Dual-mode Scramjet Combustor Numerical Simulation,

Dual-Mode ramjet engine which gathers the advantages of both ramjet and scramjet is a new-style airbreathing propulsion device. It can operate over a wide Mach number ranges(M=3-8). It is of remarkable performance and great potential application for hypersonic vehicle.Dual-Mode combustion chamber ,as the key component of the Scramjet, is the most difficult to design. In this paper, MacCormack explicit time-split scheme ,Baldwin-Lomax algebraic turbulent model and two-steps hydrogen-air nonequilibrium chemical kinetics model are employed to simulate the 2-D flow fields in a fixed geometry scramjet combustor in different injecting way of fuel in different flight conditions.The results show, in the same entrance condition , the operating mode of scramjet combustor is influenced by the control of fuel . Scramjet combustor may realize the subsonic-combustion mode and supersonic-combustion mode respectively based on the control of fuel in variable flight conditions. Isolator has great effect on mode transition and preventing unstart of inlet. Inlet can be unstarted by raising the back pressure result from chemical energy release in the combustor.