等离子体诱导圆锥前体流场的PIV测量

PIV study of induced flowfield on steady and periodic-pulsed dielectric-barrier-discharges

在封闭光学玻璃箱体内,应用介质阻挡放电等离子体对20°顶角圆锥附近的静止大气进行了定常和脉冲循环控制,对等离子体诱导的圆锥截面绕流速度场进行了二维PIV测量,在定常控制和脉冲循环控制下,比较分析了最大绕流速度及最大轴向涡量,研究了脉冲频率和电压对上述参数的影响。实验结果表明:存在一个交流电压阈值(Vp-p≈14.0 kV),当电压高于这个阈值后,相对于定常控制模式,脉冲循环控制下沿90°方位角径向线上分布的时间平均切向速度和轴向涡量迅速增加;在脉冲循环控制控制下,动量传递主要表现为分离涡的形成而不是气流的加速。

A two-dimensional particle image velocimetry is used to measure cross flow velocity field around a 20° conical cone in atmospheric air in a closed tank which is made of optical glass.The time-averaged spatial and temporal distributions of induced maximum cross flow velocity and maximum magnitude of axial-vorticity in the neighborhood of the body are investigated.The test results show that there exists a threshold of the ac voltage（Vp？p≈14.0 kV）,over the threshold voltage,the ensemble-averaged tangential velocity and axial vorticity along a radial line perpendicular to the body symmetry plane induced by steady actuation are increased sharply;The main mechanism of momentum transfer under periodic-pulsed actuation is the formation of discrete vortices,rather than the gas acceleration.