Download or read book A Computational Fluid Dynamic Study of Subsonic Compressible Flow in a Labyrinth Seal written by Lily J. Ho and published by . This book was released on 2001 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Investigation of Labyrinth Seal Flow Fields Using Computational Fluid Dynamics written by Nandita Mohleji and published by . This book was released on 2007 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mathematical and Computational Methods for Compressible Flow written by Miloslav Feistauer and published by Oxford University Press, USA. This book was released on 2003 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is concerned with mathematical and numerical methods for compressible flow. It aims to provide the reader with a sufficiently detailed and extensive, mathematically precise, but comprehensible guide, through a wide spectrum of mathematical and computational methods used in Computational Fluid Dynamics (CFD) for the numerical simulation of compressible flow. Up-to-date techniques applied in the numerical solution of inviscid as well as viscous compressible flow on unstructured meshes are explained, thus allowing the simulation of complex three-dimensional technically relevant problems. Among some of the methods addressed are finite volume methods using approximate Riemann solvers, finite element techniques, such as the streamline diffusion and the discontinuous Galerkin methods, and combined finite volume - finite element schemes. The book gives a complex insight into the numerics of compressible flow, covering the development of numerical schemes and their theoretical mathematical analysis, their verification on test problems and use in solving practical engineering problems. The book will be helpful to specialists coming into contact with CFD - pure and applied mathematicians, aerodynamists, engineers, physicists and natural scientists. It will also be suitable for advanced undergraduate, graduate and postgraduate students of mathematics and technical sciences.

Download or read book Compressible Fluid Flow written by Michel A. Saad and published by Prentice Hall. This book was released on 1985 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference develops the fundamental concepts of compressible fluid flow by clearly illustrating their applications in real-world practice through the use of numerous worked-out examples and problems. The book covers concepts of thermodynamics and fluid mechanics which relate directly to compressible flow; discusses isentropic flow through a variable-area duct; describes normal shock waves, including moving shock waves and shock-tube analysis; explores the effects of friction and heat interaction on the flow of a compressible fluid; covers two-dimensional shock and expansion waves; provides a treatment of linearized flow; discusses unsteady wave propagation and computational methods in fluid dynamics; provides several numerical methods for solving linear and nonlinear equations encountered in compressible flow; offers modern computational methods for solving nonintegrable equations; and describes methods of measurement in high-speed flow. Suitable for the practicing engineer engaged in compressible-flow applications.

Download or read book Numerical Simulation of Flow in a Whirling Annular Seal and Comparison With Experiments written by and published by . This book was released on 1996 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Analytical Experimental Study of Fluid Dynamic Forces in Seals Volume 5 Description of Seal Dynamics Code Dyseal and Labyrinth Seals Code Ktk written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-15 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of the program were to develop computational fluid dynamics (CFD) codes and simpler industrial codes for analyzing and designing advanced seals for air-breathing and space propulsion engines. The CFD code SCISEAL is capable of producing full three-dimensional flow field information for a variety of cylindrical configurations. An implicit multidomain capability allow the division of complex flow domains to allow optimum use of computational cells. SCISEAL also has the unique capability to produce cross-coupled stiffness and damping coefficients for rotordynamic computations. The industrial codes consist of a series of separate stand-alone modules designed for expeditious parametric analyses and optimization of a wide variety of cylindrical and face seals. Coupled through a Knowledge-Based System (KBS) that provides a user-friendly Graphical User Interface (GUI), the industrial codes are PC based using an OS/2 operating system. These codes were designed to treat film seals where a clearance exists between the rotating and stationary components. Leakage is inhibited by surface roughness, small but stiff clearance films, and viscous pumping devices. The codes have demonstrated to be a valuable resource for seal development of future air-breathing and space propulsion engines Shapiro, Wilbur and Chupp, Raymond and Holle, Glenn and Scott, Thomas Glenn Research Center NAS3-25644; WBS 22-00-00

