Affiliation:
1. Shell Research Ltd, Thornton Research Centre, P.O. Box 1, Chester
Abstract
As the first part of a programme in which the properties of lubricants under conditions encountered in the elastohydrodynamic régime will be measured, a low-shear-rate viscometer operating at pressures up to 120 000 lb/in2 has been constructed. It is of the falling body type in which the time of fall under gravity of a hemispherically ended cylindrical sinker through the test fluid is measured. The relationship between viscosity and fall time is of the form: A major correction is applied for the effect of pressure on the density of the fluid and a smaller one for the changes in dimensions of the viscometer under pressure. A means of measuring the change of density of the fluid is incorporated in the viscometer.