中文摘要：

数值模拟分析了高马赫数低雷诺数条件下激波边界层干扰、激波与激波相互作用、流动分离再附等流动现象的特点以及高温真实气体效应的影响。分别采用量热完全气体、平衡气体、化学非平衡气体模型对升力体由于舵面偏转引起的局部流动分离情形进行了数值模拟。研究了飞行高度、壁面温度及来流马赫数对流动分离的影响。计算结果表明:真实气体效应使空气在边界层内发生离解反应,边界层内温度降低,粘性减小,动能损失减小,克服逆压梯度的能力更强,从而使分离区明显减小。分离区的减小改变了分离/再附激波的位置和强度,进而对局部压力及热流分布产生重要影响;随高度增加,平衡气体较完全气体分离区相对减小量增大,平衡气体效应对流动分离/再附现象的影响越大;壁温对分离区影响较大,随壁温升高,分离区增大;随马赫数增大,分离区减小,真实气体和完全气体的差异增大,真实气体效应的影响更加显著。

英文摘要：

Flow separation occurs over the compression corners generated by deflected control surfaces on hypersonic vehicles.This phenomenon is coupled with shock/shock interactions, shock/boundary layer interactions and real gas effects.In order to design control surfaces of hy-personic vehicles and insure flight stability,it is important to predict this complex flowfield fea-tures on hypersonic vehicles.In this paper,a numerical study was conducted to assess the effects of real gas on the local flow separation of lifting body rudder.The effects of Mach number,wall temperature and flight altitude on separated flowfield features were highlighted.To this end, several numerical results derived for perfect gas,equilibrium gas and chemical nonequilibrium re-acting gas were provided and compared.The calculation results show that dissociation reaction occurs within boundary layer and reduces the temperature when real gas effects is considered. Viscosity of gas within boundary layer becomes smaller,the loss of kinetic energy decreases and this strengthens the ability to overcome the adverse pressure gradient,so the flow becomes har-der to separate.Real gas effects significantly decreases separation zone,and change the separa-tion/attach shock wave position and strength.As a result of shock/shock and shock/boundary layer interactions,pressure and heat flux distribution near the separation zone are changed by real gas effects at the same time.From the comparison of equilibrium gas and perfect gas result at dif-ferent altitude,a conclusion can be drawn that the flow separation becomes more sensitive to real gas effects at higher altitude. Wall temperature is an important factor to determine separatedflowfield features.As wall temperature increases,separation zone size becomes larger as well as heat flux on the rudder decreases.As Mach number increases,the separation zone size decreases and the differences between real gas and perfect gas become larger,real gas effects is more significant.