氧碘化学激光器中的化学非平衡流动数值模拟

A Numerical Simulation of the Nonequilibrium Flows in COIL

采用数值方法求解二维可压缩非定常NavierStokes(NS)方程及组分连续方程,计算氧碘化学激光器中的化学非平衡流场。采用格心格式的有限体积法对NS方程作空间离散,用四步龙格库塔方法作显式时间推进。假设混合气体为热力学完全而热值非完全气体,化学反应模型采用有限速率反应模型。使用一种松弛迭代的方法来处理化学源项的刚性问题。对3种组分配比情况下氧碘化学激光器中的化学非平衡流动进行了计算,给出了不同情况下几种组分的浓度分布,分析了2种组分的浓度对激光器性能的影响。所得结果与理论分析以及文献结论一致。

To our best knowledge , there does not exist any paper in the open literature on detailed steps involved in numerical simulation of the chemical nonequilibrium flows in chemical oxygen iodine laser (COIL). In this paper we aim to provide such details for the relatively simple case of two dimensional flows. Nonequilibrium flows in COIL are simulated by solving the Reynolds averaged Navier-Stokes equations and species continuity equations. Equations are solved using the cell-centred finite volume spatial discretization and four-stage Runge-Kutta time-stepping scheme on structured viscous mesh. The method employs finite-rate chemistry and thermodynamic perfect gas properties for chemical reaction. The stiffness problem of chemical source is overcome by a relaxation iterative scheme. The thickness distribution of some species is obtained for three different inflow boundary conditions. Analyses of the COIL capability are given with different thickness distributions of two species. The results are in good agreement with the conclusion of Paschkewitz et al [1] concerning species concentrations.