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heating element not generating heat using SS Heat Generation Rate

Question asked by Josh Lierer on Jan 27, 2021
Latest reply on Jan 29, 2021 by Josh Lierer

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I have a very simplified model of an oven to try to understand the heat source tools. I have created an SS Heat Generation Rate for my input data with the rate at 5250 Btu/h but, when I create a cut plot only the top element generated some heat. See below of the cut plot results. What have missed when defining this simulation or should I try to define the top and bottom elements as separate heat sources? Is there a certain type of test I should run? I currently defined the test as an internal test see general setting screenshot for details. Let me know if I need to provide more information or to clarify anything.

Thanks,

Josh

Sylvain Grondin Jan 29, 2021 10:31 AM

Correct Answer

Hi,

So it's a matter of mesh refinement :

The problem was that your mesh was too coarse around the heating surfaces.

You can see at the bottom and at the top, the rising of temperatures.

You should even more refine the mesh around the heating elements, so you can have a better prediction of the temperature. Around 3-4 cells for a thin thickness with the "Conduction of solid" option activated, should be the minimum. I haven't checked the basic refinement Flow does with this geometry : the mesh you see above is only the initial mesh, set to level 6.

Check for the cells around and inside the surface of the heating surface, to reach if possible 3-4 cells through the diameter of the tubes and you should have better results.

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Sylvain Grondin Jan 28, 2021 5:54 AM

Hi,,,

That's weird indeed ; if you really selected all elements of the top and bottom parts, it should apply a heat the rate to each of the elements. Did you apply other boundary condition to the bottom part ? which could replace/cancel the surface heat rate. You can test with different surface heat rate, but it should work with only one applied to all surfaces.

Did you try to check other result tools to see if there is any temperature rising on the bottom part ?

Could you provide your model so we can check on our own what could possibly fail ?

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Josh Lierer @ Sylvain Grondin on Jan 28, 2021 2:44 PM

Hi,

I had set up as an internal with only heat generation. I did try, after posting this, using a boundary condition of a real wall set to 850 Fahrenheit which produced heat on both elements. this uses a lot of ram resources so not a practical option for the actual model. I also checked surface plots with the same results of room temp at the bottom with a hot spot at the stop.

Is there a way i could upload the file with the simulation data or could I just provide the three parts in the assembly and provide input settings? i tried doing a pack and go approach with simulation but made the file huge.

thanks,

Josh

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Attilio Colangelo @ Josh Lierer on Jan 28, 2021 8:16 PM

Uncheck “include Simulation results” when you do the pack and go.

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Josh Lierer @ Attilio Colangelo on Jan 29, 2021 9:18 AM

Thank you, I have attached the simplified model. Let me know if i need to add or provide any more details.

Thanks again.

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heating test.zip1.5 MB

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Sylvain Grondin Jan 29, 2021 10:31 AM

Hi,

So it's a matter of mesh refinement :

The problem was that your mesh was too coarse around the heating surfaces.

You can see at the bottom and at the top, the rising of temperatures.

Check for the cells around and inside the surface of the heating surface, to reach if possible 3-4 cells through the diameter of the tubes and you should have better results.

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Josh Lierer @ Sylvain Grondin on Jan 29, 2021 4:31 PM

Thank you for all the help!

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6 Replies

Sylvain Grondin Jan 28, 2021 5:54 AM
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Correct Answer
Hi,,,

That's weird indeed ; if you really selected all elements of the top and bottom parts, it should apply a heat the rate to each of the elements. Did you apply other boundary condition to the bottom part ? which could replace/cancel the surface heat rate. You can test with different surface heat rate, but it should work with only one applied to all surfaces.
Did you try to check other result tools to see if there is any temperature rising on the bottom part ?

Could you provide your model so we can check on our own what could possibly fail ?
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- Josh Lierer @ Sylvain Grondin on Jan 28, 2021 2:44 PM
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  Correct Answer
  Hi,
  
  I had set up as an internal with only heat generation. I did try, after posting this, using a boundary condition of a real wall set to 850 Fahrenheit which produced heat on both elements. this uses a lot of ram resources so not a practical option for the actual model. I also checked surface plots with the same results of room temp at the bottom with a hot spot at the stop.
  
  Is there a way i could upload the file with the simulation data or could I just provide the three parts in the assembly and provide input settings? i tried doing a pack and go approach with simulation but made the file huge.
  
  thanks,
  Josh
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  - Attilio Colangelo @ Josh Lierer on Jan 28, 2021 8:16 PM
    Mark Correct
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    Uncheck “include Simulation results” when you do the pack and go.
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    - Josh Lierer @ Attilio Colangelo on Jan 29, 2021 9:18 AM
      Mark Correct
      Correct Answer
      Thank you, I have attached the simplified model. Let me know if i need to add or provide any more details.
      
      Thanks again.
      Attachments
      heating test.zip1.5 MB
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Sylvain Grondin Jan 29, 2021 10:31 AM
Unmark Correct
Correct Answer
Hi,

So it's a matter of mesh refinement :

The problem was that your mesh was too coarse around the heating surfaces.

You can see at the bottom and at the top, the rising of temperatures.
You should even more refine the mesh around the heating elements, so you can have a better prediction of the temperature. Around 3-4 cells for a thin thickness with the "Conduction of solid" option activated, should be the minimum. I haven't checked the basic refinement Flow does with this geometry : the mesh you see above is only the initial mesh, set to level 6.
Check for the cells around and inside the surface of the heating surface, to reach if possible 3-4 cells through the diameter of the tubes and you should have better results.
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- Josh Lierer @ Sylvain Grondin on Jan 29, 2021 4:31 PM
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  Thank you for all the help!
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heating element not generating heat using SS Heat Generation Rate

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