Analysis of Thermal Effects in Circumferential Groove Journal Bearings with Reference to the Divergent Zone PDF Download
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Author: Alex Florian Cristea
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
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: Alex Florian Cristea
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
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: Henry McCallion
Publisher:
ISBN:
Category : Journal bearings
Languages : en
Pages : 10
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Book Description
Author: Elsayed Morsi Aly Afify
Publisher:
ISBN:
Category : Bearings (Machinery)
Languages : en
Pages : 152
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Book Description
Author:
Publisher:
ISBN:
Category : Bearings (Machinery)
Languages : en
Pages : 0
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Book Description
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: Q. Jane Wang
Publisher: Springer
ISBN: 9780387928982
Category : Technology & Engineering
Languages : en
Pages : 4139
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Book Description
TRIBOLOGY – the study of friction, wear and lubrication – impacts almost every aspect of our daily lives. The Springer Encyclopedia of Tribology is an authoritative and comprehensive reference covering all major aspects of the science and engineering of tribology that are relevant to researchers across all engineering industries and related scientific disciplines. This is the first major reference that brings together the science, engineering and technological aspects of tribology of this breadth and scope in a single work. Developed and written by leading experts in the field, the Springer Encyclopedia of Tribology covers the fundamentals as well as advanced applications across material types, different length and time scales, and encompassing various engineering applications and technologies. Exciting new areas such as nanotribology, tribochemistry and biotribology have also been included. As a six-volume set, the Springer Encyclopedia of Tribology comprises 1630 entries written by authoritative experts in each subject area, under the guidance of an international panel of key researchers from academia, national laboratories and industry. With alphabetically-arranged entries, concept diagrams and cross-linking features, this comprehensive work provides easy access to essential information for both researchers and practicing engineers in the fields of engineering (aerospace, automotive, biomedical, chemical, electrical, and mechanical) as well as materials science, physics, and chemistry.
Author: Bernard J. Hamrock
Publisher: CRC Press
ISBN: 1135537755
Category : Technology & Engineering
Languages : en
Pages : 794
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Book Description
Specifically focusing on fluid film, hydrodynamic, and elastohydrodynamic lubrication, this edition studies the most important principles of fluid film lubrication for the correct design of bearings, gears, and rolling operations, and for the prevention of friction and wear in engineering designs. It explains various theories, procedures, and equations for improved solutions to machining challenges. Providing more than 1120 display equations and an introductory section in each chapter, Fundamentals of Fluid Film Lubrication, Second Edition facilitates the analysis of any machine element that uses fluid film lubrication and strengthens understanding of critical design concepts.
Author: Michael J Neale
Publisher: Elsevier
ISBN: 0080519660
Category : Technology & Engineering
Languages : en
Pages : 577
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Book Description
The renowned reference work is a practical guide to the selection and design of the components of machines and to their lubrication. It has been completely revised for this second edition by leading experts in the area.
Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 728
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Book Description
Author: Michael M. Khonsari
Publisher: John Wiley & Sons
ISBN: 1118700252
Category : Technology & Engineering
Languages : en
Pages : 672
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Book Description
Insightful working knowledge of friction, lubrication, and wear in machines Applications of tribology are widespread in industries ranging from aerospace, marine and automotive to power, process, petrochemical and construction. With world-renowned expert co-authors from academia and industry, Applied Tribology: Lubrication and Bearing Design, 3rd Edition provides a balance of application and theory with numerous illustrative examples. The book provides clear and up-to-date presentation of working principles of lubrication, friction and wear in vital mechanical components, such as bearings, seals and gears. The third edition has expanded coverage of friction and wear and contact mechanics with updated topics based on new developments in the field. Key features: Includes practical applications, homework problems and state-of-the-art references. Provides presentation of design procedure. Supplies clear and up-to-date information based on the authors’ widely referenced books and over 500 archival papers in this field. Applied Tribology: Lubrication and Bearing Design, 3rd Edition provides a valuable and authoritative resource for mechanical engineering professionals working in a wide range of industries with machinery including turbines, compressors, motors, electrical appliances and electronic components. Senior and graduate students in mechanical engineering will also find it a useful text and reference.
Author: J. Edward Pope
Publisher: Gulf Professional Publishing
ISBN: 0884157903
Category : Technology & Engineering
Languages : en
Pages : 417
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Book Description
Fluids -- Heat transfer -- Thermodynamics -- Mechanical seals -- Pumps and compressors -- Drivers -- Gears -- Bearings -- Piping and pressure vessels -- Tribology -- Vibration -- Materials -- Stress and strain -- Fatigue -- Instrumentation -- Engineering economics.
