DADT_MIX_PR
The enthalpy departure of a fluid that obeys the Peng-Robinson equation of state can be expressed:
The entropy departure is:
For a pure fluid, the dimensionless enthaply and entropy departures areprovided by functions H_DEP_PR and S_DEP_PR., respectively. For a mixture, a and b can be obtained directly from A and B which are provided by AB_MIX_PR since
However, it is necessary to evaluate da/dT. This function provides this service. The function is called with the following parameters:
DADT_MIX_PR(n, T, Tc[1..n], Pc[1..n], w[1..n], y[1..n], k[1..n,1..n])
where
n is the number of fluids in the mixture
Tc[1..n] is an n-dimensional array with the critical temperatures of each of the fluids in K
Pc[1..n] is an n-dimensional array with the critical pressures of each of the fluids in Pa
w[1..n] is an n-dimensional array with the acentric factors of each of the fluids
y[1..n] is an n-dimensional array with the mole fractions of each of the fluids
k[1..n,1..n] is a n by n array containing the interaction coefficients between fluid i and j. Binary interaction coefficient values must be supplied even if their values are 0.
See Example 11-4.2 in Thermodynamics by Klein and Nellis (2012) for an example.
NOTE: The value returned the DADT_MIX_PR has units of Pa-m^6/kmol^2-K. This is the only function in the Peng-Robinson library that is not dimensionless.