Download or read book Effect of Dimple Pattern on the Suppression of Boundary Layer Separation on a Low Pressure Turbine Blade written by John P. Casey and published by . This book was released on 2004-03-01 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three dimple patterns were investigated to ascertain their relative effectiveness on controlling boundary layer separation from a low-pressure turbine blade. The three cases included a single row of dimples at 65% of the axial chord with 2.22 cm spacing, a single row of dimples at 65% of the axial chord with 4.44 cm spacing, and a two-row staggered pattern with rows at 65% and 76% of the axial chord with 4.44 cm spacing. The multiple row case was such that the center of the upstream dimple set at the midpoint between two downstream dimples. The dimple spacing was measured center-on-center. Each of the dimple patterns was studied and compared to an unmodified blade at axial chord Reynolds numbers based on inlet velocity of 25k, 45k, and 100k. Experimental data was collected in a low-speed, draw down wind tunnel containing a linear turbine cascade of 8 Pak-B blades. Measurements of surface pressure, boundary layer parameters, wake velocity, and total pressure losses were made to examine the flow. No dimple pattern dramatically outperformed the others. Each of the dimple patterns studied improved the average total pressure loss coefficient by 34% for Re 25k and 1% Tu. Complementing the experimental effort was a three-dimensional computational fluid dynamics study. Four models were built and analyzed. The models included an unmodified blade, blades with dimples at 65% of the axial chord with 2 cm or 4 cm spacing, respectively, and a multiple row case consisting of dimples at 65% and 76% of the axial chord with 2 cm spacing. Again the upstream dimple set at the midpoint between two downstream dimples. The computational fluid dynamics study provided detailed flow visualization in and around the dimples as well as a comparison to experimental data for solver verification. It was shown that the computational and experimental results showed similar trends in wake loss and boundary layer traverses.

Download or read book 40th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit July 11 14 2004 Fort Lauderdale FL 04 3550 04 3599 written by and published by . This book was released on 2004 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Dimples to Suppress Boundary Layer Separation on a Low Pressure Turbine Blade written by Kurt P. Rouser and published by . This book was released on 2002-12-01 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flow separation on a low pressure turbine blade is explored at Reynolds numbers of 25k, 45k and 100k, Experimental data is collected in a low- speed, draw-down wind tunnel using a cascade of eight Pak-B blades, Flow is examined from measurements of blade surface pressures, boundary layer parameters, exit velocities, and total pressure losses across the blade, Two recessed dimple shapes are assessed for suppressing flow separation and associated losses, One dimple is spherical, and the second is asymmetric, formed from a full dimple spanwise half-filled, A single row of each dimple shape is tested at 50%, 55% and 65% axial chord, Symmetric dimples reduce separation losses by as much as 28%, while asymmetric dimples reduce losses by as much as 23%, A complementary three-dimensional computational study is conducted to visualize local flow structure, Computational analysis uses Gridgen v13,3 as a mesh generator, Fluent v6,O as a flow solver and FIELDVIEW - v8,0 for graphic display and analysis, Computational results for Pak-B blades at a Reynolds number of 25k indicate that both dimple shapes cause a span-wise vortex to rollup within the dimple and provide a localized pressure drop,

Download or read book Heat Transfer in Gas Turbines written by Bengt Sundén and published by Witpress. This book was released on 2001 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title presents and reflects current active research on various heat transfer topics and related phenomena in gas turbine systems. It begins with a general introduction to gas turbine heat transfer, before moving on to specific areas.

Download or read book Gas Turbine Blade Cooling written by Chaitanya D Ghodke and published by SAE International. This book was released on 2018-12-10 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas turbines play an extremely important role in fulfilling a variety of power needs and are mainly used for power generation and propulsion applications. The performance and efficiency of gas turbine engines are to a large extent dependent on turbine rotor inlet temperatures: typically, the hotter the better. In gas turbines, the combustion temperature and the fuel efficiency are limited by the heat transfer properties of the turbine blades. However, in pushing the limits of hot gas temperatures while preventing the melting of blade components in high-pressure turbines, the use of effective cooling technologies is critical. Increasing the turbine inlet temperature also increases heat transferred to the turbine blade, and it is possible that the operating temperature could reach far above permissible metal temperature. In such cases, insufficient cooling of turbine blades results in excessive thermal stress on the blades causing premature blade failure. This may bring hazards to the engine's safe operation. Gas Turbine Blade Cooling, edited by Dr. Chaitanya D. Ghodke, offers 10 handpicked SAE International's technical papers, which identify key aspects of turbine blade cooling and help readers understand how this process can improve the performance of turbine hardware.

