Numerical calibration for thermal resistance in discrete element method by finite volume method

Discrete element method (DEM) is a powerful tool for solid granular, while the related heat transfer model re-quires more calibrations due to the over-simplified heat transfer path. In the present study, the calibration of overall thermal resistances (R-p) was conducted between a particle and the wall, where heat conduction in the particle interior and gap is more remarkable. It was found that, the existing DEM models should be improved in a wide range of the solid-to-gas ratio of thermal conductivity (k(s)/k(g)) and the dimensionless body distance (S-x/d(p)). The ideal heat transfer path may result in larger deviations as k(s)/k(g) > 250 or S-x/d(p) > 0, which can be only mathematically modified by the empirical factor. The general descriptions for modification are still required. To overcome the limit, an effective thermal conductivity model is proposed with certain formulas, where R-p is divided into two parts in the mixing phase zone and the gas zone. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

DEM is a powerful tool for solid granular, but requires more calibrations in heat transfer models due to simplifications. Improvements are needed in models to cover a wider range of solid-to-gas thermal conductivity ratio and dimensionless body distance. Ideal heat transfer paths may lead to larger deviations that can only be mathematically adjusted by empirical factors.