Chemical Reaction Engineering Module Updates

For users of the Chemical Reaction Engineering Module, COMSOL Multiphysics® version 5.5 includes the ability to generate materials from a thermodynamic system, diffusivity models for gases and liquids, and water and steam properties. Learn more about these chemical reaction engineering features below.

Generate Material from a Thermodynamic System

When studying a mixture with multiple chemical species, the thermodynamics node can be used to analyze how mixture properties depend on the composition and on the system conditions. Recognizing that the most convenient way of defining physical properties in COMSOL Multiphysics® is to use a material, you can now automatically generate a material node from a thermodynamic system. Properties such as the density, heat capacity, dynamic viscosity, diffusivity, and the thermal conductivity can be included in the material. Once the material is created, it can be used to define properties across multiple physics interfaces, for example, to model fluid flow, heat transfer, and/or mass transfer. You can see this new functionality in the Engine Coolant Properties and Analysis of NOx Reaction Kinetics models.

The COMSOL Multiphysics UI with an engine coolant properties model in the Graphics window and a context menu with the Generate Material option selected. Selecting Generate Material from a context menu The "Liquid: ethylene glycol-water" material is created from the Generate Material wizard, available in the context menu of a Thermodynamic System.

Diffusivity Models for Gases and Liquids

A number of models for the diffusivity in gases and liquids have been added to the thermodynamic systems. When studying diluted systems where one solvent species is in excess, you can easily create functions for the diffusion coefficients at infinite dilution. To study concentrated systems, functions for the Maxwell–Stefan diffusivities can be created. You can see this new feature in the Analysis of NOx Reaction Kinetics model.

Diffusion coefficients in the COMSOL Multiphysics Model Builder tree and the mixture property settings shown for one of the diffusion coefficients. Diffusion coefficients Diffusion coefficients for solute species in a gas phase system where nitrogen is in excess.

Water and Steam Properties

A new thermodynamics model for water and steam systems is now available. The model includes property correlations suggested by the International Association for Properties of Water and Steam (IAPWS). With this functionality, you can evaluate accurate thermodynamic and transport properties across all phases, from liquid water and wet steam all the way to superheated steam. For steam, real gas properties close to saturation and near the critical point are now available. For liquid water, the vicinity of the boiling point, among others, is provided.

A pressure-enthalpy diagram for liquid water and steam. Pressure–enthalpy diagram Pressure–enthalpy phase diagram for liquid water and steam generated using the new Water (IAPWS) thermodynamics model.

Generate a Chemistry Interface from a Thermodynamic System

Similar to creating materials, you can now automatically create a Chemistry interface from a thermodynamic system. The Chemistry interface will be set up to include the same species, as well as the mixture and transport properties to be used, automatically defined from the thermodynamic counterpart. This makes it easy to start out by defining a thermodynamic system, including a number of chemical species, and then creating a corresponding chemical system. Furthermore, reactions among the species can be defined, and the Chemistry interface can be used to simulate mass transport and reactions in tanks or other chemical process equipment. You can see this new functionality in the Dissociation in a Tubular Reactor model.