An improved model for two-phase flow through beds of coarse particles

A one-dimensional model for two-phase flow in packed particle beds is presented. Compared with earlier models, the improved model takes into account the effect of interfacial drag forces between liquid and gas, which are of considerable influence in beds of coarse particles. The model is based on the momentum equations for separated flow, which are closed by empirical relations for the wall shear stress and the interfacial drag. The model is applied to the situation of a one-component two-phase flow in an internally heated bed of uniform spherical particles. An increased dryout heat flux is predicted if liquid enters the bed through the bottom.