A Study Of Parameters That Affect Pivoted Shoe Journal Bearing Performance In High-Speed Turbomachinery

Journal bearing pad temperatures, oil flow requirements, and power losses can impose limitations on the design and operation of high-speed turbomachinery. Over the past few years, the authors have conducted extensive tests and studies of parameters that affect pivoted shoe journal bearing performance. A special, high-speed test rig is described, which was designed and built for the purpose of measuring bearing steady-state performance characteristics under light to moderately heavy loads, and to very high operating speeds that are being approached in new turbine and compressor designs. Instrumentation includes a detailed array of pad temperature detectors and the direct measurement of frictional torque.

Data are presented that compare the effects of pivot offset, oil flow, load orientation, method of lubrication, and oil discharge configuration on 6 inch diameter pivoted shoe journal bearing performance. The parameters are shown to significantly influence bearing pad temperature and power loss, particularly at high loads and speeds. Pad temperature profiles, isotherms, torque, and oil outlet temperatures are compared and evaluated. Discussions address the prediction and application of these parameters, and how they may be used to improve the capacity and performance of high-speed turbomachinery. The data and discussions are intended to provide useful information to engineers, programmers, and personnel involved with the study or operation of pivoted shoe journal bearings.

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Contributed by: Scan DeCamillo and Keith Brockwell