## How to Model Heat and Moisture Transport in Porous Media with COMSOL®

##### Claire Bost June 14, 2017

When ambient air flows through porous media, it carries moisture. In this process, temperature and moisture are coupled: The vapor saturates depending on the temperature conditions, while latent heat effects due to evaporation and condensation modify the temperature. We discussed heat and moisture transport in air in a previous blog post. Let’s address the specific transport processes we need to consider in pores and how to model heat and moisture transport in porous media with the COMSOL Multiphysics® software.

Read More##### Yosuke Mizuyama June 13, 2017

Ray tracing is an effective tool for high-frequency optics simulations. The Ray Optics Module for the COMSOL Multiphysics® software uses a multiphysics-capable wavefront method for its ray tracing. In this blog post, we’ll explore what makes the ray tracing algorithm in COMSOL Multiphysics distinct from traditional ray tracing algorithms described in standard geometrical optics textbooks and suggest a series of best practices to help you get the most out of your simulation results.

Read More##### Bridget Cunningham June 12, 2017

In the last seven years, the output of the manufacturing industry has increased by a total of around 10–20%. This growth is partly thanks to technologies and processes that save on time and costs, such as 3D printing and, as is described here, powder compaction. To model this process, we can use the new porous plasticity models in the latest version of the COMSOL Multiphysics® software.

Read More##### Claire Bost June 9, 2017

Whenever ambient air is considered in an engineering context, temperature and moisture are intrinsically related. Vapor reaches a saturation point depending on the temperature and pressure conditions, while the action of latent heat modifies temperature distribution. These phenomena must be considered to optimize processes affected by phase changes, particularly when trying to prevent condensation occurring in devices. Let’s see how to model heat and moisture transport in air with the COMSOL Multiphysics® software.

Read More##### Bridget Paulus June 8, 2017

Solar-grade silicon is becoming more popular for applications such as communications and photovoltaics. While it’s important to keep up with this growing demand, the current method of producing solar-grade silicon is energy intensive and expensive. To find a more efficient process, researchers at JPM Silicon GmbH explored a novel method using a microwave furnace. By simulating the internal processes, they aim to optimize their microwave furnace design to produce low-cost solar-grade silicon.

Read More##### Sven Friedel June 7, 2017

Capacitance calculations in the COMSOL Multiphysics® software seem easy. If you only have two conductors, the recipe is simple: Take one conductor and set it to grounded, set the other as a terminal, and compute the solution. Then, a built-in variable delivers the capacitance. But what if you have more than two conductors, like in touchscreens, transmission lines, and capacitive sensors? If standard textbook terminology has you lost, follow along with this working example of calculating a capacitance matrix.

Read More##### Walter Frei June 6, 2017

Whenever light is incident on a dielectric material, like glass, part of the light is transmitted while another part is reflected. Sometimes, we add a metal coating, such as gold, which alters the transmittance and reflectance as well as leads to some absorption of light. The dielectric surface and the metal coating also often have some random variations in height and thickness. In this blog post, we will introduce and develop a computational model for this situation.

Read More##### Walter Frei June 5, 2017

Have you ever wanted to include a randomly created geometry in your model? Perhaps you want to simulate a natural material or an arrangement of parts that has some known statistical distribution of dimensional variations. In such cases, we may want to create a random geometry in the COMSOL Multiphysics® software. With the release of version 5.3, we can now create random geometries using a model method. Let’s take a look at how to do so with a tasty example.

Read More##### Bjorn Sjodin June 2, 2017

To easily generate random-looking geometric surfaces, the COMSOL Multiphysics® software provides a powerful set of built-in functions and operators, such as functions for uniform and Gaussian random distributions and a very useful sum operator. In this blog post, we show you how to generate a randomized surface with what amounts to a “one liner” expression with detailed control of the constituent spatial frequency components that determine the nature of the surface’s roughness.

Read More##### Chien Liu May 31, 2017

You can use the new Schrödinger Equation interface for modeling with the Semiconductor Module in the latest release of the COMSOL® software. Let’s look at a simple example app that uses this interface to estimate the electron and hole ground state energy levels for a superlattice structure. By building apps like this one, device engineers are able to calculate the band gap for a given periodic structure and adjust the design parameters until a desired band gap value is achieved.

Read More##### Bridget Cunningham May 30, 2017

Every year, over 40 million fire sprinkler systems are fitted worldwide. These systems are effective due to their piping designs, which are resistant to high heat and mechanical damage. A popular choice for such designs is threaded steel pipe. But analyzing a complex pipe design is challenging because of the detailed geometry. What approach can we take to efficiently combine accurate geometrical designs with reliable stress analyses? Version 5.3 of the COMSOL® software offers functionality for this purpose.

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