11 Replies Latest reply on Feb 18, 2016 4:10 AM by Ahmad Aufar

Transient thermal analysis...sandwich panels.....

Ilpo Viiliainen Mar 8, 2008 1:19 PM

Has anyone tried to run transient thermal analysis on sandwich panel structures ?
In this case sandwich is made of : sheet metal plate / rockwool / sheet metal plate.
How is this kind of problem solved in cosmosworks or is it impossible to do that

Transient thermal analysis...sandwich panels.....

Basil Gello Mar 9, 2008 3:09 PM (in response to Ilpo Viiliainen)

Ilpo,

I have some experience in that and I think it is not more complicated than the transient analysis on coupled surfaces. So, first make the contact between the coincident surfaces (set the contact meshing node-to-node or similar), define your materials, assign the initial temperature for all your parts, define the temperature change, heat flux and radiation if necessary, and try to run the analysis... Hope the results will satisfy you.

Regards,Basil.
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Transient thermal analysis...sandwich panels.....

Ian Hogg Mar 9, 2008 6:27 PM (in response to Ilpo Viiliainen)

Hi Ilpo,

I concur with Basil. This should be very doable in COSMOS. The main challenge (as always) is getting all the material properties depending on what you are studying. The thermal conductivity of Rock Wool insulation is readily found (e.g. http://www.rockwool.dk/sw44919.asp), but I've not seen any heat flux (problably since heat transfer to surrounding fluids not significant).

I am guessing you are interested in seeing the temperature transfer through from one side of the sandwich to the other through the rock wool to verify if it is adequately insulating 2 regions. Thermal conductivity should be adequate for that.

Cheers,

Ian
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- Transient thermal analysis...sandwich panels.....
  
  Ilpo Viiliainen Mar 10, 2008 7:34 AM (in response to Ian Hogg)
  
  Basil and Ian,
  
  Thanks for Your valuable information...
  I'll be studying this thermal problem more closely.
  I'll be back..maybe some new questions may rise on the way.
  
  Best regards,
  Ilpo
  
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  - Transient thermal analysis...sandwich panels.....
    
    Ilpo Viiliainen Mar 14, 2008 6:23 PM (in response to Ilpo Viiliainen)
    
    Hi again...
    
    some problems were encountered....
    
    The time dependent temperature variation of one surface of the sandwich panel is well known. Densities and temperature dependent thermal conductivities of the different materials + specific heats are known too. I also defined initial temperatures of the materials.
    As I know how one of the surfaces is heated, I of course want to know, how fast the heat is transferred to the other surface of the panel. ..that is: What is the temperature of the other surface after a given time (say 15 minutes).
    I got an error message saying: insufficient boundary conditions !?
    
    Is there something missing, ... what did I do wrong ?
    The opposite surface of of the panel (the one that is not heated) is faced to the open space. Maybe I haven't found a way to set up a proper boundary condition to this particular face... any help ?
    
    Regards,
    Ilpo
    
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    - Transient thermal analysis...sandwich panels.....
      
      Basil Gello Mar 15, 2008 5:52 PM (in response to Ilpo Viiliainen)
      
      Ilpo,
      
      to get the answer on your problem
      
      As I know how one of the surfaces is heated, I of course want to know, how fast the heat is transferred to the other surface of the panel. ..that is: What is the temperature of the other surface after a given time (say 15 minutes).
      
      you have to determine the values of heat flux, temperature, heat flow. Thinking about the error's reason, I suppose you did not used either radiation or contact between the surface directly, because in this case thermal solver does nothing about how the heat is being transferred. Check your model or upload it here - we'll have a look.
      
      Regards, Basil
      
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      - Transient thermal analysis...sandwich panels.....
        
        Ilpo Viiliainen Mar 17, 2008 10:08 AM (in response to Basil Gello)
        
        Hi Basil,
        
        How to determine the heat flux ?
        
        (let me remind You (as You have probably noticed), that I'm certainly not an expert on these kind of problems,...
        merely a rookie, but very willing to learn ... )
        So..
        I have data, which gives me air temperature at a distance of 100mm from the metal surface (the surface which is then heated by this hot air).
        The temperature of the air raises from 0 minutes at 35 deg. celsius to 60 minutes abt. 900 deg. celsius. (the temperature is a time-dependent curve, not a linear one)
        The opposite surface (the one whose temperature changes over time I'm interested in) is faced to open space or room.
        
        Let's consider the sandwich panel as a cover hatch or a "door" of a very big heated oven.
        
        regards,
        Ilpo
        
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        Transient thermal analysis...sandwich panels.....
        
        Basil Gello Mar 17, 2008 7:27 PM (in response to Ilpo Viiliainen)
        
        Ilpo,
        1. You can get the heat flux plot in Plot Results window selecting the Heat Flux parameter. Also, you can export the results to Excel.
        2. If you want to use the fluid-solid interaction like between metal and gas, you should use FloWorks first, simulating the air flow on metal surface, then using this data in Works (using the Use FloWorks Effects on simulation tab in Works). Or, you can try to run the direct analysis in Flo, but it can give not the results you want to get.
        Regards, Basil
        
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        Transient thermal analysis...sandwich panels.....
        
        Ilpo Viiliainen Mar 26, 2008 10:05 AM (in response to Basil Gello)
        
        Finally I managed to produce a time dependent temperature plot on the opposite
        surface.... but I'm not quite satisfied yet.
        Next I would like to know if it is possible in CosmosWorks to model or somehow simulate a vaporizing material ?
        I mean, that when this material (located somewhere in the middle of sandwich panel structure)
        is heated, it consumes a part of the conducted heat energy, and thus slows the
        rise of the temperature on the opposite surface.
        
        Any ideas ?
        
        (my english is not so good, but I hope You guys understand what I'm trying to say )
        
        regards,
        Ilpo
        
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        Transient thermal analysis...sandwich panels.....
        
        Basil Gello Mar 26, 2008 2:43 PM (in response to Ilpo Viiliainen)
        
        Ilpo,
        CosmosWorks currently does not support evaporation or other multi-phase effects. You have to use something more complicated to do that, for example Ansys CFX. But, he you want to make an experiment with Flo, try both gas and fluid in one tank and try setting the pressure in your gas domain simulating the evaporation. To simulate the temperature rise delay, try cooling on that specific heat simultaneously. But I have never done that in Flo, so I an not sure it works.
        
        Regards, Basil
        
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        Transient thermal analysis...sandwich panels.....
        
        Ilpo Viiliainen Mar 28, 2008 1:10 PM (in response to Basil Gello)
        
        Thanks Basil for Your comments !
        
        I'll try to figure it out, how to handle the
        temperature rise delay....
        Surely more questions will pop up on the way...
        (huh.. this is far more complicated than I expected...)
        
        Regards,
        Ilpo
        
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      - Re: Transient thermal analysis...sandwich panels.....
        
        Ahmad Aufar Feb 18, 2016 4:10 AM (in response to Basil Gello)
        
        excuse me,i am new in using thermal analysis of SOLIDWORKS simulation. right now i am doing the same case, thermal analysis on sandwich structure, but with additional gap (with natural air).
        if thermal conductivity will transfer the heat for touching face, how to make the heat transferred from one surface to another for simulating the effect of the gap in order to reduce the heat? because the desired outcome is to know the impact the difference distance in gap (not vacuum gap) to minimize the heat.
        do i have to design the part and define it as "air" or i have to use radiation "boundary condiiton"? thanks for any advice and help.
        
        Regards
        
        Aufar
        
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