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-   -   DEFINE_PR_RATE UDF is not called with the coupled solution option? (http://www.cfd-online.com/Forums/fluent-udf/116733-define_pr_rate-udf-not-called-coupled-solution-option.html)

guanql88 April 24, 2013 04:44

DEFINE_PR_RATE UDF is not called with the coupled solution option?
 
hi,

I am confused about the particle reaction rate UDF “DEFINE_PR_RATE
". In the fluent udf manul it says: "Note that a DEFINE_PR_RATE UDF is not called with the coupled solution option, so you will need to disable the Coupled Heat Mass Solution option in the Discrete Phase Model panel when using it"

but if the fluid and particle simulations were not coupled, how can I get the correct results?

vasava April 25, 2013 06:03

I think here coupling has something to do with the coupling of the differential equations and not the coupling of the solvers.

guanql88 April 25, 2013 08:09

Thank you, I have found this in Fluent help: By default, the solution of the particle heat and mass equations are solved in a segregated manner. If you enable the Coupled Heat-Mass Solution option, FLUENT will solve this pair of equations using a stiff, coupled ODE solver with error tolerance control. The increased accuracy, however, comes at the expense of increased computational expense.
Quote:

Originally Posted by vasava (Post 423064)
I think here coupling has something to do with the coupling of the differential equations and not the coupling of the solvers.



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