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1. Calculating the viscosityof a blended liquid consisting of two or more liquids having different

viscosities is a three step procedure. The first step involves calculation of the Viscosity BlendingIndex (VBI) of each component of the blend using the following equation (nown as a !efutas

equation)"

(#) VBI $ #%.&'% lnln(v * +.,)- * #+./&

where v is the viscosity in centistoes and ln is the natural logarithm (0oge).

The second step involves using this blending equation"

(1) VBI2blend $ w3 VBI3- * wB VBIB- * ... * w4 VBI4-

where w is the weight fraction (i.e.5 6 7 #++) of each component of the blend. In using the above

blending equation5 it is necessary that all viscosities are determined at the same temperature5 for

example5 #++ 89.

The third and final step is to determine the viscosity of the blend by using the invert of equation(#)"

(') v $ (ee(VBI 2 #+./&) 7 #%.&'%) : +.,

where VBI is the Viscosity Blending Index of the blend and e is the transcendental number

1./#,1,5 also nown as ;uler

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wf1=phase 1 mass fraction

wf2=phase 2 mass fraction

rho1=phase 1 density

rho2=phase 2 density