Bond Graph Aided Thermal Analysis of Finite Journal Bearing

Abstract

Finite journal bearings are very common in different engineering fields. The load carrying capacity of the journal bearings are greatly dependent on the characteristics of the lubricant used, load acting on the journal, type of loadings, operating conditions. During service, the rise in temperature greatly influences the viscosity of the oil and thus reduces load bearing capacity. A good prediction of temperature rise at different loading and operating conditions could be helpful for the designers to safely predict the behaviour and load carrying capacity of the bearing. The objective of this research work is to determine the angular velocity, and linear velocity of rotor and temperature, viscosity, flow rate of the standard commercial lubricant for a finite journal bearing. For obtaining these results the experimental setup is fabricated and simulations are carried out using Bond Graph technique. The experimental setup consists of journal bearing arrangement with rotors, coupling, base plate, motors, thermocouples and temperature indicator. In this shaft-rotor system the static and dynamic loads are given with the help of rotors i.e. concentric rotors and eccentric rotors of different masses. Four rotors are used to analyze the variation of these parameters with respect to time at different journal speeds. These rotors give different results with different journal speed and simulation results are nearly equal. The system behavior shows that the journal stability is reached very quickly. Experimental results show the increase in temperature with increase in speed, and increase in load. Higher temperature rise is predicted as well as measured when eccentric loading are applied.