Download or read book Developing Flow and Heat Transfer in Strongly Curved Ducts of Rectangular Cross section written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A numerical study of heat transfer in 90°, constant cross-section curved duct, steady, laminar flow is presented. The work is aimed primarily at characterizing the effects of duct geometry on heat transfer by considering, especially, the role of secondary motions during the developing period of the flow. However, due consideration has also been given to varying initial conditions of velocity and temperature at the entrance section to the duct. In addition, an assessment is made of the relative contributions of individual duct walls to heat transfer in the flow. It is found that, in general, heat transfer increases with Dean number with the largest transfer rates occurring through the duct side walls and outer-curvature wall. Duct geometries with aspect ratio greater or smaller than unity have weaker secondary motions and are less effective for heat transfer. Similarly, plug-flow entrance profiles for velocity retard the development of cross-section flow thus inhibiting a significant contribution to heat transfer. It is concluded that short ducts with strong curvature and intense secondary motions can be as effective for heat transfer as longer ducts which are less strongly curved. Calcuations are based on fully elliptic (in space) forms of the transport equation governing the flow. They are of engineering value and are limited in accuracy only by the degree of computational mesh refinement. A comparison with calculations based on parabolic equations has been made and it is shown how the latter can lead to erroneous results for strongly curved flows.
Download or read book Computation of Laminar and Turbulent Flow in Curved Ducts Channels and Pipes Using the Navier Stokes Equations written by R. C. Buggeln and published by . This book was released on 1980 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Both laminar and turbulent flows in strongly curved ducts, channels, and pipes are studied by numerical methods. The study concentrates on the curved square-duct geometry and flow conditions for which detailed measurements have been obtained recently by Taylor, Whitelaw, and Yianneskis. The solution methodology encompasses solution of the compressible ensemble-averaged Navier-Stokes equations at low Mach number using a split linearized block implicit (LBI) scheme, and rapid convergence on the order of 80 noniterative time steps is obtained. The treatment of turbulent flows includes resolution of the viscous sublayer region. A series of solutions for both laminar and turbulent flow and for both two- and three-dimensional geometries of the same curvature are presented. The accuracy of these solutions is explored by mesh refinement and by comparison with experiment. In summary, good qualitative and reasonable quantitative agreement between solution and experiment is obtained. Collectively, this sequence of results serves to clarify the physical structure of these flows and hence how grid selection procedures might be adjusted to improve the numerical accuracy and experimental agreement. For a three-dimensional flow of considerable complexity, the relatively good agreement with experiment obtained for the turbulent flow case despite a coarse grid must be regarded as encouraging. (Author).
Download or read book Direct and Large Eddy Simulation V written by Rainer Friedrich and published by Springer Science & Business Media. This book was released on 2004-04-30 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fifth ERCOFfAC workshop 'Direct and Large-Eddy Simulation-5' (DLES-5) was held at the Munich University of Technology, August 27-29, 2003. It is part of a series of workshops that originated at the University of Surrey in 1994 with the intention to provide a forum for presentation and dis cussion of recent developments in the field of direct and large-eddy simula tion. Over the years the DLES-series has grown into a major international venue focussed on all aspects of DNS and LES, but also on hybrid methods like RANSILES coupling and detached-eddy simulation designed to provide reliable answers to technical flow problems at reasonable computational cost. DLES-5 was attended by 111 delegates from 15 countries. Its three-day pro gramme covered ten invited lectures and 63 original contributions partially pre sented in parallel sessions. The workshop was financially supported by the fol lowing companies, institutions and organizations: ANSYS Germany GmbH, AUDI AG, BMW Group, ERCOFfAC, FORTVER (Bavarian Research Asso ciation on Combustion), JM BURGERS CENTRE for Fluid Dynamics. Their help is gratefully acknowledged. The present Proceedings contain the written versions of nine invited lectures and fifty-nine selected and reviewed contributions which are organized in four parts: 1 Issues in LES modelling and numerics 2 Laminar-turbulent transition 3 Turbulent flows involving complex physical phenomena 4 Turbulent flows in complex geometries and in technical applications.
Download or read book Investigation of Heat Transfer in Straight and Curved Rectangular Ducts written by James Claude Ballard (III.) and published by . This book was released on 1980 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental investigations have been conducted to examine the general problem of convective heat transfer in a rectangular cross section channel with both straight and curved passages. The experimental configuration was modeled as infinite parallel plates with one wall at a constant heat flux and the opposite wall adiabatic. The air flow through the channel was heated through the Joulean heating of a wall composed of Temsheet. Liquid crystals applied to the surface of the Temsheet were used to confirm the presence of the Taylor-Gortler vortices. Average Nusselt number mesurements were used to investigate their effect on heat transfer from the curved test section. Experiments were conducted for steady state laminar flow that was hydrodynamically developed and thermally developing. It was confirmed that the Taylor-Gortler vortices enhanced the heat transfer process in the curved section. The experimental data was compared with several analytic studies with good results. (Author).
