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Published March 1999 | public
Journal Article

Entrainment of fine particles from surfaces by gas jets impinging at normal incidence

Abstract

This paper describes an experimental study of the removal of fine (8.3 μm) polystyrene particles from a glass substrate using a gas jet at normal impingement. In order to avoid transient effects associated with jet startup, the sample was slowly translated under a steady jet. The translating gas jet produces a long clean path that provides very good statistics for exploring the effect of jet parameters. The dependence of the spatial distribution of removal efficiency on the jet pressure ratio, the jet height, and the translation speed is examined. Clean paths greater than 16 jet diameters wide are produced with a jet pressure ratio of 7 translating at 9.0 mm/s at a dimensionless height of 10. The path width is independent of the jet height at high pressure ratios and inversely dependent on the jet translation speed. A harmonic oscillator model for particle detachment accounts for the effect of translation speed. Results suggest that the particles act as nearly-quantized shear stress sensors that provide a direct, though as yet uncalibrated, measure of the surface shear stress. Further, knowledge of the pressure required to remove 50% of the particles from the central region of the path is sufficient to predict the extent of particle removal at higher pressures.

Additional Information

© 1999 Springer. Received: 30 June 1997/Accepted: 24 June 1998. Support for this work is provided by the FAA under Grant 93-G-060. G. Smedley acknowledges productive discussions with Prof. K. Smedley of the University of California, Irvine.

Additional details

Created:
August 19, 2023
Modified:
October 23, 2023