Download or read book The Calculation of Rotordynamic Coefficients for Labyrinth Seals written by Bradley Paul Williams and published by . This book was released on 1992 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Calculation of Rotordynamic Forces on Labyrinth Seals written by Steve John Hensel and published by . This book was released on 1986 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impact of Rotor Surface Velocity Leakage Models and Real Gas Properties on Rotordynamic Force Predictions of Gas Labyrinth Seals written by Manish Rambhau Thorat and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Rotordynamic coefficients of a gas labyrinth seal are assumed to be frequency independent. However, this assumption loses its validity as rotor surface velocity approaches Mach 1. The solution procedure of 1CV model by Childs and Scharrer which assumes frequency independent force coefficients is modified to allow for calculating frequency dependent force coefficients. A comparative study of the impact of using frequency-dependent model and the original frequency-independent model on stability analysis is made. The results indicate that frequency dependency of force coefficients should be accounted for in stability analysis as rotor surface velocity approaches a significant fraction of Mach number. The bulk flow rotordynamic analysis model by Childs and Scharrer is modified to investigate the impact of leakage-flow models on predictions. A number of leakage models are incorporated in the one-control volume model, and a comparative study is made. Kinetic energy carryover factor of a leakage equation is one of the dominant factors in seal cross-force generation. A leakage equation based on a model proposed by Gamal which uses Hodkinson's kinetic energy carryover factor is found to improve predictions of direct damping and cross-coupled stiffness. A test case is implemented to study the impact of variation of seal axial radial clearance on stability characteristics. The 1CV model by Childs and Scharrer and subsequent bulk flow models are based on the assumption of isothermal flow across the labyrinth seal. The 1CV model by Childs and Scharrer is modified to include energy equation, and the flow process is assumed to be adiabatic. However, predicted cross-coupled stiffness and direct damping coefficients using the new model do not compare well with the experimental results by Picardo as compared to the isothermal model. The impact of using real gas properties on static and rotordynamic characteristics of the seal is studied.

Download or read book Turbomachinery Rotordynamics written by Dara Childs and published by John Wiley & Sons. This book was released on 1993-04-16 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Imparts the theory and analysis regarding the dynamics of rotating machinery in order to design such rotating devices as turbines, jet engines, pumps and power-transmission shafts. Takes into account the forces acting upon machine structures, bearings and related components. Provides numerical techniques for analyzing and understanding rotor systems with examples of actual designs. Features an excellent treatment of numerical methods available to obtain computer solutions for authentic design problems.

Download or read book Experimental Measurements and Methods for Data Analysis to Determine the Rotordynamic Coefficients of a Labyrinth Seal written by Sang Kyu Choi and published by . This book was released on 1988 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Measurement and Prediction of Rotordynamic Forces for Labyrinth Seals written by D. W. Childs and published by . This book was released on 1988 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of rotordynamic (stiffness and damping) coefficients and leakage characteristics were completed for labyrinth-rotor/honeycombe stator seals. Comparisons to labryinth-rotor/smooth-stator seals showed no stability improvements. Tests were also carried out on smooth-rotor/honeycombe-stator seals and demonstrated superior stability and leakage performance for this type of seal if the entering flow is pre-rotated in the direction of rotation. A new 'bulk-flow' theory for labyrinth seals has been developed and its prediction compare well with measured results for tooth-on-rotor labyrinths. Also, a more sophisticated model was developed which solves the 3-D Reynolds-averaged Navier-Stokes equations for compressible flow. Keywords: Labyrinth seals, Rotordynamic forces, Turbine stators, Computational fluid dynamics. (jes).

Download or read book Rotordynamic Instability Problems in High Performance Turbomachinery 1996 written by and published by . This book was released on 1997 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Proceedings of the 10th International Conference on Rotor Dynamics IFToMM written by Katia Lucchesi Cavalca and published by Springer. This book was released on 2018-08-20 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: IFToMM conferences have a history of success due to the various advances achieved in the field of rotor dynamics over the past three decades. These meetings have since become a leading global event, bringing together specialists from industry and academia to promote the exchange of knowledge, ideas, and information on the latest developments in the dynamics of rotating machinery. The scope of the conference is broad, including e.g. active components and vibration control, balancing, bearings, condition monitoring, dynamic analysis and stability, wind turbines and generators, electromechanical interactions in rotor dynamics and turbochargers. The proceedings are divided into four volumes. This first volume covers the following main topics: Active Components and Vibration Control; Balancing; Bearings: Fluid Film Bearings, Magnetic Bearings, Rolling Bearings and Seals; and Blades, Bladed Systems and Impellers.

