湍流模型及施密特数对点火位置的影响研究

Research on Turbulence Model and Schmidt Number Influencing Ignition Position

准确预测燃料和空气湍流混合水平对精确模拟发动机性能至关重要。通过对Burrows&Kurkov氢气顺喷经典算例的数值模拟,研究了湍流模型和湍流关键参数(施密特数)对氢气和空气的混合程度以及点火位置的影响。数值结果表明:湍流模型对点火的位置具有一定的影响,其中Menter SST k-w湍流模型计算结果与实验值总体吻合最好;湍流施密特数严重影响着氢气和空气的混合程度以及燃烧流场的点火位置,其中Sct=0.5能满足大部分超燃冲压发动机燃烧算例的数值模拟。

Accurately predicating the fuel and air turbulence mixing level is crucially important to exact simulation of engine performance. Combined with numerical simulation of Burrows Kurkov hydrogen parallel injection case,this paper studied that turbulence model and the key turbulence parameter（ schmidt number） influenced ignition position and the mixing level of hydrogen and air. Numerical results showed that turbulence model had a certain impact on the ignition position and the result of Menter SST k- w model was best accord with experimental value. Moreover,in the combustion flow field,turbulence schmidt number seriously affected ignition position and the mixing level of hydrogen and air,which Sct = 0. 5 seemed to work well for many applications involving scramjet engines.