大间距两不对称喷嘴对置撞击流驻点偏移规律

采用热线风速仪对大喷嘴间距下两不对称喷嘴形成的对置撞击流的轴线速度分布和驻点偏移规律进行了实验研究.研究结果表明,在大喷嘴间距下,两股射流在发生碰撞前,射流已经进入了充分发展区,当两喷嘴出口动量相等时,驻点位于两个喷嘴轴线中心;在撞击区中,两股射流关于撞击面是对称的.轴线上撞击流驻点受两喷嘴动量比的控制,随着动量比偏离1撞击流驻点向动量小的一侧喷嘴移动,两喷嘴出口动量差别越大,驻点偏离中心距离越大.得到了一个描述大喷嘴间距下驻点偏移的公式,拟合结果与实验结果的平均相对误差为10%.

Stagnation Point Offset of Two Asymmetric Nozzle Opposed Jets with Large Nozzle Separation Distance

The axial velocity and stagnation point offset of two opposed jets coming from two asymmetric nozzles oppositely located with large separation distance were studied by using hot-wire anemometry (HWA). The results show that, for two nozzles with large separation, their jets develop rather independently before they impinge against each other. When the momentums per mass of the two jets at their own nozzle outlet are equal, the stagnation point is located at the center of the axis connecting the two nozzles, and in the impingment region, the two jets are symmetrical with respect to the impinging plane. The stagnation point offset increases as the momentum ratio of the two jets at two nozzle outlets shifts from 1, and the stagnation point shifts along the axis towards the nozzle with less jet momentum at its outlet. For two oppositely located asymmetric nozzles with large separation distance, an equation describing the stagnation point offset was derived, and the average relative error between the calculated results and the experimentally measured data is about 10%.