Numerical Simulation And Verification Of Liquid Surface Instability Under Microgravity Based On OpenFOAM

With the rapid development of high performance computing technology and Computational Fluid Dynamics,numerical simulation based on computer system has been widely applied in fields of science and engineering and becomes as important as experimental research method.The propellant management in tanks loading on spacecrafts has been a difficult problem in aerospace field,especially the liquid surface behaviors in processes of on-orbit refueling and sloshing have not been studied deeply.The investigation of liquid surface behaviors in the processes of on-orbit refueling and sloshing are of great significance for our country.Based on the open-source CFD toolbox OpenFOAM,a simulation platform for liquid surface unstability in tanks under microgravity is developed in this work.The major content and innovations of this work are as follows.This work analysed difficult issues of liquid surface study in the processes of on-orbit refueling and sloshing.The relative requirements for numerical simulation platform were also summarized,which include accurate numerical solution,effective simulation tools and comprehensive verification.Based on these summaries,the liquid surface unstability simulation framework is developed based on OpenFOAM,the simulation procedure and designs of extended modules were introduced.This work extended the two-phase numerical solution on the basis of interFoam solver.The boundary conditions of wedge-shaped channel were designed.The CCF one-dimensional theoretical model was applied for the computation of pressure at the inlet considering the ISS experimental equipment.Then the solver was extended with dynamic mesh solution for the simulation of liquid sloshing.For the effective simulation requirement,this work developed several analysis tools for the liquid surface simulation based on OpenFOAM.Firstly an incremental algorithm was developed to predict the critical flow rate,the average velocity of cross section at the outlet is chose to be probe for the recognisation of bubbles.The pitching excitation module was designed based on dynamic mesh solution.This work designed a parameter analysis module for the descriptions of liquid surface unstability,in which the computing methods of liquid dynamics parameters in numerical solution were provided.The numerical simulation platform were validated against International Space Station(ISS)experimental data.With the verified simulation platform,this work conducted parameter analysis of different flow phenomena during refueling process in wedge-shaped channel and firstly predicted the liquid dynamics behaviors of pitching sloshing in Cassini tank under micrograviy.The simulation methods and prediction results is hopeful to provide a valuable guidance for design of tank and efficient liquid management in space.