[user321]

Hi. I am trying to model evaporation and condensation of water in a closed container at a temperature below the saturation temperature (say 90°C). When I use evaporation-condensation model of any multiphase model of FLUENT it asks for the saturation temperature. If a saturation temperature of 100°C is assigned, there is absolutely no vapour formation till the water temperature reaches 100°C. One it reaches the saturation temperature, the water boils off from the bulk. But absolutely no evaporation is observed below the saturation temperature which is not the real case scenario. Can anyone help me regarding how this model of below saturation temperature evaporation can be implemented in any multiphase model of FLUENT? I am using FLUENT 19.2. Solution with any of the previous versions is also appreciated.

[vinerm]

Hi

Evaporation at 90 °C requires pressure to be lower than atmospheric. It implies that you have to use Ideal gas law for the vapor part, which you most likely are using. Consequently, saturation pressure and temperature have to be given as a function and not as constant. E-C model is a purely thermal, mechanistic model. Hence, evaporation or condensation will occur based on the temperature but temperature can certainly be a function of pressure.