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 fabioacfoz November 12, 2009 09:07

HVAC coarse mesh

Hello all

Im modeling an office environment with inlet air from the air conditioner at 17 and an return plenum duct. In this, people ate cilinders with the medium adult human area (1,8 m²), computers with heat flux and temperature walls taken from Energyplus simulations. But my simulation is diverging, i think because of my inlet-outlet boundary conditions and my timestep. I have three questions:

1) A coarse mesh can make my simulation diverge?

2) What should be the inlet-oulet conditions for the model? (I already tryed massflow-massflow, velocity-velocity, volocity-pressure)

3) What could be the bigger timestep that should not make the simulation diverge?

(What always happen is the overflow error, due to mommentum and mass errors in the linear solver)

Thanks 4 who´ll help!

 kingjewel1 December 3, 2009 17:03

Quote:
 Originally Posted by fabioacfoz (Post 235990) Hello all Im modeling an office environment with inlet air from the air conditioner at 17 and an return plenum duct. In this, people ate cilinders with the medium adult human area (1,8 m²), computers with heat flux and temperature walls taken from Energyplus simulations. But my simulation is diverging, i think because of my inlet-outlet boundary conditions and my timestep. I have three questions: 1) A coarse mesh can make my simulation diverge? 2) What should be the inlet-oulet conditions for the model? (I already tryed massflow-massflow, velocity-velocity, volocity-pressure) 3) What could be the bigger timestep that should not make the simulation diverge? (What always happen is the overflow error, due to mommentum and mass errors in the linear solver) Thanks 4 who´ll help!
Hi,