A dual timescale model for micro-mixing and its application in LES-TPDF simulations of turbulent nonpremixed flames

作     者：Fang WANG Rui LIU Li DOU Denghuan LIU Jie JIN 

作者机构：Aero-Engine Numerical Simulation Research CenterSchool of Energy and Power EngineeringBeihang University Collaborative Innovation Center for Advanced Aero-Engine 

出 版 物：《Chinese Journal of Aeronautics》 (中国航空学报（英文版）)

年 卷 期：2019年第32卷第4期

页      面：875-887页

核心收录：

学科分类：082502[工学-航空宇航推进理论与工程] 08[工学] 0825[工学-航空宇航科学与技术] 

基　　金：co-supported by the National Key R&D Program of China(Nos.2017YFB0202400 and 2017YFB0202402) the National Natural Science Foundation of China(No.91741125) the Project of Newton International Fellowship Alumnus from Royal Society(No.AL120003) 

主　　题：Dual time scale model Large eddy simulation Sandia methane-air jet flame TPDF molecular mixing model Turbulence combustion model 

摘      要：The numerical simulation of modern aero-engine combustion chamber needs accurate description of the interaction between turbulence and chemical reaction mechanism. The Large Eddy Simulation(LES) method with the Transported Probability Density Function(TPDF) turbulence combustion model is promising in engineering applications. In flame region, the impact of chemical reaction should be considered in TPDF molecular mixing model. Based on pioneer research, three new TPDF turbulence-chemistry dual time scale molecular mixing models were proposed tentatively by adding the chemistry time scale in molecular mixing model for nonpremixed flame. The Aero-Engine Combustor Simulation Code(AECSC) which is based on LES-TPDF method was combined with the three new models. Then the Sandia laboratory s methane-air jet flames: Flame D and Flame E were simulated. Transient simulation results show that all the three new models can predict the instantaneous combustion flow pattern of the jet flames. Furthermore,the average scalar statistical results were compared with the experimental data. The simulation result of the new TPDF arithmetic mean modification model is the closest to the experimental data:the average error in Flame D is 7.6% and 6.6% in Flame E. The extinction and re-ignition phenomena of the jet flames especially Flame E were captured. The turbulence time scale and the chemistry time scale are in different order in the whole flow field. The dual time scale TPDF combustion model has ability to deal with both the turbulence effect and the chemistry reaction effect, as well as their interaction more accurately for nonpremixed flames.