A CFD Analysis of Turbine Blade Cooling Using Isotropic and Anisotropic Turbulence Models PDF Download
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Author: Thomas P. Abraham
Publisher:
ISBN:
Category :
Languages : en
Pages : 159
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Book Description
Author: Thomas P. Abraham
Publisher:
ISBN:
Category :
Languages : en
Pages : 159
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Book Description
Author: Chandran Sundaraj
Publisher:
ISBN:
Category : Gas-turbines
Languages : en
Pages :
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Book Description
Author: Konstantin Volkov
Publisher: BoD – Books on Demand
ISBN: 9535133497
Category : Science
Languages : en
Pages : 252
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Book Description
Accurate prediction of turbulent flows remains a challenging task despite considerable work in this area and the acceptance of CFD as a design tool. The quality of the CFD calculations of the flows in engineering applications strongly depends on the proper prediction of turbulence phenomena. Investigations of flow instability, heat transfer, skin friction, secondary flows, flow separation, and reattachment effects demand a reliable modelling and simulation of the turbulence, reliable methods, accurate programming, and robust working practices. The current scientific status of simulation of turbulent flows as well as some advances in computational techniques and practical applications of turbulence research is reviewed and considered in the book.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 602
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Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author: Chaitanya D Ghodke
Publisher: SAE International
ISBN: 0768095026
Category : Technology & Engineering
Languages : en
Pages : 238
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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.
Author: Daisy Galeana
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
The limiting factor for most gas turbines has been the turbine inlet temperature. Furthermore, higher pressure ratios and turbine inlet temperatures improve the efficiencies on the gas turbine. A big focus has been on new schemes of internal cooling designs of turbine blades, using pressurized air from the engine compressor, and break-through in blade metallurgy, in order to achieve higher turbine inlet temperatures. Significant research has been ongoing for decades to design an internal cooling system for the first stage of the turbine blade consequently higher turbine inlet temperatures can be achieved. The challenging engineering intricacies related to improving the efficiency of a gas turbine engine come with the need to maximize the efficiency of the internal cooling of the turbine blade to withstand the high turbine inlet temperature. Understanding the fluid mechanics and heat transfer of internal blade cooling is therefore of paramount importance. This dissertation presents the impact of swirl flow cooling on the heat transfer of a gas turbine blade cooling passage to understand the mechanics of internal blade cooling. The focus is the continuous cooling flow that must be maintained via nonstop injection of tangential flow, whereby swirl flow is generated. The experimental investigation is presented first with three-dimensional (3-D) Stereo-Particle Image Velocimetry (Stereo-PIV) and second Thermochromic Liquid Crystal (TLC) of a swirl flow that models a gas turbine blade internal cooling configuration. The study is intended to provide an evaluation of the developments of swirl flow cooling methodology utilizing 3-D Stereo-PIV and liquid crystals. The objective of the experimental models is to determine the critical swirl number that has the potential to deliver the maximum axial velocity results with the highest heat transfer at three different Reynolds numbers, 7,000, 14,000, and 21,000. The swirl flow cooling methodology comprises of cooling air channeling through the blade's internal passages lowering the metal temperature, therefore the experimental cylindrical chamber is made of acrylic allowing detailed measurements and includes seven discrete tangential air inlets designed to create the swirl flow. Additionally, a 3D domain fluent setup employing a steady-state pressure-based solver with a standard k-epsilon turbulence model was applied. The energy equations were activated to handle the temperature effect; the gravitational acceleration is accounted for. Important variations of the swirl number are present near the air inlets and decrease with downstream distance as predicted since the second half of the chamber has no more inlets. The axial velocity reaches the maximum downstream in the second half of the chamber. The circumferential velocity decreases downstream distance and reaches the highest towards the center of the chamber. As part of the results relatively low heat transfer rates were observed near the upstream end of the cylindrical chamber, resulting from a low momentum swirl flow as well as crossflow effects. The TLC heat transfer results exemplify how the Nusselt Number (Nu) measured favorably at the midstream of the chamber and values decline downstream. Furthermore, experimental results when compared to the Computational Fluid Dynamics analysis are compatible with each other.
Author: Gwennaël Beirnaert-Chartrel
Publisher:
ISBN:
Category :
Languages : en
Pages : 236
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Book Description
Computations were run to study heat transfer coefficient augmentation with film cooling for a simulated gas turbine blade leading edge. The realizable k-[epsilon] turbulence model (RKE) and Shear Stress Transport k-[omega] turbulence model (SST) were used for the computational simulations. RKE computations completed at a unity density ratio were confirmed to be consistent with experimental measurements conducted by Yuki et al.(1998) and Johnston et al. (1999) whereas SST computations exhibited significant discrepancies. Moreover the effect of the density ratio on heat transfer coefficient augmentation was studied because experimental measurements of heat transfer coefficient augmentation with film cooling are generally constrained to unity density ratio tests. It was shown that heat transfer coefficient augmentation can be simulated using unity density ratio jets, but only when scaled with the momentum flux ratio of the coolant jets.
Author: Sibi Mathew
Publisher:
ISBN:
Category :
Languages : en
Pages : 220
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Book Description
Computations and experiments were run to study adiabatic effectiveness and thermal field contours for a simulated turbine blade leading edge. The RKE and SST k-[omega] turbulence models were used for the computational simulations. Predictions of RKE model for laterally averaged adiabatic effectiveness matched the experimental values. The computational simulations showed different flowfield for the coolant exiting the stagnation line row of holes. Both the experiments and SST k-[omega] simulations predicted coolant separation at the stagnation plane. Also, the downstream spreading of the coolant exiting the stagnation row of exit holes was better predicted by the SST k-[omega] model. At the stagnation plane, experimental thermal field measurements showed greater diffusion of the coolant into the mainstream than predicted by both turbulence models. Reasons for increased diffusion were examined. Thermal field comparison downstream of the offstagnation row of exit holes showed that the computational simulations and the experiments had the same general shape for the offstagnation coolant jet. But the computational simulations predicted greater diffusion of coolant in the direction normal to the surface than seen in the experiments.
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 780
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Book Description
Author: Chaitanya D Ghodke
Publisher: SAE International
ISBN: 0768095026
Category : Technology & Engineering
Languages : en
Pages : 238
Get Book Here
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.
