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-   -   Difference between (DEFINE_VR_RATE) & (DEFINE_HET_RXN_RATE) (https://www.cfd-online.com/Forums/fluent/198282-difference-between-define_vr_rate-define_het_rxn_rate.html)

Moha Sobhi February 1, 2018 09:35

Difference between (DEFINE_VR_RATE) & (DEFINE_HET_RXN_RATE)
 
Dear all;

Can anyone help me in understanding the main difference(s) between (DEFINE_VR_RATE) & (DEFINE_HET_RXN_RATE) user-defined function types?

Dri July 13, 2018 10:29

Hi there,

One of the main difference is the number of phases involved in your simulation. If you have one phase, then you use DEFINE_VR_RATE, while if you have multiple phases, where there is reaction among phases, then you use DEFINE_HET_RXN_RATE. There could be other differences depending on your simulation, so I encourage you to look at the theory guide and the UDF manual for further description on the macros. They are helpful.

souza.emer January 8, 2019 09:10

Quote:

Originally Posted by Dri (Post 699157)
Hi there,

One of the main difference is the number of phases involved in your simulation. If you have one phase, then you use DEFINE_VR_RATE, while if you have multiple phases, where there is reaction among phases, then you use DEFINE_HET_RXN_RATE. There could be other differences depending on your simulation, so I encourage you to look at the theory guide and the UDF manual for further description on the macros. They are helpful.

But, could am I use the two UDF's?
DEFINE_VR_RATE and DEFINE_HET_RXN_RATE at the same time?

And one more thing, the DEFINE_VR_RATE macro could be used in a heterogeneous reaction environment? Like, the reaction
C + O2 = CO2
Where I used one UDF to modify the Reaction Rate with DEFINE_HET_RXN_RATE, and now I'm having trouble with carbon (C) consumption, it's not lowering =/


:confused::confused:


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