lib.PRTwu module

class lib.EoS.Cubic.PRTwu.PRTwu(T, P, mezcla, **kwargs)[source]

Bases: PR

Peng-Robinson cubic equation of state with a modified dependence of temperature by Twu et al. [1]

\[\begin{split}\begin{array}[t]{l} P = \frac{RT}{V-b}-\frac{a}{V\left(V+b\right)+b\left(V-b\right)}\\ a = 0.457235528921\frac{R^2T_c^2}{P_c}\alpha\\ b = 0.0777960739039\frac{RT_c}{P_c}\\ \alpha = alpha^{(0)} + \omega\left(\alpha^{(1)}-\alpha^{(0)}\right)\\ \alpha^{(0)} = T_r^{-0.171813} \exp{0.125283\left(1-T_r^{1.77634} \right)}\\ \alpha^{(1)} = T_r^{-0.607352} \exp{0.511614\left(1-T_r^{2.20517} \right)}\\ \end{array}\end{split}\]

Examples

Example 4.3 from [2], Propane saturated at 300K

>>> from lib.mezcla import Mezcla
>>> mix = Mezcla(5, ids=[4], caudalMolar=1, fraccionMolar=[1])
>>> eq = PRTwu(300, 9.9742e5, mix)
>>> '%0.1f' % (eq.Vl.ccmol)
'86.8'
>>> eq = PRTwu(300, 42.477e5, mix)
>>> '%0.1f' % (eq.Vg.ccmol)
'84.1'

It give better result than in example references

OmegaA = 0.457235528921
OmegaB = 0.0777960739039
_alfa(cmp, T)[source]

Modified α correlation

References