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DEP (dielectrophoresis)separation simulation

Posted 20.06.2011, 01:27 GMT-4 2 Replies

Elnaz Poorreza
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hi
How i can intoduce DEP(electric field gradient) to comsol and see the Arrows that indicate DEP force direction?
(like fig 4in the article)(nDEP,pDEp)
i have done somthing like that,(x component of DEP force)FX_DEP=2*pi*epsilon_f*Re(kf)*r^3*diff((normEx_emes)^2+(normEy_emes)^2)
and ycomponent of DEP force as FY_DEP in scalar expression but when i want to see the results in postprocessing
plot parameters I can see electric field norm or x_component of electric field component or electric potential...(default)
but there is no DEP force or electric field gradient!!!which path I must go to see DEP force(electric field gradient)?
is that possible to calculate the twDEP
orDEP forces in different height of channel with comsol postprocessing without numerical calculations?
for seeing the displacment of particle(pDEp or ndep) which path i must go?(i am working with comsol 3.5)
best regards
2 Replies Last Post 10.08.2017, 09:53 GMT-4
COMSOL Moderator

Hello Elnaz Poorreza

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Hector Moncada
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Posted: 1 decade ago 11.08.2011, 20:30 GMT-4

hi
How i can intoduce DEP(electric field gradient) to comsol and see the Arrows that indicate DEP force direction?
(like fig 4in the article)(nDEP,pDEp)
i have done somthing like that,(x component of DEP force)FX_DEP=2*pi*epsilon_f*Re(kf)*r^3*diff((normEx_emes)^2+(normEy_emes)^2)
and ycomponent of DEP force as FY_DEP in scalar expression but when i want to see the results in postprocessing
plot parameters I can see electric field norm or x_component of electric field component or electric potential...(default)
but there is no DEP force or electric field gradient!!!which path I must go to see DEP force(electric field gradient)?
is that possible to calculate the twDEP
orDEP forces in different height of channel with comsol postprocessing without numerical calculations?
for seeing the displacment of particle(pDEp or ndep) which path i must go?(i am working with comsol 3.5)
best regards


I think what you need to do is revise the "diff((normEx_emes)^2+(normEy_emes)^2)" from your equation. At least for comsol 3.5a to calculate the gradient I used d(normE_emdc^2,x) for the x component of the force, and d(normE_emdc^2,x) for the y component of the force, that way you have Fx_DEP and Fy_DEP and if you want to calculate the overall magnitude you can calculate the normal with sqrt(FxDEP^2+FyDEP^2). For the direction of the arrows I guess you'll only need the x and y component separately. I still have to check this for comsol 4 and 4.1.

I hope this is helpful
[QUOTE] hi How i can intoduce DEP(electric field gradient) to comsol and see the Arrows that indicate DEP force direction? (like fig 4in the article)(nDEP,pDEp) i have done somthing like that,(x component of DEP force)FX_DEP=2*pi*epsilon_f*Re(kf)*r^3*diff((normEx_emes)^2+(normEy_emes)^2) and ycomponent of DEP force as FY_DEP in scalar expression but when i want to see the results in postprocessing plot parameters I can see electric field norm or x_component of electric field component or electric potential...(default) but there is no DEP force or electric field gradient!!!which path I must go to see DEP force(electric field gradient)? is that possible to calculate the twDEP orDEP forces in different height of channel with comsol postprocessing without numerical calculations? for seeing the displacment of particle(pDEp or ndep) which path i must go?(i am working with comsol 3.5) best regards [/QUOTE] I think what you need to do is revise the "diff((normEx_emes)^2+(normEy_emes)^2)" from your equation. At least for comsol 3.5a to calculate the gradient I used d(normE_emdc^2,x) for the x component of the force, and d(normE_emdc^2,x) for the y component of the force, that way you have Fx_DEP and Fy_DEP and if you want to calculate the overall magnitude you can calculate the normal with sqrt(FxDEP^2+FyDEP^2). For the direction of the arrows I guess you'll only need the x and y component separately. I still have to check this for comsol 4 and 4.1. I hope this is helpful
Honeyeh Matbaechi Ettehad
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Posted: 7 years ago 10.08.2017, 09:53 GMT-4
Do you have any suggestions how to write the real part of CM factor in Expression box of Software in order to plot this electric field gradient or DEP force?

Best regards,
H.Matbaechi
Do you have any suggestions how to write the real part of CM factor in Expression box of Software in order to plot this electric field gradient or DEP force? Best regards, H.Matbaechi

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