Showing papers on "Turbine blade published in 2006"
TL;DR: 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 as mentioned in this paper, and the role of major and minor alloying additions in multicomponent commercial cast and wrought super-alloys is discussed.
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.
1,826 citations
TL;DR: In this article, a method is proposed to let variable-speed wind turbines emulate inertia and support primary frequency control, where the required power is obtained from the kinetic energy stored in the rotating mass of the turbine blades.
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.
1,106 citations
TL;DR: A review of the literature on the effects of freestream turbulence, surface curvature, and hole shape on the performance of film cooling is presented in this article. But, it is difficult to predict film cooling performance because of the inherent complex flowfields along the airfoil component surfaces in turbine engines.
Abstract: The durability of gas turbine engines is strongly dependent on the component temperatures. For the combustor and turbine airfoils and endwalls, film cooling is used extensively to reduce component temperatures. Film cooling is a cooling method used in virtually all of today's aircraft turbine engines and in many power-generation turbine engines and yet has very difficult phenomena to predict. The interaction of jets-in-crossflow, which is representative of film cooling, results in a shear layer that leads to mixing and a decay in the cooling performance along a surface. This interaction is highly dependent on the jet-to-crossflow mass and momentum flux ratios. Film-cooling performance is difficult to predict because of the inherent complex flowfields along the airfoil component surfaces in turbine engines. Film cooling is applied to nearly all of the external surfaces associated with the airfoils that are exposed to the hot combustion gasses such as the leading edges, main bodies, blade tips, and endwalls. In a review of the literature, it was found that there are strong effects of freestream turbulence, surface curvature, and hole shape on the performance of film cooling. Film cooling is reviewed through a discussion of the analyses methodologies, a physical description, and the various influences on film-cooling performance.
636 citations
TL;DR: In this paper, a linear cascade was used to study the flow field over a generic LPT cascade consisting of Pratt and Whitney Pak B shaped blades, and the center blade in the cascade was instrumented to measure the surface-pressure coefficient distribution.
Abstract: This work involves the documentation and control of flow separation that occurs over turbine blades in the low-pressure-turbine (LPT) stage at the low Reynolds numbers typical of high-altitude cruise. We utilize a specially constructed linear cascade that is designed to study the flowfield over a generic LPT cascade consisting of Pratt and Whitney Pak B shaped blades. The center blade in the cascade is instrumented to measure the surface-pressure coefficient distribution. Optical access allows laser-Doppler-velocimetry measurements for boundary-layer profiles. Experimental conditions were chosen to give a range of chord Reynolds numbers from 10 4 to 10 5 , and a range of freestream turbulence levels from u'/U∞ = 0.08 to 2.85%. The surface-pressure measurements were used to define a region of separation and reattachment that depends on the freestream conditions
386 citations
TL;DR: In this paper, a full-scale 34m composite wind turbine blade was tested to failure under flap-wise loading and local displacement measurement equipment was developed and displacements were recorded throughout the loading history.
234 citations
TL;DR: In this paper, the lifetime prediction of a horizontal axis wind turbine composite blade is considered and load cases are identified, calculated and evaluated using a full 3D finite element method and the critical zone where fatigue failure begins is extracted.
200 citations
01 Sep 2006
TL;DR: The state of the art in condition monitoring in wind turbines, and related technologies currently applied in practice and under development for aerospace applications, are reviewed in this paper, where the authors evaluate the applicability of load history and fatigue crack growth in aircraft structures for their applicability to wind turbine blades.
Abstract: The state of the art in condition monitoring in wind turbines, and related technologies currently applied in practice and under development for aerospace applications, are reviewed. Condition monitoring systems estimate the current condition of a machine from sensor measurements, whereas prognosis systems give a probabilistic forecast of the future condition of the machine under the projected usage conditions. Current condition monitoring practice in wind turbine rotors involves tracking rotor imbalance, aerodynamic asymmetry, surface roughness and overall performance and offline and online measurements of stress and strain. Related technologies for monitoring of load history and fatigue crack growth in aircraft structures are evaluated for their applicability to wind turbine blades. Similarly, condition monitoring practice in wind turbines is compared with monitoring and prognosis in helicopter gearboxes. The state of the art in condition monitoring of electronic controls, power electronics and t...
