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How to put infinite value for permittivity of metals
Posted 2024/10/16 5:20 GMT-4 Electromagnetics, Fluid & Heat, Materials Version 6.0 3 Replies
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Hi
Why is the relative permittivity of metals set as 1 in COMSOL while the true value is infinity. Wont this affect the accuracy of simulation. I am doing simulation on generating lorentz force in a conducting fluid (magnetohydrodynamics), and the relative permittivity of the molten metal is set as 1. Is it fine to put relative permittivity as 1000000 (an extremely high value) to give the same effect as infinite relative permittivity. Kindly help.
Thank you
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In the physics formulations familiar to me, the high conductivity (rather than relative permittivity) is the essential EM constitutive property for your liquid metal, for MHD. And if you want your MHD model to work correctly, don't set that conductivity to be infinite. Use a physically-correct value.
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At RF the model for the usual metals (aluminum, copper, silver, etc. etc.) has relative permittivity 1, relative permeability 1, and conductivity large but finite. This leads to the usual values for skin depth- that is, field penetration that is small and decreases with frequency.
Some ferromagnetic metals may warrant a non-unity value for the permeability. I do not know of any circumstance where a large permittivity makes sense.
Please login with a confirmed email address before reporting spam
In the physics formulations familiar to me, the high conductivity (rather than relative permittivity) is the essential EM constitutive property for your liquid metal, for MHD. And if you want your MHD model to work correctly, don't set that conductivity to be infinite. Use a physically-correct value.
Ok Thank you