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[kavatar]

First one, i.e., Mag_B, is selected from the named expressions available in calculator, while the second one, i.e., Mag(Real(Bx,By,Bz)), is generated using field calculator as following: Quantity->B, Complex-> Real, then Mag). I am using eddy current solver in Maxwell-3D.

Note that-----------------

-Integrate(Volume(ConductingFluid), Mag_B) / Volume of ConductingFluid

This value changes when I change the Phase angle in calculator

-Integrate(Volume(ConductingFluid), Mag(Real(Bx,By,Bz)))/ Volume of ConductingFluid

          This value remains constant at all the phases in the eddy current calculation

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Which of these expressions will give the correct value of volume average of time averaged Magnetic Flux Density distribution in eddy current simulation?

I want to compute:

1) time average magnetic flux density distribution in the conducting domain then,

2) volume averaged value of the time averaged magnetic flux density distribution

Can anyone suggest me the expressions for these two in ANSYS Maxwell3D calculator?

Sincerely

Krishna

[HDLI]

Hello Krishna,

      Please review the expression in field calculator for Mag_B, that is for AtPhase. 

      I am not sure why you integrate Mag B in the volume, although you mentioned your goal, because B vectors' direction would be different for each element. 

      If you just want to integrate all the mag B, using Mag_B is good and then plot it with phase in field result plot to calculate time average value. Thanks.

HDLI

[kavatar]

Hello HDLI,

Thank you for you response. Lets me provide more details to what I want to do.

I have a mesh to compute fluid flow under the influence of Lorentz force. To solve this, I export " Volume_Force_Density" expression from ANSYS Maxwell and apply three Force density components to three momentum equations. Volume_Force_Density expression is nothing but the time averaged DC force per unit cell volume.

Similar to the above, I want to export the distribution of the magnitude of time averaged magnetic flux density (B) on fluid flow mesh and use the same in my fluid flow calculations for turbulence damping. 

So, essentially I want an expression which computes the "magnitude of the time averaged magnetic flux density B" on each grid point.

As of now, I am using the following expression:

Could you please confirm whether the above expression will give me "magnitude of the time averaged magnetic flux density" on each mesh point or not? if not then kindly help me with this expression?

- Now to answer why I intergrate, I also want to compute the volume averaged value of the magnitude of time averaged magnetic flux density B. But this I can compute if in know the above expression. 

[HDLI]

Hello Krisha,

      Mag(Real(Bx,By,Bz)) will give you the magnitude of real part. With this, I do not think we could get a accurate result on your fliud calculation.

       Do you use Ansys Fluent to simulate the fluid flow under the influence of Lorentz force?  If Yes, Fluent has magnetic solver, so we need to export real and imaginery parts of Bx, By, Bz for each element. After that, Fluent could use them to calculate Lorentz force.

HDLI

[kavatar]

Hello HDLI,

Yes, I am using ANSYS Fluent to compute the flow field in inductively stirred molten metal. The procedure you have stated (using MHD module of fluent) is to consider the velocity effect on magnetic field. This is applied when MHD problem is solved via two-way coupled approaach. 

For my case, magnetic Reynolds number is <<<1, therefore I can ignore the velocity effect on the magnetic field and simply apply the time averaged Lorentz force computed from ANSYS Maxwell (using Volume_Force_Density expression) to momentum equations in ANSYS Fluent. This part I have already completed. 

What I am interested is to study the influence of magnetic field on the turbulence damping. The damping source term of turbulence model equations (equations of turbulence kinetic energy, k, and its dissipation rate, epsilon) are in the form of |B|². Hence, I need  |B|² value in each computational cell. 

So essentially, I want to compute time averaged |B|² from eddy current solution in Maxwell-3D and use it in fluent. I believe, time averaged magnetic field |B| or |B|² would be a good way to go about it.

If I get time average |B|², I will use it as it is. Or, If i get time averaged |B| then i will have to take square of it. (I hope I stated my doubt correctly)

So just like time averaged Lorentz force, which is given in Maxwell expression as Volume_Force_Density, could you please suggest me the expression to compute either time averaged |B| or time averaged |B|²

Sincerely

Krishna