高温气体效应对高超声速磁流体控制的影响

Impact of high temperature gas effect on hypersonic magnetohydrodynamic control

高温气体效应会严重影响高温气体流场的流动特性,进而影响高超声速磁流体控制效率。基于低磁雷诺数假设,通过耦合求解带电磁源项的三维Navier-Stokes流场控制方程和电场泊松方程,开展完全气体模型、平衡气体模型、化学非平衡气体模型、热化学非平衡气体模型等条件下的高超声速磁流体控制数值模拟,分析气体模型对磁流体控制的影响,研究高温气体各种非平衡效应及焦耳热振动能量配比等对高超声速磁流体控制的影响规律。研究表明:化学非平衡效应对高超声速磁流体控制影响显著,采用化学非平衡气体模型模拟得到的磁控增阻特性介于完全气体模型和平衡气体模型之间,平衡气体和完全气体模型磁控热流变化的定性规律,与非平衡气体模型模拟结果差异很大;热力学非平衡效应对高超声速磁流体控制的影响,与焦耳热振动能量作用比率紧密相关,随该配比增大,磁场增阻效果由67%降到约12%;高温气体效应会极大地降低磁控增阻效果,会明显地增强部分表面区域的磁控热流减缓效果,要准确数值模拟高超声速磁流体控制,必须有效地考虑化学和热力学非平衡效应,同时选用接近实际情况的焦耳热振动能量配比。

High temperature gas effect can have a strong impact on the flow characteristics of plasma,thus influencing the efficiency of magnetohydrodynamic flow control.Based on the hypothesis of low magnetic Reynolds number,a numerical simulation of magnetohydrodynamic flow control of perfect gas,equilibrium gas,chemical non-equilibrium gas,and thermalchemical non-equilibrium gas is conducted by solving coupled electric field Poisson equation and three dimensional Navier-Stokes equation with electromagnetic source term.Based on this method,this paper analyzes the influence of different gas models on magnetohydrodynamic flow control,discussing the rule of the influence of high temperature gas chemical nonequilibrium effect,thermal-chemical non-equilibrium effect,and Joule heat vibrational energy ratio on magnetohydrodynamic flow control.Results show that gas model has a strong influence on magnetohydrodynamic flow control.By using chemical non-equilibrium gas model,the increase of aerodynamic drag coefficient caused by magnetic field is smaller than that by using perfect gas model but is larger than that by using equilibrium gas model.The magnetic thermal protection effect by using equilibrium gas model and perfect gas model is different from that by using the non-equilibrium gas model.The influence of thermal-chemical non-equilibrium effect on magneto hydrodynamic flow control is in close relation to the Joule heat vibrational energy ratio.As the Joule heat vibrational energy ratio increases,the influence on aerodynamic drag coefficient caused by magnetic field falls significantly from 67%to 12%.The high temperature real gas effect will significantly reduce the influence on aerodynamic drag coefficient caused by magnetic field and significantly enhance the efficiency of magnetic thermal protection.In order to precisely simulate magnetohydrodynamic flow,the thermal-chemical non-equilibrium effect must be taken into account,and the most accurate Joule heat vibrational energy ratio should be chosen.