基于微秒脉冲激励的飞翼模型等离子体流动控制试验研究

EXPERIMENTAL INVESTIGATION OF PLASMA FLOW CONTROL ON A FLYING WING MODEL BASED ON MICROSECOND PULSED EXCITATION

为了改善飞翼布局的大迎角气动特性,采用飞翼全模和半模分别在低速和跨声速风洞中开展了微秒脉冲介质阻挡放电等离子体流动控制的试验研究。通过流动显示和测力的试验方法研究了等离子体流动控制的主要作用机制和激励频率与激励电压等对飞翼模型失速特性的影响规律,验证了微秒脉冲介质阻挡放电等离子体流动控制技术从低速到亚声速的有效性,有效的试验最高马赫数Ma达到0.6、雷诺数Re达到3.05×10^(6)。试验研究表明:微秒脉冲介质阻挡放电等离子体通过非定常微尺度压缩波扰动的形式作用于翼面流场,通过频率耦合机制减弱模型的前缘分离涡、抑制翼面的流动分离;无量纲频率F^(+)是影响等离子体流动控制效果的重要参数;在低速风洞试验风速V=30 m/s时,无量纲频率F^(+)=0.35~1.06的控制效果较好,可将模型的最大升力系数提高25%以上、失速迎角推迟4°;在跨声速风洞试验马赫数Ma=0.6时,无量纲频率F^(+)=0.22和F^(+)=0.44的控制效果较好,可将模型的最大升力系数分别提高4.72%、4.77%,失速迎角分别推迟2°、1°;激励电压越高激励强度越大、等离子体流动控制效果越好。

In order to improve the aerodynamic performance of flying wing layout aircrafts at high attack angles an experimental study of microsecond pulsed dielectric barrier discharge(μs-DBD)plasma flow control was carried out in low-speed and transonic wind tunnels,using both full and half models of a flying wing.Flow visualization and force measurements are deployed to reveal the main mechanisms of plasma flow control and,to analyze the effects of excitation frequency and voltage on the stall characteristics of the flying wing model.The effectiveness ofμs-DBD plasma in manipulating low-speed to subsonic flows is successfully verified,with the highest test Mach number and Reynolds number tested being 0.6 and 3.05×10^(6),respectively.Results show thaμs-DBD plasma perturbs the model airfoil flow field by unsteady micro-scale compressive wave.These wave perturbations weaken the front separation vortex of the model and suppresses the flow separation by frequency coupling,thus leaving dimensionless frequency as a key parameter which influences the effectiveness of plasma flow control.In a low-speed wind regime(wind speed:30 m/s),the optimal dimensionless frequency range is 0.35 to 1.06,accompanied by more than 25%in the maximum lift coefficient and 4 degrees postponement in the stall attack angle.As a comparison,in the transonic regime of Mach 0.6,the favorable dimensionless frequency drops to 0.22 and 0.44,with the maximum lift coefficient increased by 4.72%and 4.77%,respectively,and the stall attack angle postponed by 1 and 2 degrees,respectively.Additionally,since the excitation voltage of plasma affects the intensity of the compressive wave perturbation,the higher the excitation voltage is,the better the effect of plasma flow control will be.