Design And Analysis Of Inverted Inward Turning Hypersonic Inlet With Precompression Bump

The bump,which is the most effective and reliable flow control means,is applied in supersonic fighter to control the development of boundary layer,reduce the shock wave boundary layer interaction and inhibit the boundary layer separation,but still not in the hypersonic inward turning inlet.Therefore,it is of great significance to design a bump for hypersonic inward turning inlet and study its performance.In this paper,we designed streamline tracing bumps and parameterized bumps,and applied the bump to the inverted inward turning inlet.The hypersonic inverted inward turning inlet with precompression bump was studied deeply and systematically by means of numerical calculation and experiment.In the numerical calculation,we studied four groups of two types of inlets,and got their self-start Mach number,the performance of total pressure recovery and pressure rise characteristics.And the law is summarized.In experiments,two inlets with bump of different length were studied.The flow field structure of the inlet self-starting was obtained by using the flow filed display technology such as schlieren.And the static pressure along the wall was also obtained.Firstly,two types of bump were generated by the simple parametric method and the method of streamline tracing,and applied to the three-dimensional inward turning inlet.Secondly,the numerical simulation of four groups of two types of inlets was carried out,and the self-starting Mach number,performance of total pressure recovery and pressure rise characteristics was obtained.The results showed that once the inlet start up,the mass flow ratio of inlet was nearly not affected by the length of bump.At the same time,there is the shortest length of bump,which results in the highest self-starting Mach number of the inlet and the worst self-starting performance.Finally,two hypersonic inlets with different lengths of bump were tested and the characteristics of the self-starting angle of attack of the inlets were obtained.The results showed that the inlet with longer bump self-start earlier.At the same time,it was found that there is a serious hysteresis in the inlet starting-up progress.