SetValue Equilibrium_Phases_Modify

[ciegolon]

Hi,

I'm trying to "set values" of mineral concentrations that were transported in a surface water model (written in Fortran) coupled to PhreeqcRM (BMIPhreeqcRM) using the Fortran interface. I've done it for the dissolved components, but now I realise that it seems there are no direct methods to SetValue for equilibrium phases.

In a previous post, it was explained that using the Phreeqc datablock EQUILIBRIUM_PHASES_MODIFY, this could be achieved, but I'm having trouble figuring out what method from the BMIPhreeqcRM module I should use to this end. Is there a particular BMI method that I should use to access Phreeqc's data blocks and modify their parameters?

Kind Regards,

Claudio

[dlparkhurst]

Yes, I have considered an extension of PhreeqcRM to allow mobile solids, but sediment transport gets very complicated, especially when you consider multiple size classes of sediment moving independently. If anyone is interested in developing a non-proprietary capability for sediment transport, you can send me a message, but no promises.

Perhaps you can brute force a simple approach. To use EQUILIBRIUM_PHASES_MODIFY n, you will need to use the method RunString(true, false, false, string). MPI parallelization gets more complicated, so let's just consider the multithreaded version OpenMP.

So, you would have to develop a string that updates the amount of phases in each cell. It would look something like this:

Code: [Select]

EQUILIBRIUM_PHASES_MODIFY 1
-component Calcite
  -moles 1.1
EQUILIBRIUM_PHASES_MODIFY 2
-component Calcite
  -moles 1.2
EQUILIBRIUM_PHASES_MODIFY 3
-component Calcite
  -moles 1.1
...
END

You would then use RunString to update the calcite concentrations before the call to RunCells. After RunCells, you would need to extract the calcite moles after reaction for sediment transport. With BMIPhreeqcRM, it is a little easier to get the calcite moles with the GetValue method (GetValue("equilibrium_phases_moles_Calcite", v), I think), rather than processing the selected-output array.

I may have not thought this through completely, so let me know if there are problems.