The single component viscosities are given by the standard kinetic theory expression, [35]
(5–1) |
where is the Lennard-Jones
collision diameter,
is the molecular mass,
is the Boltzmann constant, and
is the temperature. The collision
integral
depends on the reduced
temperature, given by
(5–2) |
and the reduced dipole moment, given by
(5–3) |
In the above expression is the Lennard-Jones potential well
depth and
is the dipole moment. The collision integral value is determined by a
quadratic interpolation of the tables based on Stockmayer
potentials given by Monchick and Mason [36].
The binary diffusion coefficients[35] are given in terms of pressure and temperature as
(5–4) |
where is the reduced
molecular mass for
the (
,
) species pair
(5–5) |
and is the reduced
collision diameter.
The collision
integral
(based on Stockmayer potentials)
depends on the reduced
temperature,
which in turn may depend on the species
dipole moments
, and
polarizabilities
. In computing the reduced quantities, we consider two cases, depending on
whether the collision partners are polar or nonpolar. For the case that the partners are
either both polar or both nonpolar the following expressions apply:
(5–6) |
(5–7) |
(5–8) |
For the case of a polar molecule interacting with a nonpolar molecule:
(5–9) |
(5–10) |
(5–11) |
where,
(5–12) |
In the above equations is the reduced polarizability for the
nonpolar molecule and
is the reduced dipole moment for the
polar molecule. The reduced values are given by
(5–13) |
(5–14) |
The table look-up evaluation of the
collision integral depends on the reduced
temperature
(5–15) |
and the reduced dipole moment,
(5–16) |
Although one could add a second-order correction factor to the binary diffusion coefficients [37] we have chosen to neglect this since, in the multicomponent case, we specifically need only the first approximation to the diffusion coefficients. When higher accuracy is required for the diffusion coefficients, we therefore recommend using the full multicomponent option.