内燃机气缸内湍流流动的数值模拟

NUMERICAL SIMULATION OF TURBULENT FLOWS IN CYLINDERS OF INTERNAL COMBUSTION ENGINES

本文基于快速压缩假设,对不可压流的标准κ-ε的双方程湍流模型进行了压缩性修正。8方程增添了两项,其系数C_3,C_4的取值根据压缩方式的空间维数确定。同时引入Richardcon来修正系数C_2,以考虑旋流影响。将此模型应用于内燃机气缸内压缩过程。计算结果表明,本模型能预测湍流参数,特别是湍流尺度的变化规律并与实验基本吻合。

A modified version of the k-δ turbulance model for strongly compressible swirling flows is deduced based on the assumption of rapid compression. The δ-equation involves two new terms, whose coefficients C_3 and C_4 depend on the dimension of the compresion types. the coefficient C_2 is modifiod by introducing the Richardson number to account the swirl effects. The modol is applied to the in-cylinder flow field of internal combustion engines. The results are in agreement with the experiments. It indicates the model may be used to correctly predict the evolution of the turbulence length scale.