# Model Gallery

The Model Gallery features COMSOL Multiphysics model files from a wide variety of application areas including the electrical, mechanical, fluid, and chemical disciplines. You can download ready-to-use models and step-by-step instructions for building the model, and use these as a starting point for your own modeling work. Use the Quick Search to find models relevant to your area of expertise, and login or create a COMSOL Access account that is associated with a valid COMSOL license to download the model files.

### Solution of the Schrödinger Equation for the Hydrogen Atom

This example shows how to compute energy levels and electron orbits for the hydrogen atom. It models the atom as a 1-particle system using the stationary Schrödinger equation. Before solving this problem in COMSOL Multiphysics, the dimension of the problem is firstly reduced from three to two by using cylindrical coordinates (rho, phi, z). The model is then set up using the PDE Coefficient ...

### Fixed Bed Reactor for Catalytic Hydrocarbon Oxidation - new

Tubular reactors are generally modelled with the assumption that the concentration and temperature gradients only occur in the axial direction. The only transport mechanism operating in this direction is the overall flow itself, which is considered to be of plug-flow. In this example a more general approach is taken, an approach that accounts for variations of the concentrations and temperature ...

### Eigenvalue Analysis of a Crankshaft - new

This model describes a modal analysis of a crankshaft. The pistons’ reciprocating movement is transferred to the crankshaft through connecting rods by means of crankshaft throws. The forces, torques, and bending moments, which are highly variable both in time and space, subject the crankshaft to very high and complex loading. The crankshaft design must therefore incorporate careful and ...

### Stresses in a Pulley

The stresses in a pulley connected to an engine that drives another pulley are studied in this model. A parametric analysis is conducted in order to study how the rotational speed affects the stress distribution in the pulley. The power at the pulley shaft remains constant, the moment (defined by the ratio of the power by the rotational speed) will thus decrease with increased speed. This ...

### Micromixer

The development of mixers does often not only have to account for effectiveness, but also other factors must be involved, such as cost and complexity for manufacturing. The three models study a laminar static micro mixer with two parallel sets of split-reshape-recombine mixing elements. The mixer works through lamination of the streams without any moving parts and the mixing is obtained through ...

### Conical Quantum Dot

Quantum dots are nano- or microscale devices created by confining free electrons in a 3D semiconducting matrix. Those tiny islands or droplets of confined “free electrons” (those with no potential energy) present many interesting electronic properties. They are of potential importance for applications in quantum computing, biological labeling, or lasers, to name only a few. Quantum dots ...

### Thermal Bridges in Building Construction—EN ISO 10211:2007

The European standard EN ISO 10211:2007 for thermal bridges in building constructions provides four test models—two 2D and two 3D—for validating a numerical method (Ref. 1). If the values obtained by a method conform to the results of all these four cases, the method is classified as a three-dimensional steady-state high precision method. This document presents COMSOL Multiphysics results ...

### An Integro-Partial Differential Equation

The heat distribution in a hollow pipe, whose ends are held at two different temperatures, is studied. The outside surface is assumed to be thermally isolated and the inner surfaces have radiation boundary conditions. The role of convection in the heat transfer is taken to be negligible. The temperature is assumed to be constant along the thickness of the pipe and rotational symmetry is also ...

### Pacemaker Electrode

This model illustrates the use of COMSOL Multiphysics for modeling of ionic current distribution problems in electrolytes, in this case in human tissue. The problem is exemplified on a pacemaker electrode, but it can be applied in electrochemical cells like fuel cells, batteries, corrosion protection, or any other process where ionic conduction takes place in the absence of concentration ...

### A 3D Model of a Diesel Particulate Filter

Several factors influence a diesel particulate filter’s (DPF) efficiency and durability. Important issues include the removal of soot particles from the filter membranes and the influence of thermal stress on the ceramic structure, stress that arises during repeated operating cycles. Mathematical modeling provides a powerful tool for investigating such critical parameters under a wide range of ...