An Introduction to Using Physics Interfaces with the Liquid & Gas Properties Module
The appropriate physics interface for modeling a system can be chosen from the Model Wizard. The interfaces available with the Liquid & Gas Properties Module correspond to the ones available in the base package of COMSOL Multiphysics. Physics interfaces are available under the following branches: AC/DC, Acoustics, Chemical Species Transport, Fluid Flow, Heat Transfer, Structural Mechanics, and Mathematics. More interfaces and additional functionality can be introduced by obtaining other add-on modules for specific physics areas.
A common setup is in terms of mass transfer is use a Transport of Diluted Species interface together with a Laminar Flow interface to study mass transport including convection and diffusion. In this case, the density of the solvent fluid, and the diffusion coefficients of the diluted species can be defined using the functionality in the Liquid & Gas Properties Module. If the system is dependent on a varying temperature, a Heat Transfer in Fluids interface can also be included. This requires further properties, namely the heat capacity and the thermal conductivity of the fluid. These can also be calculated using the functionality in the current module.
In the COMSOL Multiphysics Reference Manual:
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Creating a New Model
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Chemical Species Transport
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Fluid Flow
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Heat Transfer
When one or several physics interfaces are chosen from the Model Wizard (or if you open the Add Study window), you select an analysis type (stationary, dynamic, or parametric) and then the modeling interfaces are available as a nodes in the Model Builder along with all the other nodes required for modeling (Definitions, Geometry, and so forth).
By adding another physics interface, you can account for a phenomenon not previously described in a model. To do this, right-click a Component node in the Model Builder to open the Add Physics window. You can do this at any stage during the modeling process. This action still retains the existing geometry, equations, boundary conditions, and current solution, which you can build upon for further development of the model.
The steps involved when using physics interfaces are detailed in the COMSOL Multiphysics Reference Manual (see Where Do I Access the Documentation and Application Libraries?). Some of the most important steps are:
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Definitions of parameters and model variables.
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Creating, importing, and manipulating a geometry.
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Specifying the chemical and transport material properties. Which naturally is what the Liquid & Gas Properties Module is design for.
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Meshing a modeling domain with appropriate consideration given to the reaction system’s behavior.
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Solving the equations that describe a system for stationary or dynamic behavior, or as a parametric or optimization study.
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Analyzing results to present for further use.
Once a model is defined, you can go back and make changes to all the branches listed above, while maintaining consistency in the other definitions throughout. You can restart the solver, for example, using the existing solution as an initial guess or even alter the geometry, while the equations and boundary conditions are kept consistent through the associative geometry feature. It is also useful to review the Introduction to the Liquid & Gas Properties Module included with the module’s documentation.
In the COMSOL Multiphysics Reference Manual:
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Studies and Solvers
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The Physics Interfaces
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For a list of all the core physics interfaces included with a COMSOL Multiphysics license, see Physics Interface Guide.