跨音速喷管化学反应流数值模拟

NUMERICAL SIMULATION OF REACTING FLOWS IN NOZZLE

用时间相关的半隐格式有限差分数值方法求解了化学非平衡反应跨音速喷管流场，在喷管收敛段，流动接近化学平衡状态，控制方程的刚性问题严重，数值积分困难。通过对时间差分项隐式离散、对空间差分项显式离散，流场边界采用参考平面上的特征线法计算等，成功地解决了由于化学反应有限速率带来的数值解不稳定问题。该格式简单、需要计算机存贮空间少。本文完成了一维和轴对称非平衡化学反应喷管流动计算，并与化学平衡流和冻结流的计算结果做了比较。

The numerical simulation of chemically reacting flows in the nozzle is accomplished by a time-dependent technique using semiimplicit scheme.A second-order implicit difference approximation is applied to the time derivatives in governing equations and a noncentered difference approximation is explicitly employed to the spatial derivatives.The numerical instability caused by the stiffness of chemical relaxation equations is succesfully depressed by the above measure.The results obtained from numerical simulation of one-dimensional and axisymmetric nozzle flows are presented.