非对称腔体合成双射流矢量特性数值研究

Numerical study for the thrust-vectoring characteristic of dualsynthetic jets with unsymmetrical cavities

关键词:  合成双射流  非对称腔体  矢量特性  X-L模型⁺

Key words:  Dual synthetic jets  Unsymmetrical sealed cavities  Thrust-vectoring  X-L model⁺

摘要:

利用合成射流全流场计算X-L模型,对非对称腔体合成双射流激励器的射流矢量特性进行了数值模拟,分析了激励器不同腔体体积比、不同振动膜速度、不同频率下的合成双射流流场。研究结果表明,当激励器两腔体不对称时,所形成的合成双射流不再垂直向下游流动,而是会发生偏转,即射流具有矢量特性,偏转角度的大小可以通过激励器工作条件进行调节。其机理是振动膜对大小不同的两腔体的相对压缩量不同,使得两出口处所形成射流的能量和低压区不再对称,因此导致合成双射流向低能量(大腔体)一侧偏转。振动膜振幅和频率的提高对低压区大小分别起到增加和减弱的作用,所以偏转角度又随着振动膜最大速度的增加而增大,随工作频率的增加而减小。

Abstract:

Based on a whole flow field computational model for dual synthetic jet—X-L model, numerical computations are performed to get the thrust-vectoring characteristic of the dual synthetic jets actuator with unsymmetrical sealed cavities, and the flow field of the actuators with different cavity volume, diaphragm velocity and frequency is analyzed. The results show that when the sealed cavities are unsymmetrical, the direction of the dual synthetic jets is not vertical but gradient, and the degree of the turning can be adjusted by the parameters of the actuator. The mechanism for this is that the relative compressed degree between the cavities by the diaphragm is different, and induces that the energy of the jet and the area of the low pressure between the exits are unsymmetrical, so the dual synthetic jets turn to the side with low energy. The increased of the diaphragm velocity and frequency will augment and reduce the low pressure area separately, the angle of the vectoring is influenced as well.