Electrochemistry Module Updates
For users of the Electrochemistry Module, COMSOL Multiphysics® version 6.0 brings a new predefined formulation for adsorption-desorption in combination with electrode reactions and a new tutorial model. Learn more about these updates below.
The modeling capabilities of the existing Electrode Surface boundary condition have been expanded with a set of predefined equations that keep track of surface site occupancy and surface concentration of adsorbed species. The new Adsorbing-Desorbing Species section allows you to model the adsorption-desorption kinetics and thermodynamics at electrode surfaces in combination with multistep electrochemical reactions.
Nonisothermal Reacting Flow
There are now Nonisothermal Reacting Flow multiphysics interfaces that automatically set up nonisothermal reacting flow models. The Reacting Flow multiphysics coupling now includes the option to couple the Chemistry and Heat Transfer interfaces. Using this coupling, the cross-contributions between heat and species equations like enthalpy of phase change or the enthalpy diffusion term are included in the model. The temperature, pressure, and concentration dependence of different quantities and material properties are also automatically accounted for, making it possible to perform heat and energy balance using the corresponding predefined variables.
Porous Slip for the Brinkman Equations Interface
The boundary layer in flow in porous media may be very thin and impractical to resolve in a Brinkman equations model. The new Porous slip wall treatment feature allows you to account for walls without resolving the full flow profile in the boundary layer. Instead, a stress condition is applied at the surfaces, yielding decent accuracy in bulk flow by utilizing an asymptotic solution of the boundary layer velocity profile. The functionality is activated in the Brinkman Equations interface Settings window and is then used for the default wall condition. You can use this new feature in most problems involving subsurface flow described by the Brinkman equations and where the model domain is large.
Heat Transfer in Porous Media
The heat transfer in porous media functionality has been revamped to make it more user friendly. A new Porous Media physics area is now available under the Heat Transfer branch and includes the Heat Transfer in Porous Media, Local Thermal Nonequilibrium, and Heat Transfer in Packed Bed interfaces. All of these interfaces are similar in function, the difference being that the default Porous Medium node within all these interfaces has one of three options selected: Local thermal equilibrium, Local thermal nonequilibrium, or Packed bed. The latter option has been described above and the Local Thermal Nonequilibrium interface has replaced the multiphysics coupling and corresponds to a two-temperature model, one for the fluid phase and one for the solid phase. Typical applications can involve rapid heating or cooling of a porous medium due to strong convection in the liquid phase and high conduction in the solid phase like in metal foams. When the Local Thermal Equilibrium interface is selected, new averaging options are available to define the effective thermal conductivity depending on the porous medium configuration.
In addition, postprocessing variables are available in a unified way for homogenized quantities for the three types of porous media. View the new porous media additions in these existing tutorial models:
Nonisothermal Flow in Porous Media
The new Nonisothermal Flow, Brinkman Equations multiphysics interface automatically adds the coupling between heat transfer and fluid flow in porous media. It combines the Heat Transfer in Porous Media and Brinkman Equations interfaces.
Greatly Improved Handling of Porous Materials
Porous materials are now defined in the Phase-Specific Properties table in the Porous Material node. In addition, subnodes may be added for the solid and fluid features where several subnodes may be defined for each phase. This allows for the use of one and the same porous material for fluid flow, chemical species transport, and heat transfer without having to duplicate material properties and settings.
New Tutorial Model
COMSOL Multiphysics® version 6.0 brings one new tutorial model to the Electrochemistry Module.
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