Observation of Oil Film Behavior around Microbubbles on Journal Bearings Utilizing Photochromic Visualization Technique

(Detailed Behavior Observation by Changing Photography Method)

Abstract

Microbubbles have attracted attention as a new friction reduction method for journal bearings. Microbubbles are bubbles with a diameter of 100 μm or less that deform and rotate within the bearing clearance, suggesting that they contribute to friction reduction. Therefore, we used a photochromism visualization technique that uses an oil film that changes color when irradiated with ultraviolet light as a tracer to observe the behavior of the oil film around the microbubbles in journal bearings. As a result, we succeeded in observing a linear flow in front of the microbubbles, but the mechanism of its generation is unknown. Therefore, we changed the method of photographing at high magnification and coloring on the bubbles. As a result, we discovered an unprecedented oil film behavior that suggests that the bubbles are rotating.