198 citations
TL;DR: In this paper, the authors used single dielectric barrier plasma actuators for flow separation on turbine blades in the low-pressure turbine stage at low Reynolds numbers typical of high-altitude cruise.
Abstract: This is a continuation of our work on the use of single dielectric barrier plasma actuators for controlling flow separation on turbine blades in the low-pressure turbine stage at low Reynolds numbers typical of high-altitude cruise. This used a linear cascade of Pratt & Whitney "PakB" shaped blades to provide generic low-pressure turbine conditions. The flow over one of the blades was documented through surface pressure, laser-Doppler velocimetry, and hot-wire measurements. These were used to define the location and size of the separated flow region on the suction side of the blade. Both steady and unsteady plasma actuators were implemented and found to be effective in separation control. For the unsteady actuators, there was an optimum excitation frequency to reattach the flow that corresponded to a Strouhal number, based on the length of the separated zone and the local freestream velocity, equal to unity. The unsteady actuator was more effective than the steady actuator in reattaching the flow while also requiring less power. It was suggested by the experimental results that the mechanism for the steady actuators was turbulence tripping, whereas the mechanism for the unsteady actuators was to generate a train of spanwise structures that promoted mixing.
186 citations
TL;DR: Characteristics of the different flow regions for submerged jets ‐ free jet, stagnation flow, and wall jet ‐ are reviewed and heat transfer characteristics of both single and multiple jets are discussed with consideration of important parameters relevant to gas turbine systems.
Abstract: A review of jet-impingement heat transfer in gas turbine systems is presented. Characteristics of the different flow regions for submerged jets--free jet, stagnation flow, and wall jet--are reviewed. Heat transfer characteristics of both single and multiple jets are discussed with consideration of the effects of important parameters relevant to gas turbine systems including curvature of surfaces, crossflow, angle of impact, and rotation.
180 citations
TL;DR: A review of ice sensor technology and the challenges for icing detection for wind turbines was performed in this article, where a total of 29 different methods for detection of icing were found, and these were then compared with a list of some basic requirements for an icing sensor for wind turbine applications.
166 citations
TL;DR: In this paper, a model of BC oxidation was developed based on Wagner's theory, which predicts a parabolic law for the growth of TGO scale, and the analysis of stress distribution in the system was performed.
TL;DR: An overview of the science and technology involved in today's turbine engines is presented with specific focus on the critical rotational-to-stationary interfaces comprising axial turbine blade tips as discussed by the authors.
Abstract: An overview of the science and technology involved in today's turbine engines is presented with specific focus on the critical rotational-to-stationary interfaces comprising axial turbine blade tips. The purpose is to provide a concise informative review of turbine blade tip functional, design, and durability issues. Neither a historical account nor a bibliography is presented. Attention is paid primarily to the most challenging blade tips in high-pressure, high-temperature gas turbine systems, although most of the science discussed applies equally well to blade tips in low-pressure turbines, as well as steam turbines. As such, a wide range of both aircraft engine and power generating turbine systems are considered. Basic functional requirements, turbine systems design aspects, and transient operational considerations affecting blade tips and affected by blade tips are discussed in light of the multidisciplinary tradeoffs involved in a successful design. The three dominant design philosophies for blade tips in practice today are presented with detailed examination of the aerodynamics, heat transfer, and cooling benefits and detractors. Finally, the in-service durability aspects of turbine blade tips are noted.
TL;DR: A review of the publicly available knowledge base concerning turbine blade tip heat transfer, from the early fundamental research which laid the foundations of knowledge, to current experimental and numerical studies utilizing engine‐scaled blade cascades and turbine rigs.
Abstract: This paper presents a review of the publicly available knowledge base concerning turbine blade tip heat transfer, from the early fundamental research which laid the foundations of our knowledge, to current experimental and numerical studies utilizing engine-scaled blade cascades and turbine rigs. Focus is placed on high-pressure, high-temperature axial-turbine blade tips, which are prevalent in the majority of today's aircraft engines and power generating turbines. The state of our current understanding of turbine blade tip heat transfer is in the transitional phase between fundamentals supported by engine-based experience, and the ability to a priori correctly predict and efficiently design blade tips for engine service.
