Abstract: For the characteristics of operating together in the same expansion flowpath, three-dimensional numerical simulation has been carried out to study the formation mechanism and law of thermal throat in ramjet mode. The results show that the formation position of thermal throat can be controlled through reasonable heat release and area changes in the flowpath. The cavities that are located in the second combustor play an important role for the formation of a stable thermal throat. The combustion region formed from the cavities shear layer becomes a stable heat source which provides airflow with the transition energy of Mach number. The geometry contraction of cavities rear wall also provides impetus for the formation of congested surface. Airflow behind the cavities gradually becomes stable supersonic flow. Thermal throat is substantially formed behind the second cavities. 

Key words: Rocket based combined cycle; Thermal throat; Cavities; Numerical simulation

摘要： 针对RBCC同一扩张流道多模态匹配工作的特点,通过三维数值模拟,研究了亚燃模态热力喉道形成机理及规律,结果表明通过合理控制流道中的加热量和流道面积变化可以有效地控制热力喉道形成位置,其中位于第二级燃烧室中的凹腔组对形成稳定的热力喉道有比较关键的作用,其剪切层形成的燃烧区域成为一个稳定的放热源,给流道中的气流提供了使马赫数出现转折的能量,凹腔后壁斜面的几何收缩也为壅塞面的形成提供助力,凹腔后流道的气流逐步稳定成为超声速流,热力喉道基本形成于第二级凹腔组后。 

关键词: 火箭基组合循环;热力喉道;凹腔组;数值模拟 