Numerical Simulation of Thermal Levitation Characteristics of Double Particles with High Conductivity

By using numerical simulation, the thermal floating process of two particles with high thermal conductivity in a cold fluid is examined in order to better understand the flow and heat transfer properties of multi-particle systems. A multi-scale discrete unified gas kinetics scheme (DUGKS) is the numerical approach used. The following are the ranges of simulated parameters: vertical spacing 2 ≤ H/D ≤ 5, horizontal spacing 2 ≤ S/D ≤ 4, relative azimuth angle 15° ≤ θ ≤ 75°, Reynolds number 20 ≤ Re ≤ 80, and Grashof number 500 ≤ Gr ≤ 2 000. The findings suggest that two particles will collide again shortly after their initial encounter when placed vertically and with a small gap. Particles arranged horizontally have strong attraction effect on one another, and rotation happens before impact. There is no rolling phenomenon and the initial impact happens during the descending phase. A drop in θ results in increase in particle contact and higher probability of multiple collisions. Particles' maximum buoyancy height falls as H/D increases. Furthermore, the buoyancy ability of particles diminishes with increasing Re, whereas the buoyancy ability grows with increasing Gr due to advancement in the first collision time of particles.