Learning Forum

[b404957074]

Hi there,

I am simulating the evaporation process of a static thin water layer in natural ventilation conditions. I have tried some methods and found EWF may be a good option.

However, I am a bit confused about the phase change model in EWF. There are two phase change models in EWF, one is wall-boundary-layer, and another one is the diffusion balance model.

For wall-boundary-layer, it is quite clear. The equation considers the diffusion and convective flow of vapour on the phase interface. Please correct me if I was wrong.

However, for the diffusion balance model, there is no citation or derivation of the equations. Do you have any references elaborating the derivation of the below equations? Why there is a constant in diffusion balance model whilst there is no constant in wall-boundary-layer?

By far, I am not clear on the difference between these two, and which one better fits my simulation.

Please kindly help.

Cheers

[Rob]

We can't comment beyond what in the manual re the theory https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v212/en/flu_th/flu_th_ewf_sec_film_submodels.html%23flu_th_ewf_sec_film_submodels_phase_change I'll remove the screen grabs as that's against the T&Cs on here too.
As for "which is best" it's harder to say without knowing more about how much material etc is being transferred.

[DrAmine]

Do a comparison between both and anal6and report:). The wall boundary one is standard approach the diffusion one is the oldest one.