Download or read book Analysis of Compressible and Incompressible Flows Through See through Labyrinth Seals written by Jeng Won Woo and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The labyrinth seal is a non-contact annular type sealing device used to reduce the internal leakage of the working fluid which is caused by the pressure difference between each stage in a turbomachine. Reducing the leakage mass flow rate of the working fluid through the labyrinth seal is desirable because it improves the efficiency of the turbomachine. The carry-over coefficient, based on the divergence angle of the jet, changed with flow parameters with fixed seal geometry while earlier models expressed the carry-over coefficient solely as a function of seal geometry. For both compressible and incompressible flows, the Reynolds number based on clearance was the only flow parameter which could influence the carry-over coefficient. In the case of incompressible flow based on the simulations for various seal geometries and operating conditions, for a given Reynolds number, the carry-over coefficient strongly depended on radial clearance to tooth width ratio. Moreover, in general, the lower the Reynolds number, the larger is the divergence angle of the jet and this results in a smaller carry-over coefficient at lower Reynolds numbers. However, during transition from laminar to turbulent, the carry-over coefficient reduced initially and once the Reynolds number attained a critical value, the carry-over coefficient increased again. In the case of compressible flow, the carry-over coefficient had been slightly increased if radial clearance to tooth width ratio and radial clearance to tooth pitch ratio were increased. Further, the carry-over coefficient did not considerably change if only radial clearance to tooth width ratio was decreased. The discharge coefficient for compressible and incompressible flows depended only on the Reynolds number based on clearance. The discharge coefficient of the tooth in a single cavity labyrinth seal was equivalent to that in a multiple tooth labyrinth seal indicating that flow downstream had negligible effect on the discharge coefficient. In particular, for compressible fluid under certain flow and seal geometric conditions, the discharge coefficient did not increase with an increase in the Reynolds number. It was correlated to the pressure ratio, Pr. Moreover, it was also related to the fact that the flow of the fluid through the constriction became compressible and the flow eventually became choked. At low pressure ratios (less than 0.7), Saikishan's incompressible model deviated from CFD simulation results. Hence, the effects of compressibility became significant and both the carry-over coefficient compressibility factor and the discharge coefficient compressibility factor needed to be considered and included into the leakage model. The carry-over coefficient compressibility factor, phi, had two linear relationships with positive and negative slopes regarding the pressure ratios. This result was not associated with the seal geometry because the seal geometry ratios for each instance were located within the nearly same ranges. Further, the phi-Pr relationship was independent of the number of teeth regardless of single and multiple cavity labyrinth seals. The discharge coefficient compressibility factor, psi, was a linear relationship with pressure ratios across the tooth as Saikishan predicted. However, in certain flow and seal geometric conditions, Saikishan's model needed to be modified for the deviation appearing when the pressure ratios were decreased. Hence, a modified psi-Pr relationship including Saikishan's model was presented in order to compensate for the deviation between the simulations and his model.

Download or read book Leakage Flow in Labyrinth Seals written by Mohammed Ajaz Khan and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Compressible Flow Propulsion and Digital Approaches in Fluid Mechanics written by Michel Ledoux and published by John Wiley & Sons. This book was released on 2017-01-18 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to provide an efficient methodology of solving a fluid mechanics problem, based on an awareness of the physical. It meets different objectives of the student, the future engineer or scientist: Simple sizing calculations are required to master today's numerical approach for solving complex practical problems.

Download or read book A Numerical Investigation of Labyrinth Seal Flutter written by Richard Phibel and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates numerically the phenomenon of flutter in Labyrinth seals. Computational fluid dynamics (CFD) methods are used to predict the fluid forces produced in the labyrinth when one of the seal members is vibrating in its natural mode. The geometry of the seal, the vibrational characteristics and the flow characteristics are varied to determine their influence on the aeroelastic stability. The CFD results are used to develop a bulk-flow model for labyrinth seal flutter analysis. An aeroelastic design procedure for labyrinth seal is pro- posed.

Download or read book Labyrinth Seal Leakage Analysis written by Gaurav Chaudhary and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Seals are basic mechanical devices commonly used in machinery to avoid undesired flow losses of working fluids. To understand the working of these seals specifically those placed between relatively moving parts is still one of the major engineering challenges for the scientific community. Particularly Annular seals are one of the most widely used in rotating machinery comprising turbines, compressors and pumps. They are mounted on the shaft that rotates within a stationary case. These seal designs make an impact on (i) machinery energy conversion efficiency and (ii) rotor dynamic stability due to the interaction between rotor and stator through fluid flow leakage. Among all annular seals straight through rectangular labyrinth seals are the most commonly used ones. Their designs have not changed much a lot since its inception by C.J. Parsons [1] back in 1901. These seals provide resistance to the fluid flow through tortuous path comprising of series of cavities and clearances. The sharp tooth converts the pressure energy to the kinetic which is dissipated through turbulence viscosity interaction in the cavity. To understand the accurate amount of leakage the flow is modeled using the discharge coefficient and for each tooth and the kinetic energy carry over coefficients. This research work is aimed at understanding the fluid flow though labyrinth seals with tooth mounted on the rotor. A matrix of fluid flow simulations has been carried out using commercially available CFD software Fluent® where all parameters effecting the flow field has been studied to understand their effect on the coefficients defining the seal losses. Also the rotor surface speed has been used varied in a step by step manner to understand the fluid flow behavior in high speed turbo-machinery. The carry over coefficient is found to be the function of all the geometric elements defining the labyrinth tooth configuration. A relation between the flow parameters and the carry over coefficient has also been established. The discharge coefficient of the first tooth has been found to be lower and varying in a different manner as compared to a tooth from a multiple cavity seal. Its dependence upon flow parameters and dimensionless geometric constants has been established. The discharge coefficient of the first teeth is found to be increasing with increasing tooth width. Further the compressibility factor has been defined to incorporate the deviation of the performance of seals with compressible fluid to that with the incompressible flow. Its dependence upon pressure ratio and shaft speed has also been established. Using all the above the mentioned relations it would be easy decide upon the tooth configuration for a given rotating machinery or understand the behavior of the seal currently in use.

