Investigation On Ram Air Turbine-Pump Fuel Feed System Scheme Of Dual-combustion Ramjet Engine

With the comprehensive breakthrough of scramjet key technologies,the scramjet develops towards ground experiments to flight tests and engineering applications.The investigation of fuel feed system has important theoretical and practical value for the promotion of scramjet system engineering as well as essential significance for promoting the process of engineering.In order to expand the application of turbo-pump fuel feed system,which use ram air as energy source,from ramjet to scramjet,a scheme of turbo-pump fuel feed system based on hydrocarbon-fueled dual-combustion ramjets(DCR)was proposed in this paper.The section of turbo-pump and the control strategy of the system are introduced,and the intaking and exhausting methods of the ram air were also primarily desinged.Based on the balance relationship of pressure,mass flow rate and the power of the system,the static models of the system were established,and the Newton iterative method was used to solve the model.Using this method,the static performance of the system was analyzed at difference working conditions.The performance and regulation of the turbo-pump were analyzed at the conditions of the fight Mach numbers changing from 3.5 to 5.5.Results show that,the mass flow rate of turbine is 3% of the captured ram air,so the intaking and exhausting methods have little influence on the aerodynamic performance of the engine;the performance of pump is relatively stable,it can work with high efficiency for a long time,but the pressured fuel is underutilized,causing low utilization rate of the turbine power.Two groups of turbine-pump combined experiments were taken by using nitrogen of room temperature,one was turbine outlet sultry running experiment,the other was turbine outlet exposure experiment.It was found through the results analysis of the first experiment that,the turbine power has good linear relationship with turbine inlet pressure.The similarity analysis was made for tangent pump,and the correction terms were added based on similar principles.The results showed that the pump's lift,volume flow and power have good similarity with rotor speed.The dynamic module of fuel feed system was built by Simulink,The simulation of DCR engine starting,bypass valve controlling process are analyzed.Result show that,the ram air's mass rate,the turbine-pump's torque of this system change is very intensity.The rotor speed and fuel pressurize increase gradually;the influence of the system's characteristic parameters is not obvious by subsonic combustion chamber igniting;at the beginning of starting,the pressure of combustion chamber is significantly greater than the spray injection pressure,causing the choke phenomena of approximately 0.8s.