Download or read book Detached Eddy Simulation Analysis of Pak B Low Pressure Turbine Blade written by Kyle P. Malone and published by . This book was released on 2004-06-01 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two cases were computationally investigated using the detached eddy simulation (DES) turbulence model: an unmodified Pak-B blade and a Pak-B blade with a dimple located at 65% of axial chord. Both cases were created so that they simulated an infinite span with an infinite number of dimples. The cases were run for an inlet Reynolds number of 25,000. The computed results were used to resolve the location of separation and reattachment, visualize the streamlines for the dimpled case, build velocity magnitude contour and vector plots, and map the thickness of the boundary layer. The results were then compared to previous computational and experimental studies in order to validate the detached eddy simulation model for future research into the effect of dimples on low pressure turbine flow fields. For the unmodified blade, the performance of the DES model compared favorably to other available viscous and turbulence models. For the dimpled blade, preliminary results also compare favorably to other models although further development of the flow field is needed to verify this. Based on these results, future researchers studying dimples on turbine blades should strongly consider using the DES turbulence model.

Download or read book Gas Turbine Heat Transfer and Cooling Technology Second Edition written by Je-Chin Han and published by CRC Press. This book was released on 2012-11-27 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive reference for engineers and researchers, Gas Turbine Heat Transfer and Cooling Technology, Second Edition has been completely revised and updated to reflect advances in the field made during the past ten years. The second edition retains the format that made the first edition so popular and adds new information mainly based on selected published papers in the open literature. See What’s New in the Second Edition: State-of-the-art cooling technologies such as advanced turbine blade film cooling and internal cooling Modern experimental methods for gas turbine heat transfer and cooling research Advanced computational models for gas turbine heat transfer and cooling performance predictions Suggestions for future research in this critical technology The book discusses the need for turbine cooling, gas turbine heat-transfer problems, and cooling methodology and covers turbine rotor and stator heat-transfer issues, including endwall and blade tip regions under engine conditions, as well as under simulated engine conditions. It then examines turbine rotor and stator blade film cooling and discusses the unsteady high free-stream turbulence effect on simulated cascade airfoils. From here, the book explores impingement cooling, rib-turbulent cooling, pin-fin cooling, and compound and new cooling techniques. It also highlights the effect of rotation on rotor coolant passage heat transfer. Coverage of experimental methods includes heat-transfer and mass-transfer techniques, liquid crystal thermography, optical techniques, as well as flow and thermal measurement techniques. The book concludes with discussions of governing equations and turbulence models and their applications for predicting turbine blade heat transfer and film cooling, and turbine blade internal cooling.

Download or read book Fluid Mechanics and Fluid Power written by T. Prabu and published by Springer Nature. This book was released on 2021-08-03 with total page 901 pages. Available in PDF, EPUB and Kindle. Book excerpt: div="" style="" This book comprises select proceedings of the 46th National Conference on Fluid Mechanics and Fluid Power (FMFP 2019). The contents of this book focus on aerodynamics and flow control, computational fluid dynamics, fluid structure interaction, noise and aero-acoustics, unsteady and pulsating flows, vortex dynamics, nuclear thermal hydraulics, heat transfer in nanofluids, etc. This book serves as a useful reference beneficial to researchers, academicians and students interested in the broad field of mechanics. ^

Download or read book Selected Problems in Fluid Flow and Heat Transfer written by Artur J. Jaworski and published by MDPI. This book was released on 2019-09-20 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluid flow and heat transfer processes play an important role in many areas of science and engineering, from the planetary scale (e.g., influencing weather and climate) to the microscopic scales of enhancing heat transfer by the use of nanofluids; understood in the broadest possible sense, they also underpin the performance of many energy systems. This topical Special Issue of Energies is dedicated to the recent advances in this very broad field. This book will be of interest to readers not only in the fields of mechanical, aerospace, chemical, process and petroleum, energy, earth, civil ,and flow instrumentation engineering but, equally, biological and medical sciences, as well as physics and mathematics; that is, anywhere that “fluid flow and heat transfer” phenomena may play an important role or be a subject of worthy research pursuits.

Download or read book Advances in Wind Turbine Blade Design and Materials written by Povl Brondsted and published by Elsevier. This book was released on 2013-10-31 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind energy is gaining critical ground in the area of renewable energy, with wind energy being predicted to provide up to 8% of the world's consumption of electricity by 2021. Advances in wind turbine blade design and materials reviews the design and functionality of wind turbine rotor blades as well as the requirements and challenges for composite materials used in both current and future designs of wind turbine blades.Part one outlines the challenges and developments in wind turbine blade design, including aerodynamic and aeroelastic design features, fatigue loads on wind turbine blades, and characteristics of wind turbine blade airfoils. Part two discusses the fatigue behavior of composite wind turbine blades, including the micromechanical modelling and fatigue life prediction of wind turbine blade composite materials, and the effects of resin and reinforcement variations on the fatigue resistance of wind turbine blades. The final part of the book describes advances in wind turbine blade materials, development and testing, including biobased composites, surface protection and coatings, structural performance testing and the design, manufacture and testing of small wind turbine blades.Advances in wind turbine blade design and materials offers a comprehensive review of the recent advances and challenges encountered in wind turbine blade materials and design, and will provide an invaluable reference for researchers and innovators in the field of wind energy production, including materials scientists and engineers, wind turbine blade manufacturers and maintenance technicians, scientists, researchers and academics. - Reviews the design and functionality of wind turbine rotor blades - Examines the requirements and challenges for composite materials used in both current and future designs of wind turbine blades - Provides an invaluable reference for researchers and innovators in the field of wind energy production

