Back-Pressure Effect on Shock-Train Location in a Scramjet Engine Isolator
Back-Pressure Effect on Shock-Train Location in a Scramjet Engine Isolator
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发表时间：
2012-10
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通讯作者：
Richard I. Paek
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作者：
Richard I. Paek
摘要：超燃冲压发动机的隔振器可将来流的高马赫数减速到较低马赫数，并在进入燃烧室前对其进行稳定。由于燃烧的不稳定现象和燃烧的不完全，燃烧室内的压力会发生很大的变化。这些压力变化可以向前传播并影响隔离器中的流场-最坏的情况是关闭入口。在本研究中，对激波列车位置与背压的关系进行了实验研究。背压是通过对称的（顶部和底部）坡道人工产生的，可以关闭流动区域。升高/降低坡道会导致更高/更低的背压。较高的背压使减震系统向前移动，过高的背压导致无法启动。本实验针对雷诺数、斜坡角和两个来流马赫数的变化进行，并将得出不同气流条件下背压与激波列位置之间的关系。
Abstract : The isolator of the scramjet decelerates the incoming high Mach flow to a lower Mach number and stabilizes the flow before it enters the combustor. Because of the unsteady combustion phenomenon and inconsistent completeness of the combustion, pressures within the combustor can vary drastically. These pressure variations can propagate forward and affect the flow field in the isolator - worst case unstarting the inlet. In this research, the shock train location VS. the back-pressure is examined experimentally. The back-pressure is artificially created by symmetric (top & bottom) ramps that can close the flow area. Raising/lowering ramps result in higher/lower back-pressure. Higher back-pressure moves the shock train forward, with too high a back-pressure causing un-start. This experiment is conducted for a variation in Reynolds number, ramp angle, and two incoming Mach #s, and will result in a relationship between back-pressure and shock train location for various airflow conditions.