Identifier

etd-11052007-165817

Degree

Doctor of Philosophy (PhD)

Department

Mechanical Engineering

Document Type

Dissertation

Abstract

Mechanical seals are widely used in rotating equipment such as pumps, turbines and agitators to prevent leakage. One crucial factor for keeping seals reliable is the thermal behavior of the seal rings. The existing literature on thermal effects in seals primarily concentrates on the conduction of heat into the rings. Yet, a more complete analysis requires understanding of the flow field around the rings. In this dissertation, both the laminar and turbulent flows within the seal chamber are studied and their effects on the heat transfer in the seal rings are evaluated. Based on extensive sets of numerical simulations, heat transfer correlations for calculating the heat convection coefficients at the wetted outer surfaces of the seal rings are developed. In addition, using a commercial software FLUENT, a 3-D computational model is developed for predicting the flow and thermal behavior of conventional mechanical seal. The numerical results are verified by the experimental measurements. Numerical models are useful for predicting the thermal behavior of mechanical seals. However, numerical computation is time-consuming and the result is hard to be generalized. Therefore, a series of analytical models are developed for rapid evaluation of the heat transfer in the rings of mechanical seals. Using the separation of variable method, the 2-D heat conduction equations in cylindrical coordinates are solved simultaneously for the mating and primary rings with considering the heat generation between them. In addition, a simple and efficient method for estimating the average seal contact face temperature, surface temperature, and heat partitioning factor between the rings of a mechanical seal is presented. In the analysis of mechanical seals, it is necessary and crucial to understand the heat transfer and tribological behaviors of the lubrication film at the sealing gap between the seal rings. To this end, ThermoElastoHydroDynamic (TEHD) models are developed for the lubrication film at the seal interface. Roughness at the seal faces is considered and its effects on the lubrication film thickness at the sealing gap, power dissipation, and leakage are analyzed and discussed.

Date

2007

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Michael M. Khonsari

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