Measurement and Analysis Effective Parameters on Evaporation Process for Free, Forced and Mixed Convection Regime

In the present study, the rate of water evaporation for different convection regimes has been experimentally measured. The measurements were performed over a wide range of / (0/01< / <100) for a rectangular heated pool with different wind velocities. The results display that the evaporation rate increases with the vapor pressure difference over both forced convection and turbulent mixed convection. In addition, over the range of free convection regime, the evaporation rate is influenced not only by the vapor pressure difference but also by the density variation. Based on these experiments, a new correlation has been proposed that has the ability to predict evaporation rate and Sherwood number for a wide range of convection regimes. In addition, the comparison between water evaporation rates from free water surface and from wetted surface reveals that on low air velocities, evaporation rate from wetted surface is higher than that of free water surface. However, a reversed trend is observed on high air velocities.