thermal analysis of a vacuum chamber

[raback]

Ok, sorry for my hasty judgement. The umf4num giving the error is a routine of the umfpack package. It may be that it is also used in normalizing the view factors. I would guess that the error is due to memory running out in that process. -Peter

[slav]

My best computer (Windows 7) is 64 bit, it has 8 GB of memory and Intel i5-3470 CPU@ 3,2 GHz (max 3,6 GHz) processor. It should be good enough... Unfortunatelly, Elmer works as 32 bit program on it... And I read somwhere on this forum that 32 version uses up to 2 GB of memory. ViewFactors.exe uses less than 300 MB (the result file has about 1 GB size!!!) and 25% CPU. ElmerSolver however reaches something close to 2 GB (using also 25% CPU) and crashes. Can I somehow use more of resources of the computer? Will switching to Linux help? Is there anything like ElmerGUI on Linux (I have no idea of Linux and I don't know how to work on a console). I think my model is quite simple and small now, I will need much more complicated later. Can I estimate somehow how much memory do I need?

I read almost all about radiation on the forum. Matthias wrote about "idealized" radiation that it

means radiation exchange with the outside world which is a black body at "external temperature"

which is not my case, so I need these view factors computation.

My sif file is as follows (I used no preconditioning as suggested here viewtopic.php?f=3&t=1111&p=3490&hilit=r ... cd45#p3490 but it didn't help)

Code: Select all

Simulation
  Max Output Level = 5
  Coordinate System = Cartesian
  Coordinate Mapping(3) = 1 2 3
  Simulation Type = Steady state
  Steady State Max Iterations = 1
  Output Intervals = 1
  Timestepping Method = BDF
  BDF Order = 1
  Solver Input File = case.sif
  Post File = case.ep
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 = 2
End

Body 2
  Target Bodies(1) = 2
  Name = "Body 2"
  Equation = 1
  Material = 2
End

Body 3
  Target Bodies(1) = 3
  Name = "Body 3"
  Equation = 1
  Material = 1
End

Solver 1
  Equation = Heat Equation
  Variable = -dofs 1 Temperature
  Procedure = "HeatSolve" "HeatSolver"
  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-7
  Nonlinear System Max Iterations = 20
  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-10
  Linear System Preconditioning = None
  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"
  Convection = Constant
  Active Solvers(1) = 1
End

Material 1
  Name = "Aluminium (Fortal, 7075)"
  Heat expansion Coefficient = 23.5e-6
  Heat Conductivity = 134.0
  Sound speed = 5000.0
  Heat Capacity = 862.0
  Mesh Poisson ratio = 0.33
  Density = 2810.0
  Poisson ratio = 0.33
  Emissivity = 0.1
  Youngs modulus = 72.0e9
End

Material 2
  Name = "Glass (BK7)"
  Heat expansion Coefficient = 7.3e-6
  Heat Conductivity = 1.13
  Heat Capacity = 870.0
  Mesh Poisson ratio = 0
  Density = 2430.0
  Poisson ratio = 0
  Emissivity = 0.92
  Youngs modulus = 0
End

Boundary Condition 1
  Target Boundaries(1) = 4
  Name = "out_okno1"
  External Temperature = 294
  Heat Transfer Coefficient = 5
  Temperature = 350
End

Boundary Condition 2
  Target Boundaries(1) = 5
  Name = "in_okno1"
  Radiation = Diffuse Gray
  External Temperature = 0.001
  Heat Transfer Coefficient = 0
  Temperature = 350
  Heat Flux = 0
End

Boundary Condition 3
  Target Boundaries(1) = 6
  Name = "out_okno2"
  External Temperature = 294
  Heat Transfer Coefficient = 5
End

Boundary Condition 4
  Target Boundaries(1) = 7
  Name = "in_okno2"
  Radiation = Diffuse Gray
  External Temperature = 0.001
  Heat Transfer Coefficient = 0
  Heat Flux = 0
End

Boundary Condition 5
  Target Boundaries(1) = 8
  Name = "out_komora"
  External Temperature = 294
  Heat Transfer Coefficient = 5
End

Boundary Condition 6
  Target Boundaries(1) = 9
  Name = "in_komora"
  Radiation = Diffuse Gray
  External Temperature = 0.001
  Heat Transfer Coefficient = 0
  Heat Flux = 0
End 

[slav]

I found that there is a problem with 64 bit Windows version There was a path to the newest files here http://www.nic.funet.fi/pub/sci/physics ... n/windows/ but what to do with them? There is no .exe, should I replace the folders? I cannot compile Elmer by my own, it's a cosmos for me.


EDIT: I installed the newest 32 bit binary from the path above and than copied the files from the 64 bit version to this folder. Calculating View Factors took about an hour (it was a few minutes before) with 1-3% CPU usage and it crashed at the same point.

[annier]

Hi slav,
Have you tried about the option of installing elmer through VMWARE?
yours
Anil Kunwar

[slav]

We installed Elmer on 64bit Linux but I still get this error. I was't allowed to use wmware due to the bios manipulation.