Learning Forum

[salaisargunansp]

Hi,

I have problem with species mass transfer problem from CO2 to H2o.

In my case, four species in two phase (First gas phase: CO2 0.114, N2 0.886 and Second Liquid Phase: H20 0.8, MEA 0.2)

I used henry's law for mass transfer model, but temperature is increased, my time step is 1e-4, So I wrote udf, but udf is not initialized.

#include "udf.h"

DEFINE_MASS_TRANSFER(liq_gas_source, cell, thread, from_index, from_species_index, to_index, to_species_index)

{

real m_lg;

real T_SAT = 373.15;

Thread *gas = THREAD_SUB_THREAD(thread, from_index); /* gas phase*/

Thread *liq = THREAD_SUB_THREAD(thread, to_index); /* liquid phase*/

m_lg = 0.; /* initialisation*/

if ( (C_VOF(cell,gas) >0.0) && (C_VOF(cell,gas) <0.114))

{

m_lg = 0.1* C_VOF(cell,gas) * C_R(cell,gas) * C_YI(cell , gas , 0) ;

/*here C_YI(c, gas, 0 ), denotes species mass fraction of 1st species in the mixture denoted by phase 'gas'*/

}

return (m_lg);

}

Please give your suggestions

thank you in advanced

[Rob]

Is it not compiling, not loading, not working? I do suggest using comments, and also adding an ELSE into the IF statement.

[salaisargunansp]

Yes I added else condition, it is work now but mass transfer is occured but after a few time steps, it is diffused.

I have a doubt, is it necessary to specify a specific thread id for species in udf.

[Rob]

You'll shift from the set phase (species) to the other phase (species) so that should be OK. Check the phase volume fraction and compare that with the species.