Study Of Flow Characteristics Of Combined Cycle Engine Inlet With Ma0-7

Overall project,design method and regulation scheme of a Ma0~7 combined cycle inlet was given in this thesis.The design of geometric parameters,aerodynamic characteristics in whole Mach number of combined cycle inlet and the model transition were performed by numerical simulaition.First of all,Overall project of the Ma0~7 combined cycle inle was given,the variable range of the internal contraction ratio of this inlet is 0.69-2.0,and this can balance the contradiction between the start compability at low mach number and the aerodynamic performance at high mach number of inletSecondly,the flow characteristics in the inlet within Ma4~7 were studied.results show that the cruve shock became bent as a result of the increasing of Mach number and attack angle.The perfomance of the inlet is well.The total pressure recovery coefficent,Mach number and mass flow coefficent are 0.52,3.02,and 1 at Ma=6.0,α=0°.Then,the ERJ diffuser was designed and the control law of inlet which influenced the throat Mach number were given.And the regulation scheme was put forward according to the flow characteristics in the inlet within Ma2.5~4.0.The variable range of the internal contraction ratio of this inlet is 1.2~2.0;The outlet pressure of the inlet can meet the requirements of combustion,and the flow coupling of the two channels can be avoided.The mass flow coefficent increased linearly as zhe Mach number increased.When the pressure is smaller than the critical pressure,the total pressure recovery coefficent of ERJ diffuser are 0.641,0.395,0.243 at Ma2.5,Ma3.2,Ma4.Finally,the regulation scheme of turbine model within Mach0~2.5 was put forward according to the inlet-engine maching characteristics.The turbine diffuser is closed gradually with the increase of Mach number.The variable range of the internal contraction ratio of this inlet is 0.69~1.2.The strong coupling relationship occurs between the turbine and ramjet channel.The mass flow and the total pressure recovery at the outlet of turbine channel can be adjusted through matching the back pressure between these two channels,and total pressure recovery of turbine channel increased.The total pressure recovery coefficents of turbine channel at Ma0.8,Ma1.5 and Ma2.0 are 0.94,0.882,0.775.