› › Experimental And Computational Investigation Of Inlet Temperature Profile And Cooling Effects On A One And One Half Stage High Pressure Turbine Operating At Design Corrected Conditions

Experimental and Computational Investigation of Inlet Temperature Profile and Cooling Effects on a One and One-half Stage High-pressure Turbine Operating at Design-corrected Conditions

Author : Randall Melson Mathison

Publisher :

Page : 370 pages

File Size : 12,71 MB

Release : 2009

Category : Gas-turbines

ISBN :

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Book Description

Abstract: As the demand for greater efficiency and reduced specific fuel consumption from gas turbine engines continues to increase, design tools must be improved to better handle complicated flow features such as vane inlet temperature distortions, film cooling, and disk purge flow. In order to understand the physics behind these features, a new generation of turbine experiments is needed to investigate these features of interest for a realistic environment. This dissertation presents for the first time measurements and analysis of the flow features of a high-pressure one and one-half stage turbine operating at design corrected conditions with vane and purge cooling as well as vane inlet temperature profile variation. It utilizes variation of cooling flow rates from independent circuits through the same geometry to identify the regions of cooling influence on the downstream blade row. The vane outer cooling circuit, which supplies the film cooling on the outer endwall of the vane and the trailing edge injection from the vane, has the largest influence on temperature and heat-flux levels for the uncooled blade. Purge cooling has a more localized effect, but it does reduce the Stanton Number deduced for the blade platform and on the pressure and suction surfaces of the blade airfoil. Flow from the vane inner cooling circuit is distributed through film cooling holes across the vane airfoil surface and inner endwall, and its injection is entirely designed with vane cooling in mind. As such, it only has a small influence on the temperature and heat-flux observed for the downstream blade row. In effect, the combined influence of these three cooling circuits can be observed for every instrumented surface of the blade. The influence of cooling on the pressure surface of the uncooled blade is much smaller than on the suction surface, but a local area of influence can be observed near the platform. This is also the first experimental program to investigate the influence of vane inlet temperature profile on a cooled turbine operating at design corrected conditions. The vane inlet temperature profile has a substantial effect on the temperature measured at the blade leading edge and the Stanton Numbers deduced for the uncooled blade airfoil. While the temperature profile is slightly reshaped passing through the vane, a radial or hot streak profile introduced at the vane inlet can still be clearly measured at the blade. Hot streak magnitude and alignment also influence the blade temperature and heat-flux measurements. A concurrent effort to predict the blade leading edge and platform temperatures for the uncooled portions of this experiment using the commercial code FINE/Turbo is also presented. This investigation is not intended as a detailed computational study but as a check of current code implementation practices and a sanity check on the data. The best predictions are generated using isothermal wall boundary conditions with the nonlinear harmonic method. This is a novel prediction type that could only be performed using a development version of FINE/Turbo.





Turbine Aerodynamics

Author : Ronald H. Aungier

Publisher : American Society of Mechanical Engineers

Page : 424 pages

File Size : 16,35 MB

Release : 2006

Category : Technology & Engineering

ISBN :

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Book Description

This book provides a thorough description of actual, working aerodynamic design and analysis systems, for both axial-flow and radial-flow turbines. It describes the basic fluid dynamic and thermodynamic principles, empirical models and numerical methods used for the full range of procedures and analytical tools that an engineer needs for virtually any type of aerodynamic design or analysis activity for both types of turbine. The book includes sufficient detail for readers to implement all or part of the systems. The author provides practical and effective design strategies for applying both turbine types, which are illustrated by design examples. Comparisons with experimental results are included to demonstrate the prediction accuracy to be expected. This book is intended for practicing engineers concerned with the design and development of turbines and related machinery.



