Cavitation effects on the performance of squeeze film damper bearings /
| Main Author: | |
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| Other Authors: | , , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1989.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=745035031&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Abstract: | Cavitation effects on the performance of squeeze film damper bearings are investigated utilizing a controlled orbit test rig. Cavitation regimes in the damper are identified utilizing high speed motion pictures. These regimes are further quantified through dynamic pressure measurements corresponding to the cavitation regimes revealed in the flow visualization experiment. The type and extent of cavitation are shown to depend on many variables which include the operating speed, supply pressure, eccentricity, and the end seals' effectiveness. Both vapor and gaseous type cavitation due to air entrainment are observed to exist in the damper. While vapor cavitation has very little, if any, effect on the positive pressure region, gaseous cavitation has a drastic influence on the entire pressure profile, resulting in a significant reduction in the magnitude of the positive pressure and the shrinking of its circumferential extent which in extreme cases extends to only a quarter of the cycle. A density correlation is experimentally obtained to account for the compressibility due to air entrainment. The effect cavitation has on a squeeze film supported rigid rotor is analyzed utilizing experimentally extracted squeeze film force coefficients corresponding to a wide spectrum of operating conditions. These conditions include regimes in which air entrainment effects are dominant, and other conditions in which vapor cavitation and inertial effects are more dominant. While vapor cavitation can lead to a nonlinear hardening spring effect, cavitation due to air entrainment is shown under certain conditions to exhibit a nonlinear response characteristic of a softening spring. The response on squeeze film supports is also studied by an experimental investigation utilizing a flexible rotor. It is found that cavitation and air entrainment at low supply pressure significantly reduce the damping and allow the journal to contact the housing. The resulting bilinear support stiffness produces nonsynchronous vibrations. Increasing the supply pressure reduces the effect of air entrainment and thus attenuates both the synchronous and nonsynchronous response. The feasibility of using an elastomeric sandwiched ring as a damped flexible support in conjunction with the squeeze film is investigated. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Mechanical Engineering." |
| Physical Description: | xxi, 329 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |