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Numerical Predictions and Measurements in the Lubrication of Aeronautical Engine and Transmission Components

Moraru, Laurentiu Eugen
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1125769629

Abstract Details

2005, Doctor of Philosophy in Engineering, University of Toledo, Mechanical Engineering.
This dissertation treats a variety of aspects of the lubrication of mechanical components encountered in aeronautical engines and transmissions. The study covers dual clearance squeeze film dampers, mixed elastohydrodynamic lubrication (EHL) cases and thermal elastohydrodynamic contacts. The dual clearance squeeze film damper (SFD) invented by Fleming is investigated both theoretically and experimentally for cases when the sleeve that separates the two oil films is free to float and for cases when the separating sleeve is supported by a squirrel cage. The Reynolds equation is developed to handle each of these cases and it is solved analytically for short bearings. A rotordynamic model of a test rig is developed, for both the single and dual SFD cases. A computer code is written to calculate the motion of the test rig rotor. Experiments are performed in order to validate the theoretical results. Rotordynamics computations are found to favorably agree with measured data. A probabilistic model for mixed EHL is developed and implemented. Surface roughness of gears are measured and processed. The mixed EHL model incorporates the average flow model of Patir and Cheng and the elasto-plastic contact mechanics model of Chang Etsion and Bogy. The current algorithm allows for the computation of the load supported by an oil film and for the load supported by the elasto-plastically deformed asperities. This work also presents a way to incorporate the effect of the fluid induced roughness deformation by utilizing the “amplitude reduction” results provided by the deterministic analyses. The Lobatto point Gaussian integration algorithm of Elrod and Brewe was extended for thermal lubrication problems involving compressible lubricants and it was implemented in thermal elastohydrodynamic cases. The unknown variables across the film are written in series of Legendre polynomials. The thermal Reynolds equation is obtained in terms of the series coefficients and it is proven that it can only explicitly contain the information from the first three Legendre polynomials. A computer code was written to implement the Lobatto point algorithm for a EHL line contact. Use of the Labatto point calculation method has resulted in greater accuracy without the use of a larger number of grid points.
Theo Keith, Jr. (Advisor)
273 p.
Dual Squeeze Film Damper (SFD); Rotordynamics; Surface Roughness; Mixed Elastohydrodynamic Lubrication (EHL); Thermal Elastohydrodynamic Lubrication; Lobatto Gauss Quadrature

Recommended Citations

Citations

  • Moraru, L. E. (2005). Numerical Predictions and Measurements in the Lubrication of Aeronautical Engine and Transmission Components [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1125769629

    APA Style (7th edition)

  • Moraru, Laurentiu. Numerical Predictions and Measurements in the Lubrication of Aeronautical Engine and Transmission Components. 2005. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1125769629.

    MLA Style (8th edition)

  • Moraru, Laurentiu. "Numerical Predictions and Measurements in the Lubrication of Aeronautical Engine and Transmission Components." Doctoral dissertation, University of Toledo, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1125769629

    Chicago Manual of Style (17th edition)

toledo1125769629
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© 2005, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.