lib.vdW module

class lib.EoS.Cubic.vdW.vdW(T, P, mezcla, **kwargs)

Bases: Cubic

Equation of state of van der Waals (1873), [1].

\[\begin{split}\begin{array}[t]{l} P = \frac{RT}{V-b}-\frac{a}{V^2}\\ a = 0.421875\frac{R^2T_c^2}{P_c}\\ b = 0.125\frac{RT_c}{P_c}\\ \end{array}\end{split}\]

This equation is not accuracy and it’s implemented only by its historic relevance because it’s the first cubic equation of state.

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 = vdW(300, 9.9742e5, mix)
>>> '%0.1f' % (eq.Vl.ccmol)
'145.4'
>>> eq = vdW(300, 42.477e5, mix)
>>> '%0.1f' % (eq.Vg.ccmol)
'135.5'

_cubicDefinition(T=None)

Definition of individual components coefficients

_GEOS(xi)

Definition of parameters of generalized cubic equation of state, each child class must define in this procedure the values of mixture a, b, delta, epsilon. The returned values are not dimensionless.

Parameters:

xilist

Molar fraction of component in mixture, [-]

Returns:

parameterslist

Mixture parameters of equation, a, b, c, d

References

[1]

van der Waals, J.D.; Over de Continuiteit van den Gas- En Vloestoftoestand, Dissertation, Leiden University, Leiden, Niederlande, 1873

[2]

Poling, B.E, Prausnitz, J.M, O’Connell, J.P; The Properties of Gases and Liquids 5th Edition, McGraw-Hill, New York, 2001