Learning Forum

[admin]

How can I define mass exchange between phases in multi-phase flow?

[admin]

In the multi-phase flow model, it is possible to define the mass exchange between the phases by a constant or a UDF. If you want to set in constant, click Interaction... in the Phases panel to open the Phase Interaction panel. Then, click on the Mass tab. Change Number of Mass Transfer Mechanisms to 1. Change Mechanism to constant-rate and set a numerical value. If you want to use a UDF, use the DEFINEMASSTRANSFER or DEFINELINEARIZEDMASSTRANSFER macro to define the mass exchange and use, then compile and load it. Then, select user-defined for the Mechanism in the Phase Interaction panel and import the UDF link. In addition, you can also be set using the DEFINESOURCE macro. In this case, by the source set of Fluid panel, you need to link to each phase of the source term. Note: DEFINELINEARIZEDMASS_TRANSFER macro is available from R14.0 and up.

[vidyadhar.kpm]

Hello,

I am using VOF method to simulate evaporation from a liquid to its vapor.

I have used Phase Interaction panel with 1 number of mass transfer mechanism(s)

1) May I know what is meant by Phase Interactions

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> Mass Transfer Rate 1  which appear as field variable while post processing.

2) Does this represent mass transfer rate happening from liquid to vapor at the interface? Its units are kg/s/m3. Here, what is the denominator m3(volume) represent?

3) But, in my simulation, I am observing (Reports--->Surface Integrals) that the Mass Transfer Rate 1 has certain value at all the zones of the domain- boundary and cell zones?

I request you to explain this.

Thanks & Regards,

vidyadhar

[DrAmine]

1/That is the rate if mass transfer of the deployed mechanism
2/ It is per cell volume
3/ on surfaces the value is interpreted from neighbouring cell(s)