Author

Krieger

Date of Award

12-1993

Degree Name

Master of Science

Department

Chemical and Paper Engineering

Department

Paper Engineering, Chemical Engineering and Imaging

First Advisor

Dr. James E. Kline

Second Advisor

David K. Peterson

Access Setting

Masters Thesis-Open Access

Abstract

When using a cup and bob viscometer, it has long been recognized that errors in the viscosity measurement can arise from several factors, among them slip. Slip is a phenomenon which occurs when there are slipping layers in the fluid under shear, causing a non-uniform velocity gradient to be generated across the gap of the cup and bob viscometer. A layer of fluid at either the bob or cup wall moves faster than the adjoining layers, causing the slipping effect. This leads to a low viscosity calculation for the fluid.

In this study, experiments with coating formulations were conducted using the Hercules high shear viscometer to measure slip. The Hercules viscometer could measure a slip velocity for different formulations, however, negative slip values were generated. It was concluded that these values were the result of the generation of a negative velocity gradient caused by a bob-driven viscometer.

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