Add advanced cubic mixing rules

[ianhbell]

See method from http://dx.doi.org/10.1016/j.fluid.2016.05.015, looks pretty easy to implement.

Not clear whether to build on existing cubic approach or whether to start fresh or build a very generalized approach with lots of variants and so on.

[longemen3000]

Jaubert uses that mixing rule a lot:
https://pubs.acs.org/doi/10.1021/acs.iecr.1c03003 (Wilson, van laar, UNIQUAC, NRTL)
https://doi.org/10.1016/j.molliq.2023.122480 (GC-COSMOSAC)

[ianhbell]

@longemen3000 Is this model with advanced mixing rules and Wilson AC model implemented in Clapeyron.jl? I have some confusion and looking at Clapeyron.lj source would be helpful. I don't think it is implemented as best as I can tell.

[longemen3000]

It is implemented, in 0.5.3 (tcPR + mixing rule + residual Wilson), specifically, you can build that model with tcPRW(args...)
In theory, just Wilson suffices, (there is a specific tcPRWilson just with the parameters on the paper), but any Activity Model that defines excess_g_res could work too.
The mixing rule is implemented here: https://github.com/ClapeyronThermo/Clapeyron.jl/blob/master/src/models/cubic/mixing/gEr.jl

[ianhbell]

My question in particular is how one handles the molar volumes of the individual species since that is not documented in any of the papers as far as I can tell

[longemen3000]

This?

[ianhbell]

Yes, but this is not what is implemented in Clapeyon, which uses a Rackett approach

[longemen3000]

when excess_g_res(model::Wilson,p,T,z) is called, it calculates the wilson volumes (via Rackett), and calls excess_g_res_wilson(model,p,T,z,wilson_volume(model,T)). that behaviour is overloaded when using that specific mixing rule, here:
https://github.com/ClapeyronThermo/Clapeyron.jl/blob/2de8ab7915dc63347dc547d5fa4c508e92968e6d/src/models/cubic/mixing/gEr.jl#L66-L70

[ianhbell]

In their paper they specifically use the covolume for v_i (minus the volume translation), so you might want to do the same