Electrochemistry Module Updates
For users of the Electrochemistry Module, COMSOL Multiphysics® version 5.6 brings automatic generation of iterative solvers, a new Linearization option, and a new feature for further analysis of porous electrodes. Learn more about these electrochemistry updates below.
Automatic Generation of Iterative Solvers
The Iterative Geometric and Algebraic Multigrid solvers are now automatically generated by the study step nodes (however, a Direct solver will still always be used by default). Enabling one of the iterative solvers may decrease memory use and computational time for large simulations.
Linearization of Concentration Dependence in Electrode Kinetics
The new Linearization option improves kinetics for nonunit reaction orders by circumventing issues when evaluating powers of negative numbers. This feature is available in the Electrode Reaction and Porous Electrode Reaction nodes in the Tertiary Current Distribution interfaces when using the Nernst equation for the equilibrium potential in combination with either the Mass action law or Lumped multistep for the exchange current density. The new Linearization option is turned on by default when creating a new model and is used by all tutorial models featuring the Nernst equation and mass action law or lumped multistep kinetics options.
Highly Conductive Porous Electrode
The new Highly Conductive Porous Electrode domain node is available in most electrochemistry interfaces. This feature can be used for porous electrodes with a high conductivity in the electron-conducting electrode phase. It replaces the spatial variable for the electrode potential by a global variable, thereby reducing the number of degrees of freedom of the problem.
New Porous Medium Feature
A new feature for handling a porous medium is available for defining the different phases: solids, fluids, and immobile fluids. In the Heat Transfer in Porous Media interface, the Porous Medium feature is used to manage the material structure with a dedicated subfeature for each phase Fluid, Porous Matrix, and optionally, Immobile Fluids. This new workflow provides added clarity and improves the user experience. It also facilitates multiphysics couplings in porous media in a more natural way. Combined with the Moisture Transport and Porous Media Flow interfaces, the heat transfer in porous media improvements enable the modeling of nonisothermal flow and latent heat storage in porous media.
You can see this new setup in the following models:
Revamped Porous Media Features for Transport of Diluted Species
The Transport of Diluted Species in Porous Media interface is revamped to use the new Porous Medium node. Two new domain features, the Porous Medium and the Unsaturated Porous Medium nodes, are available in the Transport of Diluted Species in Porous Media interface. You can use the new Porous Medium node for assigning material properties to the multiple phases in a porous medium. The new nodes have dedicated containers to define the properties for the liquid, gas and porous matrix. You can see this functionality demonstrated in the Ceramic Water Filter with Activated Carbon Core tutorial model.