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On Hydrodynamic Lubrication using Perturbed Reynolds equation and CFD-FSI: Static and Dynamic Characteristics of Compliant Marine Bearings

Snyder, Troy Alan
http://rave.ohiolink.edu/etdc/view?acc_num=akron157552061871739

Abstract Details

2019, Doctor of Philosophy, University of Akron, Mechanical Engineering.
The compliant marine bearing is a type of journal bearing which features an elastomeric bushing and commonly utilizes water as the bearing lubricant. The term compliant follows from the deformation of the elastomeric bushing at substantially reduced hydrodynamic pressures compared to bearings with bushings comprised of metals such as bronze, brass, or steel. The operating regime of marine bearings under purely hydrdocynamic action is aptly called soft-EHL in which elasto-hydrodynamic lubrication occurs at sub-Hertizan pressures within the bearings' conformal contacts. Marine bearing bushings are typically profiled designs with lubricant grooves distributed around their circumference. The lubricant grooves serve as axial flow passages and contribute negligibly to the generation of hydrodynamic bearing pressures. The regions between the lubricant grooves are referred to as lands and generate hydrodynamic bearing forces which support static an dynamic radial loads applied to the bearings. Compliant marine bearings primarily serve in marine applications as stern tube and strut bearings, which support the propeller driveshaft at the rear of shipping vessels. This work provides a detailed theoretical development of a Reynolds equation-based model suitable to predict the static and dynamic performance of hydrodynamic bearings with compliant bushings. The dynamic performance is embodied in linearized dynamic coefficients which are calculated from a perturbed set of differential equations. The numerical solution of the model is exercised through a wide number of application cases to verify several modeling assumptions related to: bushing compliance, fluid inertia, and turbulence. Primarily, a simplified slider bearing geometry is investigated as it functions as a surrogate for a single stave in a full marine bearing. A FRF-based method to predict the dynamic behavior of hydrodynamic bearings (and seals) within a higher-fidelity CFD environment has been developed and deployed by leveraging the open-source continuum mechanics library OpenFOAM. The method is successfully employed in the evaluation of the dynamic coefficients of rigid slider and journal bearing geometries. The dynamic coefficients predicted by the FRF-based approach and the perturbed Reynolds equation showed good coincidence for the linear slider and journal bearing geometries and operating conditions considered. The FRF-based approach for the identification of bearing dynamic coefficients is general and applicable to bearings which feature compliant bushings or complex geometric features. Numerical results from models of varying complexity are compared with eachother in an effort to verify the assumptions associated with the compliant, perturbed Reynolds equation. Modeling assumptions regarding lubricant inertia, turbulence, and the constitutive modeling of the bearing bushing are explored in detail.
Minel Braun (Advisor)
S. Graham Kelly (Committee Member)
Scott Sawyer (Committee Member)
Atef Saleeb (Committee Member)
Kevin Kreider (Committee Member)
360 p.
Mechanical Engineering
Hydrodynamic Bearing; Compliant Bushing; Marine; CFD; Dynamics; Perturbed Reynolds Equation

Recommended Citations

Citations

  • Snyder, T. A. (2019). On Hydrodynamic Lubrication using Perturbed Reynolds equation and CFD-FSI: Static and Dynamic Characteristics of Compliant Marine Bearings [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron157552061871739

    APA Style (7th edition)

  • Snyder, Troy. On Hydrodynamic Lubrication using Perturbed Reynolds equation and CFD-FSI: Static and Dynamic Characteristics of Compliant Marine Bearings. 2019. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron157552061871739.

    MLA Style (8th edition)

  • Snyder, Troy. "On Hydrodynamic Lubrication using Perturbed Reynolds equation and CFD-FSI: Static and Dynamic Characteristics of Compliant Marine Bearings." Doctoral dissertation, University of Akron, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron157552061871739

    Chicago Manual of Style (17th edition)

akron157552061871739
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© 2019, some rights reserved.Creative Commons License On Hydrodynamic Lubrication using Perturbed Reynolds equation and CFD-FSI: Static and Dynamic Characteristics of Compliant Marine Bearings by Troy Alan Snyder is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Akron and OhioLINK.