总收缩比对RBCC进气道影响数值研究

Numerical Investigation on Effects of Contraction Ratio on RBCC Inlet

关键词:  火箭基组合循环发动机  进气道  总收缩比  抗反压能力  数值模拟

Key words:  Rocket-based combined cycle  Inlet  Contraction ratio  Anti-backpressure ability  Numerical simulation

摘要:

为研究火箭基组合循环发动机（Rocket Based Combined Cycle，RBCC）进气道隔离段内激波串传播规律，利用数值模拟研究分析了在高、低反压作用下总收缩比变化对激波串驻留位置及流动分离区范围的影响，并进一步开展了总收缩比对进气道气动性能影响的仿真研究。研究结果表明：在承受额定反压作用下，进气道总收缩比存在临界值，在临界值下提高总收缩比能显著增强进气道抗反压能力，并影响激波串驻留位置。在临界值上提高总收缩比对进气道抗反压能力无明显作用，进气道流动状态不受总收缩比变化的影响。此外，提高总收缩比能显著提高被捕获冲压空气流所承受的压缩程度，但会承受额外的空气流量损失和气动阻力。

Abstract:

In order to investigate the shock train spreading regular pattern inside inlet isolation of the rocket based combined cycle engine （RBCC）， the numerical simulation was employed to analysis the effects of inlet contraction ratio on the resident position of shock train and flow separation bubbles in both high and low backpressure， while the effects of inlet contraction ratio on the inlet aerodynamic parameters were obtained by further researches. The results show that there is a critical value of the contraction ratio for the inlet under a rated backpressure. Increasing the contraction ratio while lower than the critical value can significantly enhance the anti-backpressure ability of the inlet and affect the resident position of shock train and flow separation bubbles. However， increasing the contraction ratio while higher than the critical value has no obvious effect on the anti-backpressure ability of the inlet. The characteristics of the inlet flowfield have been little affected by the changes in the contraction ratio. Besides， increasing the contraction ratio can significantly improve the compression level of the captured airflow no matter lower or higher than the critical value， which results in the additional captured mass coefficient and aerodynamic resistance losses.