Tribological scaling

Abstract

The issues associated with tribological scaling are discussed, focusing on specific examples from (a) journal bearing lubrication, (b) piston ring lubrication, (c) elastohydrodynamic line contact lubrication, and (d) fluid scaling. It is demonstrated that in general it is possible, for two dissimilar lubricated contacts, to define dimensionless parameters (such as, for example, a Sommerfeld parameter and an eccentricity ratio) such that if they have the same value for one of these parameters, then the other dimensionless parameter will also be the same. However, other parameters of interest, such as friction, wear, and lubricant temperature rise, will in general be different. Therefore for a complete tribological understanding of a contact, the best approach is to attempt to reproduce the geometries, kinematics, and operating conditions as closely as possible.