Heat transfer through solid

Jonny6001 · September 22, 2010, 09:33

Hello, I am very new with Star CCM but so far I'm very impressed compared with Fluent, regaring the structure of the software.

Firstly I am looking at modelling a pipe with hot gases inside and ambient temperature on the outside, with the aim of predicting the temperatures in the actual solid pipe rather than the gases.

The way I have approached this is to model each flow region separately and mesh them individualy and save them as .ccm files. Then bring all 3 regions in to a new simulation and work on them from there.
I have contact interfaces between the solid and internal gas, and the solid and external ambient air.

I have ran the case and the fluid regions seem to behave as expected but the solid region has more or less a constant bulk temperature. I would expect the region to show a temperature gradient relative to the internal and ambient temperatures.
I think there is a "thermal specification" setting for the interfaces that can be altered but I am unsure what they should be, at present I have them set to adiabatic where I could chose "temperature, heat flux, convective".

One thing that Fluent does well is provides very good manuals about exactly what settings do and how they alter the solution.

I hope someone can give me some help.

Thanks a lot.

nomad · September 23, 2010, 12:46

What's the pipe material, how thin is it?
If it's a highly conductive pipe, then there might not be a noticeable gradient across it. Did you crop the temperature scale to a few degrees or even less to see if there is a gradient?

Jonny6001 · October 3, 2010, 09:35

Hello, sorry for replying late, have been away for a while.

I quickly realized the issue, the external wall had been set to adiabatic condition so the wall temperature was obviously going to match the gas it was in contact with once the system had reached steady state.

Does anyone know how the local nusselt number is used in a heat transfer situation? I mean, the heat transfer from hot gas running through a pipe is going to be dependant on the flow characteristics,so areas of slower gas will have different transfer to quicker and turbulent areas will be different again.

I am unsure how this is treated in Star CCM+ and how is best to model the situation.

Thanks a lot.

September 22, 2010, 09:33	Heat transfer through solid	#1
Jonny6001 Member Jonny Join Date: Aug 2009 Posts: 72 Rep Power: 16	Hello, I am very new with Star CCM but so far I'm very impressed compared with Fluent, regaring the structure of the software. Firstly I am looking at modelling a pipe with hot gases inside and ambient temperature on the outside, with the aim of predicting the temperatures in the actual solid pipe rather than the gases. The way I have approached this is to model each flow region separately and mesh them individualy and save them as .ccm files. Then bring all 3 regions in to a new simulation and work on them from there. I have contact interfaces between the solid and internal gas, and the solid and external ambient air. I have ran the case and the fluid regions seem to behave as expected but the solid region has more or less a constant bulk temperature. I would expect the region to show a temperature gradient relative to the internal and ambient temperatures. I think there is a "thermal specification" setting for the interfaces that can be altered but I am unsure what they should be, at present I have them set to adiabatic where I could chose "temperature, heat flux, convective". One thing that Fluent does well is provides very good manuals about exactly what settings do and how they alter the solution. I hope someone can give me some help. Thanks a lot.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Two-sided Wall Heat Transfer BC - No Separate Solid Mesh and No Heat Transfer Coeff	swahono	OpenFOAM Running, Solving & CFD	10	October 15, 2018 05:43
Convective / Conductive Heat Transfer in Hypersonic flows	enigma	Main CFD Forum	2	November 1, 2009 22:53
No Heat Transfer between two solid domains	Mike ZH	CFX	7	July 26, 2008 16:50
Convective Heat Transfer - Heat Exchanger	Mark	CFX	6	November 15, 2004 15:55
CFX4.3 -build analysis form	Chie Min	CFX	5	July 12, 2001 23:19

September 23, 2010, 12:46		#2
nomad Member John Join Date: Aug 2009 Posts: 92 Rep Power: 16	What's the pipe material, how thin is it? If it's a highly conductive pipe, then there might not be a noticeable gradient across it. Did you crop the temperature scale to a few degrees or even less to see if there is a gradient?

October 3, 2010, 09:35		#3
Jonny6001 Member Jonny Join Date: Aug 2009 Posts: 72 Rep Power: 16	Hello, sorry for replying late, have been away for a while. I quickly realized the issue, the external wall had been set to adiabatic condition so the wall temperature was obviously going to match the gas it was in contact with once the system had reached steady state. Does anyone know how the local nusselt number is used in a heat transfer situation? I mean, the heat transfer from hot gas running through a pipe is going to be dependant on the flow characteristics,so areas of slower gas will have different transfer to quicker and turbulent areas will be different again. I am unsure how this is treated in Star CCM+ and how is best to model the situation. Thanks a lot.