Immersed boundary-thermal lattice Boltzmann method for the moving simulation of non-isothermal elliptical particles

摘要

The study is concerned with the understanding of elliptical particles' transport behavior coupled with heat transfer effects. A combination of immersed boundary and lattice Boltzmann method is utilized to simulate the problem. A complementary repulsive force method is hired to treat the collision among particles and walls. The direct forcing and direct heating immersed boundary-lattice Boltzmann method due to their promising results in the case of particle-laden flows have been employed to determine hydrodynamic force and energy exchange among particles and flow. The Boussinesq approximation is used for coupling the flow field and temperature. The effect of particle acceleration is also involved. Various cases and configurations including hot and cold elliptical and circular particles are investigated. The results are properly validated against the available literature data. Effects of dimensionless numbers like Prandtl and Grashof number on particles' settling velocities and transport manners are studied. From the results, it is found out that thermal properties can strongly influence the settling behavior of particles. The higher values of Grashof and Prandtl numbers for hot particles have a negative influence on the sedimentation velocity. It is also shown that hot particles have a tendency to attract each other. A complete comparative test including the influence of shape, wall effect, collision force, and energy is carried out.