| High temperature flow control valve is one of the core components in the supply system of supersonic combustion ramjet engine. It accurately and stably controls flow in real-time. Temperature of the in the flow control valve can reach 500-600 ℃, and the heat is the key influence factors of the structure and performance of the high temperature flow control valve. The thermodynamic, flow field and flow control characteristics of the high temperature flow control valve are systematically studied according to the coupled field theory, with computational tools and testing devices.The thermodynamic of high temperature control value is studied with the method of multi-field coupling. The thermo-elastic coupling model of high-temperature valve with temperature rapidly changing is established based on the theory of elasticity and thermodynamic and the model is solved numerically. Based on the theoretical analysis and considered the interaction of temperature and stress, the thermodynamic properties of control valve which are made with 45# steel and GH783 alloy are studied with computer software. And the temperature field, thermal stress and thermal deformation are simulated too. The simulation results show that thermodynamic characteristics of the flow regulating valve made by GH783 alloy can meet the requirements of control valve, but the maximal thermal stress and thermal strain appear at the edge of valve port and the front end of valve core, which affect the flow characteristics of the control valve at the valve outlet. In order to reduce the effect of deformation on the flow adjusting precision, the filleted corner structure is applied to the valve port.The fluid-solid coupling model of high temperature flow control valve is built with according to the theory of fluid mechanics and solid mechanics. The coupling mechanism between the valve core and valve body is analyzed. The fluid domain and solid domain of flow control valve are analyzed respectively. The fluid-solid coupling equation of the high temperature flow regulation valve is built and the complete numerical calculation method is deduced. On the basis of theoretical analysis, the flow field of high temperature flow regulation valve is simulated with computer software. The relationship of valve opening degree, the pressure at the inlet and outlet of valve and flow rate and valve flow are analyzed. Flow coefficient of the flow valve with different pressure and valve opening degree is obtained. The flow coefficient equation is fitted according to the flow coefficient curve.The working principle of the pilot valve is analyzed, and established its mathematical mode. By analyzing the force on the spool of the factors, obtained the effect factors of regulating valve poppet valve flow, establishes a mathematical model of regulating valve cone valve section. With the two model combined, the transfer function is established of high temperature flow regulator valve. Using Matlab/Simulink, the pressure and displacement feedback control are simulated, and the results show that the displacement control has a higher precision than pressure control, and it partly reduces external disturbance with low temperature. While the pressure feedback control, with a lower precision than displacement control, can be adapted to high temperature, with a short response time, and it is the ideal choice for the high temperature flow regulation system.At last, Thermodynamic properties of the valve with high temperature is tested, the test results were analyzed and compared with the simulation results, and the simulation results is verified. The control characteristics of high temperature flow vavle is tested, with two exciting ways of sine and square wave, the system dynamic response with the valve spool displacement feedback control and bellows control gas pressure feedback control are tested, and according to the analysis to the test results to regulate the system parameters, then, the dynamic response and the flow response with high temperature are tested, results show that the flow control system can meet the expected requirements. |
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