Small Squeeze Of Liquid Rocket Engine System Simulation

Based on a space liquid rocket engine system, the static and dynamic characteristic of pressure-fed Liquid Propellant Rocket Engine was studied, furthermore, analyses of the static and dynamic characteristic were also carried out for the valve of the system.Firstly, the static and dynamic mathematic model of the Liquid Propellant Rocket Engine of pressure-fed providing system was established in centralized parameter method. Numerical simulations were done for a bistable latch valve of the system by FLUENT, and three groups of datum for different fluids were obtained with the same effective exit sectional area. Besides, a static mathematic model for the electromagnetic valve was established based on the obtained datum. Secondly, the motion of the valve spool was realized by UDF(User Define Function) file in FLUENT. Three kinds of motions, uniform, acceleration and motion driven by the coupling effect of the liquid resistance and the electromagnetic force, were calculated and compared. The dynamic characteristic of the electromagnetic valve was obtained by analyzing the relationship of the mass flow rate of the inside flow field of the electromagnetic valve, the change of the drop pressure of the passageway of the valve, and motion time.A simulation system was developed to simulate the static characteristic of pressure-fed Liquid Propellant, using MATLAB as the software platform. Then, this system was applied to analyze the influence of interfering factors towards the parameters of LRE for monopropellant (H₂O₂) and bipropellant (N₂O₄/UDMH) system, which include the effect of upstream pressure of the tank and the diameter of the pipelines on the thrust. Thus, the variety of main parameters such as thrust, impulse, and chamber pressure were obtained at rated condition. The sub-modules of the parts of the engine were established by SIMULINK according to the non-linear mathematical model. These sub-modules were connected as a system according to the real engineering drawing. Then, the system was simulated by using fourth order Runge-Kutta method. Through system simulation, the time sequence of the valves in the pressure-fed Liquid Propellant Rocket Engine was obtained and its effects on the dynamic system was analyzed. All of these are useful for the design of the same kind of LRE.