Research On Modal Conversion Flow Characteristics Of Parallel TBCC Adjustable Internal Rotation Inlet

With the rapid development of the global aerospace industry,hypersonic vehicles have become a research hot spot in the world.The key technology of hypersonic vehi cles is the propulsion technology,hypersonic vehicles need to work in a wide range o f Mach Numbers,however,the single dynamic propulsion system can not meet this re quirement,the combined cycle propulsion system as the dynamic system of hypersonic vehicles,which integrates several single dynamic propulsion system,enables hypersoni c vehicles to fly in a wide range of speeds.In recent years,Turbine-Based Combined Cycle(TBCC)dynamic system has become the main development direction of the co mbined power technology,the TBCC inlet as the air intake component of TBCC engi ne is an important part of the dynamic propulsion system,it can provide the air flow with suitable pressure,velocity,temperature and mass flow rate for the engine to wo rk efficiently in the different work Mach Numbers and its performance will directly in fluences the performance of propulsion system.In this paper,the mode transition's flow characteristics of a inward turning TBCC variable geometry inlet are studied,It mainl y includes the comparison of the flow characteristics of TBCC inlets which use differ ent parallel plan,and the impact of turbine channel's length and the baffle plate in tur bine channel on the mode transition process.Firstly,comparing the numerical simulation results of pure external parallel plan an d mixed internal parallel plan's mode transition at Mach number of 3,the result shows that the the total pressure recovery of pure external parallel plan's turbine channel is higher than mixed internal parallel plan,and its steady state distortion of turbine chan nel's outlet is lower than mixed internal parallel plan;Secondly,the effects of the length distribution of the sudden expansion section an d the gradual expansion segment,the length of the sudden expansion segment and the length of the gradual expansion section on the performance parameters and the flow field characteristics of the inlet during the modal transition are studied respectively.Th e results show that the inlet model with a longer expansion section,the total pressure recovery coefficient of turbine channel is higher and the steady state distortion of out let is lower.Finally,The models which turbine channel was placed baffle plate were designed.C omparing the non-baffle model,the straight baffle model and the bending baffle model's numerical simulation results of mode transition at Mach number of 3.When the tur bine channel is fully open,the bending baffle model has the best performance,and th e non-baffle model has better performance when the turbine channel is closing.