Download or read book Rotordynamic Forces Developed by Labyrinth Seals written by Dara W. Childs and published by . This book was released on 1983 with total page 43 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerous tasks have been completed in developing measurement and prediction techniques for accurately determining the fluid-structure-interaction forces on labyrinth seal rotors. The best facility has been designed, fabricated, and assembled; the drive mechanism and instrumentation system have been tested. Further, various improvements to the test apparatus have been implemented. Also, the development of two basic computational approaches for predicting seal rotor forces has been successfully completed. These consist of an improved but approximate analytical model and an extensive computer program incorporating the complete Reynolds-averaged Navier-Stokes equations. The latter model solves finite difference equations in predicting the two-dimensional (axisymmetric) compressible flow in a concentric-rotor labyrinth seal cavity. Details of a corresponding incompressible flow prediction are presented and discussed. The final numerical model will allow prediction of the desired three-dimensional, eccentric-rotor flow field and the associated rotordynamic forces.

Download or read book Rotordynamics Prediction in Engineering written by Michel Lalanne and published by John Wiley & Sons. This book was released on 1998-02-04 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this updated and revised second edition, the authors present a systematic and practical approach to the analytical and numerical aspects of the prediction of rotordynamics behaviour. The influence of bending is a main theme of the book, although the effects of torsion are also considered. The use of finite element techniques and the characteristics of rotor elements are introduced. The book goes on to consider simple models showing basic phenomena which are then linked to industrial applications such as turbocompressors, high pressure centrifugal compressors, and steam and air turbines. Key features include: The inclusion of a computer program available free of charge on the Internet The development of a simple model of co-axial multirotors New industrial applications and 1995 API specifications This book will be of great interest and value to students and engineers concerned with predictions in rotordynamics and mechanical engineering.

Download or read book Leakage and Rotordynamic Effects of Pocket Damper Seals and See through Labyrinth Seals written by Ahmed Mohamed Gamal Eldin and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation discusses research on the leakage and rotordynamic characteristics of pocket damper seals (PDS) and see-through labyrinth seals, presents and evaluates models for labyrinth seal and PDS leakage and PDS force coefficients, and compares these seals to other annular gas seals. Low-pressure experimental results are used alongside previously-published high-pressure labyrinth and PDS data to evaluate the models. Effects of major seal design parameters; blade thickness, blade spacing, blade profile, and cavity depth; on seal leakage, as well as the effect of operating a seal in an off-center position, are examined through a series of non-rotating tests. Two reconfigurable seal designs were used, which enabled testing labyrinth seals and PDS with two to six blades. Leakage and pressure measurements were made with air as the working fluid on twenty-two seal configurations. Increasing seal blade thickness reduced leakage by the largest amount. Blade profile results were more equivocal, indicating that both profile and thickness affected leakage, but that the influence of one factor partially negated the influence of the other. Seal leakage increased with increased eccentricity at lower supply pressures, but that this effect was attenuated for higher pressure drops. While cavity depth effects were minor, reducing depths reduced leakage up to a point beyond which leakage increased, indicating that an optimum cavity depth existed. Changing blade spacing produced results almost as significant as those for blade thickness, showing that reducing spacing can detrimentally affect leakage to the point of negating the benefit of inserting additional blades. Tests to determine the effect of PDS partition walls showed that they reduce axial leakage. The pressure drop was found to be highest across the first blade of a seal for low pressure drops, but the pressure drop distribution became parabolic for high pressure drops with the largest drop across the last blade. Thirteen leakage equations made up of a base equations, a flow factor, and a kinetic energy carryover factor were examined. The importance of the carryover coefficient was made evident and a modified carryover coefficient is suggested. Existing fully partitioned PDS models were expanded to accommodate seals of various geometries.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1984 with total page 1430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.

Download or read book Seals Flow Code Development 1993 written by and published by . This book was released on 1994 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Earth to orbit Propulsion Technology 1994 written by R. J. Richmond and published by . This book was released on 1994 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Comparison of Experimental and Theoretical Results for Labyrinth Gas Seals written by Joseph Kirk Scharrer and published by . This book was released on 1987 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Rotordynamic Coefficient Results for Honeycomb Seals written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Test results (leakage and rotordynamic coefficients) are presented for seven honeycomb-stator smooth-rotor seals. Tests were carried out with air at rotor speeds up to 16,000 cpm and supply pressures up to 8.2 bars. Test results for the seven seals are compared, and the most stable configuration is identified based on the whirl frequency ratio. Results from tests of a smooth-rotor/smooth-stator seal, a teeth-on-stator labyrinth seal, and the most stable honeycomb seal are compared. Elrod, David A. and Childs, Dara W. Unspecified Center AERODYNAMIC COEFFICIENTS; HONEYCOMB STRUCTURES; LABYRINTH SEALS; LEAKAGE; ROTOR AERODYNAMICS; STATORS; COMPARISON; TABLES (DATA); TEST EQUIPMENT...