Author:
Publisher:
ISBN:
Category : Bearings (Machinery)
Languages : en
Pages : 0
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A model for the thermal behavior of lubricant in the cavitated regions of a journal bearing is presented. The model assumes a bubbly mixture of liquid and air and includes the calculation of local mixture properties for the fluid film. Temperature in the film is calculated by a first order approximate energy equation that includes heat transfer between the film and its boundaries. A second order profile is assumed to represent the temperature distribution across the film. The classical Reynolds equation is applied, using a viscosity that does not vary across the film. Results of calculations are compared with published experimental results and with a prior theory that uses an effective length calculation in the cavitation zone. Results are found to be in good agreement with experiment at two different speeds, predicting the peak temperature of the bearing wall within 10 to 20 percent of the total temperature rise. The model predicts the temperature in the cavitated zone with much greater accuracy than the effective length model, with all theoretical values within 2 C of the measured values.
Author: D. Dowson
Publisher: Elsevier
ISBN: 0080875912
Category : Technology & Engineering
Languages : en
Pages : 587
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This book discusses dissipative phenomena, in particular the origins of friction at all scales, in mechanics, physics and chemistry, encountered in all fields of tribology, from thick film lubrication to dry friction.
Author:
Publisher:
ISBN:
Category : Tribology
Languages : en
Pages : 400
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Author:
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 390
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Author:
Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 404
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Author: Jane Wang
Publisher: CRC Press
ISBN: 1439815119
Category : Technology & Engineering
Languages : en
Pages : 636
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Book Description
Understanding the characteristics of material contact and lubrication at tribological interfaces is of great importance to engineering researchers and machine designers. Traditionally, contact and lubrication are separately studied due to technical difficulties, although they often coexist in reality and they are actually on the same physical ground. Fast research advancements in recent years have enabled the development and application of unified models and numerical approaches to simulate contact and lubrication, merging their studies into the domain of Interfacial Mechanics. This book provides updated information based on recent research progresses in related areas, which includes new concepts, theories, methods, and results for contact and lubrication problems involving elastic or inelastic materials, homogeneous or inhomogeneous contacting bodies, using stochastic or deterministic models for dealing with rough surfaces. It also contains unified models and numerical methods for mixed lubrication studies, analyses of interfacial frictional and thermal behaviors, as well as theories for studying the effects of multiple fields on interfacial characteristics. The book intends to reflect the recent trends of research by focusing on numerical simulation and problem solving techniques for practical interfaces of engineered surfaces and materials. This book is written primarily for graduate and senior undergraduate students, engineers, and researchers in the fields of tribology, lubrication, surface engineering, materials science and engineering, and mechanical engineering.
Author: Alex Florian Cristea
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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The main objective of the thesis is to study the thermal effects in steadily loaded circumferential groove journal bearings (CGJBs), including cavitation phenomena occurring in the divergent zone of such bearings. Experimental research conducted at University of Poitiers - Institut Pprime - France enabled a thorough determination of film pressure and temperature fields for the front land of a CGJB plus its mid-groove section, and several performance parameters. Measurements of film pressure and temperature fields under steady-state regime surpassed existing works, regardless of journal bearing design, through: sheer number of land measurement locations, 180 for pressure and for 144 temperature; high precision state of art instrumentation; broad range of operating conditions, 0.125 ... 2 MPa specific bearing pressure and 5.25 ... 21 m/s shaft speeds. Transient start-up to steady-statestabilization regimes have been investigated at low loads. Experiments at University "Politehnica" of Bucharest - Romania showed a correlation between the downforce thrust and film rupture for a Rayleigh step pin (RSP), important in evaluating divergent zone cavitation phenomena. Theoretical research consisted in developing simple models for evaluating CGJBs performance in steady-state and transient start-up regimes. Several theoretical models were employed for assessing start-up seizure, catastrophic transient thermoelastic instability and damage risk. The major result is a reliable experimental data collection that: enables development of advanced theoretical models; disprove flat film pressure distributions in divergent zones, and constant pressure and temperature in the bearing supply groov.
Author: Emmanuel E. Gdoutos
Publisher: Springer
ISBN: 331991989X
Category : Science
Languages : en
Pages : 423
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Book Description
ICTAEM_1 treated all aspects of theoretical, applied and experimental mechanics including biomechanics, composite materials, computational mechanics, constitutive modeling of materials, dynamics, elasticity, experimental mechanics, fracture, mechanical properties of materials, micromechanics, nanomechanics, plasticity, stress analysis, structures, wave propagation. During the conference special symposia covering major areas of research activity organized by members of the Scientific Advisory Board took place. ICTAEM_1 brought together the most outstanding world leaders and gave attendees the opportunity to get acquainted with the latest developments in the area of mechanics. ICTAEM_1 is a forum of university, industry and government interaction and serves in the exchange of ideas in an area of utmost scientific and technological importance.
Author:
Publisher:
ISBN:
Category : Lubrication and lubricants
Languages : en
Pages : 376
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 30
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