Tangential Injection from Overlaid Slots into a Supersonic Stream
Tangential Injection from Overlaid Slots into a Supersonic Stream
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从重叠槽切向注入超音速流
DOI：
10.2514/2.5150
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
J. Schetz
中科院分区：
文献类型：
--
作者：
D. Lewis;J. Schetz
本文介绍了在超音速气流中通过主槽上方增加一个切向亚声速槽喷射的实验研究结果。至少有两种与推进相关的应用会对这种低温度感兴趣。首先，可以通过上槽的亚音速注入模拟近分离边界层，然后通过下槽的超音速注入重新激活。其次，该喷嘴也适用于从多个覆盖槽中喷射燃料/氧化剂/先导剂。实验在间歇真空风洞中进行，自由流马赫数为2.85。超音速喷油器的马赫数为2.00，亚音速喷油器的马赫数为0.26和0.72。结果以火花纹影照片、干涉图和壁面静压测量的形式呈现。介绍了从干涉图确定的几个轴向位置的密度变化，以及沿流和沿展的静压分布。从串联注入结果中得出的主要结论是：第一，用这种方法可以模拟近分离边界层。接下来，串联注入的亚音速和超声速可分为单独的组件，非常类似于在未受干扰的自由流中各自的单独注入。此外，亚音速注入的影响在六个槽高的下游位置完全混合。因此，如果要研究超声速注入近分离边界层以使其再充能的效果，则反压梯度诱导装置应放置在超声速注入站下游至少6个槽高的位置。
The results of an experimental study of tangential supersonic slot injection into a supersonic airstream with tangential subsonic injection through an additional slot above the main slot is presented. Such a ow is of interest for at least two propulsion-related applications. First, one can simulate a near-separation boundary-layer pro le by subsonic injection through the upper slot, which is then to be re-energized by supersonic injection through the lower slot. Second, this ow is also of interest for application to fuel/ oxidizer/pilot injection from multiple overlaid slots. The experiments were performed in an intermittent, vacuum wind tunnel at a freestream Mach number of 2.85. The supersonic injectant had a Mach number of 2.00, and the subsonic injection was at Mach numbers of 0.26 and 0.72. The results are presented in the form of spark schlieren photographs, interferograms, and wall-static pressure measurements. Density pro les at several axial locations determined from the interferograms are presented, as well as streamwise and spanwise static pressure distributions. The major conclusions drawn from the tandem injection results, are rst, that a near-separation boundary-layer pro le can be simulated in this way. Next, tandemly injected subsonic and supersonic ow can be divided into separate components that closely resemble the respective individual injections into an undisturbed freestream. Also, the effects of the subsonic injection were completely mixed out at a downstream location of six slot heights. Therefore, adverse-pressuregradient-inducing devices should be positioned at least six slot heights downstream of the supersonic injection station if the effects of supersonic injection into a near-separation boundary layer for the purpose of re-energizing it are to be studied.