Qualification And Optimization Of Solid Polymer Tilting Pad Bearings For Subsea Pump Applications
MetadataShow full item record
Tilting pad bearings are used extensively in high power and/or high speed pump applications. Traditional white metallined also known as babbitted tilting pad bearings are used for oil lubricated bearings. Babbitted tilting pad bearings are not ideal for applications with low viscous lubricants, like waterbased fluids. For these applications, polymer bearings offer many advantages over traditional bearing materials including: Low friction coefficient, Higher flexibility, Wide range of operational temperature, High corrosion and chemical resistance, High shock and impact resistance, Tolerance against particle contamination, Electrical insulation. To achieve the desired improvement in performance, the material specifics of the polymer have to be carefully considered in the design process. One option available is a polymer lined tilting pad bearing which combines the excellent tribological properties of polymers and the high structural stiffness of the steel back. But a polymer lined metal pad does not provide the same equalizing effect offered by the higher compressibility of a solid polymer pad. For example the problems of an edge carrier can be reduced for a tilting pad journal bearing and the self-equalizing mechanism can be avoided for a tilting pad thrust bearing while considering the higher flexibility of solid PEEK pads. An additional advantage of a solid polymer pad is the elimination of the bonding between the polymer and the steel, so that a possible source of a bearing failure can be avoided upfront already. During a qualification test of a commercially available solid polymer tilting pad thrust bearing, the high Hertzian contact stress at the pivot let to indentations in the polymer. After a few operating hours these indentations are clearly visible and will finally lead to a complete loss of the advantages of a tilting pad bearing over a fixed geometry bearing. This lecture describes the steps involved in the optimization of the solid polymer tilting pad bearing design, with the objective to increase the reliability of the bearing assembly. The limitations of the available solid polymer tilting pad thrust bearing have been overcome by the integration of a metal reinforced pivot as mentioned by Gassmann et al. (2013). The results of the TEHD analysis presented form the base of the optimized journal and thrust bearing design. The new journal and thrust bearing design has been validated through testing of a prototype. The data collected during tests with the optimized thrust and journal bearings are in excellent agreement with the simulations. With the optimized bearing design, the limitations of the original pad design have been mitigated. The successfully qualified journal and thrust bearing are one of the building blocks required for product lubricated pumps and will be used in subsea pump applications.
Henssler, Dieter; Schneider, Lorenz; Gassmann, Simon; Felix, Thomas (2015). Qualification And Optimization Of Solid Polymer Tilting Pad Bearings For Subsea Pump Applications. Turbomachinery Laboratories, Texas A&M Engineering Experiment Station. Available electronically from