Numerical investigation on expansion–deflection nozzle flow during an ascending–descending trajectory
Numerical investigation on expansion–deflection nozzle flow during an ascending–descending trajectory
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DOI：
10.1063/5.0157607
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发表时间：
2023-08
影响因子：
4.6
通讯作者：
Ge Wang;Bocheng Zhou;Ben Guan;Haiwei Yang
中科院分区：
文献类型：
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作者：
Ge Wang;Bocheng Zhou;Ben Guan;Haiwei Yang
对大压比范围内环形膨胀偏转喷管（艾德）在上升-下降段的流动特性进行了数值研究。研究了在此弹道过程中激波的演化、喷管工作模式的转换、喷管流动滞后和推力的变化，并讨论了它们之间的相互作用。提出了一种基于扰动阵面结合声速线的艾德喷管开、闭尾迹模态判别准则。使用这个标准，可以很容易地画出开尾流模式和闭尾流模式之间的精确边界。研究表明，激波流型转变与喷管工作模态转变之间的相互作用是间接的。在上升过程中，尾流模态由开向闭的转变是下游激波形态变化的基础。然而，在下降过程中，主要马赫数杆的伸展延迟了喷管从关闭到打开的尾流模态转变。在上升和下降过程中的不同流动机制导致喷嘴操作模式转换的总体滞后。喷管推力在上升和下降过程中经历了下降-上升的发展过程（推力谷）。这些推力槽也被发现是两种截然不同的流动机制的结果，即，在喷嘴护罩上的激波分离点的向前-向后移动和关闭到打开模式转换后的枢轴基座上的压力升高。
The flow characteristics of an annular expansion–deflection (ED) nozzle are investigated numerically during an ascending–descending trajectory over a large nozzle pressure ratio span. The shock pattern evolution, nozzle operation mode transition, nozzle flow hysteresis, and thrust variation during this trajectory are examined, and the interactions between them are discussed. A new criterion for distinguishing the open and closed wake modes of the ED nozzle is proposed based on a perturbation front in combination with sonic lines. Using this criterion, an exact boundary between the open and closed wake modes can be readily drawn. The present study shows that the interaction between the shock pattern transition and nozzle operation mode transition is indirect. During the ascent, the open-to-closed wake mode transition lays the foundation of the downstream shock pattern variation. During the descent, however, the stretching of the dominating Mach stem delays the nozzle closed-to-open wake mode transition. The different flow mechanisms during the ascent and descent result in an overall hysteresis of nozzle operation mode transition. The nozzle thrust undergoes dropping-rising developments (the thrust troughs) in the ascent and descent. These thrust troughs are also found to be the results of two very different flow mechanisms, namely, the forward–backward movement of shock separation point on nozzle shroud and the pressure rise on pintle base after closed-to-open mode transition.