直流放电控制高速带斜坡锥体气动力的有效性研究

Effectiveness of direct current discharge on high speed aerodynamic control of a conical model with ramps

基于直流放电激波重构气动力控制原理,开展了带斜坡锥体模型的高速(Ma=6)气动力控制风洞试验,采用光纤天平技术,考察了模型在两种放电功率(284 W和517 W)下的气动力/力矩变化情况,并采用纹影成像研究了放电对流动拓扑的影响。纹影图像揭示了由于放电热阻塞和马赫数降低引起的波系重构现象,表现为放电诱导压缩波和再附激波弱化、角度减小。天平信号验证了放电使得模型的轴向力、法向力和俯仰力矩减小,放电功率较大时控制效果明显。通过求解带功率密度源项的Navier-Stokes方程模拟放电的加热效应,数值研究了模型气动力随功率密度的变化规律及加热位置对控制能力的影响。研究表明:模型气动力变化率与功率密度呈正相关;当以激励器的上游位置为参考点时,俯仰力矩变化显著;当加热位置靠近斜坡时,控制能力降低。

Based on the aerodynamic control principle that direct current discharge reconstructs the shock waves,wind tunnel experiments at Mach 6 were conducted for the hypersonic aerodynamic control of a conical model with ramps.The aerodynamic force/moment variations of the model at two discharge powers(284 W and 517 W)were acquired using the fiber optic balance(FOB),and the corresponding flow topology change was studied using the Schlieren imaging.The visualisation reveals the shock wave reconstruction phenomenon caused by the discharge,which blocks the flow and reduces the local Mach number.Specifically,the discharge induces a compression wave,and reduces the strength and angle of the attachment shock.The balance signal shows that the axial force,normal force and pitching moment of the model are all decreased under the discharge,and the control effect is more prominent under a larger discharge power.The heating effect of discharge was simulated by solving the Navier-Stokes equations with an energy source,and the aerodynamic force variation with the power density,as well as the control effect of the heating position were quantified.The results show that,the aerodynamic changes are positively correlated with the power density;the pitch moment of the model changes significantly taking the position upstream of the actuator as the reference point;the control efficiency decreases when the heating zone is located closer to the ramp.