Influence of high-speed channel operating back pressure on the dual flow-path inlet performance during low Mach number flight stage

In order to understand the impact of high-speed flowpath backpressure ratio (PR H ) on the performance of an over-under dual-flowpath inlet, three-dimensional numerical simulation of a typical two-dimensional TBCC inlet is carried out with the PR H as a variable. The results show that under the condition that the back pressure does not cause the high-speed flowpath to not start, the PR H has a direct impact on the performance of the high-speed flowpath. But for the low-speed flowpath, it has a slight impact on the performance under the subsonic inflow condition. Specifically, as the PR H increases, the mass flow rate of the low-speed flowpath under the certain inflow condition decreases slightly. The reason may be that the reduced partial flow in the high-speed flowpath enters the low-speed flowpath by a large flow angle, thereby increasing the separation zone of the low-speed flowpath and affecting the mass flow rate in the low-speed flowpath. At the same time, due to the increase of the separation zone, the flow loss of low-speed flowpath increases, and the total pressure recovery coefficient also decreases slightly. Under the condition that the backpressure causes the high-speed flowpath to not start, the subsonic reflux fluid from the high-speed flowpath will also flow away from the low-speed flowpath, which reduces the actual flow into the low-speed flowpath and seriously affects the normal operation of the low-speed flowpath. Overall, the research results of the paper give a detailed explanation of the impact of PR H on inlet performance.