The Influence of Film Cooling and Inlet Temperature Profile on Heat Transfer for the Vane Row of a 1-1/2 Stage Transonic High-pressure Turbine

Author : Harika Senem Kahveci

Publisher :

Page : 269 pages

File Size : 11,48 MB

Release : 2010

Category :

ISBN :

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Abstract: The goal of this research was to establish an extensive database for typical engine hardware with a film-cooled first stage vane, which represents the foundation for future turbomachinery film cooling modeling and component heat transfer studies. Until this time, such a database was not available within the gas turbine industry. Accordingly, the study focuses on determination of the local heat flux for the airfoil and endwall surfaces of the vane row of a fully-cooled turbine stage. The measurements were performed at the Ohio State University Gas Turbine Laboratory using the Turbine Test Facility. The full-scale rotating 1 and 1/2 turbine stage is operated at the proper corrected engine design conditions: Flow Function (FF), corrected speed, stage Pressure Ratio (PR), and temperature ratios of gas to wall and gas to coolant. The primary measurements of temperature, pressure, and heat flux are repeated for different vane inlet temperature profiles and different vane cooling flows to establish an understanding of the influence of film cooling on local heat transfer. Double-sided Kapton heat-flux gauges are used for heat-flux measurements at different span locations along the airfoil surfaces and along the inner endwall. The cooling scheme consists of numerous cooling holes located on the endwalls, at the airfoil leading edge, on the airfoil pressure and suction surfaces, and at the trailing edge, resulting in a fully cooled first stage vane. The unique film-cooled endwall heat transfer data demonstrated in contour plots reveals insight to the complex flow behavior that is dominant in this region, which becomes even more complicated with the addition of coolant. Varying profile shapes resulted in significant heat transfer variations in a growing fashion towards the trailing edge region, which increased in magnitude when there is no coolant supply. The largest cooling effect is observed on 5% span pressure surface and at the inner endwall region. Heat transfer decreases from tip towards hub with addition of cooling. However, a similar decrease is not observed at the inner endwall region by doing so, which suggests excess coolant once beyond an optimum blowing ratio. Cooling flow rate and temperature profile shape affect the distributions on the airfoil surface very similarly, the latter observed more clearly at the endwall region. The vane outer cooling effect is comparable to the combined coolant effect at all surfaces, while no impact of purge flow is observed. Aligning the hot streaks with the vane leading edge lowered heat transfer compared to mid-passage alignment at the mid-span suction surface and through the endwall passage, and increased it at the endwall exit, while the pressure surface is found to be insensitive to this switch. Comparison with a previous research program with the un-cooled version of the vane gave good agreement on the pressure surface and at the endwall, but significantly lower heat transfer on the suction surface due to ingestion of the hot flow through the cooling holes when there is no cooling.



Unsteady Characterization of Film Cooling Flows on a Rotating High-pressure Turbine

Author : Spencer J. Sperling

Publisher :

Page : 0 pages

File Size : 14,6 MB

Release : 2021

Category : Aerodynamics

ISBN :

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Book Description

Gas turbine performance is highly dependent on turbine inlet temperature, which often exceeds the working limitations of the materials involved. Film cooling is a widely used technology enabling highly efficient gas turbine cycles, where relatively cold air is injected as a film on the airfoil surfaces protecting the airfoils from the hot combustion gasses. Film cooled turbines exist in highly unsteady environments due to interactions between stationary and rotating components, and film cooling further complicates the flow. There is limited understanding of the unsteady nature of film cooling flows, resulting in limited ability to predict heat transfer and metal temperature on the components of a gas turbine. The goal of this work is to increase understanding of turbine cooling technology by examining time-accurate and time-averaged behaviors of the cooling flows. This dissertation incorporates experimental and computational analysis of pressure and heat transfer on an industry scale high-pressure turbine stage. Experimental measurements of pressure and heat transfer were performed on a turbine stage installed in the Turbine Test Facility at the Gas Turbine Laboratory. This facility is uniquely equipped to examine unsteady pressure and heat transfer on turbine stages operating at design corrected conditions. Heat transfer measurements are compared for multiple different cooling configurations on the rotating airfoils. Data are analyzed on time-averaged and time-resolved bases, and the results highlight cooling benefit differences among the various cooling hole shapes and coolant flow rates. Computational models of the turbine stage are also employed with steady and unsteady RANS modeling techniques. Experimental data are used for boundary conditions in the computational models as well as to evaluate the accuracy of the models. Comparisons of experimental and steady computations of film cooled turbines often result in poor agreement due to the complexity of film cooling flows.





Gas Turbine Heat Transfer and Cooling Technology, Second Edition

Author : Je-Chin Han

Publisher : CRC Press

Page : 892 pages

File Size : 18,26 MB

Release : 2012-11-27

Category : Science

ISBN : 1439855684

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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.



