Numerical investigation on the ram–scram transition mechanism in a strut-based dual-mode scramjet combustor
Numerical investigation on the ram–scram transition mechanism in a strut-based dual-mode scramjet combustor
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DOI：
10.1016/j.ijhydene.2016.01.062
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发表时间：
2016-03
影响因子：
7.2
通讯作者：
Wei Huang;Li Yan
中科院分区：
文献类型：
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作者：
Wei Huang;Li Yan
采用热阻塞方法可以在同一流道内实现冲压发动机和超燃冲压发动机两种模式，双模超燃冲压发动机燃烧室越来越受到人们的关注。对基于支杆的双模超燃冲压发动机燃烧室冲压-冲压模式过渡机理进行了数值计算，研究了隔离器入口边界条件、喷射策略和射流-横流压力比对模态过渡的影响。同时，通过紊流扩散燃烧问题验证了数值方法的有效性，验证了氢-空气化学反应机理的有效性。结果表明：隔振器入口处的入口边界条件和射流与横流压力比对冲压-冲压模态转换有较大影响，当射流与横流压力足够大时，即本研究的10.0和15.0，支板上游的流动为亚音速。热窒息点首先出现在支板的前缘，即atx= 0.25 m附近。低自由流马赫数有利于冲压发动机工作模式，随着飞行器飞行速度的增加，发动机将转换为超燃冲压发动机工作模式。本文采用的喷射策略的影响可以忽略不计，并且没有干扰支板前缘上游的马赫数分布。
The ramjet and scramjet modes can be realized in the same flowpath using the thermal choking approach, and the dual-mode scramjet combustor has attracted an increasing attention. The ram-to-scram mode transition mechanism in a strut-based dual-mode scramjet combustor has been evaluated numerically, and the influences of the inlet boundary conditions at the entrance of the isolator, the injection strategy and the jet-to-crossflow pressure ratio on the mode transition have been investigated. At the same time, the numerical approach has been validated through a turbulent diffusion combustion problem, as well as the effectiveness of the hydrogen-air chemical reaction mechanism. The obtained results show that the inlet boundary conditions at the entrance of the isolator and the jet-to-crossflow pressure ratio both have a large impact on the ram-to-scram mode transition, and the flow upstream of the strut is subsonic when the jet-to-crossflow pressure is large enough, namely 10.0 and 15.0 in the current study. The thermal choking point first appears at the leading edge of the strut, namely nearly atx= 0.25 m. The low freestream Mach number is beneficial for the ramjet mode operation, and the engine would convert into the scramjet mode with the increase of the flight velocity of the vehicle. The influence of the injection strategy employed in this paper can be neglected, and the Mach number distribution upstream of the leading edge of the strut has not been disturbed.