# COMSOL Blog

## A General Introduction to Chemical Kinetics, Arrhenius Law

##### Eyal Spier | February 13, 2014

Chemical reaction engineering is an interesting modeling challenge. At first glance, describing a reacting system seems to be very manageable. There remain, however, countless complications and pitfalls that make chemical simulations both challenging and rewarding. In this first post of a new blog series, we will introduce chemical kinetics in general and walk you through how you can use COMSOL software in chemical reaction engineering.

### Analyze your Simulation Results with Projection Operators

##### Clemens Ruhl | February 12, 2014

Have you ever used your hands to make shadow puppets on the wall? By shining a light behind your (three-dimensional) hands, you create two-dimensional projections on the wall. When analyzing your simulation data in COMSOL Multiphysics, you can do something similar with your model using projection operators.

### Implementing a Simple Temperature Controller with a Component Coupling

##### Walter Frei | February 11, 2014

When solving a thermal processing problem, such as the heating or cooling of a part, it is desirable to change the heating, or cooling, based upon the computed solution. That is, we may want to include a feedback loop into our model. In this article, we will set up a feedback loop using a component coupling to turn a heat load on or off depending upon the temperature of the part being heated.

### Which Current Distribution Interface Do I Use?

##### Melanie Noessler | February 10, 2014

When designing electrochemical cells, we consider the three classes of current distribution in the electrolyte and electrodes: primary, secondary, and tertiary. We recently introduced the essential theory of current distribution. Here, we illustrate the different current distributions with a wire electrode example to help you choose between the current distribution interfaces in COMSOL Multiphysics for your electrochemical cell simulation.

### Theory of Current Distribution

##### Edmund Dickinson | February 7, 2014

In electrochemical cell design, you need to consider three current distribution classes in the electrolyte and electrodes. These are called primary, secondary, and tertiary, and refer to different approximations that apply depending on the relative significance of solution resistance, finite electrode kinetics, and mass transport. Here, we provide a general introduction to the concept of current distribution and discuss the topic from a theoretical stand-point.

### Intro to the What, Why, and How of Shared Memory Computing

##### Pär Persson Mattsson | February 6, 2014

A couple of weeks ago, we published the first blog post in a Hybrid Modeling series, about hybrid parallel computing and how it helps COMSOL Multiphysics model faster. Today, we are going to briefly discuss one of the building blocks that make up the hybrid version, namely shared memory computing. Before that, we need to consider what it means that an “application is running in parallel”. You will also learn when and how to use shared memory with COMSOL.

### Rocket Innovations for Private Space Flight

##### Fanny Littmarck | February 5, 2014

Rockets have been refined over the past 150 years or so. Until the 1920s, when liquid-fuel rockets were invented, rockets were powered by solid propellants and oxidizers. Both these bring forth issues in how they’re handled on the ground or in flight. Private space flight companies are now working on hybrid rocket innovations to solve this problem.

### Simulating Thermal Performance in Windows

##### Lexi Carver | February 4, 2014

Keeping the inside of a building at a comfortable temperature requires well-designed windows to keep heat out during the summer and heat in during the winter. Let’s take a look at how windows provide thermal insulation and how they carry heat (or not) between the inside of a building and the outdoors.

### Computing and Controlling the Volume of a Cavity

##### Walter Frei | February 3, 2014

There are various ways of handling interactions between fluids and solids in COMSOL. You can, for example, explicitly model the fluid using the full Navier-Stokes equations for the pressure and fluid velocity fields. Although that can be a very accurate approach, it’s much more expensive than is needed for certain types of Fluid-Structure Interaction (FSI) problems. Here, we’ll introduce a method for modeling enclosed volumes containing incompressible fluids, under the additional assumption that the momentum and energy transfer via the […]

### Improving Bioreactor Performance with COMSOL Multiphysics

##### Mark Yeoman | January 31, 2014

We have the pleasure of introducing a new guest blogger, Mark Yeoman of Continuum Blue, who showcases what they can do for their biomedical engineering clients. In a recent webinar, I had the opportunity to highlight some of the great things we at Continuum Blue are doing in the biomedical field. In this guest post, I will delve deeper into how we use COMSOL software to help clients improve bioreactor performance and show you a bioreactor modeling example.