A. M. Mikula, Research Engineer
Kingsbury, Inc., Philadelphia. Pa. 19154
This paper compares the leading edge groove and pressurized supply (flooded) lubricant supply methods, and analyzes their influence on the performance of equalizing tilting pad thrust bearings. This paper presents new experimental data on 6-shoe, 267 mm (10 ½ in.) O.D. bearings, operating at shaft speeds up to 14000 rpm, with loads ranging up to 3.45 MPa (500 psi) for two different lubricants. The data presented details the power loss and babbitt temperature performance of two versions of the leading-edge-groove bearing design and contrasts the results with a pressurized supply bearing design.
The leading edge groove tilting pad thrust bearing is a hydrodynamic bearing that introduces the lubricant directly into the fluid film at the leading edge of the thrust shoe. This method of supplying cool, undiluted lubricant into the hydrodynamic wedge has been found to significantly reduce bearing power loss and babbitt temperatures .
This paper presents the most recent results of the extensive and ongoing testing performed on the leading edge groove bearing, and serves as a supplement to the test data published in reference [I]. These additional performance figures are the result of refinements that have been made to the leading-edge groove bearing's design since the original results were first published. The net result of these refinements has been to reduce internal leakage and, therefore, maximize lubricant flow into the groove. Additional new test data has also been included for a more viscous lubricant, and a further reduction of oil flow rates.
The two primary indicators of bearing performance, power loss and babbitt temperature, will be used to evaluate the leading-edge-groove and pressurized supply (flooded) bearing designs. Each bearing was tested under identical conditions of applied load, shaft speed, inlet oil temperature, and oil viscosity. A detailed description of the test rig can be found in reference .
Each bearing was evaluated using both a light and heavy oil that was supplied at 46°C (115°F). Applied loads ranged from 0-3.45 MPa (0-500 psi) and shaft speeds ranged from 2000-14000 rpm.
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