A Model for the Effects of Mixing on the Autoignition of Turbulent Flows
作者:
E. MASTORAKOS,
A. PIRESDA CRUZ,
T. A. BARITAUD,
T.J. POINSOT,
期刊:
Combustion Science and Technology
(Taylor Available online 1997)
卷期:
Volume 125,
issue 1-6
页码: 243-282
ISSN:0010-2202
年代: 1997
DOI:10.1080/00102209708935661
出版商: Taylor & Francis Group
关键词: Autoignition;direct numerical simulation;conditional moments;modelling
数据来源: Taylor
摘要:
Modelled transport equations for the conditional mean and r.m.s. temperature increments θ before autoignition in a turbulent non-premixed flow have been developed. The model is based on the recent finding that a well-defined mixture fraction, fMR, first ignites and the concept that the conditional scalar dissipation rate, χ|fMR, controls the heat losses and hence the ignition time. By introducing the fluctuations of χ|fMR, and by modelling the conditional correlation coefficients between χ and θ from results from Direct Numerical Simulations, the model is closed and calculates autoignition times in good agreement with DNS results. Extensions to complex chemistry and the relationship with the more rigorous Conditional Moment Closure are discussed. Finally, the model is incorporated in a Favre-averaged k – ϵcode(KIVA-II)to predict autoignition of a transient fuel jet in hot air with promising results.
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