الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The sliding element hydrodynamic bearings design is of great importance where they have multiple uses in different fields of engineering applications.Many researchers have studied various types of bearings in order to improve their performance and reduce their inevitable hydrodynamic frictional losses in addition to researches aiming at the improvement of their dynamic stability.Although there are many theoretical and experimental research works, which focused on studying those types of bearings there is still a lot of what is required for their development and improvement of their performance. The present research work is interested in studying the steady state performance and dynamic stability of sliding element hydrodynamic bearings of the three lobe type and provided with a bushing surface textured with uniform micro protrusions. A mathematical model has been put forward for the problem using the Reynolds equation governing the unstable fluid lubrication inside the bearing as well as the equations governing the dynamic movement of the journal.The equations have been put in their numerical forms suitable for computer solution using the finite difference method. Two types of three lobe bearings have been considered, one with its plain bushing and the other with bushing textured with uniform micro protrusions. This is in addition to other two plain journal bearings one with plain bushing and the other with textured bushing.This is for the purpose of carrying out a general comparison to include the steady performance of these bearings in terms of their load carrying capacity and the friction losses in their parts in addition to their dynamic stability.The theoretical results of those cases have been presented analyzed and necessary comparisons have been made. It was concluded in the present work that the inclusion of these textured micro protrusions in the bushing of bearings, whether they are plain or of the three lobe geometry improves their performance in terms of reducing their friction losses and raising their load carrying capacity along.It is found that the three-lobe bearing with protruded bushing surface texture is superior to the other types of bearings considered in the present work as far as steady state performance is concerned. Regarding the margin of stability to small sinusoidal disturbances the protruded three-lobe bearing shows a relatively lower margin.Some useful recommendations for future research work in this field of study are given in this work and the most important one is to carry out extensive experimental studies on sliding bearings surfaces fitted with textured bushings of different micro protrusions designs.