A hybrid LES (Large Eddy Simulation)/assumed sub-grid PDF (Probability Density Function) model for supersonic turbulent combustion  

作　　者：WANG HongBo QIN Ning SUN MingBo WU HaiYan WANG ZhenGuo 

机构地区：[1]College of Aerospace and Material Engineering, National University of Defense Technology, Changsha 410073, China [2]Department of Mechanical Engineering, University of Sheffield, Sheffield,S1 3JD, UK

出　　处：《Science China(Technological Sciences)》2011年第10期2694-2707,共14页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 50906098 and 91016028)

摘　　要：A hybrid LES (Large Eddy Simulation)/assumed sub-grid PDF (Probability Density Function) closure model has been devel-oped for supersonic turbulent combustion. Scalar transport equations for all species in a given chemical kinetic mechanism were solved, which are necessary in the supersonic combustion where the non-equilibrium chemistry is essentially involved. The clipped Gaussian PDF of temperature and multivariate ? PDF of composition were used to close the sub-grid chemical sources that appear in the conservation equations. The sub-grid variances of temperature and composition were constructed based on scale similarity approach. A semi-implicit approach based on the PDF model was proposed to tackle the resulting numerical stiffness associated with finite rate chemistry. The model was applied to simulate a supersonic, coaxial H2-air burner, where both the mean and rms (root mean square) results were compared with the experimental data. In general, good agree-ments were achieved, which indicated that the present sub-grid PDF method could work well in simulating supersonic turbu-lent combustion. Moreover, the calculation showed that the sub-grid fluctuations of temperature and major species in the combustion region were of the order of 10%-20% of their rms, while the sub-grid fluctuation of hydroxyl might be as high as 40%-50% of its rms.

关 键 词：LES（Large Eddy Simulation） assumed PDF（Probability Density Function） SUPERSONIC turbulent combustion 

分 类 号：O211[理学—概率论与数理统计] TK121[理学—数学]