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.