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 Prediction of Laminar and Turbulent Primary and Secondary Flows in Strongly Curved Ducts written by J. P. Kreskovsky and published by . This book was released on 1981 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Single Phase Convective Heat Transfer written by Sadik Kakaç and published by Wiley-Interscience. This book was released on 1987-11-03 with total page 1268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Very Good,No Highlights or Markup,all pages are intact.
Download or read book Investigation of Heat Transfer in Straight and Curved Rectangular Ducts for Laminar and Transition Flows written by Robert George Holihan (Jr) and published by . This book was released on 1981 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation was conducted to examine convection heat transfer in a duct of rectangular cross-section, having both a straight and curved flow passage. One wall was kept at a constant temperature, with the opposite wall being adiabatic. Heating of the air flowing in the channel was accomplished through Joulean heating of a wall composed of Temsheet. The experiments were conducted for steady state in Laminar and Transition flows. Development and propagation of the Taylor-Gortler vortices was shown to enhance the heat transfer rate in the curved section as compared to the straight section. (Author).
Download or read book Convective Heat Transfer Coefficients for Pipe Flow with Curvature Induced Secondary Motion written by Gregory Martin Chrysler and published by . This book was released on 1984 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laminar Flow Forced Convection in Ducts written by R. K. Shah and published by . This book was released on 1978 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heat Transfer Fluid Flow Digest written by and published by . This book was released on 1981 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book General Papers in Heat Transfer written by M. K. Jensen and published by . This book was released on 1992 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ASME Proceedings of the 1988 National Heat Transfer Conference HTD 96 written by and published by . This book was released on 1988 with total page 796 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Momentum and Heat Transfer Processes in Recirculating Flows written by American Society of Mechanical Engineers. Winter Annual Meeting and published by . This book was released on 1980 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book written by 李光地 and published by . This book was released on 1987 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Review of Flow and Heat Transfer in Ducts of Rectangular Cross Section written by W. D. Morris and published by . This book was released on 1974 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Forced Convection in Curved Ducts written by Fang Liu and published by . This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Forced Convection in Curved Ducts: Multiplicity and Stability" by Fang, Liu, 劉方, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled FORCED CONVECTION IN CURVED DUCTS: MULTIPLICITY AND STABILITY Submitted by Fang LIU for the degree of Doctor of philosophy at the University of Hong Kong in October 2006 Numerical studies are made on fully developed forced convection in slightly / tightly curved ducts of square / rectangular cross-sections, which are encountered in wide applications. The investigation is confined to fully developed flow and heat transfer under peripherally uniform wall temperature. Thermo-physical properties of fluid are taken as the constants. The study focuses on flow bifurcation and stability in curved ducts with different curvature ratios and aspect ratios: slightly curved square ducts, tightly curved square ducts and tightly curved rectangular ducts. Steady bifurcation structures in these curved ducts are obtained. The physical mechanisms and driving forces of the flow structures are discussed. The stability on various branches is determined by direct transient computation on dynamic responses of the multiple solutions. The characteristics of the flow oscillations are revealed by Hilbert spectral analysis. The investigation is divided into three parts according to the curvature ratio and aspect ratio of the curved ducts. In the first part, bifurcation and stability of forced convection in a slightly curved square duct are studied. Six known solution branches are extended to the high Dean number region and four new asymmetric branches are found. As the Dean number increases, fully-developed flows evolve from a stable steady 2-cell solution to a periodic oscillation, another stable steady solution, an intermittent oscillation and a chaotic oscillation. In the second part, bifurcation and stability of forced convection in a tightly curved square duct are studied. Ten solution branches are found, including five asymmetric branches and some sub-branches of the known branches that are new for tightly curved ducts. As the Dean number increases, finite random disturbances lead the flows from a stable steady state to the co-existence of two kinds of periodic oscillations, the co-existence of several kinds of intermittent oscillations, and a chaotic oscillation. In the third part, bifurcation and stability of forced convection in a tightly curved rectangular duct of aspect ratio 10 are investigated. Eleven solution branches are found, seven symmetric and four asymmetric. Ekman vortices are considerably long due to large aspect ratio. As the Dean number increases, finite random disturbances lead the flows from a stable steady state to another stable steady state, a periodic oscillation, an intermittent oscillation, another periodic oscillation and a chaotic oscillation. The mean friction factor and the mean Nusselt number are obtained for all physically-realizable fully-developed flows in these curved ducts. A significant enhancement of heat transfer can be obtained at the expense of a slight increase of flow friction. DOI: 10.5353/th_b3701583 Subjects: Tubes - Fluid dynamics Heat - Convection Bifurcation theory
