Hypersonic Inlet Design And Performance Study

Due to the good performance and huge potential dominace of the scramjet, the attention of many countries focuses on the study of scramjet. Consequently the study of hypersonic inlet is significant in theory and engineering application. This thesis introduces the development of scramjet technology domestically and abroad. The scramjet inlet with isolator is studied based on the condition of cruise Mach number 6.0. Characteristics of hypersonic inlet are analyzed in this paper. The design methods of two-dimensional and three-dimensional mixed compression hypersonic inlet and isolater are studied. The two-dimensional mixed compression hypersonic inlet with wedge lip and plane lip are designed by using the method of equal shock wave intensity. The software was employed to simulate the flow field of the design and off-design conditions. The optimal scheme was determined by adjusting the model size of two-dimensional inlet.Based on the two-dimensional inlet optimal scheme, a new three-dimensional inlet is designed, which replaces the third lean plane of the two-dimensional inlet by sidewall. The numerical simulation results show that the performance parameters of the three-dimensional sidewall compression inlet are less sensitive to freestream condition, and flow parameters change much more gently at different work conditions. In all flight conditons, three-dimensional sidewall compression inlet has better adaptability.The principal parameters of three-dimensional sidewall compression inlet are studied, three-dimensional sidewall compression inlet with one lean plane and two lean planes are designed. Flow field performance parameters are attained by numerical simulation. On the ground of the analyzed calculation results, the three-dimensional sidewall compression inlet scheme was modified to satisfy the scramjet inlet requestment.The effects of sidewall sweep angle and cowl position on three-dimensional sidewall compression inlet performance are analyzed and discussed in the paper.Changes of sidewall sweep angle and cowl position can influence inlet performance such as mass capture, total pressure recovery coefficient and uniformity of isolator exit flow field. The results indicate three-dimensional sidewall compression inlet with 45-deg. sweep angle has high total pressure recovery coefficient and isolator exit flow flied parameters distribution is homogeneous. And three-dimensional sidewall compression inlet with 25 percent cowl position has high mass capture and total pressure recovery coefficient and isolator exit flow flied is homogeneous.