Study On Control Method Of Bellow-Type Fuel Flow Rate Control Valve

Fuel supply control is one of the key techniques for the development of scramjet technology. In order to generate steady thrust force, the flow rate of the fuel, which flow into the scramjet combustion chamber, should be accurately, smoothly and fastly regulated. Scramjet engine uses active cooling method for coolant system. The fuel circulates across the engine surface as coolant before going into the combustion chamber. The temperature of fuel is raised up. Hence the valve works under adverse conditions. It is necessary to study the control method about the fuel flow rate control valve to ensure the scramjet engine performencs.A pneumatic bellow-type fuel flow rate control valve is developed. The theoretical analysis and experimental investigation are carried out. Being considered as a pneumatic servo valve-controlled cylinder with elastic loads, the mathematical models of the valve are built. The transfer functions based on the bellows control pressure and spool displacement are obtained respectly. Pressure closed loop control method and spool displacement closed loop control method are presented. According to the different feedback transfer function, different correction methods are adopted. And the PID controller is used to control the system. The system simulation is carried out by matlab/simulink software. A test rig for high temperature flow rate control valve is set up and the experiment on the valve is carried out. The valve control characteristics about the pressure closed loop control and spool displacement closed loop control are obtained and compared with the simulation results.