Heat and mass transfer of a liquid drop evaporating into a flow of gas capable of condensing

Abstract

Results of experimental investigation of a liquid nitrogen droplet evaporating into a flow of carbon dioxide, helium, nitrogen and water vapour and of a diethyl ether droplet evaporating into a flow of water vapour at atmospheric pressure are reported. The gas flow temperature varied from 20 to 400°C. The Reynolds numbers ranged from 3 to 600, the Prandtl numbers, from 0.3 to 1.0 and the heat- and mass-transfer parameter, from 1.5 to 15. Both volumetric and surface condensation of the ambient gas have been detected. It has been established that in the case of volumetric condensation the heat-transfer rate described by the Stanton number is related to the Peclet and Prandtl numbers and the heat- and mass-transfer parameter as St= 2 ln(1+B) B·Pe (1+0.276Pe 1 2 Pr − 1 6 ). A conclusion has been made that heat and mass transfer is the process which limits volumetric condensation.