宽Ma数范围固定几何进气道设计问题研究

Study on fixed-geometry supersonic inlet design for wide Mach number range application

针对Ma=2～3.5中等超声速宽范围的设计要求,通过实例方案设计和CFD数值模拟分析表明,按工程上现行的折中设计思想,固定几何进气道的内流道型面实质上是为满足低速接力要求而设计的。在高速巡航时,其超声速扩压段气流总折转角偏小,且喉道高度偏大,对捕获来流压缩不充分,导致喉道段的气流流速过高,且畸变显著,致使结尾正激波总压损失过大,是进气道高速性能差的主要成因。

A 2-D fixed-geometry inlet design case study and CFD simulation for wide range of Mach 2 to 3.5 applications,show that the present engineering design is based on compromised design philosophy,and its inner flow passage is essentially designed for satisfying low speed takeover need in essence.During high speed cruising,however,its total flow turning angle over supersonic diffuser is smaller while throat height is larger than ideal,thus,resulting in insufficient compression of captured free stream,and flow passing throat passage has excessive high speed and considerable distortion causing excessive total pressure loss due to terminal normal shock.These factors are the main causes of poor performance of fixed-geometry inlet under high speed cruising situation.