一种用于前缘钝化高超声速进气道设计评估的CFD/特征线组合方法及其应用

A Combined CFD/Characteristic Method for Design and Performance Prediciton of Hypersonic Inlet with Leading Edge Bluntness

关键词:  高超声速  进气道设计  前缘钝化  特征线法 

Key words:  Hypersonic  Inlet design  Leading edge bluntness  Method of characteristics

摘要:

为便于前缘钝化高超声速进气道设计与性能分析,将CFD方法与特征线法相结合,提出一种高超声速钝化锥/楔流场的快速精确计算方法(CCM方法)。该方法将CFD方法的精度与特征线方法的效率相结合,可进行前缘钝化高超声速进气道的快速设计与性能分析。利用CCM方法设计了一种前缘钝化两级锥轴对称进气道构型,分析了前缘钝化对进气道前体波系位置的影响,并采用CFD模拟开展了相应的对比考察和性能参数影响研究。结果表明,对于轴对称进气道,当前缘钝化半径较小时,进气道前体波系位置及流动性能基本不变；当钝化半径增至一定的尺度后,前缘激波向外偏移以及进气道性能参数的下降开始显露并渐趋明显。在设计状态点附近,低来流Ma下前缘钝化对轴对称进气道性能影响更为显著。对于该轴对称进气道构型,前缘钝化半径在10%捕获半径内变化时,进气道流量系数、出口截面总压恢复系数等参数变化幅度均在10%以内；进气道自起动Ma数略有下降。 

Abstract:

A combined CFD with characteristic method (CCM) was proposed for fast and accurate computation of hypersonic blunt cone/wedge flowfield. Both the accuracy of CFD and the efficiency of characteristic method are well combined in CCM, and it can be used for design and performance analysis of hypersonic inlet with leading edge bluntness. By using CCM, a bi-cone axisymmetric inlet with leading edge bluntness was designed and the effects of leading edge bluntness on its performance were evaluated. Correlated validation and inlet performance research were carried out by using CFD simulation and good agreement was found between CFD and CCM. The results show that the effect of leading edge bluntness on axisymmetric inlet performance is related to blunt scale and freestream condition. As the blunt radius varies within a limited scale, the changes in the behaviors of the inlet flow are negligible, beyond which the decrease in the performance appears and tends to be more severe. As the freestream Mach number decreases, more effects of leading edge bluntness on axisymmetric inlet performance are shown up. It was also found that for the present designed inlet configuration, flow parameters of exit cross section vary within 10% and the self-start Ma decreases a little as the blunt scale increases to 10% cowl radius. 