高超声速二维混压式前体/进气道设计方法研究

以飞行Ma数Ma=6,H=25km为设计点,分别采用等激波角和等激波强度设计方法,并考虑变比热、激波与附面层干扰等因素的影响,分别对唇口平直和唇口带有斜楔的超燃冲压发动机二维混压式前体/进气道进行了初步设计,分析并比较了几种方案进气道的设计点和非设计点性能及二维流场。研究表明,在低飞行Ma数下,唇口带有斜楔的前体/进气道起动性能和总压恢复优于唇口平直的,在高飞行Ma数下,唇口平直的前体/进气道冲压比高、外罩阻力小,而唇口带有斜楔的前体/进气道总压恢复系数高,外罩阻力相对较大。另外,分别采用等激波角和等激波强度方法设计的前体/进气道性能相近。本文提出的方法对于二维混压式高超声速前体/进气道方案的初步筛选具有一定的适用性。

Design Method of Two-Dimensional Hypersonic Forebody/Inlet of Mixed Compression

It is possible to define a fixed geometry hydrocarbon fuel dual-mode scramjet operating in a large Mach number range (between Ma=3 to 8).The efficient design of an inlet is crucial to the successful operations of the scramjet.The goal in the design of any hypersonic inlet is to define a minimum weight geometry that provides an efficient compression process,generates low drag,produces nearly uniform flow entering the combustor,and provides these characteristics over a wide range of flight and scramjet operating conditions.A two-dimensional hypersonic forebody/inlet of mixed external and internal compression with plane lip and wedged lip is designed in this paper by using constant shock angle method and constant shock intensity method.The design point of the designed forebody/inlet is determined to be Ma=6,H=25 km.The effects of temperature and shock/boundary-layer interaction are considered in the design.The design and off-design performance and flow field of several types of designed forebody/inlet are calculated and compared.The comparison results indicate,at lower flight speed,the starting performance and total pressure recovery coefficient of forebody/inlet with wedge lip are better than that with plane lip.At high flight speed,the forebody/inlet with plane lip shows higher pressure ratio and lower cowl drag,but the forebody/inlet with wedge lip exhibits high total pressure recovery coefficient and high cowl drag.Moreover,the performance of inlet designed by constant shock angle method or constant shock intensity method is similar.The presented method is applicable to the preliminary scheme choice of hypersonic forebody/inlet.