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Topic Summary

Posted by: william
« on: May 11, 2012, 10:36:23 PM »

Closed rooms have no outlets or openings so there is no boundary for the solver to use as a pressure reference region.
In addition, if there is heat transfer into the room it will heat up and the pressure will increase.
The following advice should improve convergence:

(1)
Compute an expression for the average room pressure from P = <rho>*R*<T>/W, where <> implies volumed averaged.
For example:

AverageDensity = volumeAve(density )@Domain 1
AverageTemperature = volumeAve(T)@Domain 1
AveragePressure = AverageDensity*R*AverageTemperature/W

The above expression for the average pressure assumes that W is the molecular weight of the fluid and that an ideal gas is being used.

(2)
Set the reference pressure equal to the average room pressure.

(3)
Run in double precision.
Posted by: pitney1
« on: May 11, 2012, 10:35:58 PM »

How can I get good convergence when simulating heat transfer in a closed room?