将近年发展的详细反应机理简化方法:反应-扩散流形(REDIM)方法与假定滤波密度函数相结合,构造了新的亚网格燃烧模型.由于REDIM方法既能描述快速反应状态又能描述扩散过程起主导作用的慢速反应状态,因此新构造的燃烧模型理论上可用于计算扩散和化学反应均起重要作用的湍流部分预混燃烧及分层燃烧模式.为了验证其性能,利用新模型对基准的Darmstadt湍流分层火焰燃烧器进行了大涡模拟(LES)计算:首先分别采用粗、细两种网格对无反应湍流状态进行了计算,以检验网格精度;随后对一个有分层效应的湍流燃烧状态进行了计算.LES计算得到的速度、温度、组分等统计信息与实验结果吻合良好,验证了新亚网格燃烧模型在预测湍流分层火焰方面的能力.%A recently developed method for reducing reaction mechanism, the reaction-diffusion manifolds (REDIM) method, is combined with the presumed filtered density function (PFDF) to construct a new sub-grid scale (SGS) combustion model for large eddy simulation (LES) of turbulent combustion. Unlike its predecessor intrinsic low-dimensional manifolds method, the REDIM method takes into account the coupling of reaction and molecular transport processes explicitly, so it is capable of describing fast reaction regions as well as regions where chemical kinetics are slow and diffusion governs the overall process. Because of this advantage of REDIM, the new SGS combustion model is theoretically capable of simulating turbulent partially premixed flames and stratified flames, in which reaction and diffusion processes are both important. For validating its performance, the new model is employed to simulate the benchmark Darmstadt turbulent stratified flame (TSF). First, a grid resolution study is conducted by computing isothermal flow field with two grids. Then the finer grid is used to simulate a turbulent flame with stratified effect. The overall good agreement of the statistics of velocity, temperature and species with the experimental data demonstrates the capability of the LES method and the REDIM-PFDF model for dealing with TSF. More simulations for other Darmstadt TSF cases are still ongoing, to obtain a deeper insight of the complex chemistry-physical process in the TSF combustion.
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