超高速流动模拟及热化学反应模型对比研究

超高速流动是飞行器再入大气层时所面临的高速高温流动环境,膨胀管是少数几种能模拟超高速流动的地面设备之一。采用数值模拟方法对超高速试验进行辅助分析诊断,流动模拟时热化学反应模型的选择对流场特性影响较大,分别选择5组分、11组分热平衡及5组分热非平衡模型,对比研究3种不同热化学反应模型对双楔试验模型数值模拟结果的影响,以进一步评估超高速流动模拟时热化学反应模型的适用范围。结果表明,试验气流条件下5组分化学模型即可满足要求,加速气流条件则必须采取11组分化学模型,而对于流动中热非平衡效应显著时,热化学非平衡模型更为适用。

Comparative study of thermal-chemical reaction models on simulation of hypervelocity flow

Hypervelocity flow is the high-speed high-temperature flow environment that space vehicles or capsules face when they reenter the atmospheric layer.An expansion tube is one of the few qualified test facilities on the ground to simulate it.Numerical simulation is presented as a powerful assistant tool for hypervelocity flow diagnosis and analysis.Thermal-chemical reaction model plays an important role in simulation of hypervelocity flow.Thermal-chemical reaction models of 5 and 11 species based on thermal equilibrium condition,and 5 species based on thermal nonequilibrium condition are applied on the numerical technique.A comparative study of the influence on the computation for double-wedge test model employed with the above three models has been conducted to evaluate their applicability.The results indicate that 5 species chemical model canmeet the test gas simulation requirement,but 11 species chemical model must be taken into account for the acceleration gas.However,if the thermal nonequilibrium phenomenon is strong in the flow,we must employ the thermal-chemical nonequilibrium model to guarantee the reliability of the numerical simulation.