Selecting Heat Transfer Boundary Conditions

Hoppe · June 28, 2016, 19:14

Hello,

I am trying to model cooling fin heat transfer with convection. My problem definition includes having the heat sink have a power of 120 W, a heat transfer coefficient of 250 W/m^2-K, and a stream temp of 25 C. I am trying to model this in fluent. When trying to specify the wall boundary conditions, I can either specify the heat flux from the wall OR the heat transfer coefficient, free stream temp, and heat generation rate (W/m^3-K). I do not want to specify a heat generation rate, because at the base of my solid material, a volume of the heat sink is not specified. I would prefer to specify the heat transfer coefficient, the stream temperature and the power (or power per unit area), instead of trying to make up a heat sink volume. Is there a way to do this?

nvarma · June 29, 2016, 15:33

define some wall thickness say (1mm) and then specify heat generation rate.

Far · July 1, 2016, 04:20

did you try mixed boundary condition?

Hoppe · July 10, 2016, 23:23

Creating a wall thickness does seem like a straightforward solution which I will try.

I was originally trying to create mixed boundary conditions, but Fluent would not allow me to specify what I wanted to.

Thank you both for the advice!

June 28, 2016, 19:14	Selecting Heat Transfer Boundary Conditions	#1
Hoppe New Member Tyler Join Date: Oct 2015 Posts: 7 Rep Power: 10	Hello, I am trying to model cooling fin heat transfer with convection. My problem definition includes having the heat sink have a power of 120 W, a heat transfer coefficient of 250 W/m^2-K, and a stream temp of 25 C. I am trying to model this in fluent. When trying to specify the wall boundary conditions, I can either specify the heat flux from the wall OR the heat transfer coefficient, free stream temp, and heat generation rate (W/m^3-K). I do not want to specify a heat generation rate, because at the base of my solid material, a volume of the heat sink is not specified. I would prefer to specify the heat transfer coefficient, the stream temperature and the power (or power per unit area), instead of trying to make up a heat sink volume. Is there a way to do this?

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June 29, 2016, 15:33		#2
nvarma Senior Member nm Join Date: Mar 2013 Posts: 100 Rep Power: 13	define some wall thickness say (1mm) and then specify heat generation rate.

July 1, 2016, 04:20		#3
Far Super Moderator Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,553 Blog Entries: 6 Rep Power: 54	did you try mixed boundary condition?

July 10, 2016, 23:23		#4
Hoppe New Member Tyler Join Date: Oct 2015 Posts: 7 Rep Power: 10	Creating a wall thickness does seem like a straightforward solution which I will try. I was originally trying to create mixed boundary conditions, but Fluent would not allow me to specify what I wanted to. Thank you both for the advice!