Viscosity profile measurement in journal bearing by shear ultrasonic reflection

In a journal bearing application, viscosity is a key property of the lubricant that affects bearing performance. Viscosity of the lubricant controls the film thickness established during an operation. In the present work, an ultrasonic method has been used to measure the viscosity profile around an operating journal bearing. The reflection coefficient profile around the journal was established. A transducer was mounted inside the hollow shaft and the signal passed through slip rings. The journal bearing was run at a series of loads and rotational speeds. The transducer continuously pulsed and received as it swept around the bush circumference. This has enabled the viscosity profile to be established. The technique introduced to measure viscosity in journal bearing achieved acceptable results in certain regions of the journal bearing flow.