Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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This study is an investigation of the film cooling effectiveness and heat transfer coefficient of a two-dimensional turbine rotor blade in a linear transonic cascade. Experiments were performed in Virginia Tech's Cascade Wind Tunnel with an exit Mach number of 1.2 and an exit Reynolds number of 5 x 10 (exp 6) to simulate real engine flow conditions. The freestream and coolant flows were maintained at a total temperature ratio of 2 +0.4 and a total pressure ration of 1.04. The freestream turbulence was approximately 1%. There are six rows of staggered, discrete cooling holes on and near the leading edge of the blade in a showerhead configuration. Cooled air was used as the coolant. Experiments were performed with and without film cooling on the surface of the blade. The heat transfer coefficient was found to increase with the addition of film cooling an average of 14% overall and to a maximum of 26% at the first gauge location. The average film cooling effectiveness that suggest either a transition from a laminar to a turbulent film regime or the regime or the existence of three-dimensionality in the flow-field over the gauges.
Author: H. O. Demuren
Publisher:
ISBN:
Category :
Languages : en
Pages : 139
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Book Description
The goal of these studies has been to gather the necessary heat transfer data and develop the design procedure for high performance, film cooled, highly loaded transonic turbine stages. In the pursuit of this goal, three key tasks were accomplished: the measurement of heat transfer rates and film effectiveness in the low supersonic range, a study of the flow at the trailing edge of transonic turbine blades and the heat transfer at this critical part of the blade, and a determination of an optimum profile for a turbine stage providing high work per unit of cooled blade surface.
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781721189052
Category :
Languages : en
Pages : 26
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A computational study has been performed to predict the distribution of convective heat transfer coefficient on a simulated blade tip with cooling holes. The purpose of the examination was to assess the ability of a three-dimensional Reynolds-averaged Navier-Stokes solver to predict the rate of tip heat transfer and the distribution of cooling effectiveness. To this end, the simulation of tip clearance flow with blowing of Kim and Metzger was used. The agreement of the computed effectiveness with the data was quite good. The agreement with the heat transfer coefficient was not as good but improved away from the cooling holes. Numerical flow visualization showed that the uniformity of wetting of the surface by the film cooling jet is helped by the reverse flow due to edge separation of the main flow. Ameri, A. A. and Rigby, D. L. Glenn Research Center NASA/CR-1999-209165, NAS 1.26:209165, E-11756
Author: Ali A. Ameri
Publisher:
ISBN:
Category :
Languages : en
Pages : 14
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Author: Louis M. Russell
Publisher:
ISBN:
Category : Flow visualization
Languages : en
Pages : 30
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Book Description
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.
Author: Ernst Rudolf Georg Eckert
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 44
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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.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 24
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Author: Cengiz Camci
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 0
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Book Description
This study investigates the influence of incidence on convective heat transfer to highly curved surfaces of a film-cooled turbine rotor blade. A computational study of free-stream inviscid aerodynamics without cooling at various incidences is followed by well-documented measured heat transfer data sets. The heat transfer experiments are discussed for cases with and without film cooling, performed under realistic gas turbine flow conditions in the short-duration heat transfer facility of the von Karman Institute for Fluid Dynamics. The precise location of the stagnation point and the iso-Mach number contours in the passage for each incidence (−10, 0, 10, +15 deg) are presented for a nominal exit Mach number of 0.94. The free-stream mass flow rate was kept constant for each experiment at different incidence levels. Three rows of compound angled discrete cooling holes are located near the leading edge in a showerhead configuration. Two rows of staggered discrete cooling holes are located on the suction side and a single row of cooling holes is located on the pressure side. The short-duration measurements of quantitative wall heat fluxes on nearly isothermal blade surfaces both in the presence and absence of coolant ejection are presented. The study indicated that the change of the position of the stagnation point strongly altered the aerodynamic behavior and convective heat transfer to the blade in approximately the first 30 percent of both the pressure side and the suction side in the presence and absence of film cooling. The immediate vicinity of the stagnation point was not significantly affected by changing incidence without cooling. Transitional behavior both on the suction surface and on the pressure surface was significantly influenced by the changes in approaching flow direction. Flow separation associated with incidence variations was also observed. Extremely low levels of the convective heat transfer coefficients were experienced near the regions where small separation bubbles are located.
Author: M. J. Rigby
Publisher:
ISBN:
Category : Turbines
Languages : en
Pages : 252
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Book Description
Author: Bengt Sundén
Publisher: Witpress
ISBN:
Category : Medical
Languages : en
Pages : 544
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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.
