两电极等离子体高能合成射流流场及其冲量实验研究

两电极等离子体高能合成射流激励器通过腔体内电极间的瞬时电弧放电加热腔内气体,在激励器出口产生压差并喷出高速射流,从而产生反作用力和冲量。针对两电极等离子体高能合成射流响应快、持续时间短的特点,设计了单丝扭摆式微冲量测量系统,并结合高速阴影系统,对两电极等离子体高能合成射流的流场发展过程及其单脉冲冲量特性进行了实验研究。实验结果表明,两电极等离子体高能合成射流响应时间小于10μs,射流持续时间约为1ms,射流前锋最大速度约为190m/s,射流流场发展过程中存在多道强压缩波,并以当地声速向下游传播。单丝扭摆式微冲量测量系统可实现μN·s量级冲量测量精度,单脉冲冲量约为32μN·s,并且在低频状态下射流总冲量随激励器放电频率成线性增加。

Experimental study on the flow field and impulse of a two-electrode plasma high energy synthetic jet

The gas inside the cavity of the two-electrode plasma high energy synthetic j et actu-ator is electrothermally heated by the transient discharge of electric arc,that leads to a rapid in-crease in pressure within the cavity.This high-pressure gas ejects through the orifice and forms the high-speed jet.Considering the fast response character of the high energy synthetic jet,a sin-gle line torsion pendulum system for the impulse measurement is designed.Combined with the high-speed shadowgraphy,the development of the flow field and the impulse of the plasma jet are experimentally studied.The results show that the response time of the two-electrode plasma high energy synthetic jet is less than 10μs,and the duration time of the single-pulse jet is about 1ms. The maximum velocity of the jet front is about 190m/s,and there are shocks spreading at the speed of sound.The measurement accuracy of the single line torsion pendulum system isμN·s. The impulse of the two-electrode plasma high energy synthetic jet actuator is about 32μN·s. The total impulse increases linearly with the discharge frequency when the discharge frequency is low.