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April 26, 2016, 07:16 |
Problem with cooling of a block.
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#1 |
New Member
Wojtek
Join Date: Apr 2016
Posts: 6
Rep Power: 9 |
Hi,
I'm trying to calculate the process of cooling of a block made of alluminium. The block is supposed to be suspended in space with some initial temperature. The geometry looks like this: https://i.gyazo.com/78e770987f3a9e71...76562cbbdb.png The main issues that I have are how to set boundary conditions- in some threads I read that I need to choose "coupled" option for the box, but I don't know where I need to set the initial temperature then. I also don't understand what kind of type I need to choose for the walls of the "air box". Please help. |
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April 26, 2016, 09:07 |
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#2 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,654
Rep Power: 65 |
The initial temperature is an initial condition, not a boundary condition. The initial temperature is specified in the initialization pane. The exact value of the initial temperature need not be correct since it is merely an initial guess, unless you are running a transient simulation.
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April 26, 2016, 10:19 |
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#3 |
New Member
Wojtek
Join Date: Apr 2016
Posts: 6
Rep Power: 9 |
Thank you very much for your reply.
I'm going to describe a problem that is actually more important. My project goal is to check how the temperature of solar module changes due to wind loads. As I am new to CFD I created the most simple model I could think of (just to get the basic rules) which you can see here: https://i.gyazo.com/cb5c88f8ae2cd634...b1e2d6df29.png I set the "enclosure" part to fluid and the other block was created as one part. Next in the mesher I created most basic mesh and named my selections as follows: inlet: https://i.gyazo.com/0f40fbe9649200f4...41ea23be25.png outlet: https://i.gyazo.com/e41a52cc2dcbc825...d30ba1867a.png symmetry: https://i.gyazo.com/828f21f7fe52adcc...bff9a78324.png ground (wall): https://i.gyazo.com/1d5edb6871b4287e...3c2c451853.png Next I connected those parts: https://i.gyazo.com/73e0b57f5a5fbf73...0c256289a2.png In solver I turned energy equation on and moved to boundary conditions which look as follows: https://i.gyazo.com/6760894347ed266b...8578ff7191.png I set inlet to 2m/s and temperature of 273K and wall-solid to 300K. Then I initialized the calculation and got following results: https://i.gyazo.com/53329ad10e3ee80d...cef2c914e2.png (the wall is the inlet), so I see there is no change in the temperature of the module despite the blowing wind. What should I change? I tried to check those videos: https://www.youtube.com/watch?v=72NpJd2LiGE https://www.youtube.com/watch?v=4y_wcH8MpAE But still didn't get that much of help. |
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April 26, 2016, 15:16 |
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#4 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,654
Rep Power: 65 |
Is this a steady or transient simulation? Did you even run any calculation?
All I see are the initial conditions. Is there even any flow? |
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April 26, 2016, 15:21 |
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#5 |
New Member
Wojtek
Join Date: Apr 2016
Posts: 6
Rep Power: 9 |
It is a steady one. Yes, i ran a calculation and the results are shown in the last photo.
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April 27, 2016, 01:23 |
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#6 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,654
Rep Power: 65 |
You need a coupled wall at the fluid|solid interfaces. Which surfaces are wall-13 14 and 7? There is already a coupled BC on wall-7 but what about 13 and 14?
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May 2, 2016, 12:16 |
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#7 |
New Member
Wojtek
Join Date: Apr 2016
Posts: 6
Rep Power: 9 |
Honestly, I have no idea which walls those are. When I try to highlight them while checking the mesh, there is nothing and when I try to check results for them I get an ainformation: Note: zone-surface: cannot create surface from sliding interface zone.
Creating empty surface. |
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