Abstract:

The flow field of two opposed jets was experimentally investigated with the smoke-wire technique and hot-wire anemometer for the stability of impingement plane and stagnation point offset at various nozzle separations and exit velocity ratios.The results showed that at 2D≤L≤4D（where L is nozzle separation and D is nozzle diameter），the impingement plane was instable and oscillated at equal exit velocities，while the impingement plane deviated from the mid-point to a large extent and the flow field became stable comparatively at a small difference of exit velocities.At 2D≤L≤8D，the stagnation position was very sensitive to the change of velocity ratio; while at L<2D or L>8D，the position of stagnation point became insensitive to the change of exit velocity ratio.

Key words:

撞击流, 驻点偏移, 稳定性, 烟线法, 热线风速仪

摘要：

运用烟线法和热线风速仪对两喷嘴撞击流流场进行了实验研究，考察了不同喷嘴间距、不同气速比下撞击面的稳定性和撞击面驻点的偏移规律。结果发现，当2D≤L≤4D（L为喷嘴间距，D为喷嘴直径）时，若两喷嘴气速相等，撞击面不稳定，在轴线上发生振荡;当两喷嘴气速有小的差异时，撞击面驻点将发生大幅度的偏移，此时流场变得相对比较稳定。当2D≤L≤8D时，撞击面驻点位置对气速比变化很敏感;当L<2D和L>8D时，撞击面驻点位置对两喷嘴气速比的变化逐渐变得不敏感。

关键词:

撞击流, 驻点偏移, 稳定性, 烟线法, 热线风速仪