Prediction of two-phase flow and heat transfer in vertical pipes

A prediction procedure for gas-solid flows in vertical pipes with and without heat transfer is presented. Separate conservation equations are formulated for each phase and the interaction between the phases is accounted for by including interfacial drag and energy exchange terms in the corresponding equations. A 'two-phase two-equation model' of turbulence is used. The logarithmic wall function for single phase is modified for two-phase flow, in order to account for heat and momentum transfer to each phase at the wall. Good agreement is obtained between predictions and experimental data for flow and heat transfer in vertical pipes for particle sizes 30,100 and 800 microns.