收缩比对RBCC进气道影响数值研究

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,本文利用数值模拟研究分析了在高、低反压作用下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,进气道收缩比存在临界值,在临界值下提高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收缩比变化的影响。此外,提高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。

Numerical Investigation on the Effects of Contraction Ratio on RBCC Inlet

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 in this paper to analysis the influence of inlet contraction ratio on the resident position of shock train and flow separation bubbles in both high and low backpressure, while the influence of inlet contraction ratio on the inlet aerodynamic parameters was obtained by further researches. The results show that there is a critical value of the contraction ratio for the inlet under a rated backpressure. The increasing in 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, the increasing in 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 contractions. Besides, increasing in the contraction ratio can significantly improve the compression level of the captured airflow no matter lower or higher than the critical value, which resulting in the additional captured mass coefficient and aerodynamic resistance losses.