Effects of Film Cooling on Turbine Blade Tip Flow Structures and Thermal Loading

Author : Louis Edward Christensen

Publisher :

Page : 0 pages

File Size : 44,91 MB

Release : 2022

Category : Aerospace engineering

ISBN :

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Book Description

Gas turbine engines are an essential technology in aviation and power generation. One of the challenges associated with increasing the efficiency of gas turbines is the thermal loading experienced by the engine components downstream of the combustors especially the high-pressure turbine blades. High temperatures and rotational velocities can cause blade failures in numerous ways such as creep or stress rupture. Technologies like film cooling are implemented in these components to lower the thermal loading and reduce the risk of failure. However, these introduce complexities into the flow which in turn increases the difficulty of predicting the performance of film cooled turbines. Accurately predicting the capabilities of these components is essential to prevent failure in gas turbine engines. Engineers use a combination of experiments and computational simulations to understand how these technologies perform and predict the operating conditions and lifespan of these components. A combined experimental and numerical program is performed on a single stage high-pressure turbine to increase understanding of film cooling in gas turbines and improve computational methods used to predict their performance. The turbine studied is a contemporary production model from Honeywell Aerospace with both cooled and uncooled turbine blades. The experimental work is performed at The Ohio State University Gas Turbine Laboratory Turbine Test Facility, a short duration facility operating at engine corrected conditions. The experiments capture heat flux, temperature, and pressure data across the entire blade, but this work will focus on the turbine blade tip data. Tip temperature data are captured using a high-speed infrared camera providing a unique data set unseen in the current literature. In addition to the experiments, transient conjugate heat transfer simulations of a single turbine passage are performed to recreate the experiments and give insight into the flow field in the tip region of the turbine blades. The experiments and simulations are conducted to provide a better understanding of the interactions of the film cooling and tip flows along with their relationship to the thermal loading on the turbine blade tip. Film cooling in the tip region adds complexity to the flow and a non-intuitive relationship exists between film cooling and thermal loading. Addition of cooling is not guaranteed to reduce the thermal loading on the blade tips. Cooling jets can displace hot gases protecting the blade, but they are also capable of shifting flow structures and trapping hot gases near the blade surface especially so in corners of the blade tips. These direct and indirect methods of altering the thermal loading open a new path to optimization where engineers consider how the coolant alters the flow in addition to forming a protective layer of cool gas. This can be done to more effectively use coolant not only in the blade tips but elsewhere on the turbine blades leading to higher engine efficiencies and more sustainable gas turbine engines.





Experimentation, Validation, and Uncertainty Analysis for Engineers

Author : Hugh W. Coleman

Publisher : John Wiley & Sons

Page : 404 pages

File Size : 25,13 MB

Release : 2018-04-09

Category : Technology & Engineering

ISBN : 1119417708

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Book Description

Helps engineers and scientists assess and manage uncertainty at all stages of experimentation and validation of simulations Fully updated from its previous edition, Experimentation, Validation, and Uncertainty Analysis for Engineers, Fourth Edition includes expanded coverage and new examples of applying the Monte Carlo Method (MCM) in performing uncertainty analyses. Presenting the current, internationally accepted methodology from ISO, ANSI, and ASME standards for propagating uncertainties using both the MCM and the Taylor Series Method (TSM), it provides a logical approach to experimentation and validation through the application of uncertainty analysis in the planning, design, construction, debugging, execution, data analysis, and reporting phases of experimental and validation programs. It also illustrates how to use a spreadsheet approach to apply the MCM and the TSM, based on the authors’ experience in applying uncertainty analysis in complex, large-scale testing of real engineering systems. Experimentation, Validation, and Uncertainty Analysis for Engineers, Fourth Edition includes examples throughout, contains end of chapter problems, and is accompanied by the authors’ website www.uncertainty-analysis.com. Guides readers through all aspects of experimentation, validation, and uncertainty analysis Emphasizes the use of the Monte Carlo Method in performing uncertainty analysis Includes complete new examples throughout Features workable problems at the end of chapters Experimentation, Validation, and Uncertainty Analysis for Engineers, Fourth Edition is an ideal text and guide for researchers, engineers, and graduate and senior undergraduate students in engineering and science disciplines. Knowledge of the material in this Fourth Edition is a must for those involved in executing or managing experimental programs or validating models and simulations.