Mathematical modeling of dynamic processes in feeding system of space stage main engine of launch vehicle at active and passive flight

Abstract

An approach is developed for operability diagnostic of liquid propulsion feeding system of launch vehicle space stages in microgravity conditions in active and passive flight, including multiple start-ups of main engines with minimal levels of tank filling. The approach is based on the method of finite elements, liquid volume method (VOF), technologies of 3D-computer analysis (CAE-systems), and impedance method. As a part of the proposed approach based on mathematical modeling of dynamic processes in the stage propulsion feeding system in microgravity conditions, the slosh motion parameters of the «gas-liquid» interface in propellant tanks are determined together with the free gas bubbles' parameters. At the same time, the effectiveness of the propellant management device is evaluated during stage propulsion system operation. Along the way, the parameters of transient processes in the propulsion feeding system of main engines are calculated during its multiple start-ups and shutdowns, and amplitudes and frequencies of propulsion feeding system are determined. The computed fluid motion parameters and the liquid propellant-free surface shapes showed a good agreement with data obtained in test studies of the motion of the experimental model of the «Centaur» upper stage propellant tank in a «drop tower». The transient process parameters of the space stage feed system showed satisfactory agreement with experimental data obtained in water testing. The developed approach will reduce the amount of testing of developed and upgraded launch vehicle space stages.