Learning Forum

[snr1]

Dear sir, i run mycase in parallel mode with 4 cores. I loaded udf . Its giving following error and exiting the fluent. How to resolve it? need urgent help.

[Rob]

Scroll up and see what triggered it: something has failed in Fluent, and the MPI error is part of the error message. 

 

Moving to Fluids too. 

[snr1]

Divergence detected in temperature and some mutigrid solver error

[Rob]

OK, so the solver is struggling with the energy equation, that then diverged and the solution stops.  Check the mesh quality and boundary conditions. 

[snr1]

I checked boundary conditions and mesh quality. Everything is fine. But still i am getting same error

[Rob]

OK, so there's something else causing the problem. What does the UDF do? 

[snr1]

UDF is for mass tranfer between phases of water and water vapour

[Rob]

Try running without the UDF and see what happens. If it works you need to review the UDF code and see what's causing the problems. 

[Rob]

snr1 posted this 15 minutes ago

 

Dear sir, if I run without UDF, it results floating point exception error and temperature limited in 20 cells of zone1. How to resolve these issues?

 

Actually, I am simulating the water evaporation process in the helical coil. The boundary conditions are

inlet: water (100%) with mass flow rate inlet and temperature (370K)

wall: constant temperature (500K)

outlet: outflow

operating conditions: 101325 Pa and 300K

saturation temperature in the evaporation and condensation model: 373K with 0.1 frequency.

model: VOF implicit with implicit body force

[Rob]

First off check the model runs OK without any boiling turned on. Then turn on boiling: I suspect you either have too big a time step or the amount of boiling near the wall is giving too great a source term (gas generation) for the solver. 

[snr1]

Time step i have given as 0.0005 and wall temperature is 500k while saturation temperature is 373K