Turbine blade

About: Turbine blade is a research topic. Over the lifetime, 26920 publications have been published within this topic receiving 292855 citations.

Nickel-Based Superalloys for Advanced Turbine Engines: Chemistry, Microstructure and Properties

Abstract: The chemical, physical, and mechanical characteristics of nickel-based superalloys are reviewed with emphasis on the use of this class of materials within turbine engines. The role of major and minor alloying additions in multicomponent commercial cast and wrought superalloys is discussed. Microstructural stability and phases observed during processing and in subsequent elevated-temperature service are summarized. Processing paths and recent advances in processing are addressed. Mechanical properties and deformation mechanisms are reviewed, including tensile properties, creep, fatigue, and cyclic crack growth. I. Introduction N ICKEL-BASED superalloys are an unusual class of metallic materials with an exceptional combination of hightemperature strength, toughness, and resistance to degradation in corrosive or oxidizing environments. These materials are widely used in aircraft and power-generation turbines, rocket engines, and other challenging environments, including nuclear power and chemical processing plants. Intensive alloy and process development activities during the past few decades have resulted in alloys that can tolerate average temperatures of 1050 ◦ C with occasional excursions (or local hot spots near airfoil tips) to temperatures as high as 1200 ◦ C, 1 which is approximately 90% of the melting point of the material. The underlying aspects of microstructure and composition that result in these exceptional properties are briefly reviewed here. Major classes of superalloys that are utilized in gas-turbine engines and the corresponding processes for their production are outlined along with characteristic mechanical and physical properties.

Gas Turbine Heat Transfer and Cooling Technology

Abstract: Fundamentals Need for Turbine Blade Cooling Turbine-Cooling Technology Turbine Heat Transfer and Cooling Issues Structure of the Book Review Articles and Book Chapters on Turbine Cooling and Heat Transfer New Information from 2000 to 2010 References Turbine Heat Transfer Introduction Turbine-Stage Heat Transfer Cascade Vane Heat-Transfer Experiments Cascade Blade Heat Transfer Airfoil Endwall Heat Transfer Turbine Rotor Blade Tip Heat Transfer Leading-Edge Region Heat Transfer Flat-Surface Heat Transfer New Information from 2000 to 2010 2.10 Closure References Turbine Film Cooling Introduction Film Cooling on Rotating Turbine Blades Film Cooling on Cascade Vane Simulations Film Cooling on Cascade Blade Simulations Film Cooling on Airfoil Endwalls Turbine Blade Tip Film Cooling Leading-Edge Region Film Cooling Flat-Surface Film Cooling Discharge Coefficients of Turbine Cooling Holes 3.10 Film-Cooling Effects on Aerodynamic Losses 3.11 New Information from 2000 to 2010 3.12 Closure References Turbine Internal Cooling Jet Impingement Cooling Rib-Turbulated Cooling Pin-Fin Cooling Compound and New Cooling Techniques New Information from 2000 to 2010 References Turbine Internal Cooling with Rotation Rotational Effects on Cooling Smooth-Wall Coolant Passage Heat Transfer in a Rib-Turbulated Rotating CoolantPassage Effect of Channel Orientation with Respect to the RotationDirection on Both Smooth and Ribbed Channels Effect of Channel Cross Section on Rotating Heat Transfer Different Proposed Correlation to Relate the Heat Transferwith Rotational Effects Heat-Mass-Transfer Analogy and Detail Measurements Rotation Effects on Smooth-Wall Impingement Cooling Rotational Effects on Rib-Turbulated Wall ImpingementCooling New Information from 2000 to 2010 References Experimental Methods Introduction Heat-Transfer Measurement Techniques Mass-Transfer Analogy Techniques Liquid Crystal Thermography Flow and Thermal Field Measurement Techniques New Information from 2000 to 2010 Closure References Numerical Modeling Governing Equations and Turbulence Models Numerical Prediction of Turbine Heat Transfer Numerical Prediction of Turbine Film Cooling Numerical Prediction of Turbine Internal Cooling New Information from 2000 to 2010 References Final Remarks Turbine Heat Transfer and Film Cooling Turbine Internal Cooling with Rotation Turbine Edge Heat Transfer and Cooling New Information from 2000 to 2010 Closure Index

Wind turbines emulating inertia and supporting primary frequency control

Abstract: The increasing penetration of variable-speed wind turbines in the electricity grid will result in a reduction of the number of connected conventional power plants. This will require changes in the way the grid frequency is controlled. In this letter, a method is proposed to let variable-speed wind turbines emulate inertia and support primary frequency control. The required power is obtained from the kinetic energy stored in the rotating mass of the turbine blades.

A review of shaped hole turbine film-cooling technology

Abstract: Film cooling represents one of the few game-changing technologies that has allowed the achievement of today's high firing temperature, high-efficiency gas turbine engines. Over the last 30 years, only one major advancement has been realized in this technology, that being the incorporation of exit shaping to the film holes to result in lower momentum coolant injection jets with greater surface coverage. This review examines the origins of shaped film cooling and summarizes the extant literature knowledge concerning the performance of such film holes. A catalog of the current literature data is presented, showing the basic shaping geometries, parameter ranges, and types of data obtained. Specific discussions are provided for the flow field and aerodynamic losses of shaped film hole coolant injection. The major fundamental effects due to coolant-to-gas blowing ratio, compound angle injection, cooling hole entry flow character, and mainstream turbulence intensity are each reviewed with respect to the resulting adiabatic film effectiveness and heat transfer coefficients for shaped holes. A specific example of shaped film effectiveness is provided for a production turbine inlet vane with comparison to other data. Several recent unconventional forms of film hole shaping are also presented as a look to future potential improvements

Current status of thermal barrier coatings — An overview

Abstract: The science and technology of thermal barrier coatings has advanced considerably since reports of the first test on turbine blades in a research engine in 1976. Today thermal barrier coatings are flying in revenue service in a low risk location within the turbine section of certain gas turbine engines. The state-of-the-art coating system for gas turbine applications is currently a plasma-sprayed ZrO 2 -(6%–8%) Y 2 O 3 ceramic layer over an MCrAlY (M ≡ Ni, Co or NiCo) bond coat layer plasma sprayed at low pressure. Although the potential for meeting current and short-term goals is high, longer-range goals may not be attainable with current coating concepts. These longer-range goals will involve high risk designs where coating loss could lead directly to component loss. Several steps must be taken to help meet these goals. Improved understanding of coating failure mechanisms is required. Models are needed to predict lifetimes. Process automation and quality control procedures must be instituted. Finally, new concepts in plasma-sprayed coatings must be developed and alternatives to the plasma- spraying process may be required. The current status of thermal barrier coatings and prospects for future progress in the above areas are summarized.