RKPR Function

public function RKPR(tc, pc, w, zc, kij, lij, delta_1, k) result(model)

RKPR Equation of State

The RKPR EoS extends the classical formulation of Cubic Equations of State by freeing the parameter $\delta_1$. This extra degree provides extra ways of implementing the equation in comparison of other Cubic EoS (like PR and SRK) which are limited to definition of their critical constants.

Besides that extra parameter, the RKRR includes another $\alpha$ function: $$\alpha(T_r) = \left(\frac{3}{2+T_r}\right)^k$$

In this implementation we take the simplest form which correlates the extra parameter to the critical compressibility factor $Z_c$ and the $k$ parameter of the $\alpha$ function to $Z_c$ and $\omega$:

$$\delta_1 = d_1 + d_2 (d_3 - Z_c)^d_4 + d_5 (d_3 - Z_c) ^ d_6$$ $$k = (A_1 Z_c + A_0)\omega^2 + (B_1 Z_c + B_0)\omega + (C_1 Z_c + C_0)$$

Arguments

Return Value type(CubicEoS)