A New Method to Visualize Grease Flow in a Double Restriction Seal Using Microparticle Image Velocimetry

Abstract

A new method to visualize and quantify grease flow in between two sealing lips or, in general, a double restriction seal is presented. Two setups were designed to mimic different types of seals; that is, a radial and an axial shaft seal. The flow of the grease inside and in between the sealing restrictions was measured using microparticle image velocimetry. The results show that grease flow due to a pressure difference mainly takes place close to the rotating shaft surface with an exponentially decaying velocity profile in the radial direction. Consequently, contaminants may be captured in the stationary grease at the outer radius, which explains the sealing function of the grease.

KEY WORDS:

• Seals
• Rolling Element Bearing
• Lubrication Grease
• μPIV Measurement

ACKNOWLEDGEMENTS

The work in this article was financed by the Swedish Research Council and SKF Engineering & Research Centre. The authors thank A. J. C. de Vries, Director of SKF Group Product Development, for his kind permission to publish this article. The authors also thank Tooltech AB and Centralverkstaden at Luleå University of Technology for producing the DRS setups.

Review led by Alan Lebeck