一种单反馈通道振荡射流激励器设计

Design of a single feedback channel oscillating jet actuator

为了设计一种有利于分离控制的振荡射流激励器,选取单反馈通道的形式,重点研究第二喉道与扩张段参数对射流振荡特性与偏转襟翼分离控制效果的影响,并总结几何参数设计依据,完成激励器设计并对比了其与典型激励器的分离控制效果。结果表明:反馈段参数应使射流在混合段扩张部分的偏角最大;混合段参数应使射流附着于混合段壁面;第二喉道应使射流向流场中均匀传递动量,其过小或过大均会减小射流偏角并导致射流向流场中传递动量不均匀;扩张段扩张角应增大至刚好不阻挡射流偏转,过大会使扩张段内射流发生不对称附着现象;增大出口高度可以增大射流偏移量,但其过大会延长射流在扩张段两侧的停滞时间。不同激励器的分离控制效果对比表明,采用自主设计激励器时的偏转襟翼减阻量是采用典型激励器时的3.8倍。

In order to design an oscillating jet actuator conducive to separation control,a single feedback channel form of the actuator is studied with focus on the influence of parameters of the second throat and the expansion section on the oscillation characteristics of the jet as well as on the separation control effect of a deflection flap.The selection of geometric parameters for the actuator is summarized,and the separation control effect of the present designed actuator is compared with that of other typical actuators.The results show that,for an optimal design,the feedback section should maximize the deflection angle of the jet in the expansion part of the mixing section,and the mixing section should make the jet attach its wall.The second throat should make the jet momentum transfer uniformly in the flow field.If the second throat is too small or too large,it can reduce the jet deflection angle and make the jet momentum transfer non-uniformly in the flow field.The expansion angle of the expansion section should be increased to just enough to not prevent the jet from deflecting,as the jet can attach the wall asymmetrically if the expansion section is too large.A large outlet height can increase the jet offset,but if the outlet is too high,it can prolong the stagnation of the jet on both sides of the expansion section.Comparison of the separation control effect of different actuators shows that the drag reduction rate of the deflection flap with the present designed actuator is 3.8 times that of other typical actuators.