A DEM-CFD numerical model for the prediction of the effective thermal conductivity of pebble beds with contact conduction

The effective thermal conductivity of pebble beds (keff ) is an important thermal property used in the thermal hydraulic design of solid blankets. In this study, a 3D DEM-CFD one-way coupling method considering contact conduction is applied to analyze the influence of solid contact conduction and solid-fluid-solid conduction on the effective thermal conductivity of pebble beds.

The current numerical model gives a keff consistent with experimental data in a wide range of solid-to-fluid conductivity ratio k k s f / from 1 to 10,000. It can be concluded that when the k k s f / is more than 20, contact conduction should be taken into account to make a good prediction for keff .