Download or read book Effects of injection hole geometry high freestream turbulence and surface roughness on film cooling heat transfer written by Basav Sen and published by . This book was released on 1995 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Leading Edge Film Cooling and Surface Roughness on the Downstream Film Cooling Along a Transonic Turbine Blade for Low and High Free Stream Turbulence written by and published by . This book was released on 2008 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is the culmination of a two year effort to demonstrate the capability for performing near wall high resolution Time Resolved Particle Image Velocimetry (TRDPIV) measurements in a transonic turbine. Performing TRDPIV in high speed wall bounded flows with high resolution/magnification often posses significant difficulties. For this reason, two preliminary studies where conducted in order to further understand the challenges that would be present in this type of environment. Hardware and algorithm advancements and developments ultimately enabled performing TRDPIV in the transonic cascade facility. However, high pressure, high speed and the turbine blade complex geometries (high curvature and acceleration) significantly inhibit our ability to deliver homogeneous distribution of flow tracers, especially in the near wall region resulting in low quality measurements and regions with randomly missing data. In addition to our experimental results this effort delivers a novel advanced data reconstruction methodology based on proper orthogonal decomposition that was developed to overcome the aforementioned limitation. The following report documents in detail the methods and results generated throughout this effort.

Download or read book Influence of In Hole Roughness and High Freestream Turbulence on Film Cooling From a Shaped Hole written by Robert Schroeder and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas turbines are heavily used for electricity generation and aircraft propulsion with a strong desire in both uses to maximize thermal efficiency while maintaining reasonable power output. As a consequence, gas turbines run at high turbine inlet temperatures that require sophisticated cooling technologies to ensure survival of turbine components. One such technology is film cooling with shaped holes, where air is withdrawn from latter stages of the compressor, is bypassed around the combustor, and is eventually ejected out holes in turbine component surfaces. Air ejected from these shaped holes helps maintain components at temperatures lower than flow from the combustor. Many studies have investigated different factors that influence shaped hole performance. However, no studies in open literature have investigated how cooling performance is affected by roughness along interior walls of the shaped hole. The effect of in-hole roughness on shaped hole film cooling was the focus of this research. Investigation of in-hole roughness effects first required the determination of behavior for a shaped hole with smooth walls. A public shaped hole, now used by other investigators as well, was designed with a diffused outlet having 7 degree expansion angles and an area ratio of 2.5. At low freestream turbulence intensity of 0.5%, film cooling adiabatic effectiveness for this smooth hole was found to peak at a blowing ratio of 1.5. Measurements of flowfields and thermal fields revealed causes of this behavior. Blowing ratio increases above 1.5 caused the jet from the smooth hole to penetrate higher into the surrounding mainstream, exhibit a stronger counter-rotating vortex pair, and have narrower contact with the wall than at lower blowing ratios. Experiments performed at high freestream turbulence intensity of 13% revealed dynamics of how freestream turbulence both diluted and laterally spread coolant. At the high blowing ratio of 3 the dilution and spreading were competing effects, such that elevated freestream turbulence did not cause a decrease in area-averaged effectiveness. At the blowing ratio of 1.5, high freestream turbulence caused area-averaged effectiveness to decrease 17% relative to the low freestream turbulence case. Film cooling performance was measured for the shaped hole geometry with several different configurations of in-hole roughness. At low freestream turbulence intensity, in-hole roughness caused decreases in area-averaged adiabatic effectiveness up to 61% relative to the smooth hole performance. These percent decreases in adiabatic effectiveness were more severe with increasing roughness levels and with increasing blowing ratios. Flowfield and thermal field measurements for the configuration with largest roughness size showed that the decrease in adiabatic effectiveness for rough holes as compared to smooth holes was due to thicker boundary layers along the interior walls of the cooling holes. The thicker boundary layers resulted in faster jet core flow, which in turn caused increased penetration of coolant into the mainstream and increased turbulence intensity inside the jet, with both leading to reduced adiabatic effectiveness. Detrimental effects of in-hole roughness persisted at the high freestream turbulence conditions as well.

Download or read book An Experimental Investigation of the Effect of Freestream Turbulence on Film Cooling Using Thermochromic Liquid Crystal Thermography written by James Edward Mayhew and published by . This book was released on 1999 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Free stream Turbulance and Surface Roughness on Film Cooling written by Donald L. Schmidt and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the International Gas Turbine and Aeroengine Congress & Exhibition, Birmingham, UK, Jun 10-13, 1996.

Download or read book Effects of Hole Length Supply Plenum Geometry and Freestream Turbulence on Film Cooling Performance written by and published by . This book was released on 2000 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Free stream Turbulence on Film Cooling written by Cecil J. Marek and published by . This book was released on 1975 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of High Freestream Turbulence on Film Cooling Effectiveness written by and published by . This book was released on 1994 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigated adiabatic wall cooling effectiveness of a single row of film cooling holes injecting into a turbulent flat plate boundary layer below a turbulent, zero pressure gradient freestream. Levels of freestream turbulence (Tu) up to 17.4% were generated using a method which simulates conditions at a gas turbine combustor exit. Film cooling was injected from a single row of five 35 degree slant-hole injectors (length/diameter = 3.5. pitch/diameter = 3.0) at blowing ratios from 0.55 to 1185 and at a nearly constant density ratio (coolant density/freestream density) of 0.95. Film cooling effectiveness data is presented for Tu levels ranging from 0.9% to 17% at a constant freestream Reynolds number based on injection hole diameter of 19000. Results show that elevated levels of freestream turbulence reduce film cooling effectiveness by up to 70% in the region directly downstream of the injection hole due to enhanced mixing. At the same time, high freestream turbulence also produces a 50-100% increase in film cooling effectiveness in the region between injection holds. This is due to accelerated spanwise diffusion of the cooling fluid, which also produces an earlier merger of the coolant jets from adjacent holes.

