Phase change modelling

[atulbhagat]

Hi all,
I am trying to model phase change of a aluminum member 10mm in diameter and 50 mm in length.
When i use any of the phase change models in heat equation, the equation fails to converge.
If i give the input in Latent heat of the boundary condition i get the following msg
"WARNING:: HeatSolve: Parent not associated
WARNING:: GetParentMatProp: Property Latent Heat not in either parents!"
If i dont use any of these i just get the temperature results w.r.t. time
My sif file is,
Header
CHECK KEYWORDS Warn
Mesh DB "." "."
Include Path ""
Results Directory ""
End

Simulation
Max Output Level = 4
Coordinate System = Cartesian
Coordinate Mapping(3) = 1 2 3
Simulation Type = Transient
Steady State Max Iterations = 1
Output Intervals = 1
Timestepping Method = BDF
BDF Order = 2
Timestep intervals = 100
Timestep Sizes = $ 10/100
Solver Input File = case.sif
Post File = case.ep
coordinate scaling = 0.001
End

Constants
Gravity(4) = 0 -1 0 9.82
Stefan Boltzmann = 5.67e-08
Permittivity of Vacuum = 8.8542e-12
Boltzmann Constant = 1.3807e-23
Unit Charge = 1.602e-19
End

Body 1
Target Bodies(1) = 1
Name = "Body 1"
Equation = 1
Material = 1
Initial condition = 1
End

Solver 1
Equation = Heat Equation
Procedure = "HeatSolve" "HeatSolver"
Variable = -dofs 1 Temperature
Exec Solver = Always
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e-5
Nonlinear System Convergence Tolerance = 1.0e-8
Nonlinear System Max Iterations = 1
Nonlinear System Newton After Iterations = 3
Nonlinear System Newton After Tolerance = 1.0e-3
Nonlinear System Relaxation Factor = 1
Linear System Solver = Iterative
Linear System Iterative Method = BiCGStab
Linear System Max Iterations = 500
Linear System Convergence Tolerance = 1.0e-8
Linear System Preconditioning = ILU1
Linear System ILUT Tolerance = 1.0e-3
Linear System Abort Not Converged = False
Linear System Residual Output = 1
Linear System Precondition Recompute = 1
End

Equation 1
Name = "Heat"
Active Solvers(1) = 1
End

Material 1
Name = "Aluminium (generic)"
Pressure Coefficient = 0.101
Enthalpy = 953100
Reference Temperature = 293.0
Heat expansion Coefficient = 23.1e-6
Reference Pressure = 0.101
Specific Heat Ratio = 910.0
Heat Conductivity = 237.0
Sound speed = 5000.0
Heat Capacity = 897.0
Mesh Poisson ratio = 0.35
Density = 2700.0
Poisson ratio = 0.35
Youngs modulus = 70.0e9
End

Initial Condition 1
Name = "room temp"
Temperature = 293
End

Boundary Condition 1
Target Boundaries(1) = 3
Name = "Fixed"
Displacement 3 = 0.0
Displacement 2 = 0.0
Displacement 1 = 0.0
End

Boundary Condition 2
Target Boundaries(1) = 4
Name = "Heating"
Phase Change = True
Heat Flux = 40450820
End

Is elmer capable of doing the phase change modelling, i need to see the physical behavior of the al member as it melts.
any help is highly appreciated.

Regards

[raback]

Hi

Are you trying to perform a Lagrangian or Eulerian phase change model?

There are some phase change consistency tests in elmer source files trunk/fem/test/PhaseChange*

Now an immediate problem seems to be that the BCs do not have parents. However, that is certainly not the only problem. How do you create your mesh from the STEP file?

-Peter

[atulbhagat]

Hi peter,
I m trying to follow Eulerian phase change model, and yes i did created my mesh from the step file

- atul

[raback]

Hi atul

Ok, if you use Eulerian methods you should end up with something like in tests/PhaseChange. The definition of the PhaseChange for BCs is related to Lagrangian models whereas the "Phase Change Model" is related to Eulerian, and it has no BC related to it. I admit that these are rather confusing. It might have been a good idea to add the Lagrangian/Eulerian to the keywords.

-Peter

[atulbhagat]

Hi Peter,
I tried adding the Eulerian key word to the BC's ,

Boundary Condition 2
Target Boundaries(1) = 4
Name = "Heating"
Phase Change = Eulerian
Heat Flux = 40450820.0
End

Still not getting the desired results

-Atul

[raback]

Hi

Look at the test case for the correct definitions. There is no BC related to Eulerian phase change.

-Peter

[atulbhagat]

Hi,
Ive modified the Sif as per the test case,
Header
CHECK KEYWORDS Warn
Mesh DB "." "."
Include Path ""
Results Directory ""
End

Simulation
Max Output Level = 4
Coordinate System = Cartesian
Coordinate Mapping(3) = 1 2 3
Simulation Type = Transient
Steady State Max Iterations = 1
Output Intervals = 1
Timestepping Method = BDF
BDF Order = 1
Timestep intervals = 100
Timestep Sizes = $ 10/100
Solver Input File = case.sif
Post File = case.ep
coordinate scaling = 0.001
End

Constants
Gravity(4) = 0 -1 0 9.82
Stefan Boltzmann = 5.67e-08
Permittivity of Vacuum = 8.8542e-12
Boltzmann Constant = 1.3807e-23
Unit Charge = 1.602e-19
End

Body 1
Target Bodies(1) = 1
Name = "Body 1"
Equation = 1
Material = 1
Initial condition = 1
End

Solver 1
Equation = Heat Equation
Procedure = "HeatSolve" "HeatSolver"
Variable = -dofs 1 Temperature
Exec Solver = Always
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e-5
Nonlinear System Convergence Tolerance = 1.0e-8
Nonlinear System Max Iterations = 500
Nonlinear System Newton After Iterations = 3
Nonlinear System Newton After Tolerance = 1.0e-3
Nonlinear System Relaxation Factor = 0.25
Linear System Solver = Iterative
Linear System Iterative Method = BiCGStab
Linear System Max Iterations = 500
Linear System Convergence Tolerance = 1.0e-8
Linear System Preconditioning = ILU0
Linear System ILUT Tolerance = 1.0e-3
Linear System Abort Not Converged = True
Linear System Residual Output = 1
Linear System Precondition Recompute = 1
End

Equation 1
Name = "Heat"
Phase Change Model = Eulerian
Check Latent Heat Release = True
Active Solvers(1) = 1
End

Material 1
Name = "Aluminium (generic)"
Pressure Coefficient = 0.101
Enthalpy = Variable Temperature
Real
1 9.1
400 3276
550 4641
650 9531
End
Phase Change Intervals (2,1) = 400 650
Reference Temperature = 293.0
Heat expansion Coefficient = 23.1e-6
Reference Pressure = 0.101
Specific Heat Ratio = 910.0
Heat Conductivity = 237.0
Sound speed = 5000.0
Heat Capacity = 897.0
Mesh Poisson ratio = 0.35
Density = 2700.0
Poisson ratio = 0.35
Youngs modulus = 70.0e9
End

Initial Condition 1
Name = "room temp"
Temperature = 293
End

Boundary Condition 1
Target Boundaries(1) = 3
Name = "Fixed"
Displacement 3 = 0.0
Displacement 2 = 0.0
Displacement 1 = 0.0
End

Boundary Condition 2
Target Boundaries(1) = 4
Name = "Heating"
Temperature = 700
End

Still not getting what im doing wrong

-atul

[raback]

Hi

Check the Models manual of the HeatSolver. There are some options of phase change model but 'Eulerian' is not any of those.

-Peter