Effect of journal misalignment on the static characteristics of an innovative journal bearing with adjustable elements in load-on-pad and load-between-pad configurations

Abstract

Purpose The purpose of this paper is to theoretically analyze an innovative form of variable bearing configuration having four pads with unique adjustability principle operated under journal misaligned conditions. The parameters such as load positions, degrees of misalignment (DM) and pad adjustment configurations influencing the steady-state performance of the four-pad adjustable bearing are detailed in this paper. Design/methodology/approach The proposed adjustable pad geometry possesses the ability to undergo radial and tilt motions in both inward and outward directions. Analysis is carried out by considering journal misalignment in vertical and horizontal planes with bearing modelled for load-on-pad and load-between-pad configurations. The film thickness equation derived to incorporate the radial and tilt adjustment parameters is further modified to accommodate the different load orientations and misaligned journal conditions. The pressure field equation is solved by applying finite-difference technique combined with Gauss Siedel iterative method. Findings At higher DM, peak pressures generated in the minimum film thickness region near the pad ends highly influences the bearing load carrying capacity. Results indicated that the adjustable four-pad bearing geometry is highly efficient in withstanding the journal misalignment by radially displacing and tilting the four pads in negative directions. Originality/value For bearing designers, this research highlights the importance of considering the misalignment factor during the design stages of an adjustable journal bearing. The proposed adjustability concept is proven to be effective enough to improve the bearing performance and, in turn, withstand the journal misalignment.

Experimental Study on Low Speed Lubrication Characteristics of Large Tilting Pad Bearings

“…With the development of computer and testing technology, the problems of tilting pad bearings in practical applications are found, dealt with and a new model to solve the problem is established. The mathematical model of fluid lubrication of tilting pad bearings is developed from a simple two-dimensional thermo hydrodynamic analysis model to a complex three-dimensional thermo hydrodynamic analysis model, and further to a complex three-dimensional thermoelastic hydrodynamic analysis model, whose computational accuracy and speed have been continuously improved [6] [7] .The effects of turbulence effect [19] [20] , rotor tilting and misalignment [17] [18] , and cavitation effect on the bearing performance such as power consumption, lubrication characteristics, temperature rise of bearing shell, and dynamic characteristics at high speeds are also considered in the theoretical analysis.…”

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