Download or read book A Study of the Compressible Flow Through a Diffusing S Duct 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 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Benchmark aerodynamic data are presented for compressible flow through a representative S-duct configuration. A numerical prediction of the S-duct flow field, obtained from a subsonic parabolized Navier-Stokes algorithm, is also shown. The experimental and numerical results are compared. Measurements of the three-dimensional velocity field, total pressures, and static pressures were obtained at five cross-sectional planes. Aerodynamic data were gathered with calibrated pneumatic probes. Surface static pressure and surface flow visualization data were also acquired. All reported tests were conducted with an inlet centerline Mach number of 0.6. The Reynolds number, based on the inlet centerline velocity and duct inlet diameter, was 2.6 x 10(exp 6). Thin inlet turbulent boundary layers existed. The collected data should be beneficial to aircraft inlet designers and the measurements are suitable for the validation of computational codes. The results show that a region of streamwise flow separation occurred within the duct. Details about the separated flow region, including mechanisms which drive this complicated flow phenomenon, are discussed. Results also indicate that the duct curvature induces strong pressure driven secondary flows. The cross flows evolve into counter-rotating vortices. These vortices convect low momentum fluid of the boundary layer toward the center of the duct, degrading both the uniformity and magnitude of the total pressure profile. Wellborn, Steven R. and Okiishi, Theodore H. and Reichert, Bruce A. Glenn Research Center COMPRESSIBLE FLOW; COMPUTATIONAL FLUID DYNAMICS; DUCTED FLOW; FLOW DISTRIBUTION; NAVIER-STOKES EQUATION; PRESSURE DISTRIBUTION; SUBSONIC FLOW; THREE DIMENSIONAL MOTION; VELOCITY DISTRIBUTION; WIND TUNNEL TESTS; BOUNDARY LAYER SEPARATION; CROSS FLOW; FLOW VISUALIZATION; INLET FLOW; REYNOLDS NUMBER; STAGNATION PRESSURE; STATIC PRESSURE; TURBULENT BOUNDARY LAYER; VORTICES...

Download or read book The Finite Volume Method in Computational Fluid Dynamics written by F. Moukalled and published by Springer. This book was released on 2015-08-13 with total page 799 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook explores both the theoretical foundation of the Finite Volume Method (FVM) and its applications in Computational Fluid Dynamics (CFD). Readers will discover a thorough explanation of the FVM numerics and algorithms used for the simulation of incompressible and compressible fluid flows, along with a detailed examination of the components needed for the development of a collocated unstructured pressure-based CFD solver. Two particular CFD codes are explored. The first is uFVM, a three-dimensional unstructured pressure-based finite volume academic CFD code, implemented within Matlab. The second is OpenFOAM®, an open source framework used in the development of a range of CFD programs for the simulation of industrial scale flow problems. With over 220 figures, numerous examples and more than one hundred exercise on FVM numerics, programming, and applications, this textbook is suitable for use in an introductory course on the FVM, in an advanced course on numerics, and as a reference for CFD programmers and researchers.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advancement of Shock Capturing Computational Fluid Dynamics Methods written by Keiichi Kitamura and published by Springer Nature. This book was released on 2020-10-31 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a compact primer on advanced numerical flux functions in computational fluid dynamics (CFD). It comprehensively introduces readers to methods used at the forefront of compressible flow simulation research. Further, it provides a comparative evaluation of the methods discussed, helping readers select the best numerical flux function for their specific needs. The first two chapters of the book reviews finite volume methods and numerical functions, before discussing issues commonly encountered in connection with each. The third and fourth chapter, respectively, address numerical flux functions for ideal gases and more complex fluid flow cases— multiphase flows, supercritical fluids and magnetohydrodynamics. In closing, the book highlights methods that provide high levels of accuracy. The concise content provides an overview of recent advances in CFD methods for shockwaves. Further, it presents the author’s insights into the advantages and disadvantages of each method, helping readers implement the numerical methods in their own research.

Download or read book Computational Fluid Dynamic Simulation of a Straight Labyrinth Seal written by Paul Hiester and published by . This book was released on 2013 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On the Flow of a Compressible Fluid by the Hodograph Method written by I. E. Garrick and published by . This book was released on 1944 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: Elementary basic solutions of the equations of motion of a compressible fluid in the hodograph variables are developed and used to provide a basis for comparison, in the form of velocity correction formulas, of corresponding compressible and incompressible flows. The known approximate results of Chaplygin, von Kármán and Tsien, Temple and Yarwood, and Prandtl and Glauert are unified by means of the analysis of the present paper. Two new types of approximations, obtained from basic solutions, are introduced; they possess certain desirable features of the other approximations and appear preferable as a basis for extrapolation into the range of high stream Mach numbers and large disturbances to the main stream. Tables and figures giving velocity and pressure-coefficient correction factors are included in order to facilitate the practical application of the results.