三维等离子体MHD气动热环境数值模拟

电磁流动控制技术是一个多学科交叉融合的重要研究方向,在高超声速飞行器气动特性优化、气动热环境减缓、边界层转捩和等离子体分布等流动控制方面显示出广阔的应用前景。考虑高超声速飞行器绕流流场中发生的离解、复合、电离和置换等化学反应,气体分子振动能激发以及化学非平衡效应,耦合电磁场作用并基于低磁雷诺数假设,通过数值模拟求解三维非平衡Navier-Stokes流场控制方程和Maxwell电磁场控制方程,建立磁场与三维等离子体流场耦合数值模拟方法及程序,采用典型算例进行考核。在此基础上,开展不同条件下磁场对再入三维等离子体流场以及气动热环境影响分析。研究表明:建立的高超声速飞行器的等离子体流场与磁场耦合计算方法及程序,其数值模拟结果与文献符合,外加磁场使飞行器头部弓形激波外推,磁场强度越强,激波面外推距离越大;不同磁场强度环境下,流场中温度峰值大小略有变化,变化幅度较小;磁场对绝大部分区域的热流有减缓作用,作用的大小与飞行高度、马赫数以及磁场的配置紧密相关;当前的计算条件下,飞行的高度越高,磁场的作用越明显。

Numerical simulation of 3D plasma MHD aero-thermal environment

Electromagnetic flow control technique,a significant multidisciplinary intersecting direction,shows wide application prospects in aerodynamic characteristics optimization,aerodynamic thermal environment mitigation,boundary layer transition and plasma distribution for flow control over hypersonic vehicle.In this paper,chemical reactions,molecular vibration excitation and chemical non-equilibrium effects are considered in the flow field of hypersonic vehicle,coupled with electromagnetic field effect and with the assumption of low magnetic Reynolds number.By solving 3D chemical non-equilibrium Navier-Stokes equations and Maxwell equations,numerical simulation method and the corresponding computational codes are developed for extra magnetic field coupled with reentry plasma flow,and are validated by numerically calculating two typical examples.These simulation results are in agreement with those in literatures.On this basis,the influence of extra magnetic field on 3D plasma flows and aero-thermal environment under different flight conditions is studied.The results show that extra magnetic field can obviously change the standoff distance of shockwave and reduce the surface heat flux in most surface regions.It is found that the greater the magnetic field strength is,the more obvious the modification effect is.The influence degree is relevant to the factors of flight altitude,velocity and extra magnetic field configuration.Under current calculation conditions,the influence degree is more obvious when the flight altitude is higher.