电导率模拟对高超声速MHD控制影响

高温气体电导率是高超声速电磁流动控制数值模拟最重要的参数之一。针对电导率模拟准确性及其对高超声速磁流体控制影响的问题，考虑高超声速飞行器流场中高温气体热化学非平衡效应，采用三维低磁雷诺数磁流体动力学（MHD）数值模拟方法及程序，结合国内外常见电导率处理方法开展典型状态高超声速MHD控制数值模拟，分析电导率模拟对高超声速磁流体流场分布、气动力/热特性的影响。研究表明：磁控热流减缓效果与电导率呈非线性关系，电导率较大时将出现电导率的磁控热饱和现象，其产生的原因可能与化学反应趋向于平衡态存在一定关系；采用定电导率方法，会人为放大磁场洛仑兹力的磁阻力效果，使阻力系数的预测值偏大；不同电导率模型计算得到的电导率分布差异很大，甚至存在数量级的差别，显著影响了磁流体的控制效果，这与电导率模型的适用范围、参数选取原则存在很大关联；对于含多种离解、电离组分的高温气体流动来说，采用基于多电离组分迁移碰撞的电导率模型（本文模型M8），计算与试验一致性最好。

Impact of simulation of electrical conductivity on hypersonic MHD control

Electrical conductivity of high temperature air is one of the most import parameters in numerical studies of hypersonic flow Magneto-Hydro-Dynamic(MHD) control. Considering the thermochemical non-equilibrium effect in the hypersonic flow, a numerical simulation of MHD method using 3D low magnetic Reynolds number and the corresponding computational codes is carried out, addressing the accuracy of the electrical conductivity simulation and its impact on hypersonic flow MHD control. Based on several common computational approaches to electrical conductivity, the numerical simulation analyzes the impact of simulation of electrical conductivity on the hypersonic flow MHD control. The results show that the relationship between the descent degree of heat flux by using MHD control and electrical conductivity is nonlinear. The thermal saturation phenomenon of electrical conductivity in MHD control exists at high electrical conductivity, and its mechanism may be related to chemical equilibrium state.Using the given electrical conductivity condition will magnify the magneto-resistance effect, overestimating the predicted drag coefficient. Electrical conductivities calculated by different conductivity models can be quite different, even not of the same order, thus can have a great influence on the control effect of hypersonic MHD flow. This is relevant to the application scope of conductivity model and select principle of parameter. For the high temperature hypersonic flow that contains multiple dissociated and ionized components, using electrical conductivity model, identified as M8 in this paper, which is based on multiple ionized components, can produced best consistency between the computational results and the experimental results.