• Description

Chemical Reaction Engineering Module Updates

For users of the Chemical Reaction Engineering Module, COMSOL Multiphysics ® version 5.2a brings a newReacting Flow multiphysics interface to couple fluid flow and reactions in gases and liquids, as well as capabilities to model surface species reactions in the Reactive Pellet Bed feature and export surface reaction kinetics in the Reation Engineering interface. Continue reading for a complete list of updates to the Chemical Reaction Engineering Module.

New Functionality for the Reactive Pellet Bed Feature: Surface Reactions

The Reactive Pellet Bed feature now allows you to model surface species reactions using the Surface Reactions functionality. Available in the Transport of Diluted Species interface and the Transport of Diluted Species in Porous Media interface, surface species are assumed to be adsorbed (immobile) at the pore walls inside the porous pellets. You can model any number of surface species and their corresponding reactions.

The surface concentration inside porous particles forms a catalytic bed (concentration at the surface of the pores inside the pellet), simulated using the Reactive Pellet Bed feature. A bulk species is transported past and through catalytic porous particles. The species reacts on the fluid- matrix interface inside the pellets that form the particle. The velocity of the bulk fluid and the surface concentration are visualized. The resulting average surface concentration in the porous particle is shown together with the concentration inside a single pellet at a particular position and at three different times.

New Functionality in Reaction Engineering: E​​xport Surface Reactions

You can now export surface reaction kinetics, defined in the Reaction Engineering interface, to a space-dependent model where the surface reactions occur inside porous pellets. The Generate Space-Dependent Model feature exports the reaction kinetics and automatically defines material properties in a Reactive Pellet Bed feature.

Surface reactions are exported to a Reactive Pellet Bed feature using the Generate Space-Dependent Model feature in the Reaction Engineering interface.

Surface reactions are exported to a Reactive Pellet Bed feature using the Generate Space-Dependent Model feature in the Reaction Engineeringinterface.

New Reacting Flow Multiphysics Interface

To enhance the study of fluid flow and reactions in gases and liquids, the new Reacting Flow multiphysics interface combines the Single-Phase Flow and Transport of Concentrated Species interfaces. Previously available as a standalone interface, the new Reacting Flow multiphysics interface gives better control of the settings in each physics interface as well as the multiphysics coupling between them.

Using the new Reacting Flow coupling, the process of solving any of the coupled interfaces separately, or at the same time, has been significantly improved. For reacting flow, this is important in order to generate suitable initial conditions or to test how the results are affected by coupling. The Reacting Flow multiphysics interface supports both laminar and turbulent reacting flows, as well as flow and reactions in porous media.

Application Library path for an example that uses the new Reacting Flow multiphysics interface:Chemical_Reaction_Engineering_Module/Reactors_with_Mass_and_Heat_Transfer/round_jet_burner

In the new Reacting Flow multiphysics interface, the Reacting Flow node, under the Multiphysics node, couples a Single-Phase Flow interface with a Transport of Concentrated Species interface.

In the new Reacting Flow multiphysics interface, the Reacting Flow node, under the Multiphysics node, couples aSingle-Phase Flow interface with aTransport of Concentrated Speciesinterface.

New Functionality in Transport of Concentrated Species: Porous Media Transport Properties

The new Porous Media Transport Properties feature enables you to study multicomponent transport in a solution flowing through a porous medium. The new functionality includes models for computing effective transport properties that are dependent on the porosity of the material in combination with transport in concentrated mixtures.

Application Library path for an example that uses the new Porous Media Transport Properties feature in theTransport of Concentrated Species interface:Chemical_Reaction_Engineering_Module/Reactors_with_Porous_Catalysts/carbon_deposition

The porosity distribution in a rea​​ctor for the thermal decomposition of methane on a solid Ni-Al2O3 catalyst is studied using the Porous Media Transport Properties feature. The porosity decreases as soot forms in the decomposition reaction.
The porosity distribution in a reactor for the thermal decomposition of methane on a solid Ni-Al 2 O 3 catalyst is studied using the Porous Media Transport Properties feature. The porosity decreases as soot forms in the decomposition reaction.

Pseudo Time Stepping in the Transport of Concentrated Species Interface

The new pseudo time-stepping functionality for the Transport of Concentrated Species interface significantly improves the convergence rate for the solvers for stationary studies. It is specifically beneficial when the flux of species is dominated by advection (large Péclet numbers), for example, in turbulent reacting flows.