非结构混合网格化学非平衡粘性绕流数值模拟

Numerical simulation of hypersonic viscous flow with chemical non-equilibrium effects on hybrid grid

在非结构混合网格上对化学非平衡粘性绕流进行了数值模拟。控制方程为考虑了化学非平衡效应的二维Navier-Stokes方程,化学动力学模型为7组元、7反应模型。控制方程中的对流项采用VanLeer逆风分裂格式处理,并应用MUSCL方法及Minmod限制器扩展到二阶精度,粘性项用中心差分格式处理。时间推进采用显式5步龙格-库塔方法。为了适应高超声速流场计算,对VanLeer通量分裂方法进行了改进,并引入了化学反应时间步长。对RAMC-II模型的飞行试验流场进行了数值模拟,计算结果与试验测量数据符合较好,并与参考文献中的数值模拟结果吻合。

Viscous flow with chemical non-equilibrium effects is numerically simulated on unstructured hybrid grid. The governing equations are 2D Navier-Stokes equations with finite rate kinetic chemical non-equilibrium model, where 7 species and 7 reactions are considered. The convective fluxes are approximated using VanLeer flux-splitting method, a MUSCL approach with Minmod limiter is implemented to increase the numerical accuracy, and central difference method for the viscous fluxes. The time integration is a 5-step explicit Runge-Kutta scheme with the consideration of chemical reacting time step. Some special modifications for hypersonic flow are made in original VanLeer scheme. Numerical results are shown for the RAMC-II flight test model and compared with the experimental data and limited related references.