Dynamic Response Analysis of High-Pressure Rocket Pumps

Abstract

With regard to the development of a liquid rocket engine, it is very important to know the unsteady characteristics of turbopumps for the increase of rocket reliability. Numerical simulation is very advantageous to know the unsteady characteristics of turbopumps, which contributes to decrease the cost and the number of experiments. In the dynamic analysis, the dynamic characteristics of a cavitating inducer are known as very critical and complex factors. However, almost all analytical models of cavitating flow of a rocket engine feed system have assumed such flow to be incompressible and have treated it linearly. In the present study, the effect of compressibility of a liquid hydrogen (LH2), which is the cryogenic propellant, and the effect of non-linearity of flow on the dynamic response of a high pressure turbopump were taken into consideration. The results of calculation were compared with a non-linear incompressible mathematical model. Design parameters of the LE-7 engine were used to simulate the steady state conditions. The effects of dynamic characteristics of a cavitating inducer, such as cavitation compliance and mass flow gain factor, and the effect of pipe elasticity were also analyzed.