Solid-liquid two-phase flow characteristics in pipe during large solid particles lifting
SONG Longbo1, TENG Shuang2, CAO Qian2, KANG Can2*, DING Kejin3, LI Changjiang3
1. National Pump Product Quality Inspection Center(Shandong), Zibo, Shandong 255209, China; 2. School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 3. 704th Research Institute of CSIC, Shanghai 200031, China
Abstract:In order to study the influence of large particle two-phase flow with different properties on the deep-sea mining transportation system, the flow characteristics in vertical pipe under different conditions were analyzed numerically by using the discrete element method(DEM)in commercial computational fluid dynamics(CFD)software STAR-CCM+. The results show that when transporting solid-liquid two-phase flow with different particle sizes, the average velocity of particles decreases with the increase of particle diameter. With the increase of the volume ratio of middle size particles(dp=15.0 mm), the average velocity of particles decreases, and the slip velocity of large particles decreases but that of small particles increases. Large particles tend to gather in the area with lower liquid velocity, while small particles tend to gather in the area with higher liquid velocity. When transporting solid-liquid two-phase flow with different shapes of particles, decreasing the particle shape coefficient causes that the average velocity of particles first decreases and then increases, the slip velocity of particles first increases and then decreases. Compared with spherical particles, particles with smaller shape coefficient suffer more serious wall effect and are prone to experience sudden velocity drop at the vicinity of wall. The average velocity of spherical particles(the shape coefficient of particles is 1.0)is the hig-hest, the slip velocity is the lowest, and the distribution of spherical particle velocity along the radial direction of the pipe is the most uniform.