Download or read book Aerodynamics of Low Reynolds Number Flyers written by Wei Shyy and published by Cambridge University Press. This book was released on 2011-04-28 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low Reynolds number aerodynamics is important to a number of natural and man-made flyers. Birds, bats, and insects have been of interest to biologists for years, and active study in the aerospace engineering community, motivated by interest in micro air vehicles (MAVs), has been increasing rapidly. The primary focus of this book is the aerodynamics associated with fixed and flapping wings. The book consider both biological flyers and MAVs, including a summary of the scaling laws-which relate the aerodynamics and flight characteristics to a flyer's sizing on the basis of simple geometric and dynamics analyses, structural flexibility, laminar-turbulent transition, airfoil shapes, and unsteady flapping wing aerodynamics. The interplay between flapping kinematics and key dimensionless parameters such as the Reynolds number, Strouhal number, and reduced frequency is highlighted. The various unsteady lift enhancement mechanisms are also addressed, including leading-edge vortex, rapid pitch-up and rotational circulation, wake capture, and clap-and-fling.

Download or read book Impingement Jet Cooling in Gas Turbines written by R.S. Amano and published by WIT Press. This book was released on 2014-05-28 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the requirement for enhanced cooling technologies on modern gas turbine engines, advanced research and development has had to take place in field of thermal engineering. Among the gas turbine cooling technologies, impingement jet cooling is one of the most effective in terms of cooling effectiveness, manufacturability and cost. The chapters contained in this book describe research on state-of-the-art and advanced cooling technologies that have been developed, or that are being researched, with a variety of approaches from theoretical, experimental, and CFD studies. The authors of the chapters have been selected from some of the most active researchers and scientists on the subject. This is the first to book published on the topics of gas turbines and heat transfer to focus on impingement cooling alone.

Download or read book Failure Analysis of Heat Treated Steel Components written by Lauralice de Campos Franceschini Canale and published by ASM International. This book was released on 2008 with total page 651 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications written by Thomas J. Mueller and published by AIAA. This book was released on 2001 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title reports on the latest research in the area of aerodynamic efficency of various fixed-wing, flapping wing, and rotary wing concepts. It presents the progress made by over fifty active researchers in the field.

Download or read book Lecture Series Boundary Layer Theory Laminar flows written by Hermann Schlichting and published by . This book was released on 1949 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Training Guidelines in Non destructive Testing Techniques written by International Atomic Energy Agency and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of Boundary Layer Development in a Two Stage Low Pressure Turbine written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-11 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental data from jet-engine tests have indicated that unsteady blade row interactions and separation can have a significant impact on the efficiency of low-pressure turbine stages. Measured turbine efficiencies at takeoff can be as much as two points higher than those at cruise conditions. Several recent studies have revealed that Reynolds number effects may contribute to the lower efficiencies at cruise conditions. In the current study numerical simulations have been performed to study the boundary layer development in a two-stage low-pressure turbine, and to evaluate the transition models available for low Reynolds number flows in turbomachinery. The results of the simulations have been compared with experimental data, including airfoil loadings and integral boundary layer quantities. The predicted unsteady results display similar trends to the experimental data, but significantly overestimate the amplitude of the unsteadiness. The time-averaged results show close agreement with the experimental data.Dorney, Daniel J. and Ashpis, David E. and Halstead, David E. and Wisler, David C.Glenn Research CenterJET ENGINES; TWO STAGE TURBINES; COMPUTERIZED SIMULATION; BALDWIN-LOMAX TURBULENCE MODEL; BOUNDARY LAYER TRANSITION; TRANSITION FLOW; FLOW VISUALIZATION; BOUNDARY LAYER SEPARATION; SEPARATED FLOW; ROTOR BLADES (TURBOMACHINERY); TAKEOFF; CRUISING FLIGHT; COMPUTATIONAL GRIDS; NOZZLE FLOW; SKIN FRICTION; TURBINE BLADES; REYNOLDS NUMBER; FLOW CHARACTERISTICS; FLOW DISTRIBUTION