Learning Forum

[jiangtao.lu]

I noticed the following statement in theory guide

does that mean it is not allowed to do, e.g., a Euler-Euler bubble columne with only oxygen being the gas phase? 

[Rob]

If you don't have a mixture on both sides it's basic mass transfer between phases. So, we routinely run water with water-vapour (evaporation/condensation mass transfer mechanism) or water to water-vapour & air (still evaporation/condensation mass transfer mechanism but water>water-vapour). 

[jiangtao.lu]

Thanks Rob. Ok, so it is allowed to use one side “liquid” (in my case, oxygen) and the other side “mixture” (in my case, dissolved oxygen and water).

In this case, if I use UDF (DEFINE_MASS_TRANSFER (name, c, mixture_thread, from_phase_index, from_species_
index, to_phase_index, to_species_index)) for interficial mass transfer, Fluent will pass -1 to “from_species_index” to represent the “liquid”. If I understand correctly? 

 

 

 

[Rob]

That should work. 

Check the macro settings, you need to make sure you've picked the correct species! But, yes, -1 is mentioned in the text.  https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v231/en/flu_udf/flu_udf_MultiphaseDEFINE.html%23flu_udf_sec_define_mass_transfer