The Application Gallery features COMSOL Multiphysics® tutorial and demo app files pertinent to the electrical, structural, acoustics, fluid, heat, and chemical disciplines. You can use these examples as a starting point for your own simulation work by downloading the tutorial model or demo app file and its accompanying instructions.

Search for tutorials and apps relevant to your area of expertise via the Quick Search feature. To download the MPH-files, log in or create a COMSOL Access account that is associated with a valid COMSOL license. Note that many of the examples featured here can also be accessed via the Application Libraries that are built into the COMSOL Multiphysics® software and available from the File menu.

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Quadrupole Mass Spectrometer

The principle component of a quadrupole mass spectrometer is the mass filter which is used to filter ions with different charge to mass ratios. The quadrupole mass filter has been well studied over the years, Ref. 1 and the physics and optimal design are well understood. In a real quadrupole mass spectrometer, fringe fields exist at both the entrance and exit of the mass filter. These fringe ...

Iron Sphere in a 60 Hz Magnetic Field

An iron sphere is exposed to a spatially uniform, sinusoidally time-varying, background magnetic field. The frequency of the field is low enough such that the skin depth is larger than the radius of the sphere. A reduced field formulation is used to impose the background field. Two approaches for solving this problem are shown. The induced currents in the sphere and the perturbation to the ...

Electric Impedance Sensor

Electric impedance measurements are used for imaging and detection. Applications range from nondestructive testing and geophysical imaging to medical imaging. Several alternative techniques are shown to model such a system. One of them shows how to use conditional expressions to define spatially dependent material properties. Another shows how to use multiple terminals for distributed sensing ...

Electrodynamics of a Power Switch

Electrical events, such as an overcurrent or overload, can seriously damage electrical circuits or power lines. To avoid expensive replacements of critical parts, electric switch circuit breakers can be installed. These mechanically interrupt the current flow or surge by moving a plunger as soon as a critical current is reached. In contrast to a fuse, which has to be replaced after it has been ...

Iron Sphere in a 20 kHz Magnetic Field

An iron sphere is exposed to a spatially uniform, sinusoidally time-varying, background magnetic field. The frequency of the field is such that there skin depth is smaller than the sphere radius. The induced currents in the sphere and the perturbation to the background field are computed. Proper meshing of domains with significant skin effect is addressed.

Effective Nonlinear Magnetic Curves Calculator

The Effective Nonlinear Magnetic Curves Calculator application is a companion to the *Effective Nonlinear Constitutive Relations* functionality. Magnetic-based interfaces in the AC/DC Module support the Effective HB/BH Curve material model that can be used to approximate the behavior of a nonlinear magnetic material in a frequency domain simulation without the additional computational cost of a ...

Magnetic Stiffness of an Axial Magnetic Bearing in 3D

The model illustrate the technique to calculate the magnetic stiffness in a 3D geometry of a permanent magnet axial magnetic bearing. The *Magnetic Fields* physics is used to model the bearing and compute the magnetic forces. The *Deformed Geometry* and *Sensitivity* physics are used to compute the magnetic stiffness. This model is featured and explained in much greater detail in the following ...

Small-Signal Analysis of an Inductor

If an inductor's magnetic material is nonlinear, then the inductance depends on the current passing through it. This model consists of an inductor with a nonlinear magnetic core, where the small-signal inductance is simulated as a function of current. The model also investigates how the small-signal inductance depends on the DC current.

Tubular Permanent Magnet Generator

This tutorial shows how to model the tubular permanent magnet generator in 2D axisymmetry. The generator consists of a modular stationary stator and moving/oscillating slider. The stator is made of three-phase multiturn windings and an iron core. The slider is made of permanent magnets and iron spacers. The open circuit voltage in the three-phase stator windings due to the periodic motion of the ...

Electrodynamic Bearing

This model illustrates the working principle of a passive electrodynamic bearing. An electrically conducting rotor rotating in a magnetic field produced by a permanent magnets induces eddy currents on the conducting rotor. The eddy currents, in turn, produce a magnetic field that opposes the magnetic fields by the magnets and induces a force that opposes the motion of the rotor. The radial ...