[SOLVED]multiple object heating simulation with phase change

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chatpall
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[SOLVED]multiple object heating simulation with phase change

Post by chatpall »

Hi all.

I would like to ask you for some advice. I would like to simulate "indirect" heating of object (which is changing it´s phase). This object is situated in another object with distinc boundary between both object. Heating is set with dirichlet BC to constant temperature. Boundary condition between two objects is set to constant heat transfer coeficient. Enthalpy in object with phase change is set to be temperature variable, with clear phase change interval. I am using two heat solvers, one for object 1(priority 1) and second for object 2 (with phase change) (priority 2). My attempts for solutios are ending with this message:

Code: Select all

ERROR:: Model Input: 
ERROR:: Model Input:  Unknown specifier: [target boundaries]
ERROR:: Model Input:  In section: [material 1]
ERROR:: Model Input:  For property name:[boundary condition 1]
Phase change is definded to spatial 2 model.

I am attaching my sif file and geometrical representation of my mode.

Thank you very much for all your time!!!

P.
Attachments
case.sif
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Last edited by chatpall on 21 Mar 2015, 22:21, edited 1 time in total.
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mzenker
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Re: multiple object heating simulation with phase change

Post by mzenker »

Hi,

looks like you forgot to specify the boundaries for your boundary condition.
If you don't find the problem, you might post your sif file.

HTH,

Matthias
chatpall
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Re: multiple object heating simulation with phase change

Post by chatpall »

hello matthias,

sif file is attached... over the picture. boudary conditions are considered and are in sif file.
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mzenker
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Re: multiple object heating simulation with phase change

Post by mzenker »

Hmmm...
I think there is an "End" missing at your Enthalpy declaration in Material 1.
See solver manual, "Keyword Syntax".

HTH,

Matthias
chatpall
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Re: multiple object heating simulation with phase change

Post by chatpall »

mathias, that was my oversight.

after corecting this mistake i am getting this kind of error:

Code: Select all

WARNING:: HeatSolve: Parent not associated
i am getting solution, but without visible latent heat "conservation" of the energy.
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mzenker
Posts: 1999
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Re: multiple object heating simulation with phase change

Post by mzenker »

Hi,

this is the relevant section of the code (HeatSolve.src):

Code: Select all

!------------------------------------------------------------------------------
!     BC: -k@T/@n = (rho*L)*v.n 
!     Heating related to pulling is possible only in ss cases where pull velocity
!     is desrcibed.
!------------------------------------------------------------------------------

      IF( GetLogical( BC, 'Phase Change',Found ) ) THEN
         PhaseVelocity(1,1:n) = GetReal( BC,'Phase Velocity 1', Found  )
         PhaseVelocity(2,1:n) = GetReal( BC,'Phase Velocity 2', Found  )
         PhaseVelocity(3,1:n) = GetReal( BC,'Phase Velocity 3', Found  )
  
         ! Ensure that the latent heat and density come from the same side
         LatentHeat(1:n) = GetParentMatProp( 'Latent Heat', &
              UElement = Element, UParent = Parent )
         IF(.NOT. ASSOCIATED(Parent) ) THEN
           CALL Warn('HeatSolve','Parent not associated')
         ELSE
           k = GetInteger(Model % Bodies(Parent % BodyId) % Values,'Material')
           Density(1:n) = GetReal( Model % Materials(k) % Values, 'Density' )
         END IF

         ! This could be rather put as a new type of BC into the assembly routine and 
         ! then the Normal could be taken at the proper Gaussian integration points. 
         Normal = NormalVector( Element, ElementNodes, 0.0_dp, 0.0_dp, .TRUE. )

         DO i=1,n
            LOAD(i) = LOAD(i) + &
                 LatentHeat(i) * Density(i) * SUM( Normal(1:3) * PhaseVelocity(1:3,i))
         END DO
      END IF
I am not familiar with this part of the heat solver, so I cannot tell what happens exactly. It seems that somehow it doesn't find the material properties it is looking for. But it is just a warning, so you could try to go on anyway and see what happens and if the results are reasonable.

HTH,

Matthias
chatpall
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Re: multiple object heating simulation with phase change

Post by chatpall »

Mtthias please, where can I find some description of GetParentMatProp function?
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raback
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Re: multiple object heating simulation with phase change

Post by raback »

Hi

Best description of given function is the code ;-)

The problem may be that you have boundary elements without parent elements defined.

-Peter
chatpall
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Re: multiple object heating simulation with phase change

Post by chatpall »

raback wrote:Hi

Best description of given function is the code ;-)

The problem may be that you have boundary elements without parent elements defined.

-Peter
Peter, yes you are right the code is the best description.

Is there any additional information about parental elements and their relation to simulations?

My simulation with phase change is going quite well , I acquired results I was looking for. (with big help from julien givernaud thread). But let´s say I really don´t understand every aspect of the code, nevertheless thank you guys for your patience and your help!
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annier
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Re: [SOLVED]multiple object heating simulation with phase change

Post by annier »

Hi Chatpall,
Boundary elements and Parental elements are simply the elements for FEM (my rough guess however). In my guess, when two surfaces have a common boundary like "liquid" confined in a "surrounding" vessel, the boundary for both of them will be common. The user has then not clearly indicated to the solver whether the boundary belongs to body 1 or body 2. I don't know how the solver will deal with that boundary.
Have you studied more on this?

Yours Sincerely
Anil Kunwar
Anil Kunwar
Faculty of Mechanical Engineering, Silesian University of Technology, Gliwice
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