等压比热在基于壁面放电的激波控制中的影响

放电等离子体对流动的控制机理可按热效应和非热效应分为两大类,其中放电等离子体的热效应对流场中激波结构有着明显的控制作用. 目前在放电等离子体热激励对激波控制的数值模拟过程中,通常采用等效热源的方式来实现放电的热效应,数值模拟和实验的结果显示放电产生的局部温度可达到上万度. 如果数值模拟的过程中没有考虑到气体等压比热随温度的非线性变化,计算得到的结果是有失真实性的. 本文以5 马赫的超音速进气道为平台,对基于壁面放电的激波控制过程进行了数值模拟. 选取了随温度非线性变化的等压比热,并且将其结果与定等压比热的计算结果进行了对比. 结果发现:(1) 两种等压比热下,计算结果显示放电热激励在激波控制上都有着显著的效果;(2) 两种计算结果在模拟与温度相关的参数(温度、马赫数和总压恢复系数)上的差别非常明显. 因此,为了获得壁面放电对激波控制更真实的计算结果,必须考虑到等压比热随温度发生非线性变化效应的影响. 

EFFECT OF CONSTANT PRESSURE SPECIFIC HEAT IN SHOCK WAVE CONTROL USING SURFACE DISCHARGE

The flow control mechanism of discharge plasma is divided into two categories, namely, thermal effect and non-thermal effect, and the thermal effect of the discharge plasma has obvious control effect on the shock wave structure of the flow field. In the numerical simulation of the shock wave control using discharge plasma, the local temperature of the surface discharge region can reach above ten thousand degree centigrade or kelvin degree. If not considering the nonlinear change of the specific heat at constant pressure(C_p) with gas temperature in the process of numerical simulation, the result is lack of authenticity. In this article, a Mach 5 supersonic inlet is considered, and the process of shock wave control using surface discharge is numerically simulated. Both constant C_p and varied C_p are considered. Results show that: 1) for both cases, the electric excitation has a significant effect on shock wave control; 2) the temperature associated parameters (temperature, Mach number, total pressure recovery coefficient) are effected to great extent. Therefore, in order to obtain more realistic calculation results of surface plasma for shock wave control, the effect of variation of C_p with temperature should be considered.