A quantitative experimental study of oil transport around a rolling point contact zone using pixel-dependent fluorescence method

The insufficient oil replenishment to the inlet of rolling point contact zones is significantly harmful to the lubrication of rolling bearings. We presented a quantitative study on the oil transport around a ball-disc rolling point contact zone based on laser-induced fluorescence method using novel pixel-dependent calibration of fluorescence intensity and oil film thickness relationship. It is found that under butterfly and tunnel flow patterns, the oil film migrates as oil ridges and decayed area forms along the rolling point contact track. Oil volume integration results support that the replenishment ratio (RR) is closely related with capillary number (Ca) values as a negative exponential relationship. It indicates that Ca may be a critical number in the prediction of insufficient oil replenishment.