Numerical Study On Flow Control And Combustion Process Of Variable Thrust Liquid Propellant Space Rocket Engine

The mass flux controller, spray combustion process and control scheme of variable thrust liquid propellant space rocket engine were investigated.Based on the analysis of the phenomena of cavitation flow of the controllable cavitating venturi, a two-phase model of cavitation flow was developed and simulation of gas-liquid two-phase flow in controllable cavitating venturi (used for variable thrust engine, VTE) was performed. The effect on the coefficient of pressure recovery and mass flux by different structure parameters, venturi taper stroke, working fluid, temperature etc. were calculated and analyzed with the model. The result can provide valuable information to the design of high performance controllable cavitating venturi.The spray combustion process of pintle engine with NTO/MMH propellants was simulated. First, the pintle injector and thrust chamber were designed with demand. An integrated physical model and a numerical method were developed to simulate the spray combustion process. Then the reacting flow field under different operating conditions or with different injectors under a certain operating condition were simulated. Results obtained from CFD modeling will provide valuable information to future engine designers.The fuzzy control of variable thrust engine was investigated with MATLAB/SIMULINK. Based on the analysis of the characteristics and control demand of VTE, applying fuzzy control to the control of VTE was proposed. Then fuzzy control, optimal control based on different optimization criteria, fuzzy-PI two mode control and fuzzy self-adaptive PID control were applied to the control of VTE. The results show that only fuzzy control cannot meet the demand of control, while fuzzy control combined with other strategies can elevate dynamic control performance of VTE significantly.