convergence rate, and therefore the computational efficiency. In these methods, the random numbers are replaced by low-

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A computational study of spherical diffusion flames in microgravity with gas radiation. Part II: Parametric studies of the diluent effects on flame extinction

Cited by 21 publications

References 10 publications

Extinction of premixed methane/air flames in microgravity by diluents: Effects of radiation and Lewis number

Extinction of premixed methane/air flames in microgravity by diluents: Effects of radiation and Lewis number

Comparative Study on the Dimethyl Ether Combustion Characteristics in Normal and Inverse Diffusion Spherical Flame Geometries

The impact of radiative heat transfer in combustion processes and its modeling – with a focus on turbulent flames

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