Eddy currentwith moving magnet

[Gilles]

Hello everyone,


Below is my model:
- On the left, a set of polar plates and magnets. This set is mobile, it goes up and down.
- On the right a set of coils and the outer body (barrel). This part is fixed.
In the drawing, the two parts are visibly separated by a vertical line.


I am looking for eddy current losses at the level of the external body (barrel).
The values are too small compared to the actual measurements.

In the program I use to recover the value, the variable "joule heating e" which I think is in, W and the sum of the volume.
In the documentation it is stated that this value is calculated in harmonic mode. But I move in temporal mode. I don't know if that's the problem.

If anyone has an idea. Thank you.
Best regards
Gilles

[Gilles]

Hello everyone,

Maybe I wasn't very clear. Sorry.

In fact I have doubts about the activation of the different solvers and the fact that I am in

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Simulation Type = Transient

I tested first:

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Active Solvers(4) = 1 2 3 4

Then :

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Active Solvers(2) = 1 2
Active Solvers(3) = 2 3 4

But the results are very close. I'm missing about a factor of 16. (The coils in this case are not connected. I replaced them with air.)

I statically tested the B field, the current density and the force generated by the assembly. The results are correct.


Best regards
Gilles

[Gilles]

Hello everyone,

Well after all this time I will still find the answer.
I added this command line

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    Steady State Condition = 1.0 

in the "MagnetoDynamics2D" solver.
Since then I have had consistent results.

I have finished my magnetic study on my project, I will move on to the mechanical part now.

I wanted to thank all of Elmer's contributors. Thanks a lot.



Below is the program and dependency

parm_elmer.txt

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$ F=100       ! Frequence  (Hz)   
$ X=0.013        ! Déplacement  (m) 
$ JElmer=983110.9427        ! Densite de courant  (A/m2)  Courant à Fr

Acier2.txt

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0.00000 0.00000	     
0.25030 238.73250	 
0.92500 795.77500	 
1.25000 1591.55000	 
1.39000 2387.32500	 
1.52500 3978.87500	 
1.71000 7957.75000	 
1.87000 15915.50000	 
1.95500 23873.25000	 
2.02000 39788.75000	 
2.11000 79577.50000	 
2.22500 159155.00000
2.43000 318310.00000

case.sif

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INCLUDE parm_elmer.txt

Header
  CHECK KEYWORDS Warn
  Mesh DB "." "mesh"
  Include Path ""
  Results Directory ""
End


$Npas=180         ! Nombre de point pas cycle
$Cy=1                   ! Nombre de cycle

Simulation
  Max Output Level = 6
  Coordinate System = "Axi Symmetric"
  Coordinate Scaling(3)=Real 0.001 0.001 0
  Coordinate Mapping(3) = 1 2 3

    Simulation Type = Transient    !Steady   
    Timestepping Method = BDF
    BDF Order = 2
    Timestep Sizes = $ 1/F/Npas
    Timestep Intervals = $ Npas*Cy

  Output Intervals = 1
  Steady State Max Iterations = 1
  Solver Input File =/home/fleury/Documents/ElmerCad_Ocean/case.sif
  Post File = case.vtu
End

Constants
  Gravity(4) = 0 -1 0 9.82
  Stefan Boltzmann = 5.670374419e-08
  Permittivity of Vacuum = 8.85418781e-12
  Permeability of Vacuum = 1.25663706e-6
  Boltzmann Constant = 1.380649e-23
  Unit Charge = 1.6021766e-19
End



! %%%%%%%%%% Solver %%%%%%%%% 
Solver 1
  Equation = MeshDeform
  Exec Solver = Before Timestep
  Procedure = "RigidMeshMapper" "RigidMeshMapper"

  Variable = MeshRelax
  Nonlinear System Max Iterations = 1

  Linear System Solver = Direct   ! Iterative
  Linear System Iterative Method = BiCGStab
  Linear System Max Iterations = 500
  Linear System Convergence Tolerance = 1.0e-10
  Linear System Preconditioning = ILU1
  Linear System Residual Output = 20
End



