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-   -   unsteady heating EFD.V5 (http://www.cfd-online.com/Forums/floefd-floworks-flotherm/27194-unsteady-heating-efd-v5.html)

martin September 17, 2008 07:19

unsteady heating EFD.V5
 
Hi together, I want to simulate a gas flow wich heats a solid geometry in an oven from a beginning temperature up to a higher temperature with EFD.V5. Velocity is subsonic. I defined a volume floe rate at the inlet and an environment pressure at the outlet. I tried different Mesh settings up to 3 million cells. In every case the model crashed - either there is no error message and the solver closes automatically or I get a message that a problem has been detected and the solver needs to be closed, but no information where the error is caused. Does anyone simulate a similar problem and has an idea what I can try further?

Thanks and regards

Martin

Ive September 17, 2008 10:21

Re: unsteady heating EFD.V5
 
First check that there are no big pressure drops at the start moment. To check this, try to load the r_000000.fld file which contains the initial flow and see the pressure distribution at the cut plot. The default pressure is the atmospheric pressure. If you specify additional thermodynamic parameters of the inlet flow, make sure that the pressure at the inlet do not differ too much from the initial pressure and the pressure at the outlet. Otherwise you must specify a gradient with Dependency. Also try to specify reasonably small time step. I this case you will probably need to use flow freezing to allow the solid to heat up. Any transient simulation requires some additional time and attention in comparison to a steady one.


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