Study of collisions between particles and unloaded bubbles with point-particle model embedded in the direct numerical simulation of turbulent flows

Wan, Dongdong1; Yi, Xuan2; Wang, Lian-Ping3,4; Sun, Xun1; Chen, Songying1; Wang, Guichao1,5

2020

10.1016/j.mineng.2019.106137

MINERALS ENGINEERING   影响因子和分区

0892-6875

Simulations of a particle-bubble collision system composed of monosized spherical solid particles and air bubbles in a quiescent liquid and homogeneous isotropic turbulence have been performed using the pseudo-spectral method for the fluid flow and Lagrangian tracking for particles and bubbles. Particle-bubble collisions in a quiescent liquid were first simulated and compared to the existing theoretical models of particle-bubble collisions. Both numerical results and theoretical models indicate that decreasing bubble size and increasing particle size can increase the particle-bubble collision efficiency. A DNS model for studying the effect of turbulence on the collisions between particles and unloaded bubbles was then developed. A nonuniform time-dependent stochastic forcing scheme was implemented to maintain turbulence intensity at targeted levels. A statistical analysis of a group of particles and bubbles in the forced turbulent flow was performed to probe the mechanism of particle-bubble collision in a turbulent flow. A simplifying assumption (motivated purely by computational limitations) has been made that bubbles and particles can be randomly relocated during the simulation, unlike what happens in reality, but the size of the effect that this simplifying assumption will have on our results is unknown. Reductions in particle-bubble collisions due to preferential concentrations of particles and bubbles in different flow regions were not found. Comparing respectively the contributions of radial relative velocity and radial distribution function to the collision kernel, the contribution of radial distribution function could be neglected because the radial relative velocity increases by about 1900% (from 1.55 cm/s to 28.87 cm/s) while the radial distribution function decreases by only 33% (from 1.33 to 1.00). Collisions between particles and bubbles increased with turbulent dissipation rate primarily due to the fact that radial relative velocities between particles and bubbles increased with the flow dissipation rate.
© 2019 Elsevier Ltd

DNS Particle-bubble collision Turbulence Point-particle model

EI ; SCI

英语

通讯

Southern University of Science and Technology[] ; Division of Chemical, Bioengineering, Environmental, and Transport Systems[] ; National Center for Atmospheric Research[CISL-UDEL0001] ; National Sleep Foundation[CNS1513031] ; Shandong University[YSPSDU 31360088964058] ; National Natural Science Foundation of China[91741101]

Engineering ; Mineralogy ; Mining & Mineral Processing

Engineering, Chemical ; Mineralogy ; Mining & Mineral Processing

WOS:000509630400021

Elsevier Ltd

20194907775582

Air ; Distribution functions ; Particle size ; Stochastic systems ; Turbulence ; Turbulent flow

Fluid Flow, General:631.1 ; Chemical Products Generally:804 ; Probability Theory:922.1 ; Materials Science:951 ; Systems Science:961

GEOSCIENCES

EV Compendex

1.Key Laboratory of High-efficiency and Clean Mechanical Manufacture, School of Mechanical Engineering, Shandong University, Jinan; 250061, China
2.International Economic & Technical Cooperation and Exchange Center, Ministry of Water Resources, Beijing; 100038, China
3.Department of Mechanics and Aerospace Engineering, Southern University of Science and Technology, Shenzhen; 518055, China
4.Department of Mechanical Engineering, 126 Spencer Laboratory, University of Delaware, Newark; DE; 19716-3140, United States
5.SUSTech Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen; 518055, China

Wan, Dongdong,Yi, Xuan,Wang, Lian-Ping,et al. Study of collisions between particles and unloaded bubbles with point-particle model embedded in the direct numerical simulation of turbulent flows[J]. MINERALS ENGINEERING,2020,146.

Wan, Dongdong,Yi, Xuan,Wang, Lian-Ping,Sun, Xun,Chen, Songying,&Wang, Guichao.(2020).Study of collisions between particles and unloaded bubbles with point-particle model embedded in the direct numerical simulation of turbulent flows.MINERALS ENGINEERING,146.

Wan, Dongdong,et al."Study of collisions between particles and unloaded bubbles with point-particle model embedded in the direct numerical simulation of turbulent flows".MINERALS ENGINEERING 146(2020).