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heat transfer coefficient

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Hello Evrybody!

I'm a new Comsol user.
I'm trying to solve laminar fluid flow and heat transfer in minichannel (2D) in order to calculate de heat transfer coefficient h.
considering that the temperature of the walls (up and down) are equal and constants, the fluid flows from the inlet to the outlet with a velocity exchanging heat with the walls.
How can i determine the h coefficieint with COMSOL?

Thanks for help

3 Replies Last Post 26 oct. 2011, 08:52 UTC−4
Nagi Elabbasi Facebook Reality Labs

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Posted: 1 decade ago 24 oct. 2011, 11:27 UTC−4
Check out Model ID #1448 titled "Natural Convection Cooling of a Thermos". It shows the procedure you need.

Nagi Elabbasi
Veryst Engineering
Check out Model ID #1448 titled "Natural Convection Cooling of a Thermos". It shows the procedure you need. Nagi Elabbasi Veryst Engineering

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Posted: 1 decade ago 26 oct. 2011, 04:41 UTC−4
I tried the solution you told me, but it doesn't work.

The formula used in the "thermos laminar hcoeff" is the following: mat4.def.h_ave(T[1/K],htgh.Text[1/K],Length[1/m])[W/(m^2*K)].

i tried to copy and paste it in my model but it results an error: the term "mat4.def.h-ave" is not recognized.

Else i don't understand wath is the signification of this formula.

I would like to determine and draw on graphic de h value depending of the length of the minichannel.

i attached in this post the model file.

Thankyou
I tried the solution you told me, but it doesn't work. The formula used in the "thermos laminar hcoeff" is the following: mat4.def.h_ave(T[1/K],htgh.Text[1/K],Length[1/m])[W/(m^2*K)]. i tried to copy and paste it in my model but it results an error: the term "mat4.def.h-ave" is not recognized. Else i don't understand wath is the signification of this formula. I would like to determine and draw on graphic de h value depending of the length of the minichannel. i attached in this post the model file. Thankyou


Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 26 oct. 2011, 08:52 UTC−4
Hi

probably your material has another "tag", turn on the "tags" and see which of the 1,2,3 ... materials id you should refer to

--
Good luck
Ivar
Hi probably your material has another "tag", turn on the "tags" and see which of the 1,2,3 ... materials id you should refer to -- Good luck Ivar

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