VISCOSITY
HELP
Calculates the viscosity of organic liquids using the
Souders’ method:
Viscosity calculations use Souders' equation.As per below.
log(log 10u) = (I/M)d x 10^3  2.9
u = viscosity, mNs/m^2
M = molecular weight
I = Souders index, estimated from the group contributions
d = density at the required temperature, kg/m^3
Method of use :/p>


To use Souders equation, Click the Viscosity Data Button, the below entry form will be displayed. Enter the group contributions associated with the Liquid, Click
the button when completed.
i.e. For the chemical Toluene :
you would enter 7 for the amount of carbon atoms
8 “ “ “ “ Hydrogen atoms
3 “ “ “ “ double bonds
1 “ “ “ “ six  member ring
1 “ “ “ “ side group
The total of this provides for the
variable I in Souders equation.
Then enter the molecular weight and density of the liquid the viscosity will be calculated and displayed as above.
For Binary Liquid Mixtures :
The following formulae,
procedure is used :
log(log 10um) = dm((x1I1 + x2I2)/(x1M1 + x2M2)) x 10^3  2.9
um = viscosity of mixture.
dm = density of mixture.
x1, x2 = mol fraction of components.
M1, M2 = molecular weights of components.
I1, I2 = Souders’ index of each component
Method of use :
Determine Souders index for each component. (As
detailed in the step above via the viscosity data entry form)
Click the Binary mixtures buton and enter all the required
data into the displayed entry form as example below.
press the calculate button and the mixture viscosity will
be calculated as example below.