Chemical Reaction Engineering Module
New Functionality in Version 6.4
Aggregation, Breakage, and Dissolution Supported for precipitation and crystallization
The Size-Based Population Balance interface has been updated with added support for aggregation, breakage, and dissolution of particles. A new logarithmic size discretization option is available and is recommended when modeling either aggregation or breakage.
Predefined size variables are now available in the Size-Based Population Balance interface and can be used in many of the available input fields. When defining a size distribution using a size-dependent input, the discretized representation now more accurately represents the continuous function.
The Precipitation and Crystallization in Fluid Flow multiphysics interface has been improved to account for turbulent particle transport defined by the turbulent viscosity and a turbulent Schmidt number.
Nonisothermal Reacting Flow Large Eddy Simulations
Three Large Eddy Simulation interfaces, LES RBVM, LES RBVMWV, and LES Smagorinsky, have been added to the Model Wizard in the Chemical Species Transport branch under Nonisothermal Reacting Flow. These physics interfaces simulate fluid flow with mass and heat transfer in the turbulent regime and apply large eddy simulation (LES) modeling for the unresolved scales of all three physics. In addition to a Chemical Reaction Engineering Module license, these interfaces require a license for the CFD Module.
Reaction Features with Improved Chemistry Coupling
Reaction features in mass transfer interfaces are now automatically linked to the reactions in a selected Chemistry interface. When these are coupled, the species matching in the Chemistry interface is used to assign mass sources in accordance with the chemical equations. Furthermore, the reaction features now include functionality to specify and report the resulting heat of reaction as a heat source, using the geometry selection where the reaction occurs. The heat source, which is automatically defined when coupling to a Chemistry interface, can be applied in a Heat Transfer interface.
In the Transport of Diluted Species interface, this improved coupling functionality is available in the following features:
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 Reactions
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 Heterogeneous Reactions
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 Equilibrium Reaction
In the Transport of Concentrated Species interface, this improved coupling functionality is available in the following features:
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 Reactions
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 Equilibrium Reaction
Support for moving packed beds
The Packed Bed feature has been extended to support bed translation relative to the reactor. When enabled, the name of the feature changes to Moving Packed Bed. The new functionality is available in the Transport of Diluted Species in Porous Media interface and the Transport of Concentrated Species in Porous Media interface.
Three new multiphysics interfaces supporting translation of the packed bed have been added:
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Reacting Flow in Moving Packed Beds, Transport of Diluted Species
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 Reacting Flow in Moving Packed Beds, Transport of Concentrated Species
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 Reacting Flow in Moving Packed Beds, Transport of Diluted Species with Shrinking Core Model
These all combine the functionality of the Brinkman Equations interface, a mass transfer interface for a dilute or concentrated solution, and a reacting flow multiphysics coupling. When added, the mass transfer interface includes a Moving Packed Bed feature.
Support for using Nonideal Thermodynamics models in Vapor–Liquid Equilibria
Support has been added for nonideal mixtures from the Thermodynamics node for vapor–liquid features (Vapor Inflow, Vapor–Liquid Interface, and Vapor–Liquid-Solution Interface). This allows the user to leverage the COMSOL® software’s database of thermodynamic properties (vapor pressure, heat of vaporization, and more) for multicomponent solutions.
Improved Multiphysics Setup for Vapor–Liquid Equilibria in Two-Phase Flow
When adding a Laminar Two-Phase Flow multiphysics interface from the Vapor–Liquid Equilibrium branch, a Fluid–Fluid Interface node is now automatically added to the Laminar Flow interface. Additionally, two nodes are now automatically added to the Transport of Concentrated Species in Vapor interface: a Vapor–Liquid-Solution Interface node for internal boundaries and a Vapor–Liquid Interface node for external boundaries.
Enhanced support for The CHEMKIN® format
The cost of computing transport properties for mixtures scales quadratically with the number of species; for this reason, there is now a customizable threshold for the maximum number of species for these expressions to be generated.
Chemical species with special characters in their names are now automatically renamed, with their original name available in the shape function’s description.
Other improvements
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The Reaction node, which implements a single reaction in laminar or turbulent flow, has been reintroduced in the Transport of Concentrated Species interface.
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The Size-Based Population Balance interface has a new Number of Intervals input field, available in the Size intervals section together with the settings for the minimum and maximum particle sizes.
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The Vapor–Liquid-Mixture Interface feature in the Transport of Concentrated Species interface is now named Vapor–Liquid-Solution Interface.
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The Species Source feature in the Transport of Diluted Species interface has been renamed Heterogeneous Reactions and is used to describe phase-transfer reactions in a system.
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The Feed Inlet feature in the Reaction Engineering interface has been improved to allow for temperature-dependent specification of enthalpies.
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The Reaction Thermodynamics subfeature of the Reversible Reaction Group and Equilibrium Reaction Group features in the Reaction Engineering interface has been removed due to being redundant and susceptible to misconfiguration.