Is there a way to scale heat transfer strength at a coupled wall boundary?

bgp723 · April 7, 2023, 11:28

Maybe this is blasphemous, but I would like to see if there's a way to adjust heat transfer strength at a coupled wall boundary condition. Maybe something like surface area enhancement factor or the like.

The reason why I'm looking into this is because:

* I want to have a "low" element count CFD model and, therefore, I do not necessarily want to capture every surface feature in convection participating surfaces (i.e. think of a surface having various small ribs and protrusions)

* I want to be able to correlate my CFD model with test data knowing that my model has deficiencies in capturing all the surface features that are present in the real-world data

* I only mainly care about a bulk thermal behavior of the surface/component. The CFD model I'm working with is very high level, where I mainly want to capture air recirculation zones, get the energy balances/component temperatures right, and make sure upstream component temperatures properly affect things downstream (easier said than done when I want to simplify things)

I could take the interested surfaces out of the coupled boundary condition, and strictly set a test calculated h value based on my measured free stream air temperature (which is not necessarily near the interested component), but I do not like that approach because I want to be able to capture the thermal influences of upstream components.

If anyone has any suggestions on how to go about doing something like this (or if you have other approach suggestions), I would very much appreciate it!

Thanks,

DB

LuckyTran · April 15, 2023, 15:12

Run your case. Export the wall heat flux. Go into excel and apply your amplification. Import the amplified wall heat flux as a boundary condition.

Break large complicated problems that you can't solve into (multiple) smaller ones that you can solve and don't expect there to always be a one-click buy now feature, CFD isn't amazon.

April 7, 2023, 11:28	Is there a way to scale heat transfer strength at a coupled wall boundary?	#1
bgp723 New Member Daniel B Join Date: Jul 2014 Posts: 20 Rep Power: 12	Maybe this is blasphemous, but I would like to see if there's a way to adjust heat transfer strength at a coupled wall boundary condition. Maybe something like surface area enhancement factor or the like. The reason why I'm looking into this is because: * I want to have a "low" element count CFD model and, therefore, I do not necessarily want to capture every surface feature in convection participating surfaces (i.e. think of a surface having various small ribs and protrusions) * I want to be able to correlate my CFD model with test data knowing that my model has deficiencies in capturing all the surface features that are present in the real-world data * I only mainly care about a bulk thermal behavior of the surface/component. The CFD model I'm working with is very high level, where I mainly want to capture air recirculation zones, get the energy balances/component temperatures right, and make sure upstream component temperatures properly affect things downstream (easier said than done when I want to simplify things) I could take the interested surfaces out of the coupled boundary condition, and strictly set a test calculated h value based on my measured free stream air temperature (which is not necessarily near the interested component), but I do not like that approach because I want to be able to capture the thermal influences of upstream components. If anyone has any suggestions on how to go about doing something like this (or if you have other approach suggestions), I would very much appreciate it! Thanks, DB

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Table bounds warnings at: END OF TIME STEP	CFXer	CFX	4	July 17, 2020 00:44
Question about adaptive timestepping	Guille1811	CFX	25	November 12, 2017 18:38
Centrifugal fan-reverse flow in outlet lesds to a mass in flow field	xiexing	CFX	3	March 29, 2017 11:00
Multiphase flow - incorrect velocity on inlet	Mike_Tom	CFX	6	September 29, 2016 02:27
Water vapour condensation in CFX-5.7.1	hdj	CFX	1	November 27, 2005 08:15

April 15, 2023, 15:12		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,761 Rep Power: 66	Run your case. Export the wall heat flux. Go into excel and apply your amplification. Import the amplified wall heat flux as a boundary condition. Break large complicated problems that you can't solve into (multiple) smaller ones that you can solve and don't expect there to always be a one-click buy now feature, CFD isn't amazon.