different surface areas in 2D transport calculation

[Frank Bok]

Hi!

I would like to model a 2D transport calculation with two spatially separated mineral phases. Is this possible to set up a model with different minerals in different blocks?

And, due to the effects of grain boundaries and surface roughness, is it somehow possible to have different surface areas for the minerals in different blocks?

Thanks in advance and best regards,

Frank

[JohanFourie]

Hi Frank

Don't know If I understand your problem correctly. Will it help if you make a copy of the mineral in the database: e.g. calcite1 and calcite2 and then give it the different surface areas you want in the model?

 

[Jia Wang]

Hello Frank,

Sorry for the late response. There are several options to set heterogeneous mineral mass distribution in X1t and X2t. X1t and X2t require the initial system to be configured with a single set of basis species. Therefore, an equilibrium mineral in the initial pane must be have some mass present in every node in order for the program to equilibrate the fluid with the mineral. For this reason, you would not be able to set a zero mineral mass for an equilibrium mineral. You can, however, set a heterogenous distribution for its abundance in the initial pane. For more information, please refer to the Heterogeneity Appendix in the GWB Reactive Transport Modeling Guide.

Kinetic minerals are a different story. For purely kinetic minerals (those not swapped into the basis), you can set their abundance heterogeneously on the Reactants pane. There’s no issue with setting a reactant mineral in some nodes and no mass in others. For each kinetic mineral using the built-in rate law, you can supply a specific surface area (m2/g), which gets multiplied by the current mass to calculate the surface area. This property can also be set heterogeneously.

Going back to the issue of different equilibrium minerals, you could alternatively write a simple flow program that uses ChemPlugin instances to figure reaction and transport. ChemPlugin is a self-linking software object based off the GWB’s compute engine. You spawn a ChemPlugin instance for each nodal block, and there’s no requirement that each instances uses the same set of basis species, so you can configure each instance in equilibrium with different minerals. To learn more about ChemPlugin, you can visit the ChemPlugin page.

Hope this helps.

Best,

Jia