Journal bearings are known to be intrinsic components in different marine applications. They are regarded as the most instrumental means by which large loads could be transmitted at mean speed of rotation. Hydrodynamic journal bearings, based on hydrodynamic lubrication, have undoubtedly proved to be among the most effective types of journal bearings designs, commonly used in marine applications. In hydrodynamic lubrication, metal-to-metal contact could be prevented via a separation between the load carrying surfaces of the bearing, that could be attained by means of a relatively thick film of lubricant. Extending bearing life in marine propulsion systems, auxiliary equipment and diesel engines, reducing friction energy losses and wear, minimizing maintenance expenses and downtime of machinery due to frequent bearing failure are the most important objectives being born in mind on launching the bearing design procedures.
In the study at hand, an attempt has been made to perform a study of pressure distribution within hydrodynamic journal bearing on experimental bases. The experimental study has entailed the use of versatile lubrication oils, among of which comprised SEA 20W50, SEA 10W40 and SEA 5W30, for the sake of identifying their individual role in determining the condition of lubrication “hydrodynamic or hydrostatic". Besides, the study has been extended to cover the pressure behaviour of different lubricants within the hydrodynamic journal bearing, at different speeds ranging from 50 to 400 RPM at constant loads. For accurately testing the 105 mm internal diameter, 58 mm bearing length and “l/d = 0.5" made of white metal, a use has been made of the universal journal bearing test rig “UJBTR". Pressure distribution is further circumferentially investigated under constant loading, with operating at different journal rotational speeds.