Dependence of the rate of water evaporation on the pressure of its vapour

Abstract

Some recent papers 1 ’ by French scientists report the discovery of a complicated dependence of the evaporation rate of liquid water, v, on the pressure of its vapour, PHzo (Fig. 1, curve 1). The presence of extrema on the curve v-P,,, is attributed by these authors’ 5 to a complicated dependence of the heat conductivity coefficient of gas-phase water on P HzO, because they consider the Iimiting stage of the evaporation process to be the stage of heat-feed through the gas-phase to the surface of evaporating liquid, the temperature of which, due to the effect of self-cooling, is lower than that of the thermostat. The dependence of the rate of the dehydration reaction on PHlo has a similar form (with a minimum and maximum) for many crystallohydrates and is referred to as the TopIey-Smith effect 6_ The qualitative coincidence of the functions of v(pH2o) for various processes led the authors of refs_ l-5 to the conclusion about