AC/DC

Fanny Littmarck | January 3, 2014

Before conducting certain blood sample analyses, researchers need to separate the red blood cell particles from the blood plasma. Using lab-on-a-chip (LOC) technology, red blood cell separation can be achieved via magnetophoresis, i.e. motion induced by magnetic fields. Since the magnetic permeability of the particles is different from the blood plasma, their trajectory can be controlled within the flow channel of the LOC device and thereby separated out from the fluid.

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Magnus Olsson | December 2, 2013

When designing inductive devices, both challenges and possibilities are associated with the nonlinear behavior of ferromagnetic materials. COMSOL Multiphysics is well-adapted to the solution of highly nonlinear numerical models but high-fidelity modeling of nonlinear inductive devices also requires accurate material data. To meet this challenge, a library of 165 nonlinear magnetic materials is provided in COMSOL 4.4, bringing new powers to the design and modeling of electric motors, transformers, relays, etc. Here, we will discuss how the modeling process is […]

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Supratik Datta | August 26, 2013

If you have ever stood next to a transformer, you have probably heard a humming sound coming from it and wondered if there were bees close by. When you hear that sound the next time, you can rest assured that it’s not bees but the magnetostriction of the transformer core that is making that humming sound.

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Fanny Littmarck | June 21, 2013

I’ve written several blog entries involving permanent magnets, in one way or another. Reading those may have raised the question “what about a more simple introduction to permanent magnet simulations?” Fair enough, here’s how to model a permanent magnet and its surrounding magnetic field.

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Walter Frei | April 2, 2013

A question that comes up occasionally is whether or not you can compute the inductance of a single straight wire. This seemingly simple question actually does not really have an answer, and gives us the opportunity to talk about a very interesting point when solving Maxwell’s equations. Anybody working in the field of computational electromagnetics should have an understanding of this key concept, as it will help you properly set up and interpret models involving magnetic fields.

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Fanny Littmarck | April 1, 2013

In the world of bearings, there are many different types to choose from. For certain applications, magnetic bearings trump their mechanical counterparts in several regards. In order to understand how the bearing will perform, using a simulation tool to calculate design parameters is a good idea.

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Daniel Smith | March 27, 2013

In a previous blog entry I discussed some of the exotic properties of graphene. The fact that graphene consists of a single layer of atoms means the aspect ratio of any graphene-based structure may be very high. High aspect geometries present their own array of modeling challenges.

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Fanny Littmarck | March 4, 2013

Last week you saw how you can simulate the heating of a car’s brake discs. This reminded me of another type of brake — the eddy current brake (also known as magnetic brake). Whereas the other model was a study in heat transfer, eddy current brakes deal with electromagnetics.

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Andrew Griesmer | February 18, 2013

Induction occurs when a metal object moves in the presence of a magnetic field inducing a current in that object. The induced current causes it to heat up (called inductive heating), as all current does. Yet, simulating these two coupled physics together can be difficult to do as they are intrinsically based on different time scales. COMSOL Multiphysics is able to cleverly simulate them through combining the frequency domain modeling of the magnetic field with a stationary simulation of the […]

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Fanny Littmarck | November 6, 2012

Permanent magnet generators, or PM generators as they are also called, generate power without batteries. PM generators consist of a magnetic stator coiled with wire and a wheel with permanent magnets rotating inside the stator. From motorcycles to wind farms, PM generators can be used in many electrical machinery applications. Let’s take a look at how these types of generators work and how they can be simulated.

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