DESIGN OF NONRECESSED HYBRID JOURNAL REARING FOR OPTIMAL PERFORMANCE CHARACTERISTICS

Abstract

The design of externally pressurized journal bearing is of considerable importance to the development of rotating machinery. In spite of the wealth of literature on the analysis and performance of these bearings, the selection of the main bearing parameters relies heavily on empirical guides. This is primarily due to the complexity of the interaction between the different parameters governing the behavior of such bearings. The analytical relationship describing the bearing performance is generally based on Reynolds's equation. The Reynolds's equation is solved together with restrictor equation along with appropriate boundary conditions. Finite element method is used as a tool to find a numerical solution. Based on analysis a computer program is developed and performance characteristics are computed. In the present study an attempt has been made to optimize the performance characteristics of the Hole entry hybrid journal bearings. An optimizing function has been chosen taking into consideration a set of important performance characteristics. The main parameters taken into consideration are minimum fluid film thickness (h n,;,, ), bearing lubricant flow (Q), direct Fluid Film stiffness coefficient (S22) and direct Fluid Film damping coefficient (C22). Proper weightage is given to these parameters by selecting different weighting factors. The main variables for optimization are the number of holes per row and the ab /L ratio. The results for different configurations have been compared and bearing configuration is selected for an optimum performance.