微秒脉冲等离子体流动控制延迟效应研究

Experimental Investigation of Hysteresis Effect by Microsecond Pulse Plasma Actuator

关键词:  等离子体流动控制  延迟效应  流动分离  微秒脉冲

Key words:  Plasma flow control  Hysteresis effect  Flow separation  Microsecond pulse

摘要:

等离子体流动控制（PFC）能有效抑制翼型附面层分离，增加升力，推迟失速，应用前景广阔。流场的延迟效应是指采用PFC进行流动控制时，激励关闭后，流动控制效果仍存在的现象。本文对新型微秒脉冲介质阻挡放电（μs-DBD）的体积力和冲击波特性进行测试，并在此基础上开展风洞实验，进行流场的延迟效应研究，测试μs-DBD的延迟时间和参数影响规律。结果表明，μs-DBD能同时产生体积力和冲击波作用，同时也能在流场中产生明显的延迟效应，延迟时间不小于1200s，远大于毫秒脉冲介质阻挡放电（AC-DBD）产生的延迟时间（150s）；激励电压和来流速度越大，翼型迎角越小，延迟效应越强；等离子体激励能使流场失稳分岔，并转变为更优的分岔解；延迟效应研究在节约能耗、延长激励器寿命、PFC控制律设计和风洞实验方法优化等方面有重要意义。

Abstract:

Plasma flow control (PFC) can suppress the airfoil boundary layer separation effectively to increase lift and delay stall, which has a broad application prospect. The hysteresis effect refers to the phenomenon that the flow control effects keep existing in large angles of attack even after the plasma actuation is turned off. In this paper, the body force and shock wave characteristics of the microsecond pulse dielectric barrier discharge (μs-DBD) were tested. On this basis, wind tunnel tests were carried out to study the hysteresis effect. The hysteresis time was tested and the influences of different parameters were studied. Results show that μs-DBD can generate both body force and shock wave, and it can also produce significant hysteresis effect in the flow field, with the hysteresis time of no less than 1200s, much larger than that (150s) generated by alternating current dielectric barrier discharge (AC-DBD). There is stronger hysteresis effect with larger pulse voltage, larger freestream velocity and smaller angles of attack. Plasma actuation can make the flow field lose stability and make the bifurcation happen, changing the flow field into a better bifurcation solution. The study of hysteresis effect has important significance in saving energy, prolonging the life of actuators, designing the control law of PFC and optimizing the wind tunnel test method.