Research On Inlet Flow Regulation System Of Solid Rocket Ramjet Engine

The solid rocket ramjet combines ramjet technology with solid rocket technology,which not only has a simple structure and reliable operation,but also has a higher specific impulse.However,when maneuvering a missile,its air-fuel ratio needs to be adjusted to adapt to changes in complex flight conditions,so variable flow technology has become the focus of research.At present,ground simulation experiments are one of the main methods for variable flow experiments of solid-impact engines,and direct-connected simulation experiments are widely used because of their simplicity and economy.In this paper,the flow adjustment of the inlet of the direct experimental system is carried out through control system design,algorithm simulation,numerical simulation,and experimental verification.(1)According to the principle of inlet flow rate adjustment,a variable geometry adjustment plan for the inlet is designed.The throat width of the directly connected experimental system is changed by the linear movement of the slider.At the same time,an algorithm design is carried out for possible slider position error.What’s more,the PID control based on the output delay observer is compared with the traditional PID control.Algorithm simulation through MATLAB and analysis of the simulation results can be obtained.Compared with traditional PID control,PID control based on the output delay observer shortens the response time and has no overshoot.Furthermore,it has good tracking performance and anti-interference.Therefore,the PID control based on the output delay observer can effectively improve the control accuracy of the entire system.(2)Through the design and production of the embedded hardware platform based on STM32 and the program design for the lower computer(Single Chip Microcomputer),the designed algorithm can be applied to the actual experiment so that the slider motion curve is obtained.The high-precision control of the slider position closed-loop system is adopted,which further reduces the difference in intake flow that may occur due to position errors.(3)The calculation model of the internal flow of the inlet with different throat areas was established,and the characteristics were studied.The similarities and differences of Mach number,pressure and temperature distribution in the inlet with different throat areas were analyzed.At the same time,through the fitting analysis of the inlet flow with different sliding distance,the fitting curve of the inlet flow rate adjustment rule was obtained.(4)The simulation experiment of the inlet flow regulation system was studied.The directconnected experimental mechanism was used to simulate the air flow parameters at the throat of the inlet.Intake simulation experiments of inlets with different throat areas were performed,and the measurement results were compared with the numerical simulation results.The numerical simulation error was less than 5%,which verified the credibility of the numerical simulation results and the control algorithm reliability.At the same time,the correction coefficients between the experimental and simulated flow values were obtained by combining the simulated flow values,and the fitting curve was obtained.