TL;DR: In this article, the authors highlight some fatigue and lifetime aspects on wind turbine rotor blades made of composite materials, including an historical part in connection with glider technology, the presentation of relevant S-N curves not only for the 0°-orientated fibres representing the spar cap but also for ±45°-layups in shear web and shell, the influence of fibre content and architecture, of environmental effects, a view on lifetime prediction on structural elements as well as on present and future work.
09 Jan 2006
TL;DR: In this article, the results of 3D and time-accurate Computational Fluid Dynamics (CFD) simulations of the flow field around the National Renewable Energy Laboratory (NREL) Phase VI horizontal axis wind turbine rotor are presented.
Abstract: This paper presents the results of three-dimensional and time-accurate Computational Fluid Dynamics (CFD) simulations of the flow field around the National Renewable Energy Laboratory (NREL) Phase VI horizontal axis wind turbine rotor. The 3-D, unsteady, parallel, finite volume flow solver, PUMA2, is used for the simulations. The solutions are obtained using unstructured moving grids rotating with the turbine blades. Three different flow cases with different wind speeds and wind yaw angles are investigated: 7 m/s with 0◦ yaw (pre-stall case I), 7 m/s with 30◦ yaw (prestall, yawed case II), and 15 m/s with 0◦ yaw (post-stall case III). Results from the inviscid simulations for these three cases and comparisons with the experimental data are presented. Some information on the current work in progress towards Large Eddy Simulations (LES), including details about the viscous grid and the implementation of wall-functions, are also discussed. The inviscid results show that the flow is attached for cases I and II, with the latter having an asymmetrical wake structure, whereas there is massive separation over the entire blade span in case III. There are considerable spanwise pressure variations in addition to the chordwise variations, in all three cases. Comparisons of sectional pressure coefficient distributions with experimental data show good agreement. These threedimensional and time-accurate CFD results can be used for the far-field noise predictions based on the Ffowcs Williams Hawkings method (FWH), which can provide a first-principles prediction of both the noise and the underlying turbulent flow that generates the noise, in the context of the wind turbine application.
TL;DR: In this article, the authors present the design of individual pitch control systems for implementation on the Controls Advanced Research Turbine (CART) in Colorado to verify controller performance for load attenuation.
Abstract: Pitching the individual blades of a horizontal-axis wind turbine allows control of asymmetric aerodynamic loads, which in turn influences structural loads in the nonrotating frame such as tower side-side bending. These loads are not easily controlled by traditional collective pitch algorithms. This paper presents the design of individual pitch control systems for implementation on the Controls Advanced Research Turbine (CART) in Colorado to verify controller performance for load attenuation. The control designs are based on linear time-periodic state-space models of the turbine and use optimal control methods for gain calculation. Comparisons are made between new individual pitch, new collective pitch, and baseline controller performance in both above rated and below rated wind conditions. Results from simulations show the potential of individual pitch to reduce tower side-side fatigue damage in above rated wind speeds (by 70% compared to baseline control) but with no improvement over collective pitch in below rated wind speeds. Fatigue load reductions in tower fore-aft, shaft torsion, and blade flap are also observed. From 13h of field testing, both collective and individual pitch controllers achieve a reduction in fatigue damage. However, the superior performance of individual pitch control observed in simulation was not verified by the field test results.
TL;DR: In this article, an improved design of a recessed blade tip for a highly loaded axial turbine rotor blade with application in high pressure axial turbines in aero engine or power generation is presented.
