高速火箭增强冲压发动机内转进气道气动设计与风洞试验OA

Applying inward-turning inlet with high compression efficiency,good internal flow quality,high flow coeffi-cient,and low overflow resistance to a rocket-augmented ramjet engine can effectively improve the performance of rocket-combined ramjet inlet within the typical flight range and greatly enhance the application potential of rocket-augmented ramjet engine.Based on the typical central strut configuration of a rocket-augmented ramjet engine,if only a simple structural integration method is adopted,the physical intervention of the central strut would seriously damage the compression performance of the inward-turning inlet while its wedge-shaped leading edge would divide the high-speed airflow downstream of the inlet isolator and cause oblique shock and expansion wave interference,resulting in additional compression and an increase in internal contraction ratio,causing a significant decrease in the total pressure recovery coefficient.To address these issues,this paper proposes a structural integration design method between an inward-turning inlet and central strut based on streamline tracing technique.By integrating the central strut with the inlet compression surfaces,not only additional compression effects can be eliminated,but the inflow compression capabil-ity of its special precursor can also be fully utilized.The numerical simulation and wind tunnel test verification results in-dicate that this design method can enable the integrated inward-turning inlet to fully exert the compression performance of the basic flow field while introducing the central strut.Compared with the traditional wedge-shaped central strut,its length can be reduced by 60%at most,and the internal contraction ratio can be reduced by 25%,thus ensuring better start capability.Under the conditions of high contraction ratio and strong compression with the incoming flow of Mach number 6 and the throat pressure rise ratio of 34.8,the total pressure recovery coefficient is improved by 17%.