Download or read book EFFECT OF VELOCITY AND TEMPERATURE DISTRIBUTION AT THE HOLE EXIT ON FILM COOLING OF TURBINE BLADES NASA TM 97 208146 AUG 6 1998 written by United States. National Aeronautics and Space Administration and published by . This book was released on 1999* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Velocity and Temperature Distribution at the Hole Exit on Film Cooling of Turbine Blades written by Vijay K. Garg and published by . This book was released on 1995 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the International Gas Turbine and Aeroengine Congress & Exposition, Houston, Texas - June 5-8, 1995.

Download or read book Effect of Film Hole Shape on Turbine Blade Film Cooling Performance written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-30 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The detailed heat transfer coefficient and film cooling effectiveness distributions as well as tile detailed coolant jet temperature profiles on the suction side of a gas turbine blade A,ere measured using a transient liquid crystal image method and a traversing cold wire and a traversing thermocouple probe, respectively. The blade has only one row of film holes near the gill hole portion on the suction side of the blade. The hole geometries studied include standard cylindrical holes and holes with diffuser shaped exit portion (i.e. fanshaped holes and laidback fanshaped holes). Tests were performed on a five-blade linear cascade in a low-speed wind tunnel. The mainstream Reynolds number based on cascade exit velocity was 5.3 x 10(exp 5). Upstream unsteady wakes were simulated using a spoke-wheel type wake generator. The wake Strouhal number was kept at 0 or 0.1. Coolant blowing ratio was varied from 0.4 to 1.2. Results show that both expanded holes have significantly improved thermal protection over the surface downstream of the ejection location, particularly at high blowing ratios. However, the expanded hole injections induce earlier boundary layer transition to turbulence and enhance heat transfer coefficients at the latter part of the blade suction surface. In general, the unsteady wake tends to reduce film cooling effectiveness.Han, J. C. and Teng, S.Glenn Research CenterHEAT TRANSFER COEFFICIENTS; COOLANTS; TEMPERATURE PROFILES; SUCTION; TURBINE BLADES; HEAT MEASUREMENT; FILM COOLING; BOUNDARY LAYER TRANSITION; CASCADE WIND TUNNELS; CYLINDRICAL BODIES; EJECTION; GAS TURBINES; HOLE DISTRIBUTION (MECHANICS); LIQUID CRYSTALS; LOW SPEED; THERMAL PROTECTION; THERMOCOUPLES; WIND TUNNELS

Download or read book Survey of Advantages and Problems Associated with Transpiration Cooling and Film Cooling of Gas turbine Blades written by Ernst Rudolf Georg Eckert and published by . This book was released on 1951 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: Transpiration and film cooling promise to be effective methods of cooling gas-turbine blades; consequently, analytical and experimental investigations are being conducted to obtain a better understanding of these processes. This report serves as an introduction to these cooling methods, explains the physical processes, and surveys the information available for predicting blade temperatures and heat-transfer rates. In addition, the difficulties encountered in obtaining a uniform blade temperature are discussed, and the possibilities of correcting these difficulties are indicated. Air is the only coolant considered in the application of these cooling methods.

Download or read book An Experimental Study of the Effect of Wake Passing on Turbine Blade Film Cooling written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-16 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of wake passing on the showerhead film cooling performance of a turbine blade has been investigated experimentally. The experiments were performed in an annular turbine cascade with an upstream rotating row of cylindrical rods. Nickel thin-film gauges were used to determine local film effectiveness and Nusselt number values for various injectants, blowing ratios, and Strouhal numbers. Results indicated a reduction in film effectiveness with increasing Strouhal number, as well as the expected increase in film effectiveness with blowing ratio. An equation was developed to correlate the span-average film effectiveness data. The primary effect of wake unsteadiness was found to be correlated by a streamwise-constant decrement of 0.094.St. Steady computations were found to be in excellent agreement with experimental Nusselt numbers, but to overpredict experimental film effectiveness values. This is likely due to the inability to match actual hole exit velocity profiles and the absence of a credible turbulence model for film cooling. Heidmann, James D. and Lucci, Barbara L. and Reshotko, Eli Glenn Research Center NASA-TM-107425, NAS 1.15:107425, E-10671 RTOP 505-62-10...

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 Effect of Film Hole Shape on Turbine Blade Film Cooling Performance written by and published by . This book was released on 2000 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effect of Wake Passing on Turbine Blade Film Cooling written by James D. Heidmann and published by . This book was released on 1996 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Numerical Study of the Effect of Wake Passing on Turbine Blade Film Cooling written by James D. Heidmann and published by . This book was released on 1995 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Leading Edge Film Cooling Effects on Turbine Blade Heat Transfer written by Vijay K. Garg and published by . This book was released on 1995 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the International Gas Turbine and Aeroengine Congress and Exposition, Houston, Texas - June 5-8, 1995.

