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An assessment of large eddy simulations of premixed flames propagating past repeated obstacles

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posted on 20.11.2009 by Sreenivasa Rao Gubba, Salah Ibrahim, Weeratunge Malalasekera, Assaad R. Masri
This paper presents an assessment of Large Eddy Simulations in calculating the structure of turbulent premixed flames propagating past solid obstacles. One objective of the present study is to evaluate the LES simulations and identify the drawbacks in accounting the chemical reaction rate. Another objective is to analyse the flame structure and to calculate flame speed, generated overpressure at different time intervals following ignition of a stoichiometric propane/air mixture. The combustion chamber has built-in repeated solid obstructions to enhance the turbulence level and hence increase the flame propagating speed. Various numerical tests have also been carried out to determine the regimes of combustion at different stages of the flame propagation. These have been identified from the calculated results for the flow and flame characteristic parameters. It is found that the flame lies within the ‘thin reaction zone’ regime which supports the use of the laminar flamelet approach for modelling turbulent premixed flames. A sub-model to calculate the model coefficient in the algebraic flame surface density model is implemented and examined. It is found that the LES predictions are slightly improved due to the calculation of model coefficient by using sub-model. Results are presented and discussed in this paper are for the flame structure, position, speed, generated pressure and the regimes of combustion during all stages of flame propagation from ignition to venting. The calculated results are validated against available experimental data.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Citation

GUBBA, S.R... et al, 2009. An assessment of large eddy simulations of premixed flames propagating past repeated obstacles. Combustion Theory and Modelling, 13(3), pp.513-540.

Publisher

© Taylor & Francis

Version

AM (Accepted Manuscript)

Publication date

2009

Notes

This article was published in the journal, Combustion Theory and Modelling [© Taylor & Francis]. The definitive version is available from: http://dx.doi.org/10.1080/13647830902928532

ISSN

1741-3559;1364-7830

Language

en

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