Measurement of circumferential viscosity profile in stationary journal bearing by shear ultrasonic reflection

Viscosity is the most important property of a lubricant that can affect bearing performance. It controls the film thickness that is established during an operation. In this study, the ultrasonic method was used to measure the static viscosity profile around a journal bearing by using shear reflection coefficients at several locations around the journal bearing. This enables the viscosity profile to be established. The technique introduced was found to be successful and acceptable results were obtained from certain regions of the journal bearing flow. This study serves as a preliminary work for developing viscosity measurement in a rotating journal bearing.

► This paper describes a viscosity profile measurement around a journal bearing.
► A shear wave reflection measurement was deployed to profile the viscosity.
► Specific models were used to correlate reflection coefficient to viscosity.
► Spring model is valid in thin layer and the Bulk model in thick layer.
► The technique introduced was successful and acceptable results were obtained.