关键词: 火箭基组合循环发动机；进气道；中心支板顶角；数值模拟

Abstract: In order to investigate the effects of strut angle on the rocket-based combined cycle engine (RBCC) inlet and optimize its design method， the numerical simulation was employed. The influence of various strut angles on the minimum length of internal compression section had been detailed. The numerical simulation presented herein demonstrated the influence of various strut angles on inlet flow field and performance quantitatively and qualitatively in typical conditions. The results show that the increase of the strut angle results in the decrease of the inlet length (the isolator length of Strut_2， Strut_3， Strut_4 and Strut_5 decreases by 47%， 62%， 70%， 75% when compared with Strut_1) and viscous drag force coefficient (the internal compression section viscous drag force coefficient of Strut_2， Strut_3， Strut_4 and Strut_5 decreases by 33%， 45%， 55%， 59% at [Ma∞]=1.5 and decreases by 37%， 50%， 57%， 61% at [Ma∞]=5.5 when compared with Strut_1). But no influence have been imposed on captured mass flow coefficient or flow uniformity. The inlet was optimized according to the preceded analysis in this paper， the starting performance and other performance parameters are improved effectively. The inlet internal drag coefficient decreases by 13.5% while the inlet external drag coefficient decreases by 5.7%. The total pressure recovery coefficient increases by 2.6% while the cycle static temperature ratio increases by 0.5%.

Key words: Rocket-based combined cycle；Inlet；Strut angle；Numerical simulation