An Investigation on The Dependence of The Lubricating Oil’s Performance on The Ambient Temperature in Journal Bearings

Abstract

Maximum temperature rise is one of the design criteria for a journal bearing. It implies that the difference between the maximum allowable journal bearing temperature and the ambient temperature is constant. On the other hand, minimum lubricating oil film thickness is another design criteria for a journal bearing. Therefore we can establish a correlation between the minimum film thickness and the ambient temperature for a given lubricating oil in a journal bearing. In this thesis, we took the minimum oil film thickness recommended by Trumpler (known as Trumpler’s criteria) as the performance parameter for the journal bearing. Then we evaluated the performance of different lubricating oils used in journal bearings with respect to journal bearing diameter, length to diameter ratio, clearance to diameter ratio, rotational speed and load. We conducted this evaluation for three different kinds of journal bearings: natural fed, pressure fed and self contained journal bearings. Through this study, we investigated whether lubricating oil recommended by the machinery manufacturer after being tested in the machinery manufacturer’s ambient temperature delivers acceptable performance in the user’s ambient temperature.