opening temperature for the opening BC

sujay · June 1, 2010, 08:03

How to define the opening temperature for opening BC as temperature is unknown at the defined location.

ghorrocks · June 1, 2010, 18:42

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).

sujay · June 1, 2010, 23:58

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.

Pocket · June 2, 2010, 01:34

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.

sujay · June 2, 2010, 03:21

Can you quote the reference of the tutorial where CEL is used.

Pocket · June 2, 2010, 08:04

It's the conjugate heat transfer in a heating coil.
And they use

areaAve(T)@outflow

June 1, 2010, 08:03	opening temperature for the opening BC	#1
sujay Member Sujay Join Date: Apr 2010 Location: Karnataka, India Posts: 41 Rep Power: 15	How to define the opening temperature for opening BC as temperature is unknown at the defined location.

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June 1, 2010, 18:42		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	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).

June 1, 2010, 23:58		#3
sujay Member Sujay Join Date: Apr 2010 Location: Karnataka, India Posts: 41 Rep Power: 15	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.

June 2, 2010, 01:34		#4
Pocket New Member Daniel Paukner Join Date: Apr 2010 Posts: 17 Rep Power: 16	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.

June 2, 2010, 03:21		#5
sujay Member Sujay Join Date: Apr 2010 Location: Karnataka, India Posts: 41 Rep Power: 15	Can you quote the reference of the tutorial where CEL is used.

June 2, 2010, 08:04		#6
Pocket New Member Daniel Paukner Join Date: Apr 2010 Posts: 17 Rep Power: 16	It's the conjugate heat transfer in a heating coil. And they use areaAve(T)@outflow