Learning Forum

[mkrsmanovic]

I'm simulating air handling system treating a large space seeing buoyancy effects and stratification due to envelope and internal heat fluxes. The mass balance between air conditioning inlets and outlets is zero, i.e. I do not have any infiltration into or leaks out of the space. I'm currently using velocity inlet boundary condition for air supply into the space, and pressure outlet (0 gauge) for air exhaust. But I would like to somehow prescribe that outlets are not at 0 gauge but are actually exhausting the air at the same rate it's been supplied to the space. What would be the best way to do this? I just want to see what the difference in the results would be if the simulation accounted for the prescribed flow rate through the outlets, instead of working backwards from the 0 gauge outlet condition.

I was looking into specifying Target Mass Flow but that is specifying mass flow at the exit against what is effectively volumetric flow rate (area x velocity inlet) at the entrance. With energy equation on I'm not sure how I'd want to go about specifying the Target Mass Flow flow rate as my density varies across the space floorplan and different outlet heights. So this may not be a good idea, or there may be a different, better way to achieve what I want.

Any suggestions are appreciated, thanks!

[Essence]

Hello,

Can you try using velocity BC at outlet with negative direction provided to the magnitude of the velocity?