Download or read book Effects of Pulsing on Film Cooling of Gas Turbine Airfoils written by Sarah Marie Coulthard and published by . This book was released on 2005 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project was to determine the effects of pulsed film cooling on turbine blades. High combustor temperatures, resulting in elevated turbine inlet temperatures, produce high engine efficiency. At current operating temperatures, the turbine inlet temperature is above the melting point of the turbine blades. Thus cooling the blades in the first stages after the combustor is essential. Current methods for film cooling utilize a continuous stream of bleed air from the compressor. This air is routed into a cavity inside each blade and bled out of holes onto the blade surface, creating a film of cool air. Pulsed film cooling may reduce the amount of bleed air used, thus increasing the efficiency of the engine by allowing more air to flow through the combustor, while providing equivalent protection for the blades. In this study, a section of a turbine blade was modeled using a plate with a row of five film cooling holes. Coolant air was pulsed via solenoid valves from a plenum, while a wind tunnel provided a mainstream flow. Temperature and velocity fields were measured over the blade surface with varying blowing rates of the coolant and frequencies of pulsing. The film cooling effectiveness, a measure of how well the coolant protects the blade surface, was calculated based on the measured temperatures. The results were compared to baseline cases with continuous blowing and no blowing. The overall best case was continuous film cooling with the jet velocity one fourth of the mainstream velocity. However, results showed that pulsed film cooling has the potential to provide an equivalent or greater film cooling effectiveness for higher jet velocities. The case of pulsed jets with a jet velocity equal to the mainstream velocity, pulsing frequency of 20 Hertz, and 75% duty cycle showed an increased film cooling effectiveness and decreased heat transfer compared to the continuous blowing case. This study suggests that pulsed film cooling has the potential to adequately protect gas turbine blades with additional research, ultimately allowing for an increased efficiency in a gas turbine engine.

Download or read book Unsteady High Turbulence Effects on Turbine Blade Film Cooling Heat Transfer Performance Using a Transient Liquid Crystal Technique written by and published by . This book was released on 2000 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unsteady High Turbulence Effects on Turbine Blade Film Cooling Heat Transfer Performance Using a Transient Liquid Crystal Technique 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 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unsteady wake effect, with and without trailing edge ejection, on detailed heat transfer coefficient and film cooling effectiveness distributions is presented for a downstream film-cooled gas turbine blade. Tests were performed on a five-blade linear cascade at an exit Reynolds number of 5.3 x 10(exp 5). Upstream unsteady wakes were simulated using a spoke-wheel type wake generator. Coolant blowing ratio was varied from 0.4 to 1.2; air and CO2 were used as coolants to simulate different density ratios. Surface heat transfer and film effectiveness distributions were obtained using a transient liquid crystal technique; coolant temperature profiles were determined with a cold wire technique. Results show that Nusselt numbers for a film cooled blade are much higher compared to a blade without film injection. Unsteady wake slightly enhances Nusselt numbers but significantly reduces film effectiveness versus no wake cases. Nusselt numbers increase only slic,htly but film cooling, effectiveness increases significantly with increasing, blowing ratio. Higher density coolant (CO2) provides higher effectiveness at higher blowing ratios (M = 1.2) whereas lower density coolant (Air) provides higher 0 effectiveness at lower blowing ratios (M = 0.8). Trailing edge ejection generally has more effect on film effectiveness than on the heat transfer, typically reducing film effectiveness and enhancing heat transfer. Similar data is also presented for a film cooled cylindrical leading edge model. Han, J. C. and Ekkad, S. V. and Du, H. and Teng, S. Glenn Research Center NAG3-1656; RTOP 714-01-4A

Download or read book On Aerothermal Effects of Film Cooling on Turbine Blades with Flow Separation written by Reinaldo Araújo Gomes and published by . This book was released on 2010 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Investigation of Air cooled Turbine Blades in Turbojet Engine written by Vernon L. Arne and published by . This book was released on 1951 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Cooling hole Geometry on Aerodynamic Performance of a Film cooled Turbine Van Tested with Cold Air in a Two dimensional Cascade written by John F. Kline and published by . This book was released on 1978 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurements of Heat Transfer Flow and Pressures in a Simulated Turbine Blade Internal Cooling Passage written by Louis M. Russell and published by . This book was released on 1997 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was made to obtain quantitative information on heat transfer, flow, and pressure distribution in a branched duct test section that had several significant features of an internal cooling passage of a turbine blade. The objective of this study was to generate a set of experimental data that could be used for validation of computer codes that would be used to model internal cooling. Surface heat transfer coefficients and entrance flow conditions were measured at nominal entrance Reynolds numbers of 45 000, 335 000, and 726 000. Heat transfer data were obtained by using a steady-state technique in which an Inconel heater sheet is attached to the surface and coated with liquid crystals. Visual and quantitative flow-field data from particle image velocimetry measurements for a plane at midchannel height for a Reynolds number of 45 000 were also obtained. The flow was seeded with polystyrene particles and illuminated by a laser light sheet. Pressure distribution measurements were made both on the surface with discrete holes and in the flow field with a total pressure probe. The flow-field measurements yielded flow-field velocities at selected locations. A relatively new method, pressure sensitive paint, was also used to measure surface pressure distribution. The pressure paint data obtained at Reynolds numbers of 335 000 and 726 000 compared well with the more standard method of measuring pressures by using discrete holes.