连续超声速射流对撞诱导激波聚焦的机理研究

发布时间：2018-06-07 03:49

本文选题：超声速射流 + 啸声　；参考：《推进技术》2016年12期

【摘要】：为研究连续超声速射流对撞诱导激波聚焦的机理,在喷口间距为70mm,不同入射压力的条件下进行了自由射流对撞、二维凹面腔内的射流对撞及三维凹面腔内的射流对撞诱导激波聚焦实验。通过对比自由射流对撞辐射啸声频谱和凹面腔内射流对撞中凹面腔底部的动态压力频谱,结合纹影照片对连续超声速射流对撞诱导激波聚焦的机理进行了研究。结果表明,沿射流对撞面两侧的椭球形激波阵面的高频拉锯式振荡是连续射流对撞诱导激波聚焦的本质。当两侧的波阵面同时到达凹面腔底部发生碰撞时,激波聚焦得以完成;在一定的入射压力范围内,由于射流对撞面不稳定,两侧椭球形激波阵面不能同时到达两喷口中间的对称面,因此在自由射流对撞的辐射噪声频谱上共存两种模式的啸声。在凹面腔内的射流对撞中,凹面腔底部的压力脉动频谱上也同时存在两个频率十分接近的峰值;随着入射压力的进一步提高,两侧的椭球形激波阵面经过一段时间的协调同步后同时到达喷口中间的对称面,辐射噪声和压力脉动频谱中双频率值共存的现象消失,并统一为单一值。
[Abstract]:In order to study the mechanism of shock focusing induced by continuous supersonic jet collision, the free jet collision was carried out under the conditions of 70 mm nozzle spacing and different incident pressure. Two dimensional concave cavity jet collision and three dimensional concave cavity jet collision induced shock wave focusing experiment. The mechanism of shock focusing induced by continuous supersonic jet collision was studied by comparing the whistling sound spectrum of free jet collision and the dynamic pressure spectrum at the bottom of concave cavity. The results show that the high frequency saw oscillations along the ellipsoidal shock front along the two sides of the jet collision surface are the essence of the shock focusing induced by the continuous jet collision. When the wave front on both sides reaches the bottom of the concave cavity at the same time, the shock wave focus is completed, and in a certain range of incident pressure, the jet collision surface is unstable. The ellipsoid shock front on both sides cannot reach the symmetric surface between the two vents at the same time, so the whistling sound of the two modes can coexist on the radiation noise spectrum of the free jet collision. In the jet collision of concave cavity, there are also two peaks in the spectrum of pressure pulsation at the bottom of concave cavity, which are very close to each other. After a period of coordination and synchronization, the ellipsoidal shock front on both sides reaches the symmetrical plane in the middle of the nozzle simultaneously. The phenomenon of the coexistence of dual frequency values in the spectrum of radiation noise and pressure pulsation disappears and is unified into a single value.
【作者单位】：空军工程大学航空航天工程学院;陆航研究所;中国人民解放军94710部队;
【基金】：国家自然科学基金重大培育项目(91541109);国家自然科学基金(51406234) 陕西省自然科学基金(2015JQ5124)
【分类号】：V231

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