Download or read book An Experimental Investigation on the Effects of Freestream Turbulence Intensity on Film Cooling Effectiveness and Heat Transfer Coefficient for an Anti vortex Hole written by Stephen Andrew Hayes and published by . This book was released on 2014 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Hole Length Supply Plenum Geometry and Freestream Turbulence on Film Cooling Performance written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-27 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental measurements are presented in this report to document the sensitivity of film cooling performance to the hole length and coolant delivery plenum geometry. Measurements with hot-wire anemometry detail velocity, local turbulence, and spectral distributions over the exit plane of film cooling holes and downstream of injection in the coolant-freestream interaction zone. Measurements of discharge coefficients and adiabatic effectiveness are also provided. Coolant is supplied to the film cooling holes by means of a large, open plenum and through plenums which force the coolant to approach the holes either co-current or counter-current to the freestream. A single row of film cooling holes with 35 degree-inclined streamwise at two coolant-to-freestream velocity ratios, 0.5 and 1.0, is investigated. The coolant-to-freestream density ratio is maintained in the range 0.96 to 1.0. Measurements were taken under high-freestream (FSTI = 12%) and low-freestream turbulence intensity (FSTI = 0.5%) conditions. The results document the effects of the hole L/D, coolant supply plenum geometry, velocity ratio, and FSTI. In general, hole L/D and the supply plenum geometry play influential roles in the film cooling performance. Hole L/D effects, however, are more pronounced. Film cooling performance is also dependent upon the velocity ratio and FSTI. Burd, Steven W. and Simon, Terrence W. and Thurman, Douglas (Technical Monitor) Glenn Research Center NAG3-1638; RTOP 714-01-4A...

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 Film Cooling Heat Transfer with High Free Stream Turbulence written by John J. Schauer and published by . This book was released on 1996 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Suction Side Roughness Effects on Film Cooling Heat Transfer on a Turbine Vane written by and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was conducted in a simulated three vane linear cascade to determine the effects of surface roughness and film cooling on the heat transfer coefficient distribution in the region downstream of the first row of suction side coolant holes. Suction side film cooling was operated in the range 0 less than M less than 1.4. The showerhead was tested at M(sub sh) = 1.6. In addition to the completely smooth condition, simulated airfoil roughness was used upstream of the coolant holes, downstream of the coolant holes, and both upstream and downstream of the coolant holes. Two levels of mainstream turbulence intensity were tested. The heat transfer measurements were conducted by application of a uniform heat flux in the region downstream of the coolant holes. The resulting surface temperature distributions were measured with infrared thermography. Because the upstream region was unheated, the influence of film cooling on the heat transfer coefficient was due to only to hydrodynamic effects and not thermal effects. The coolant to mainstream density ratio of the majority of the experiments was unity; however, a single experiment was conducted at a density ratio of DR = 1.6 to determine how the coolant to mainstream density ratio affects heat transfer. Net heat flux reduction calculations were performed by combining the heat transfer coefficient measurements of the present study with adiabatic effectiveness measurements of a separate study. In order to gain insight into the hydrodynamics that affect the heat transfer, boundary layer measurements were conducted using hot-wire anemometry.

Download or read book Effect of Surface Roughness on Local Film Cooling Effectiveness and Heat Transfer Coefficients written by Douglas Neal Barlow and published by . This book was released on 1994 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of injection hole geometry surface roughness and freestream condition on film cooling written by Donald Lee Schmidt and published by . This book was released on 1995 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Investigaton Into the Effects of High Freestream Turbulence on Full Coverage Shaped Hole Film Cooling in an Accelerating Boundary Layer written by Joseph Elliott Kingery and published by . This book was released on 2015 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Heat Transfer written by and published by Academic Press. This book was released on 2017-11-11 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Heat Transfer, Volume 49 provides in-depth review articles from a broader scope than in traditional journals or texts. Topics covered in this new volume include Heat Transfer in Rotating Cooling Channel, Flow Boiling and Flow Condensation in Reduced Gravity, Advances in Gas Turbine Cooling, and Advanced Heat Transfer Topics in Complex Duct Flows. While the articles in this series will be of great interest to mechanical, chemical and industrial engineers working in the field of heat transfer, the book is also ideal for those in graduate schools or industry, and even non-specialists interested in the latest research. Compiles the expert opinions of leaders in the industry Fills the information gap between regularly scheduled journals and university-level textbooks by providing in-depth review articles over a broader scope than in traditional journals or texts Essential reading for all mechanical, chemical and industrial engineers working in the field of heat transfer, or in graduate schools or industry