Investigation of a variable geometry 2D inlet for combined cycle engine

A 2D variable geometry inlet with double passages is put forward in the paper. A baffle divides the inner passage into two passages. The bellow passage could be close by rotating the last compression face at high fight Mach number, with the cowl rotating at the same time. So regulations of inlet compress angle and contraction ratio could be achieved at the same time. Numerical simulation investigation show that: the variable geometry inlet has well performance from flight Mach number 2.2 to 7.0, such as higher total pressure recovery coefficient and proper exit Mach number. it is most important that the inlet has high mass flow during the wide flight Mach number range. In addition, the regulation process is simple, dependable and easily actualized.