中科院等离子体物理研究所知识库

Pebble beds are main schemes for tritium breeding zones in the solid blanket for fusion reactors. The effective thermal conductivity of pebble beds (k_eff) 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 k_eff consistent with experimental data in a wide range of solid-to-fluid conductivity ratio k_s/k_f from 1 to 10,000. It can be concluded that when the k_s/k_f is more than 20, contact conduction should be taken into account to make a good prediction for k_eff.