Author: United States. National Aeronautics and Space AdministrationPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
EFFECT OF VELOCITY AND TEMPERATURE DISTRIBUTION AT THE HOLE EXIT ON FILM COOLING OF TURBINE BLADES... NASA/TM-97-208146... AUG. 6, 1998
Author: United States. National Aeronautics and Space AdministrationPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Effect of Velocity and Temperature Distribution at the Hole Exit on Film Cooling of Turbine Blades
Author: Vijay K. GargPublisher:
ISBN:
Category :
Languages : en
Pages : 18
Book Description
Presented at the International Gas Turbine and Aeroengine Congress & Exposition, Houston, Texas - June 5-8, 1995.
Effect of Film-Hole Shape on Turbine Blade Film Cooling Performance
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781720482284
Category :
Languages : en
Pages : 64
Book Description
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
Survey of Advantages and Problems Associated with Transpiration Cooling and Film Cooling of Gas-turbine Blades
Author: Ernst Rudolf Georg EckertPublisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 44
Book Description
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.
An Experimental Study of the Effect of Wake Passing on Turbine Blade Film Cooling
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781725097346
Category :
Languages : en
Pages : 28
Book Description
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...
Gas Turbine Blade Cooling
Author: Chaitanya D GhodkePublisher: SAE International
ISBN: 0768095026
Category : Technology & Engineering
Languages : en
Pages : 238
Book Description
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.
Effect of Film-Hole Shape on Turbine Blade Film Cooling Performance
Author: The Effect of Wake Passing on Turbine Blade Film Cooling
Author: James D. HeidmannPublisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 272
Book Description
A Numerical Study of the Effect of Wake Passing on Turbine Blade Film Cooling
Author: James D. HeidmannLeading Edge Film Cooling Effects on Turbine Blade Heat Transfer
Author: Vijay K. GargPublisher:
ISBN:
Category :
Languages : en
Pages : 26
Book Description
Presented at the International Gas Turbine and Aeroengine Congress and Exposition, Houston, Texas - June 5-8, 1995.