Solver 2
  Equation = "MGDynamics"
  Exec Solver = Always
  Procedure = "MagnetoDynamics2D" "MagnetoDynamics2D"
  Variable = "A"
  Steady State Condition = 1.0
  
  Stabilize = True
  Optimize Bandwidth = True
  Steady State Convergence Tolerance = 1.0e-5
  Nonlinear System Convergence Tolerance = 1.0e-7
  Nonlinear System Max Iterations = 30
  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
  BiCGstabl polynomial degree = 2
  Linear System Preconditioning = ILU0
  Linear System ILUT Tolerance = 1.0e-3
  Linear System Abort Not Converged = False
  Linear System Residual Output = 10
  Linear System Precondition Recompute = 1
  

End


Solver 3
  Equation = MgDynPost
  Exec Solver = After Timestep ! After Saving
  Procedure = "MagnetoDynamics" "MagnetoDynamicsCalcFields"
  Discontinuous Bodies = Logical True
  Discontinuous Galerkin = True
  Average Within Materials = True
  Potential Variable = "A"
  
    Calculate Magnetic Field Strength = Logical True
    Calculate Magnetic Vector Potential = Logical True
    Calculate Electric Field = Logical True
    Calculate JxB = Logical True
    Calculate Magnetic Flux Density = Logical True
    Calculate Current Density = Logical True
    Calculate Nodal Forces = Logical True
    Calculate Elemental Fields  = Logical True
    Calculate Nodal Fields = Logical True
    Calculate Maxwell Stress= Logical True
    Calculate Current Density= Logical True
    Calculate Joule Heating= Logical True
    Calculate Nodal Heating= Logical True
    Calculate eddy current power= Logical True

  Stabilize = True
  Optimize Bandwidth = True
  Steady State Convergence Tolerance = 1.0e-5
  Linear System Solver = Direct
  Linear System Direct Method = Umfpack
  
End

Solver 4
  Exec Solver = after saving
  Equation = SaveScalars
  Procedure = "SaveData" "SaveScalars"
  Filename = "forces.csv"

    Variable 1 = time2
     Expression 1 = Variable "time"
      Real MATC "X*sin(2*pi*F*tx(0))"
    
    Variable 2 = time
      Expression 3 = Variable "time"
       Real MATC "tx(0)"
       
    Variable 3 =  joule heating 
      Mask Name 3 =String "FUT"   ! Nom de varable Bodie
      Operator 3 = body int

    Variable 4=  joule heating 
      Mask Name 4 =String "PPs"   ! Nom de varable Bodie
      Operator 4 = body int

    Variable 5 = jxb 2
      Mask Name 5 = String "BBp"   ! 
      Operator 5 = body int
      
    Variable 6 = jxb 2
      Mask Name 6 = String "BBm"   ! 
      Operator 6 = body int
        
    Variable 7 = nodal force 2
      Mask Name 7 = String "PPs"   ! 
      Operator 7 = body int    
      
    Variable 8 = current density 3
      Mask Name 8 = String "BBp"   ! 
      Operator 8 = body int   
      
      
     Save Component Results = logical true
    
End

! %%%%%%%%%Equation %%%%%%%%%


Equation 1
  Name = "Moving elstat"
  Active Solvers(4) = 1 2 3 4
End


! %%%%%%%%% Material%%%%%%%%% 

Material 1
  Name = "Air"
  Relative Permeability = 1.0                                !  µr 
  Magnetic Permeability = 1.2566e-6
  Electric Conductivity = 0
End

Material 2
  Name = "Acier"
  Relative Permeability = 100        !  µr  valeur FEMM 100 ou 5000 
  Magnetic Permeability =1.26e-4
  Electric Conductivity = 1e7  
  H-B Curve = Variable "nonlin"
  Real Cubic Monotone
    include Acier2.txt
    End
End

