DEVELOPMENT OF WRIGHT BLENDING METHOD IN VISCOSITY ESTIMATION OF LIQUID-BINARY MIXTURE OF BASE OIL AND OLEFIN COPOLYMERS (OCPs)

Abstract

This study aims to develop mathematical equations used in Wright’s method to predict
kinematic viscosity of liquid-binary mixture consisting of base oil and additive. The equation
is developed by addition of specific constants (α
i and αc), representing interaction of
each component in the mixtures. Evaluation is done using 70 empirical data from 35 samples
derived from liquid blending of 4 types of base oils (B.1, B.2, B.3 and B.4) and olefin
copolymers (OCPs), varied in the range of 5-30 % of weight. Kinematic viscosity is measured
at 40oC and 100oC using a cannon automatic viscometer series 2000 (CAV 2000)
according to ASTM method D 445. Validation of the equation (Developed-Wright’s method)
is performed over all of liquid-binary mixtures of base oil-OCPs, and the accuracy is
indicated by percent average absolute deviation (%AAD). The results show that the addition
of specific constants could minimize the deviations of estimated values. The average
deviation of Developed-Wright’s method on kinematic viscosity estimation at 40oC and
100oC becomes 2.056 % and 1.917% respectively, lower than Wright’s method which are
8.341 % and 14.696%; meanwhile the maximum deviation reaches 5.821 % and 4.657%,
lower than Wright’s method which are 21.256 % and 25.265% respectively. These values
indicate that the Developed-Wright’s method has better accuracy.