中心支板参数对RBCC发动机性能影响研究

Effects of Central-Strut Parameters on Performance of RBCC Engine

关键词:  RBCC  中心支板参数  发动机性能  引射模态  亚/超燃模态

Key words:  RBCC  Central-strut parameters  Engine performance  Ejector mode  Ramjet/scramjet mode

摘要:

针对某宽域加速飞行任务下RBCC发动机中心支板主要几何参数设计问题，采用全流道一体化数值模拟方法，在Ma0.4~6速域内研究支板阻塞比、顶角及长宽比等参数对发动机引射、亚/超燃模态的性能影响规律。结果表明，随着阻塞比增大，各模态下空气流动受压缩作用增强，燃烧反应更加充分，发动机总推力有0.13%~5%的提升；随着顶角增大，除Ma2.5工况由流道截面构型变化引起激波形成外，增强的支板前缘激波使得燃烧反应位置较为集中，燃料喷注贯穿主流深度提高，较为充分的燃烧释热使得发动机总推力有2.2%~5.7%的提升；随着长宽比减小，在Ma0.4~4条件下，增大的流道面积有利于煤油横向扩展，较好的氧燃掺混使得发动机总推力有2%~4.8%的提升，而在Ma6条件下，支板前缘激波的减速增压作用逐渐减弱，发动机总推力可降低5.2%~7.1%。

Abstract:

Focusing on the critical geometric parameters settings of the RBCC central-strut under a wide-speed acceleration mission， the effects of parameters such as blockage ratio， strut angle and aspect ratio on the performance characteristics of the engine in terms of ejector， ramjet/scramjet modes were studied by using the full-channel integrated numerical simulation method within the speed range of Ma0.4~6. The results show a significant effect of compression on the air flow in each mode， which in turn contributes to a more sufficient combustion reaction as the ratio of blockage increasing， and the total thrust is improved by 0.13%~5%. With the increase of the strut angle， except for the shock wave caused by the change of flow path cross section configuration at Ma2.5， the enhanced leading shock of the strut makes the combustion reaction position more concentrated. Meanwhile， the fuel injection penetration is much deeper and the full combustion heat release makes the total thrust of the engine improved by 2.2%~5.7%. As the aspect ratio decreasing， under the flight condition of Ma0.4~4， the increased flow path area is beneficial to the lateral expansion of kerosene， and the better oxygen-fuel mixing elevates the total thrust of the engine by 0.2%~5.8%. However， at the speed of Ma6， the deceleration and pressurization of the shock wave at the front edge of the strut gradually weakens and the total thrust is reduced by 5.2%~7.1%.