type, public, extends(CubicMixRule) :: MHV

Michelsen’s modified Huron-Vidal mixing rule

Mixing rule at zero-pressure which allows for the inclusion of an excess-gibbs model.

Description

This mixing rule is based on the aproximate zero-pressure limit of a cubic equation of state. At the aproximate zero-pressure limit the attractive parameter can be expressed as:

$$\frac{D}{RTB}(n, T) = \sum_i n_i \frac{a_i(T)}{b_i} + \frac{1}{q} \left(\frac{G^E(n, T)}{RT} + \sum_i n_i \ln \frac{B}{nb_i} \right)$$ Where $q$ is a weak function of temperature. In the case of MHV and simplicity it is considered that depends on the model used.

Examples

To use the modified Huron-Vidal mixing rule it is necessary to define a CubicEoS and replace its original mixing rule with the one generated by the user.

type(MHV) :: mixrule
type(NRTL) :: ge_model
type(CubicEoS) :: model

! Define the Ge model to be used and the CubicEoS
ge_model = NRTL(a, b, c)
model = SoaveRedlichKwong(tc, pc, w)

! Use the initialization function to setup
mixrule = MHV(ge=ge_model, q=-0.593_pr, bi=model%b)

! Replace the original mixrule on the previously defined model
model%mixrule = mixrule

! Ready to do calculations
call pressure(model, n, v, T)

References