用MPS-DEM法数值分析输运速度对立管混输特性的影响

Numerical analysis of influence of liquid velocity on characteristics of vertical pipe transportation by MPS-DEM method

船舶与海洋工程在深海领域会采用立管进行矿物输运,涉及固液两相流混输的水动力学问题。近些年,随着海洋工程向深海发展,立管长度很大,液体流速较高,可能引起管道的破坏,输运效率降低等问题。利用数值模拟高雷诺数下的长管道流动,计算量很大。考虑多相流自身的复杂性,该文采用无网格粒子法中的移动粒子半隐式方法(Moving Particle Semi-Implicit Method,MPS)和离散单元法(Discrete Element Method,DEM)相结合的方法,对不同输运速度下颗粒的水力输运进行了数值研究。基于此该文采用课题组自主开发的MPSDEM-SJTU求解器,针对定长圆管,分析不同输运速度工况下的瞬时流态和时间平均变量(包括轴向液体速度,颗粒位置分布和转动角速度等),这些结果有望为优化水力输运提供参考。

In the field of deep sea,ships and ocean engineering will use vertical pipes to transport minerals,so it involves the hydrodynamics of solid-liquid two-phase flow.In recent years,with the development of ocean engineering to the deep sea,the pipe length is very large,and the liquid flow velocity is high,which may cause the damage of the pipeline and reduce the transportation efficiency.Numerical simulation of long pipe flow at high Reynolds number requires a lot of calculation.Considering the complexity of multiphase flow,the Moving Particle Semi-implicit method(MPS)and the Discrete Element Method(DEM)of meshless particle method are combined to study the hydraulic transport of particles at different liquid velocities.Based on this,the MPSDEM-SJTU solver developed by the researc h group is used to analyze the instantaneous flow pattern and time average variables(including axial liquid velocity,particle p osition distribution and rotational angular velocity)under different transport speeds for the fixed length circular pipe.These r esults are expected to provide reference for the optimization of hydraulic transportation.