An Experimental Study of the Ability of Similarity Theory to predict Water Evaporation Rate for Different Convection Regimes

Indexed on: 04 Sep '13Published on: 04 Sep '13Published in: Arabian Journal for Science and Engineering

Abstract

In the present study, the applicability of a standard model (similarity theory) has been experimentally investigated for natural, forced and combined convection regimes. A series of experimental measurements are carried out over a wide range of water temperatures and air velocities for $${0.01 \leq {\rm Gr}_{\rm m} /{\rm Re}^{2} \leq 100}$$ in a heated rectangular pool. The results show that for forced convection regime due to the appearance of ripples on the water free surface, similarity theory underpredicts the evaporation rate. In the free convection regime, the similarity theory considers correctly the effects of both vapor pressure difference and vapor density difference. For mixed convection regime, although the similarity theory is not able to predict the mild nonlinearity dependence of water evaporation rate to the vapor pressure difference, but satisfactory results can be achieved using the modified correlation proposed in this study.