On the thermal boundary conditions of particulate-fluid modeling

- LBM-IBM-DEM model with the Neumann thermal BC is proposed.
- Effects of thermal BC on the particle behavior are quantized.
- Effect of Dirichlet thermal BC on particle behavior is higher than Neumann one.
- Temperature distributions are different in particle clusters with different BCs.

Sedimentation processes of solid particles in a fluid with heat transfer are simulated using a coupled Lattice Boltzmann Method, Immersed Boundary Method and Discrete Element Method (LBM-IBM-DEM) scheme. In the numerical simulations, solid particles are specified either by a given temperature which is termed Dirichlet boundary condition or by a temperature gradient which is termed Neumann boundary condition. Several cases are examined containing one, two and 504 solid particles settling in a fluid, respectively. All the considered cases could be divided into two groups: Group Dirichlet and Group Neumann according to different styles of boundary conditions employed but under exactly the same initial states. The effects of these two boundary conditions on the particle behavior are quantized.

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