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-   -   velocity or mass flow inlet? (http://www.cfd-online.com/Forums/fluent/37556-velocity-mass-flow-inlet.html)

Silvia August 12, 2005 11:24

velocity or mass flow inlet?
 
I have to model combustion in industrial furnace and I decided to model a section of the furnace (2d problem). When I set the boundary condition for air inlet I can't decide if I have to choose "velocity inlet" or "mass flow inlet". In the first case, my 2d simulation doesn't respect the mass balance of the real furnace; in the second case my 2d simulation doesn't respect the effective flow velocity in the furnace. What I have to do? Is it a limitation of 2d simulation in comparison with 3d simulation? I hope my question were clear… thanks

Evan Rosenbaum August 12, 2005 13:55

Re: velocity or mass flow inlet?
 
A two-dimensional analysis assumed a unit depth, so the velocity inlet does respect the mass balance. To use a mass flow inlet, you need to reduce the mass flow accordingly. For example, if you have 100 kg/s entering a 10 m deep furnace and your 2-D model is built in meters, you need to enter 10 kg/s.


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