含固氧颗粒的液氢传输管路中静电积聚仿真研究

Simulation Study of Electrostatic Accumulation in Liquid Hydrogen Transmission Pipeline Containing Solid Oxygen Particles

为探究含固态氧颗粒的液氢管道传输中静电积聚规律,基于COMSOL Multiphysics软件,开展了液氢-固氧体系荷电规律仿真预示。采用拉格朗日颗粒轨道法与计算流体动力学分别描述连续液氢流与离散固氧颗粒的运动,采用Materials Studio软件计算获得固氧电学性质,并通过电容器法描述固氧颗粒碰撞起电规律,实现固液两相流与静电场的耦合求解。仿真结果发现,当液氢流速为10 m·s^(-1),固氧颗粒粒径为1000μm时,固氧颗粒比电荷达10μC·kg^(-1),颗粒饱和电量约为84 pC,两相流电荷密度为2.84×10^(-4)C·m^(-3),较纯液氢流静电大8个量级。随着颗粒-壁面碰撞次数增多,颗粒荷电量趋于饱和。管流参数对荷电规律影响显著,颗粒比电荷随颗粒质量流量增加略有降低,随管长增加和管径减小而增大,随液氢流速增加呈现先减小后增大的趋势,即存在极小值。颗粒物性也会对荷电量产生影响,颗粒比电荷随粒径增大存在极小值和极大值,颗粒杨氏模量、电阻率、密度等也对荷电规律具有一定影响。研究工作可为液氢传输系统设计与安全防护提供理论支撑。

In order to explore the law of electrostatic accumulation in liquid hydrogen transmission pipeline containing solid oxygen particles,the simulation of charging law of liquid hydrogen-solid oxygen system is carried out using COMSOL Multiphysics software.Lagrange particle orbit method and computational fluid dynamics are used to describe the motion of continuous liquid hydrogen flow and discrete solid oxygen particles,respectively.Materials Studio software is used to calculate the electrical properties of solid oxygen particles and the electricity-generating law of solid oxygen particles is described by capacitor method to realize the coupling solution of solid-liquid two-phase flow and electrostatic field.The simulation results show that when the flow rate of liquid hydrogen is 10 m·s^(-1)and the particle size of solid oxygen is 1000μm,the specific charge of solid oxygen particles reaches 10μC·kg^(-1);the saturation charge of particles is about 84 pC;the charge density of two-phase flow is 2.84×10^(-4)C·m^(-3),which is 8 orders of magnitude larger than that of pure liquid hydrogen flow.With the increase of particle-wall collisions,the particle charge tends to be saturated.The parameters of pipe flow have significant influence on the charging law.The particle specific charge decreases slightly with the increase of particle mass flow rate,increases with the increase of tube length and the decrease of tube diameter.The particle specific charge decreases first and then increases with the increase of liquid hydrogen flow rate,so there is a minimum value.The particle property also has an effect on the charged energy.The particle specific charge has minimum and maximum value with the increase of particle size,and the particle Young’s modulus,resistivity and density also have a certain effect on the charging law.The research work can provide theoretical support for the design and safety protection of liquid hydrogen transmission system.