To assign air to the model, notice that there is no domain to click. In this example, we study this component as “hanging in midair” to get its idealized electrostatics properties. We assume that the space between and outside the plates is filled with air, which is the only material property in this model. In the real case, this filter would be held in a frame, which we have neglected here to keep things simple. The electrostatic precipitation filter example.
.png "comsol 5.3 electrostatics")
The wires are modeled as parametric curves and held at 50 kV. The filter in this example consists of 6 ground plates and 60 wires, as shown in the figure below. If you want to know more about the details of modeling an electrostatic precipitation filter, see page 21 of COMSOL News 2012. This keeps the model simple, yet quite general, and illustrates a modeling approach that is applicable to a wide range of other electrical devices. Instead, let’s look at the filter from a purely electrostatics perspective. Simulating the entire physical process of corona discharge, ionization, and charged particle migration is complicated and beyond the scope of this blog post. The charged particles then migrate in the electric field toward grounded metal plates (the collecting electrodes) and are periodically scraped off when the layer of particles becomes so thick that it deteriorates the performance of the filter. An array of high-voltage wires creates a corona discharge region surrounding them, which in turn charges the unwanted particles. This type of filter is used in various industrial settings to filter particles from, for example, exhaust gases from coal power plants. To illustrate using the Electrostatics, Boundary Elements interface, let’s create a simplified model of an electrostatic precipitation filter. Example: Electrostatic Precipitation Filter For example, you can have one domain with an anisotropic material modeled with the traditional Electrostatics interface in the AC/DC Module and a surrounding isotropic domain modeled with the new Electrostatics, Boundary Elements interface.
Requires meshing the diameter of the wires to avoid mesh-dependent solutionsīy combining domains modeled with FEM and regions modeled with BEM, you can get the best of both worlds. Requires recomputing with a larger truncation domain Requires infinite elements or an approximation of an infinite domain through using large enclosing truncation domains The table below summarizes the pros and cons of BEM and FEM in the COMSOL Multiphysics implementation. The COMSOL Multiphysics implementation of BEM cannot be used to model, for example, nonlinear or general inhomogeneous materials. However, this advantage comes at a price. BEM eliminates the problem by only requiring a surface mesh, which is significantly easier to generate. In contrast to FEM, BEM doesn’t require the generation of a robust volumetric mesh throughout your computational domain, which can be difficult and resource-intensive to achieve. Although this blog post focuses on the interface for electrostatics, some of the techniques shown here are applicable if you are interested in the other two interfaces. There are three different types of interfaces that are based on BEM, summarized in the table below: InterfaceĬurrents in electrochemical applications in 2D and 3DĮlectrodeposition Module, Corrosion ModuleĬOMSOL Multiphysics (no add-on product required)
Comsol 5.3 electrostatics software#
The boundary element method (BEM) is complementary to the finite element method (FEM) and is generally available in the COMSOL Multiphysics® software as of version 5.3. Interfaces Based on the Boundary Element Method in COMSOL Multiphysics® In this blog post, let’s see how the new functionality can be used to conveniently set up a model that includes a number of very thin spiral wires. The technology is known as the boundary element method and can be used on its own or in combination with finite-element-method-based modeling. The latest version of the AC/DC Module enables you to create electrostatics models that combine wires, surfaces, and solids.
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