EXPERIMENTAL INVESTIGATION OF VIBRATION CHARACTERISTICS FOR VAPOR CAVITATION EROSION IN PLAIN JOURNAL BEARING

• Main Author: HJ YUSOF, ROSLI
• Format: Thesis
• Language: English
• Published: 2014
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://utpedia.utp.edu.my/21366/1/2014-MECHANICAL-EXPERIMENTAL%20INVESTIGATION%20OF%20VIBRATION%20CHARACTERISTICS%20FOR%20VAPOR%20CAVITATION%20EROSION%20IN%20PLAIN%20JOURNAL%20BEARING-ROSLI%20BIN%20HJ%20YUSOF.pdf; http://utpedia.utp.edu.my/21366/

The phenomenon of vapor cavitation in hydrodynamic bearings and its detrimental effects have been documented in many literatures. Collapse of vapor cavitation bubbles may cause erosion wear that limits the life of the bearings. The ability to detect the occurrence of vapor cavitation using a well established condition monitoring technique is essential for the equipment operator. The occurance of vapor cavitation, particularly in elliptical journal bearings, is not well reported in literature. An experiment was therefore conducted to investigate the vibration characteristics of vapor cavitation erosion in steadily loaded, elliptical journal bearings of a running gearbox. Vibration data were collected from the bearings operating under the influence of vapor cavitation erosion. The results showed that, vapor cavitation erosion exhibit distinct characteristics on the vibration plots. Low amplitude, forward and reverse 0.063X frequency components, and a series of harmonics with frequencies lower than 0.5X, were observed on the full spectrum. A unique, asymmetrical waveform with the positivepeakamplitude fluctuating above and below the zero axis line was also observed. The whirling shaft was also unstable under the vaporcavitation condition. When the vaporcavitation was removed by increasing the oil supply flow and pressure, the subsynchronous vibration components lower than 0.5X were not seen on the full spectrum. The waveform was symmetrical and the whirling shaft was also stable without the vapor cavitation erosion.