Simulation Study On Flow Characteristics Of Xenon In The Feed System Of The Electric Thruster

With the continuous advancement of China’s deep space exploration missions,the complexity of the space environment faced by spacecraft in orbit has increased,requiring the spacecraft to provide a wide range and smaller level of micro-thrust.The stability,rapidity and accuracy of working fluid flow and adjustment have become key factors affecting posture orbit correction.Related in-orbit experiments have found that the feed systems using Xenon gas as the propellant had different degrees of working fluid liquefaction during work,which will affect the output performance of the system and the life expectancy.Therefore,it is of great significance to study the phase change heat transfer characteristics of the Xenon flow in the feed system and the gas-liquid two-phase flow under different conditions.In this paper,firstly,a model of the Xenon feed system considering the phase change of the fluid is built using the AMESIM platform,which mainly includes two-stage pressure adjustment modules,different types of system piping and flow adjustment devices.The effects of different pipeline diameters,valve openings,valve core diameters,system initial temperature,pressure and tank pressure on the flow characteristics,state changes,heat transfer characteristics and output characteristics of Xenon in the feed system are studied.The generation mechanism and change law of Xenon liquefaction are summarized,and the influence law of component structure parameters,temperature and pressure on Xenon filling,morphological evolution and micro-flow output are revealed.Secondly,using the CFD method combined with the phase change heat and mass transfer function to analyze the two-phase flow characteristics and heat transfer characteristics of Xenon in the pipeline after the first-stage pressure reducing valve at different initial flow rates,pipeline diameters,wall temperatures,and saturation temperatures,and the evolution and spatial distribution of the Xenon gas-liquid two-phase flow under various working conditions are explored in detail.The changes of flow velocity,temperature,dryness and wall heat transfer coefficient of Xenon two-phase flow in local heat leakage and adiabatic pipelines are summarized.Finally,the influence of the two-phase flow and phase change heat transfer characteristics of the Xenon gas under different pipe diameters and initial flow rates when the system piping is heated by two heating methods with different constant wall heat flux density and linearly changing heat flow along the wall is studied.Reveals the changing laws of working fluid flow rate,dryness,temperature and wall heat transfer coefficient under different heating power and heating methods.The effects of the two heating methods on the two-phase flow and evolution are compared and analyzed,and it is concluded that the non-constant wall heat flow conditions can achieve the same effect as the constant heat flow under the premise of saving energy.