# Application Gallery

The Application Gallery features COMSOL Multiphysics tutorial and demo app files pertinent to the electrical, mechanical, fluid, and chemical disciplines. You can download ready-to-use tutorial models and demo apps with step-by-step instructions for how to create them yourself. The examples in the gallery serve as a great starting point for your own simulation work.
Use the Quick Search to find tutorials and apps relevant to your area of expertise. Log in or create a COMSOL Access account that is associated with a valid COMSOL license to download the MPH-files.

### Semibatch Polymerization

As reactant monomer converts into polymer chains, the density of the reacting mixture often changes notably. In this example you will look at how this effect impacts the total production of polymer in a process. The liquid phase polymerization takes place in a semibatch reactor, where two operating conditions are compared. In the first scenario, the feed of monomer to the reactor is turned off ...

### Optimization of a Catalytic Microreactor

In this model, a solution is pumped through a catalytic bed where a solute species reacts as it gets in contact with the catalyst. The purpose of the model is to maximize the total reaction rate for a given total pressure difference across the bed by finding an optimal catalyst distribution. The distribution of the porous catalyst determines the total reaction rate in the bed. A large amount of ...

### Monolithic Reactor

This model simulates the catalytic abatement of a volatile organic compound (VOC), in this case a contaminant in a waste gas. An analytical expression describes the velocity profile in the free channel, while reaction occurs in the washcoat that makes up the tubular shape of the free channel. For simple geometries, the reactor can be described by a 2D model using time as the axial direction ...

### Variations in Density in Porous Media Flow

This example studies the steady flow of an ideal gas in porous media, where variations in gas density are taken into account through Equation-based Modeling. Darcy’s law describes the velocity vector in the porous structure and the conservation of mass is accounted for by the ideal gas law. The studied system is a packed bed reactor of the type used for example in small scale reforming ...

### Estimating Thermal Dispersion in a Packed Bed

Thermal dispersion in a porous medium results from the combined effects of heat conduction in the fluid and solid phases, and from convective transport in the fluid. In chemical process engineering, the modeling of thermal dispersion is of central importance as the temperature distribution in a catalyst bed controls not only chemical conversion but also the catalyst life-time. In this model ...

### Ammonia Synthesis PFR

This example demonstrate the modeling of a plug flow reactor for the synthesis of ammonia in the Haber-Weiss process. The catalytic reactor in this process operates under non-isothermal conditions, where temperature and pressure varies substantially along the length of the reactor, in addition to the variation in composition.

### Chemical Reactions and Soot Build-Up in a Diesel Filter

In this model, a filter system for a diesel engine is modeled, including where a soot layer builds up and is oxidized. The build-up of the layer is held in check by both catalytic and non-catalytic reactions, where carbon is oxidized to carbon monoxide and carbon dioxide, which in turn passes through the membrane. A filter system's efficiency and durability is closely related to the manner in ...

### Space-Dependent HI Reactor

This model deals with a reacting system comprising of an equimolar mixture of hydrogen and iodine gas which is allowed to react and form HI. Composition and temperature are allowed to vary both in space and time. This means that you have to define material balances, energy balances, and transport properties in the Reaction Engineering interface. These balances and properties are exported to ...

### Buoyancy–driven μPCR for DNA Amplification

Polymerase chain reaction (PCR) is one of the most effective methods in molecular biology, medical diagnostics, and biochemical engineering in amplifying a specific sequence of DNA. There has been a great interest in developing portable PCR-based lab-on-a-chip systems for point-of-care applications and one strategy that seems very promising is natural convection-based PCR. This model studies ...

### Parameter Estimation for Nonideal Reactor Models

Real reactors can be modeled as combinations of ideal reactors. In this example two ideal CSTRs with interchange are used to model a real reactor with one highly agitated region and another region with less agitation. Two parameters, relating the volume and exchange rate of the two regions, need to be found by comparing the model results to experimental tracer data. Using the Parameter Estimation ...