چكيده به لاتين
Abstract:
Bearings are divided to both sliding bearing and rolling bearing models. Considering the vast applications of sliding bearings and their advantages over rolling bearings in high velocities and loads, designing a monitoring system is indispensable. In this research, by studying a various models of sliding bearing bearings and their prevalent defects, cutting-edge technologies in the case of flaw detection have been surveyed. Afterwards, an especial and applicable kind of sliding bearing, Babbitt journal bearings associated to gas turbin coperesors, has been surveyed. A very common defect through these bearings is oil wipe and whirl. These defects causes instability within oil film and as a byproduct, drastic vibrations have been emerged. In current research, detection and prevention methods have been studied. A prevalent method to condition monitoring of journal bearings is uasage of two proximity probes by 90 degree angles which check the position of journal and center of bearing. If instability of oil film and vibration pass threshold, these sensors start to alarm. Yet, in this research. It has been shown that using a load cell and a combination of two proximity probe sensors, it would be able to detect this defects very sooner and act as required. Illustrationing the capability of proposed method, dynamic model of bearing has been surveyed and by helping Matlab swoftware, simulator has been provided.
Then, experimental testing setup to simulate the aforementioned defects has been designed and built. In three status, without defect, beginning defect and developing defect, signals of proximity probe sensors and load cell have been saved and after processing, they have been compared to results obtained from simulator. Finally, it has been indicated that load cell which is new in this research, is able to predict and detect the whirl and wipe of oil and reduce the time interval of defect detection by practicing load cell.
Keywords:
Sliding bearing, Oil whirl, Detection methods, Condition monitoring systems, Load cell sensors.