Abstract: In axial turbine the tip clearance flow occurring in rotor blade rows is responsible for about one third of the aerodynamic losses in the blade row and in many cases is the limiting factor for the blade lifetime. The tip leakage vortex forms when the leaking fluid crosses the gap between the rotor blade tip and the casing from pressure to suction side and rolls up into a vortex on the blade suction side. The flow through the tip gap is both of high velocity and high temperature, with the heat transfer to the blade from the hot fluid being very high in the blade tip area. In order to avoid blade tip burnout and a failure of the machine, blade tip cooling is commonly used. This paper presents the physical study and an improved design of a recessed blade tip for a highly loaded axial turbine rotor blade with application in high pressure axial turbines in aero engine or power generation. With use of three-dimensional Computational Fluid Dynamics (CFD), the flow field near the tip of the blade for different shapes of the recess cavities is investigated. Through better understanding and control of cavity vortical structures, an improved design is presented and the differences to the generic flat tip blade are highlighted. It is observed that by an appropriate profiling of the recess shape, the total tip heat transfer Nusselt Number was significantly reduced, being 15% lower than the flat tip and 7% lower than the baseline recess shape. Experimental results also showed an overall improvement of 0.2% in the one-and-1/2-stage turbine total efficiency with the improved recess design compared to the flat tip case. The CFD analysis conducted on single rotor row configurations predicted a 0.38% total efficiency increase for the rotor equipped with the new recess design compared to the flat tip rotor.Copyright © 2006 by ASME
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09 Jun 2006TL;DR: In this paper, a wind turbine blade is characterized as having at least one joint area of the turbulence generating strips and a surface of the blade is completely or partially covered by sealing means.
Abstract: The invention relates to a wind turbine blade comprising one or more turbulence generating strips, where the strips are placed on a surface of the blade. The blade is characterized in that at least one joint area of the turbulence generating strips and the surface of the blade are completely or partially covered by sealing means. The invention further relates to a pitch controlled wind turbine comprising at least two pitch controlled wind turbine blades and pitch controlling means for pitching the blades. The pitch controlled wind turbine is characterized in that the blades comprises one or more turbulence generating strips, wherein at least one joint area of the turbulence generating strips and a surface of the blades are completely or partially covered by sealing means.
TL;DR: The most important contributions on turbine blade cooling studies at Texas A&M University's Turbine Heat Transfer Laboratory from 1980 to 2004 are summarized in this article, where the focus is on the effect of rotation on rotor blade coolant passage heat transfer with rib turbulators, pin fins, dimples, and impinging jets.
Abstract: Gas turbines are used extensively for aircraft propulsion, land-based power generation, and industrial applications. Developments in turbine cooling technology play a critical role in increasing the thermal efficiency and power output of advanced high-temperature gas turbine engines. Gas turbine blades are cooled internally by passing the coolant through several rib-enhanced serpentine passages to remove heat conducted from the outside surface. External cooling of turbine blades by film cooling is achieved by injecting relatively cooler air from the internal coolant passages out of the blade surface to form a protective layer between the blade surface and hot gas-path flow. The most important research contributions on turbine blade cooling studies at Texas A&M University's Turbine Heat Transfer Laboratory from 1980 to 2004 are summarized. For turbine blade internal cooling, the focus is on the effect of rotation on rotor blade coolant passage heat transfer with rib turbulators, pin fins, dimples, and impinging jets. For turbine blade external cooling, the focus is on unsteady high freestream turbulence effects on film-cooling performance with a special emphasis on turbine blade edge region heat transfer and cooling problems.
TL;DR: A continuous wavelet transform-based approach was applied to discriminate the damaged structure from the healthy one under several scenarios, demonstrating the practicality and advantages of the proposed method for the application considered.
Abstract: In this paper, a continuous wavelet transform-based approach is applied to enhance the damage-detection capability of wind turbine blades. With the time--frequency localization features embedded in wavelets, the time and scale information of the acquired signals can be presented as a visualization scheme, where the condition monitoring of turbine blades can be better realized. Based on these sensor signals, this proposed approach was applied to discriminate the damaged structure from the healthy one under several scenarios. Test results have demonstrated the practicality and advantages of the proposed method for the application considered
TL;DR: In this paper, a nonlinear multidegree-of-freedom (mdof) model of bladed disk system is analyzed in frequency domain by applying a quasi-linearization technique, which transforms the nonlinear differential equations into a set of nonlinear algebraic equations.
