静止空气中重频脉冲火花放电等离子体的气动激励特性

Characteristics of Pulse Recurrence Frequency Spark Discharge Plasma Aerodynamic Excitation in Quiescent Air

不同的状况下的重频脉冲(PRF)火花放电等离子体气动激励特性并不相同。为此,采用重频脉冲电源和激励器在静止空气中产生火花放电等离子体气动激励,研究了其激励特性。实验结果表明:由于重复脉冲火花放电存在快速加热,因此会瞬间产生很大的温度升和气压升,进而诱导产生冲击波;冲击波在流场中以声速传播,随后强度逐渐减弱,一定时间后衰减为弱扰动。保持脉冲重复频率不变,当激励电压绝对值增大时,注入流场的单脉冲能量和冲击波波速都随之增大。而保持激励电压不变,增大脉冲重复频率时,注入流场的单脉冲能量和冲击波波速基本不变,同时由于放电周期变短,因此上一个放电周期产生的弱扰动在下一次放电时仍然存在。

The aerodynamic excitation by pulse recurrence frequency（PRF） spark discharge plasma performs diversely under different conditions.For investigating this variation,we produced plasma aerodynamic excitation in quiescent air by using a PRF power supply and an actuator,and studied its excitation characteristics.Test results show that,the rapid heating generated by PRF spark discharge results in rapid rises of temperature and pressure,which will induce shock waves.The shock wave spreads abroad at the speed of sound at first,and its strength gets weaker in the spreading process before it finally attenuates into weak disturbance in a certain period.When the pulse repetitive frequency is fixed,the rise of excitation voltage will lead to both increases in the single pulsed energy injected into the flow field and the velocity of shock wave.Whereas,with a fixed excitation voltage,the rise of pulse repetitive frequency hardly affects the injected energy and shock wave speed;however,since the cycle becomes shorter,in a discharge cycle there is the weak disturbance attenuation of the last discharge cycle.