用DHR型k-ε紊流模型对锥形渐扩管内紊流的数值仿真——壁面函数·BFC法之时间步长、加速系数和数值方法的影响

Numerical Simulation for Turbulence in a Conical Diffuser by DHR k-ε Turbulence Model:Effects of Time Step,Relaxation Coefficient and of Wall Function·BFC Method Numerical Method

用DHR型k-ε紊流模型及其壁面函数·BFC(边界拟合曲线坐标变换)法,对总扩散角为80、扩散度为4的锥形渐扩管内充分发展的不可压粘性紊流场进行了数值仿真.所研究紊流的入口雷诺数为1.16×105和2.93×105.在不同的时间步长、加速系数和数值方法等计算条件下进行了数值仿真.分别给出了时均流速和紊流动能分布的计算结果,并分别将其与实验结果进行比较和分析,得知不同计算条件对计算结果的影响程度,计算结果与实验结果较好符合.

Fully developed incompressible turbulent flow in a conical diffuser having a total divergence of 8° and an area ratio of 4 has been simulated by DHR k -ε turbulence model and its Wall Function · BFC （Boundary Fit Coordinates）approach. The research has been done for entry Reynolds numbers of 1.16 ×10^5 and 2.93 × 10^5 . The calculated results of the distribution of the mean flow velocity and turbulence energy have been given under the different calculated conditions, such as time step, relaxation coefficient and numerical methods. They were analysed and compared with the experimental results respectively, we got the effects of calculated results under the different calculated conditions, The caculated results agree well with the experimental results.