3 / 2025-03-05 01:06:03

Pore-Scale Simulations for Thermal Flows in Porous Materials: Boundary Treatments and Apparent Thermal Conductivity

Porous thermal flows, Pore-scale simulations, Thermal conductivity, Boundary treatments, Volume averaging method, Lattice Boltzmann method

Thermal flows through porous materials are of great interests for their important roles in numerous natural and industrial processes. Although the detailed matrix structure could be complicated, similarity does exist in the general matrix-void configuration. For this reason, pore-scale simulations are often employed to explore the flow and thermal transport behaviors in porous media. Various numerical techniques have been utilized, especially the lattice Boltzmann method for its advantage in dealing with complex boundary geometry. In such pore-scale simulations, the porous material is assumed as an assembly of identical units repeating in space. The flow and thermal calculation is conducted only in one of such repeating units, and detailed matrix-void configuration and fluid and matrix properties can be considered. However, caution needs be exercised for the treatments on the artificial boundaries over the unit sides, especially for the thermal field. In addition, the apparent thermal conductivity of a porous material is often calculated from the pore-scale simulation results, and the volume average method has been used for this purpose. In this presentation, typical temperature boundary conditions utilized in the literature will be discussed. Concerns on the thermal conductivity calculation from the volume averaging method will also be presented.