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.
Leading 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.
Numerical Simulation of a Film Cooled Turbine Blade Leading Edge Including Heat Transfer Effects
Author: Laurene D. DobrowolskiPublisher:
ISBN:
Category :
Languages : en
Pages : 436
Book Description
Computations and experiments were run to study heat transfer and overall effectiveness for a simulated turbine blade leading edge. Computational predictions were run for a film cooled leading edge model using a conjugate numerical method to predict the normalized "metal" temperatures for the model. This computational study was done in conjunction with a parallel effort to experimentally determine normalized metal temperatures, i.e. overall effectiveness, using a specially designed high conductivity model. Predictions of overall effectiveness were higher than experimentally measured values in the stagnation region, but lower along the downstream section of the leading edge. Reasons for the differences between computational predictions and experimental measurements were examined. Also of interest was the validity of Taw as the driving temperature for heat transfer into the blade, and this was examined via computations. Overall, this assumption gave reasonable results except near the stagnation line. Experiments were also conducted on a leading edge with no film cooling to gain a better understanding of the additional cooling provided by film cooling. Heat flux was also measured and external and internal heat transfer coefficients were determined. The results showed roughly constant overall effectiveness on the external surface.
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.
Unsteady High Turbulence Effects on Turbine Blade Film Cooling Heat Transfer Performance Using a Transient Liquid Crystal Technique
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781721933846
Category :
Languages : en
Pages : 228
Book Description
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
The Effects of Leading Edge and Downstream Film Cooling on Turbine Vane Heat Transfer
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781723439759
Category :
Languages : en
Pages : 178
Book Description
The progress under contract NAS3-24619 toward the goal of establishing a relevant data base for use in improving the predictive design capabilities for external heat transfer to turbine vanes, including the effect of downstream film cooling with and without leading edge showerhead film cooling. Experimental measurements were made in a two-dimensional cascade previously used to obtain vane surface heat transfer distributions on nonfilm cooled airfoils under contract NAS3-22761 and leading edge showerhead film cooled airfoils under contract NAS3-23695. The principal independent parameters (Mach number, Reynolds number, turbulence, wall-to-gas temperature ratio, coolant-to-gas temperature ratio, and coolant-to-gas pressure ratio) were maintained over ranges consistent with actual engine conditions and the test matrix was structured to provide an assessment of the independent influence of parameters of interest, namely, exit Mach number, exit Reynolds number, coolant-to-gas temperature ratio, and coolant-to-gas pressure ratio. Data provide a data base for downstream film cooled turbine vanes and extends the data bases generated in the two previous studies. The vane external heat transfer obtained indicate that considerable cooling benefits can be achieved by utilizing downstream film cooling. The data obtained and presented illustrate the interaction of the variables and should provide the airfoil designer and computational analyst the information required to improve heat transfer design capabilities for film cooled turbine airfoils. Hylton, L. D. and Nirmalan, V. and Sultanian, B. K. and Kaufman, R. M. Unspecified Center EQUIPMENT SPECIFICATIONS; FILM COOLING; HEAT TRANSFER; LEADING EDGES; STRUCTURAL DESIGN; VANES; AIRCRAFT ENGINES; CASCADE FLOW; DATA PROCESSING; GAS TURBINES; HIGH TEMPERATURE; PARAMETERIZATION; TWO DIMENSIONAL FLOW...
Gas Turbine Heat Transfer and Cooling Technology, Second Edition
Author: Je-Chin HanPublisher: CRC Press
ISBN: 1439855684
Category : Science
Languages : en
Pages : 892
Book Description
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.
Heat Transfer in Gas Turbines
Author: Bengt SundénPublisher: Witpress
ISBN:
Category : Medical
Languages : en
Pages : 544
Book Description
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.
Investigations of Flow and Film Cooling on Turbine Blade Edge Regions
Author: Huitao YangPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The inlet temperature of modern gas turbine engines has been increased to achieve higher thermal efficiency and increased output. The blade edge regions, including the blade tip, the leading edge, and the platform, are exposed to the most extreme heat loads, and therefore, must be adequately cooled to maintain safety. For the blade tip, there is tip leakage flow due to the pressure gradient across the tip. This leakage flow not only reduces the blade aerodynamic performance, but also yields a high heat load due to the thin boundary layer and high speed. Various tip configurations, such as plane tip, double side squealer tip, and single suction side squealer tip, have been studied to find which one is the best configuration to reduce the tip leakage flow and the heat load. In addition to the flow and heat transfer on the blade tip, film cooling with various arrangements, including camber line, upstream, and two row configurations, have been studied. Besides these cases of low inlet/outlet pressure ratio, low temperature, non-rotating, the high inlet/outlet pressure ratio, high temperature, and rotating cases have been investigated, since they are closer to real turbine working conditions. The leading edge of the rotor blade experiences high heat transfer because of the stagnation flow. Film cooling on the rotor leading edge in a 11/2 turbine stage has been numerically studied for the designand off-design conditions. Simulations find that the increasing rotating speed shifts the stagnation line from the pressure side, to the leading edge and the suction side, while film cooling protection moves in the reverse direction with decreasing cooling effectiveness. Film cooling brings a high unsteady intensity of the heat transfer coefficient, especially on the suction side. The unsteady intensity of film cooling effectiveness is higher than that of the heat transfer coefficient. The film cooling on the rotor platform has gained significant attention due to the usage of low-aspect ratio and low-solidity turbine designs. Film cooling and its heat transfer are strongly influenced by the secondary flow of the end-wall and the stator-rotor interaction. Numerical predictions have been performed for the film cooling on the rotating platform of a whole turbine stage. The design conditions yield a high cooling effectiveness and decrease the cooling effectiveness unsteady intensity, while the high rpm condition dramatically reduces the film cooling effectiveness. High purge flow rates provide a better cooling protection. In addition, the impact of the turbine work process on film cooling effectiveness and heat transfer coefficient has been investigated. The overall cooling effectiveness shows a higher value than the adiabatic effectiveness does.
Author: James D. Heidmann
Author: