Design And Numerical Simulation Of Intake Port In Full-speed Domain Under The Coupled Effect Of Pre-cooling

Synergetic Air Breathing Engine(SABRE)is a combined pre-cooling engine with highly integrated air-breathing engine and rocket engine.Its flight speed range is wide,the turbine combustor and sub-combustion ramjet combustor work independently in the air-breathing mode(Ma0-5).A compressor is installed in front of the turbine combustor.Therefore,the requirement for the recovery coefficient of the total pressure of the inlet is not high,but the turbine channel is required to maintain a relatively stable air flow.The precooler is composed of micro-channel heat exchange tube bundles.The flow field of the precooler and the inlet flow field are coupled together and affect each other.The appropriate numerical simulation method is the research difficulty.In this paper,the pre-cooling engine's inlet is designed based on the structure of the SABRE engine,and the physical precooler is replaced by two simulation methods to obtain the flow field characteristics of the pre-cooling engine's inlet.First,a single-cone axisymmetric adjustable inlet is designed,numerical simulation is performed on it under full-speed range conditions,and the throttling characteristics of the inlet without pre-cooling are studied.The results show that:the inlet basically achieves full-speed operation,and the flow rate of the turbine channel changes smoothly;the turbine mass flow of Ma5 without pre-cooling conditions is almost choked;Under high Mach number conditions,the inlet has stronger anti-interference ability to the turbine channel mass flow.Secondly,through the porous media coupling source term method,numerical simulation of the inlet in the pre-cooling condition is carried out,and the throttle characteristics of the inlet in the pre-cooling condition are studied.The results show that the total temperature at the outlet of the turbine channel under the Ma2-5 pre-cooling condition is reduced to 200-300K;after pre-cooling,the Mach number of the turbine channel under the Ma5 condition is reduced to 0.3,which greatly alleviates the congestion state;The various aerodynamic parameters in the virtual pre-cooling zone are uneven,and a low-speed low-temperature zone is formed downstream;the larger the flow of the turbine channel,the better the cooling effect of the virtual pre-cooling zone,and the total temperature of the stamping channel is hardly affected by the flow distribution;The two-channel total pressure recovery coefficient is negatively correlated with the turbine channel flow coefficient,and part of the turbine channel flow can be sacrificed to increase the two-channel total pressure recovery coefficient.Finally,a preliminary exploration of the different numerical heat transfer methods of the hole wall heat transfer is carried out,and at the same time,starting from the geometric characteristics of the SABRE precooler,it is simplified to an axisymmetric tube bundle model without circulating flow.The flow field of the inlet based on the hole wall heat transfer was simulated under the Ma2-5 and compared with the flow field without precooling under different outlet conditions.The results show that it is feasible to simulate the flow heat exchange of the precooler through the hole wall heat exchange zone.Under the condition of 50-100m/s incoming flow,the cooling effect of the convective flow of the tube bundle model with the heat transfer coefficient h_cool=3000W/(m²·k)on the cold side is closest to the experimental fitting formula;The higher the flying Mach number,the greater the cooling rate of the turbine channel of the inlet,but the outlet temperature is still on the rise;The hole wall heat exchange zone has a strong rectification effect,and the total temperature and Mach number downstream of the heat exchange zone are evenly distributed;The total pressure recovery coefficient at the downstream of the hole wall heat exchange zone is only about 40%of the upstream.