Abstract: The key factors of a propellant cross feed system are studied by simulation to get in depth knowledge of the cross feed system characteristics and grasp the influence law of these key factors. The mathematical model of the major components of the cross feed system is built and a simulation model is developed in AMESim. The research shows that the different ullage pressure of the propellant tanks and the flow resistance of the pipeline are the two key factors. In order to maintain the rate of cross flow, the ullage pressure of every propellant tank must be precisely regulated. The flow resistance of the upstream pipeline of the booster and cross feed pipeline has the greatest impact on system performance, therefore the upstream pipeline of the booster and cross feed pipeline should be shortened and the difference between the upstream pipelines of the two boosters should be reduced when a cross feed system is designed.

Key words: Launch vehicle, Cross feed; Different ullage pressure, Flow resistance of pipeline