Simulation of the working process of launch vehicle pressurization system in random vibration condition

To study the dynamic characteristic and stability of the launch vehicle tank pressurization system working in random vibration condition, harmony superposition method was used to simulate the random process; and component-shell-placement was introduced as vibration excitation to modify the existing model. The gas pipes and components were respectively modeled using the one-dimensional flow equations under the Lagrange reference frame and the ordinary differential equations, working processes of the pressurization system in/without the vibration condition were simulated. In the vibration condition, pressure fluctuation was observed, which may lead to the oscillation of the regulator, and destroy the stability of the component. The vibration presents little conspicuous influence with the ullage pressure during the full course of work. The data of the system working in non-vibration condition was compared to the given test record, a satisfying agreement was reported. The mathematical model and calculating method are validated to be effective in the calculation of the working process of the launch vehicle tank pressurization system.