TL;DR: In this article, a specific fatigue procedure was proposed with the following three steps: first, from the sample load spectrum data during short period operation, the spectrum data were rearranged as layer numbers, wind speeds, cycles per layer, normalized maximum, minimum, cyclic and average loads, and stress ratios in time order.
TL;DR: In this paper, a free wake vortex model is used to derive the angle of attack distributions for the NREL Phase VI wind turbine under different operating conditions, and the derived free wake geometry solutions are plotted together with the corresponding wake circulation distribution, providing better insight into how circulation formed at the blades is eventually diffused into the wake.
Abstract: Blade element momentum (BEM) methods are still the most common methods used for predicting the aerodynamic loads during the aeroelastic design of wind turbine blades. However, their accuracy is limited by the availability of reliable aerofoil data. Owing to the 3D nature of the flow over wind turbine blades, the aerofoil characteristics will vary considerably from the 2D aerofoil characteristics, especially at the inboard sections of the blades. Detailed surface pressure measurements on the blade surfaces may be used to derive more realistic aerofoil data. However, in doing so, knowledge of the angle of attack distributions is required. This study presents a method in which a free wake vortex model is used to derive such distributions for the NREL Phase VI wind turbine under different operating conditions. The derived free wake geometry solutions are plotted together with the corresponding wake circulation distribution. These plots provide better insight into how circulation formed at the blades is eventually diffused into the wake. The free wake model is described and its numerical behaviour is examined. Copyright © 2006 John Wiley &Sons, Ltd.
TL;DR: In this paper, the optimal TSR and the power factor of a wind turbine were predicted using artificial neural networks (ANN) based on the parameters involved for NACA 4415 and LS-1 profile types with 3 and 4 blades.
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22 May 2006TL;DR: In this paper, a wind turbine blade pitch system for moving the blades to control their pitch in the event of a power failure is described, which includes at least one backup that has a non-electrical component that can pitch the blades in the case that the power failure adversely affects the electrical blade pitch actuator system.
Abstract: This document discusses, among other things, a wind turbine blade pitch system for moving the blades to control their pitch in the event of a power failure. The system includes at least one backup that has a non-electrical component that can pitch the blades in the event that the power failure adversely affects the electrical blade pitch actuator system. Embodiments include pitch systems that have a plurality of pitch driving systems including, but not limited to electrical systems, hybrid electrical/mechanical systems and non-electrical systems. The non-electrical systems include mechanical, pneumatic or hydraulic systems.
01 Jan 2006
TL;DR: In this article, the design and property status of CMC materials for implementation within the combustor and turbine sections for gas turbine engine applications is reviewed, and it is shown that although CMC systems have advanced significantly in thermo-structural performance within recent years, certain challenges still exist in terms of producibility, design, and affordability for commercial CMC turbine components.
Abstract: The development of ceramic materials for incorporation into the hot section of gas turbine engines has been ongoing for about fifty years. Researchers have designed, developed, and tested ceramic gas turbine components in rigs and engines for automotive, aero-propulsion, industrial, and utility power applications. Today, primarily because of materials limitations and/or economic factors, major challenges still remain for the implementation of ceramic components in gas turbines. For example, because of low fracture toughness, monolithic ceramics continue to suffer from the risk of failure due to unknown extrinsic damage events during engine service. On the other hand, ceramic matrix composites (CMC) with their ability to display much higher damage tolerance appear to be the materials of choice for current and future engine components. The objective of this paper is to briefly review the design and property status of CMC materials for implementation within the combustor and turbine sections for gas turbine engine applications. It is shown that although CMC systems have advanced significantly in thermo-structural performance within recent years, certain challenges still exist in terms of producibility, design, and affordability for commercial CMC turbine components. Nevertheless, there exist some recent successful efforts for prototype CMC components within different engine types.
15 Feb 2006
TL;DR: In this paper, a numerical investigation of the aerodynamics around a wind turbine blade with a winglet using Computational Fluid Dynamics, CFD is presented. But the effect of sweep and cant angles is not accounted for in the present investigation and could improve the winglets even more.
