补气式等离子体合成射流激励器工作机制

Working mechanism of air-supplemented plasma synthetic jet actuator

补气式等离子体合成射流(PSJ)激励器通过在常规激励器的腔体上外接单向阀,增加吸气复原阶段的补气量,提升射流能量。为防止漏气,对单向阀结构进行了特别设计,并在单向阀进气口打开和封闭时,分别测量了激励器射流峰值速度、腔体内部压力,及其放电电压和电流,探究单向阀补气改善射流性能的工作机制。结果表明,单向阀能够显著提高等离子体合成射流性能。射流穿透高度提升达30.0%,射流峰值速度增加达到18.7%,射流作用范围面积扩大达76.3%。但其有效作用频段仍与单向阀的响应频率和承受反向冲击压力的能力及激励器饱和工作频率密切相关。补气工作机制是单向阀补气与放电之间形成正向反馈作用,通过单向阀在吸气复原阶段扩大进气口面积,吸气复原更充分,腔内气压增大,使得气体击穿电压升高,增大能量沉积阶段的放电能量,提高腔内压力,产生更大内外压差,从而提升射流性能。射流喷出后腔内负压更大,也进一步促进了吸气复原,通过单向阀补气的作用更显著。

In order to improve the jet energy,a check valve is connected to the cavity of the conventional Plasma Synthetic Jet(PSJ)actuator to increase the air supply during the recovery stage.To prevent air leakage,the structure of check valve is specially designed.When the inlet of the check valve is open or closed,the peak velocity of the jet,the pressure inside the cavity,the discharge voltage and the discharge current of the actuator are measured respectively,and the working mechanism of the check valve to improve the jet performance is explored.The results show that the improved check valve can significantly improve the performance of PSJ.The jet height is increased by 30.0%,the jet peak velocity is increased by 18.7%,and the jet effective area is expanded by 76.3%.However,its effective working frequency range is still closely related to the response frequency of the check valve,the ability to withstand the reverse impact pressure and the saturation working frequency of the actuator.The working mechanism of the air-supplemented check valve is that the positive feedback is formed between the air supply and discharge of the actuator.Through the check valve,the area of the air inlet is expanded in the recovery stage and the recovery is more sufficient.Therefore,the air pressure in the cavity is increased,which increases the breakdown voltage of the gas,increases the discharge energy in the energy deposition stage,increases the peak discharge pressure,and produces a greater internal and external pressure difference,so as to improve the jet performance.