Research On Curved Compression System In Supersonic/Hypersonic Non-uniform Inflow

A detailed study is performed in current dissertation on the newly curved compression system and its curved shock wave at the typical scramjet working environment by theoretical analysis, wind tunnel testing and numerical simulation methods.First, design methods of the two-dimensional plane compression, isentropic compression and cone wave compression are discussed. Then, the design method of a two-dimensional curved compression system that can form curved shock is given.Secondly, analysis the effect of the initial ramp length, total compression surface length, deflection angle of a small curved line forming compression system and increased yaw angle on the performance of different curved compression systems in the inviscid condition. The evaluation of software to predict characteristics of the inlet is assessing by selected the classic NASA inlet experiment example. Analysis and comparison of the numerical simulation and experimental results, different turbulence models forecast the performance of inlet obtained. The selected turbulence model is given.Then, constant pressure gradient wall and constant Mach number gradient wall are designed, quick and convenient approximate calculation method access to curved shock wave shape, performance parameters on the compression surface, performance parameters after the shock and export performance parameters is given by applications of oblique shock wave theory and the theory of isentropic compression. The estimation formulas of estimating the shape of curved compression surface and its shock wave are given.Next, a constant pressure gradient compression system modified by boundary layer with design point Mach number 5.3 is selected, tested in NUAA Mach number 3.85/5.3 wind tunnel in uniform and non-uniform inflow.The results showed that: at the design point Mach number 5.3, the wall pressure distribution of bending compression system is constant pressure gradient; so does at the off-design Mach number 3.85. In the non-uniform flow conditions, wall pressure distribution is closer to the constant pressure gradient at Mach number 3.85 than at Mach number 5.3. All results prove that the design method is feasible.Detailed study on the performance of a two-dimensional constant pressure gradient non-conventional compression inlet and two-dimensional wedge compression inlets are performed. At design point, the pressure ratio of a two-dimensional non-conventional compression inlet is higher , its length of the compression surface can be reduced about 20.5 percent, greatly reducing the inlet weight. In Mach number 4 uniform inflow, a two-dimensional non-conventional compression inlet gets a higher mass capture ratio and total pressure recovery. Swallowed inflow boundary layer about 36 percent height of inlet height, mass capture ratio and total pressure recovery of the two-dimensional non-conventional compression inlet is increased 0.6 percent and 4.8 percent, respectively than two wedges compression inlet, but three wedges compression inlet is unstarted.In uniform and non-uniform inflow, the performance of three-dimensional sidewall compression inlets with plane sidewall + plane topwall, curved sidewall + plane topwall, plane sidewall + curved topwall,and curved sidewall +curved topwall,respetively are presented. In uniform inflow conditions, three-dimensional sidewall compression inlet with plane sidewall + curved topwall is of good performance. In non-uniform inflow, three-dimensional sidewall compression inlet with curved sidewall + curved topwall is of higher mass capture ratio and total pressure recovery .The study of a curved compression system with a shorter length, compression surface pressure gradient controlled, better ability to withstand non-uniform supersonic inflow is presented. The research results will be founded a new base for development of future scramjet research.