In cases where transport occurs in a fractured, porous 3D structure, the new Fracture boundary condition lets you model transport in the thin fractures without having to mesh them as 3D entities. View screenshot Fracture Surfaces in the Transport of Diluted Species in Porous Media Interface Additionally, chemical reactions can be defined to occur within the fractures, at its surfaces, or in a porous medium that encompasses the fracture. Convective transport can be coupled to a Thin-Film Flow interface or through including your own equations to define fluid flow through the fracture. For the transport of the chemical species, the interface allows definition of effective diffusivity models to include the effects of porosity. The interface allows you to define the average fracture thickness, as well as the porosity in cases where the fracture is considered to be a porous structure. The new Transport of Diluted Species in Fractures interface treats the fracture as a shell, where only the transverse dimensions are meshed as a surface mesh. It is often difficult to model the transport of chemical species in such fractures through having to mesh the thickness of the fracture surface, due to the aspect ratios brought about by the large differences in size dimensions. View screenshot New Transport of Diluted Species in Fractures Interfaceįractures have thicknesses that are very small compared to their length and width dimensions. The interface allows you to consider the ionic current without having to mesh this liquid layer in 3D. Here, a very thin electrolyte film may form on metal surfaces. The physics interface is suitable for modeling thin electrolytes where the potential variation in the normal direction is negligible, for instance, in atmospheric corrosion problems. The Current Distribution, Shell interface models ionic current conduction in the tangential direction along a boundary. A fraction of the impressed current goes from the sacrificial anodes (rods) through seawater, into the ship hull, out of the ship hull, through seawater and then into the oil rig structure. The oil rig structure close to the ship is cathodically polarized. Here, the stem works as an anode while the stern works as a cathode. The figure here shows a ship where parts are of the hull are bare steel, where the hull may work as a bipolar electrode. The ship hull is subjected to the electric field from the cathodic corrosion system. You typically use this interface in order to reduce the meshing and solver time for large geometries, where a significant part of the geometry can be approximated as tubes along edges.Ī ship is anchored close to an oil platform. The interface uses a boundary element method (BEM) formulation to solve for the charge transfer equation in an electrolyte of constant conductivity, where the electrodes are specified on boundaries or as tubes with a given radius around the edges. The Current Distribution, Boundary Elements interface can be used for solving primary and secondary current distribution problems on geometries based on edge (beam or wire) and surface elements. Current Distribution, Boundary Elements Interface Learn more about these and more Corrosion Module updates here. For users of the Corrosion Module, COMSOL Multiphysics ® version 5.3 includes a new Current Distribution, Shells interface, a new Current Distribution, Boundary Elements interface, and a new physics interface for modeling chemical species transport in fractures.

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