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opening temperature for the opening BC

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Old   June 1, 2010, 08:03
Default opening temperature for the opening BC
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Sujay
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How to define the opening temperature for opening BC as temperature is unknown at the defined location.
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Old   June 1, 2010, 18:42
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Glenn Horrocks
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If you are doing a thermal model and don't know the inlet temperature then you can't use an opening (or inlet) boundary. You have to either specify a temperature or move the boundary to somewhere you do know the temperature, or move the boundary somewhere you can use a boundary which does not require temperature to be specified (such as a wall or symmetry).
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Old   June 1, 2010, 23:58
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The domain has reverse flow at the outlet so needs to define as a opening. The inlet tempearure is specified at the inlet, the fluxes are assigned.

At the outlet tempearure is required output....but as it defined as a opening ask for opening or static temperature....guide to guess the temperature or any other choice.
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Old   June 2, 2010, 01:34
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Daniel Paukner
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I remember reading in one of the tutorials that it is suggested to use a CEL expression and take the average temperature of the opening

ave(T)@REGION:Outlet

maybe "areaAve" would be even better.

But keep in mind that this is not the best solution.
A better way to do it would be to put the outlet further downstream, so that no backflow occurs.
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Old   June 2, 2010, 03:21
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Can you quote the reference of the tutorial where CEL is used.
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Old   June 2, 2010, 08:04
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Daniel Paukner
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It's the conjugate heat transfer in a heating coil.
And they use

areaAve(T)@outflow
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