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Electric field between two electrodes

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Hi,

First of all let me tell you that I am a new user of comsol. Indeed, after some research, I trully believe in the significant impact that this software might have on my work. However, I am a chemical engineering trying to figure out how to work with this software regarding the simulation of electric fields.

So, after searching some issues on this forum, I continue to not overcome my problem.

I am trying to simulate an Eletric field between a grounded plate (180x180x1 mm) and a charged electrode (Radius 0.4 mm and Height 30 mm). There is a potential of 10 kV on the electrode and I aim to evaluate the electric field established (value and direction). Despite of my efforts, I am not being successful.

I am uploading the file itself, and hopping that someone might provide some help and guidance.

Best regards,
Tiago


8 Replies Last Post 12 ott 2012, 04:52 GMT-4
Robert Koslover Certified Consultant

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Posted: 1 decade ago 3 giu 2012, 23:17 GMT-4
I opened and ran your model with version 4.3.

1. The run appears to have been successful, in the sense that it executes and computes electric potentials and fields that appear to be in accordance with the boundary conditions that you specified.

2. That said, your geometry setup of the problem could use some improvement. First of all, your problem volume should likely extend well beyond both your probe and plate (assuming that both your probe and plate are intended to be finite). But you have put both the probe and plate right up against the problem boundaries, which is not a good way to allow the fields to relax to their correct orientations there.



I opened and ran your model with version 4.3. 1. The run appears to have been successful, in the sense that it executes and computes electric potentials and fields that appear to be in accordance with the boundary conditions that you specified. 2. That said, your geometry setup of the problem could use some improvement. First of all, your problem volume should likely extend well beyond both your probe and plate (assuming that both your probe and plate are intended to be finite). But you have put both the probe and plate right up against the problem boundaries, which is not a good way to allow the fields to relax to their correct orientations there.

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Posted: 1 decade ago 4 giu 2012, 04:39 GMT-4
Oh, I see.

Thank you for your guidance. Let me ask you another questions.

1) What is the difference between ploting (in volume) es.Ex+es.Ey+es.Ez vs. sqrt(es.Ex*es.Ex+es.Ey*es.Ey+es.Ez*es.Ez)

2) Is it possible in a volume-plot select a plane and represent it in a 2D-plot only (example: xy-plane when z=1)

Thank you in advance.

Oh, I see. Thank you for your guidance. Let me ask you another questions. 1) What is the difference between ploting (in volume) es.Ex+es.Ey+es.Ez vs. sqrt(es.Ex*es.Ex+es.Ey*es.Ey+es.Ez*es.Ez) 2) Is it possible in a volume-plot select a plane and represent it in a 2D-plot only (example: xy-plane when z=1) Thank you in advance.

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 4 giu 2012, 04:57 GMT-4
Hi

E is a vector, if you sum the three spatial components as scalars, or if you take the norm (sqrt(x^2+y^2+z^2) you will get different results

You can use the Data-Set (right click) "cut plane" to define a sub-solution set with the results interpolated to your cut plane, then you apply a 2D plot on that cut plane

--
Good luck
Ivar
Hi E is a vector, if you sum the three spatial components as scalars, or if you take the norm (sqrt(x^2+y^2+z^2) you will get different results You can use the Data-Set (right click) "cut plane" to define a sub-solution set with the results interpolated to your cut plane, then you apply a 2D plot on that cut plane -- Good luck Ivar

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Posted: 1 decade ago 4 giu 2012, 05:28 GMT-4
So lets say that I aim to plot the Electric field in a certain volume. How I should plot:

a) es.Ex+es.Ey+es.Ez

b) sqrt(es.Ex*es.Ex+es.Ey*es.Ey+es.Ez*es.Ez)

c) sqrt(es.Ex*es.Ex+es.Ey*es.Ey+es.Ez*es.Ez) and add arrows according to es.Ex+es.Ey+es.Ez

Best regards
So lets say that I aim to plot the Electric field in a certain volume. How I should plot: a) es.Ex+es.Ey+es.Ez b) sqrt(es.Ex*es.Ex+es.Ey*es.Ey+es.Ez*es.Ez) c) sqrt(es.Ex*es.Ex+es.Ey*es.Ey+es.Ez*es.Ez) and add arrows according to es.Ex+es.Ey+es.Ez Best regards

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 4 giu 2012, 05:59 GMT-4
Hi

a) I do not understand, perhaps you mean the vector (Ex,Ey,Ez) ?
b) has already a name by COMSOL es.normE
c) is the default volumic arrow setting

I have made up a quick example hereby, but I'm not sure I catch all your desire ;)

note that the arrow plot is not possible on a Data Set Surface = existing boundary, but OK on a free surface = Cut Plane

--
Good luck
Ivar
Hi a) I do not understand, perhaps you mean the vector (Ex,Ey,Ez) ? b) has already a name by COMSOL es.normE c) is the default volumic arrow setting I have made up a quick example hereby, but I'm not sure I catch all your desire ;) note that the arrow plot is not possible on a Data Set Surface = existing boundary, but OK on a free surface = Cut Plane -- Good luck Ivar

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Posted: 1 decade ago 11 ott 2012, 10:21 GMT-4
I am following this discussion. I have similar senario..but I would like have a different physics rather than electrostatics.
Bcause I want to set both plate (domain - not the boundaries) to an alternating potential at high frquency such as 20MHz.
anyone has any idea?

Kind regards,

Nada Manivannan
I am following this discussion. I have similar senario..but I would like have a different physics rather than electrostatics. Bcause I want to set both plate (domain - not the boundaries) to an alternating potential at high frquency such as 20MHz. anyone has any idea? Kind regards, Nada Manivannan

Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 11 ott 2012, 10:34 GMT-4
Hi

check the doc abour ACDC nad RF frequency "assumptions" and choose your physics accordingly, by comparing the model geometrical size and your wavelength size

--
Good luck
Ivar
Hi check the doc abour ACDC nad RF frequency "assumptions" and choose your physics accordingly, by comparing the model geometrical size and your wavelength size -- Good luck Ivar

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Posted: 1 decade ago 12 ott 2012, 04:52 GMT-4
Hi Tiago
I had a similar problem recently. I summarized my approach in this post. Maybe it helps you.
www.comsol.com/community/forums/general/thread/31204/

Martin
Hi Tiago I had a similar problem recently. I summarized my approach in this post. Maybe it helps you. http://www.comsol.com/community/forums/general/thread/31204/ Martin

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