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How to Couple Free and Porous Media Flow with Heat Transfer In Solids
Posted 11 mar 2012, 20:01 GMT-4 Fluid & Heat, Heat Transfer & Phase Change, Studies & Solvers Version 4.1, Version 4.4 6 Replies
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I am new to COMSOL and I am trying to simulate a solar panel cooling system. I am trying to simulate in 2D the heat transfer between a thin rectangular layer (the photovoltaic cell), another thin rectangular layer (thermal paste), and finally a porous layer through which water is flowing. Ultimately, I want specify a heat flux and initial temperature on the top layer (PV cell) and obtain the heat removed and temperature change achieved by using the porous media as a heat sink. I can couple the heat transfer between the 2 solid layers easily, however, I am having trouble simulating the heat transfer between all three layers (i.e. PV cell, thermal paste, and porous media).
Currently, I am using the following physics packages:
"Free and Porous Media Flow" - Models water flow through porous media
"Heat Transfer in Porous Media" - Models heat transfer in porous media layer
"Heat Transfer in Solids" - Models heat transfer in top two layers
My problem is that I can't get the top layers to "talk to" the porous media layer.
Any help would be greatly appreciated.
Thank you,
Brad
Hello Bradley Fontenault
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I was wondering if you ever figured out how to couple the two physics involving porous media (heat transfer and flow)? I am working on something similar, where I need to remove heat from a porous media by blowing air through it, but I can't seem to get flow to occur through the porous media.
Thank you in advance for any help you can provide,
Alfredo
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Stefano.
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If anyone managed to solve this problem, it will be a great help if you describe how you did it.
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this is actually quite simple. An easy example can be given by modifying this model available in the Subsurface Flow model Library:
www.ch.comsol.com/model/free-convection-in-porous-medium-278
1) Draw a square in the middle.
2) Deactivate the new domain in the Brinkman Eq. because it shall be the non-porous part, that will take part only in the heat transfer but not the flow.
3) Right click on Heat Transfer in Porous Media and Add a Feature "Heat Transfer in Solids" specify the thermal properties of the domain.
Compute.
That should be it - you have the porous and non-porous parts "talking" to each other and need only one interface.
Best regards,
Sven Friedel
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Hi,
this is actually quite simple. An easy example can be given by modifying this model available in the Subsurface Flow model Library:
www.ch.comsol.com/model/free-convection-in-porous-medium-278
1) Draw a square in the middle.
2) Deactivate the new domain in the Brinkman Eq. because it shall be the non-porous part, that will take part only in the heat transfer but not the flow.
3) Right click on Heat Transfer in Porous Media and Add a Feature "Heat Transfer in Solids" specify the thermal properties of the domain.
Compute.
That should be it - you have the porous and non-porous parts "talking" to each other and need only one interface.
Best regards,
Sven Friedel
Hi,
I've actually download this file. however, there is something I couldn't figure out yet, I understand that we can use the velocity from Brinkman Eq. as velocity field to the heat transfer in porous media, but how can we use the temperature as input in Brinkman eq. so that we have two way coupling.
I would really appreciate any help.
thanks,
Manar
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I am building a model and my final objective is to know the temperature of the air in the outlet in a porous channel. I have done this:
- physics Brinkman equation
- physics Heat transfer in Fluids (to know the the heat transfer in the air) and in Heat Transfer in Solids ( to know the heat transfer in the channel) .
I used the following boundary conditions:
Brinkman eq.
- initial values: u=(0,01;0;0) m/s , p=0,01 Pa
- inlet: normal inflow, u=0,01 m/s
- outlet: p=0 Pa
HT in Solids
- thermal insulation except on the front facing the air
- initial values of the channel 800°C
- Surface-to-surface radiation (to simulate radiation inside the channel) with emissivity=0,4 and Tamb=20°C
HT in Fluids
- NO thermal insulation
- Initial values: T=20°C
- Temperature: T=150°C
- Outflow: outlet convective flow
- Heat source (absorption of the solar radiation of the channel as well as the heat transfer to the fluid )
An error is appearing
"Failed to find a solution.
In segregated group 1:
Divergence of the linear iterations.
There was a warning message from the linear solver.
Ill-conditioned preconditioner. Increase factor in error estimate.
Returned solution is not converged.
- Feature: Stationary Solver 1 (sol1/s1)"
It is because the 3 physics might be not coupled? How to couple the 3 physics?
Thank you and best regards,
Ana Tostao