Volumetric Heat-Transfer Coefficients for Direct-Contact Evaporation

An analytical model has been developed for calculating volumetric heat-transfer coefficients for direct-contact evaporation. Heat transfer is modeled using single droplet correlations for the Nusselt number, while the fluid dynamics are described by a drift-flux model. The analysis is divided into a preagglomerative and a postagglomerative stage on the basis of an assumed maximum value for the dispersed phase volume fraction. The analytical results showed good agreement with data obtained from an experimental direct-contact evaporator using cyclopentane and water.