Material 3
  Name = "Aimant"
  Relative Permeability = 1.05  
  Magnetic Permeability = 899000
  Magnetization 2 = Real 939000  
  Electric Conductivity = 0
End

Material 4
  Name = "Aimant"
  Relative Permeability = 1.05
  Magnetic Permeability = 899000
  Magnetization 2 = Real -939000
  Electric Conductivity = 0
End

Material 5
  Name = "Cuivre"
  Relative Permeability = 0.999
  Magnetic Permeability = 1.2566e-6
  Electric Conductivity = 59.59e6
End


!!
! %%%%%%%%%  Force  %%%%%%%%% 
Body Force 1
  Name = "Move"
   Mesh Translate 2 = Variable "time" 
    Real MATC "X*sin(2*pi*F*tx(0))"
End

Body Force 2
  Name = "I+"
  !Current Density = $ JElmer 
  Current Density = Variable "time" 
   Real MATC "JElmer*sin(2*pi*F*tx(0))"
End

Body Force 3
  Name = "I-"
  !Current Density =$ -JElmer
  Current Density = Variable "time" 
   Real MATC "-JElmer*sin(2*pi*F*tx(0))"

End
 
! %%%%%%%%%  Bodies  %%%%%%%%% 
! Fut    ++++++++++++++++++++++
Body 1
 Target Bodies(1) = 2
 Name = "fut"
 Equation = 1
 Material = 2
 FUT = logical True
 !Save Scalars = True
End
 
! Bobine ++++++++++++++++++++++
Body 2
 Target Bodies(2) = 3 5
 Name = "BBp"
 Equation = 1
 Material = 1
 BBp = logical True
 Body Force  = 2
End
 
Body 3
 Target Bodies(1) = 4
 Name = "BBm"
 Equation = 1
 Material = 1
 BBm= logical True
 Body Force  = 3
End
 
! Plaque polaire  +++++++++++++
Body 4
 Target Bodies(1) = 6
 Name = "PPs"
 Equation = 1
 Material = 2
 Body Force  = 1
 PPs = logical True
End
 
! Aimant  +++++++++++++
Body 5
 Target Bodies(1) = 7
 Name = "AimantP"
 Equation = 1
 Material = 3
 Body Force  = 1
 AimantP = logical True
End

Body 6
 Target Bodies(1) = 8
 Name = "AimantM"
 Equation = 1
 Material = 4
 Body Force  = 1
 AimantM = logical True
End

 
! Air tranlateur  +++++++++++++
Body 7
 Target Bodies(1) = 9
 Name = "Air translateur"
 Equation = 1
 Material = 1
 Body Force  = 1
End
  
! Air Stator  +++++++++++++
Body 8
 Target Bodies(1) = 1
 Name = "Air Stat"
 Equation = 1
 Material = 1
End
 
! %%%%%%%%%   Condition limite  %%%%%%%%% 
 
Boundary Condition 1                     ! Contour Masse mobile
  Name = "Ensemble masse mobile "or
  Target Boundaries() =  5
  Moving Boundary = Logical True
End
 
Boundary Condition 2                     ! Contour air stator   zero
  Name = "Zero Stator "
  Target Boundaries (1) = 1
  !Pz=0
End
 
Boundary Condition 3                     ! Contour air translateur Fix  zero
  Name = "Zero Translator "
  Target Boundaries (1) = 6
  Fixed Boundary = Logical True
   !Pz=0
End
 
Boundary Condition 4                      !liaison des deux surfaces (5)
  Name = " Jonction Stator"               ! Coté stator
  Target Boundaries (1) = 2 
  Mortar BC = 5
  Plane Projector = Logical True
  Galerkin Projector = Logical True
End
 
Boundary Condition 5                     !liaison des deux surfaces (4)
  Name = "Jonction Translateur"          ! Cote translateur
  Target Boundaries (1) = 7
End
 

[raback]

Hi

Nice work! Unfortunately Xmas time was bad for asking questions so these we unanswered for some time.

-Peter