Herein, the geometric
similitude concept is applied to propose
a cubic equation that relates surface tension, saturation pressure,
and temperature for
n
-alkanes. The input properties
for each fluid are the molecular mass, pressure, temperature, and
compressibility factor at the critical point. The model is applied
to temperatures below 0.93·
T
c
(critical
point temperature). A total of 2429 surface tension values have been
selected for 32
n
-alkanes. The parameters of the
model have been obtained with a fit of the surface tension values
for 19 pure
n
-alkanes that are randomly chosen. Then,
it is tested for the other 13 pure
n
-alkanes and
used to predict the surface tension for 11 binary and 4 ternary mixtures.
These predictions are compared with the reported experimental data.
For pure
n
-alkanes, the overall absolute average
deviation is 2.4%, including the correlation and testing sets. No
additional adjustable coefficients are used for mixtures, yielding
an overall absolute average deviation of 2.98% for the binary systems
and 7.97% for the ternary ones. The results show that the model is
accurate enough for predictions and that the highest deviations are
due to the lack of agreement in the values of surface tension of pure
fluids obtained from different sources.