Interfacial conditions during evaporation or condensation of water.

Thermodynamics and Kinetics Laboratory, Department of Mechanical Engineering and Industrial Engineering, University of Toronto,5 King’s College Road, Toronto, Canada M5S 3G8~Received 16 April 2001; revised manuscript received 15 June 2001; published 29 October 2001!Steady-state evaporation and condensation experiments have been conducted with water under conditionswhere buoyancy-driven convection is not present. The temperature profile in each phase has been measured. Atthe interface, independently of the direction of the phase change, a temperature discontinuity has been found toexist in which the interfacial vapor temperature is greater than that in the liquid. In a thin layer immediatelybelow the interface the temperature is uniform in a layer ~;0.5 mm! and below that the temperature profile islinear, indicating thermal conduction. The uniform temperature layer indicates a mixing process occurs nearthe interface that could result from surface-tension driven~Marangoni-Be´nard! convection and/or from ‘‘en-ergy partitioning’’ that is necessary to account for the measured temperature discontinuity near the interface.When the measured interfacial properties are used with the expression for the phase change rate that is obtainedfrom statistical rate theory, it is found that the predictions are in close agreement with the measurements.DOI: 10.1103/PhysRevE.64.051509 PACS number~s!: 64.70.FxI. INTRODUCTION