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-   -   Too low temperature in sonicFoam result (http://www.cfd-online.com/Forums/openfoam/65944-too-low-temperature-sonicfoam-result.html)

stevendarkes July 1, 2009 12:56

Too low temperature in sonicFoam result
 
4 Attachment(s)
Hi everybody,

I have a problem to solve a gas-flow-problem in low pressure conditions (magnitude: 10-100 Pa). The geometry is a reactor with a perforated plate as inlet and a differently perforated plate as outlet. Symmetry reasons allow to divide the flow volume in dentritic tubes with four inlets and one outlet (see attached image!). Experiments deliver temperatures around ambient temperature (273+/-20C), but the simulation results in very low temperatures of a few Kelvin in some cells!

solver: sonicFoam

Boundary conditions: (see also attached files!)
- U: plane with inlet surfaces: zeroGradient
plane with outlet surfaces: zeroGradient
side faces: zeroGradient
boundary surfaces with cut part: fixedValue - uniform (0 0 0)
- p: plane with inlet surfaces: fixedValue - uniform 257 Pa
plane with outlet surfaces: fixedValue - uniform 13 Pa
side faces: zeroGradient
boundary surfaces with cut part: zeroGradient
- T: plane with inlet surfaces: fixedValue - uniform 293
plane with outlet surfaces: fixedValue - uniform 300
side faces: zeroGradient
boundary surfaces with cut part: fixedValue - uniform 313

I'm aware of my assumption of heat isolated walls apart from the boundary surface. But because of symmetry reasons the Temperature Gradient between two of these cutouts (like the one simulated here) should be zero.

Do you have an idea, why temperature does not increase in simulation?
Thank's a lot in advance!


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