Abstract: The present report describes the numerical investigation of the aerodynamics around a wind turbine blade with a winglet using Computational Fluid Dynamics, CFD. Five winglets were investigated with different twist distribution and camber. Four of them were pointing towards the pressure side (upstream) and one was pointing towards the suction side (downstream). Additionally, a rectangular modification of the original blade tip was designed with the same planform area as the blades with winglets. Results show that adding a winglet to the existing blade increase the force distribution on the outer approx 14 % of the blade leading to increased produced power of around 0.6% to 1.4% for wind speeds larger than 6 m/s. This has to be compared to the increase in thrust of around 1.0% to 1.6%. Pointing the winglet downstream increases the power production even further. The effect of sweep and cant angles is not accounted for in the present investigation and could improve the winglets even more. (au)
TL;DR: In this article, a fiber optic laser Doppler position sensor for single blade tip clearance and vibration measurements at turbo machines is presented, which offers high temporal resolution and high position resolution simultaneously.
Abstract: This paper presents a novel fibre optic laser Doppler position sensor for single blade tip clearance and vibration measurements at turbo machines, which offers high temporal resolution and high position resolution simultaneously. The sensor principle is based on the generation of a measurement volume consisting of two superposed fan-like interference fringe systems with contrary fringe spacing gradients using wavelength division multiplexing. A flexible and robust measurement system with an all-passive fibre coupled measurement head has been realized employing diffractive and refractive optics. Measurements of tip clearance and rotor vibrations at a transonic centrifugal compressor performed during operation at up to 50 000 rpm (833 Hz) corresponding to 21.7 kHz blade frequency and 586 m s−1 blade tip velocity are presented. The results are in excellent agreement with those of capacitive probes. The mean uncertainty of the position measurement was around 20 µm and, thus, considerably better than for conventional tip clearance probes. Consequently, this sensor is capable of fulfilling the requirements for future active clearance control systems and has great potential for in situ and online tip clearance and vibration measurements at metallic and non-metallic turbine blades with high precision.
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22 Mar 2006TL;DR: In this paper, the authors describe a wind turbine with a rotor attached to the hub and rotatable in response to wind acting on the blades to rotate the rotor relative to the stator to generate electricity.
Abstract: A wind generator (10) includes: a nacelle (16); a hub (12) rotatably carried by the nacelle and including at least a pair of wind turbine blades (14); and an electricity producing generator including a stator (22,26) and a rotor (24,28) carried by the nacelle. The rotor is connected to the hub and rotatable in response to wind acting on the blades to rotate the rotor relative to the stator to generate electricity. A cooling system is carried by the nacelle (16) and includes at least one ambient air inlet port (46) opening through a surface of the nacelle downstream of the hub and blades, and a duct (44) for flowing air from the inlet port in a generally upstream direction toward the hub and in cooling relation to the stator.
TL;DR: In this paper, an experimental study of the flow mechanisms of tip leakage across a blade of an unshrouded turbine rotor is presented, with particular attention paid on the flow in the blade tip region.
Abstract: This paper presents an experimental study of the flow mechanisms of tip leakage across a blade of an unshrouded turbine rotor. It shows the design of a new one-and-1/2stage, unshrouded turbine configuration, which has been developed within the Turbomachinery Laboratory of ETH Zurich. This test case is a model of a high work (∆h/u 2 =2.36) axial turbine. The experimental investigation comprises data from unsteady and steady probe measurements, which has been acquired around all the bladerows of the one-and-1/2-stage, unshrouded turbine. A newly developed 2-sensor Fast Response Aerodynamic Probe (FRAP) technique has been used in the current measurement campaign. The paper contains a detailed analysis of the unsteady interaction between rotor and stator blade rows, with particular attention paid on the flow in the blade tip region. It has been found that the pressure field of the second stator row has a influence on the development of the tip leakage vortex downstream of the rotor. The vortex is modulated by the stator profiles and shows variation in size and relative position to the rotor trailing edge when it stretches around the stator leading edge. Thereby a deflection of the tip leakage vortex has been observed, which expresses in a varying circumferential distance between two neighboring vortices of ±20% of a rotor pitch. Furthermore, a significant influence of quasi-stationary secondary flow features of the upstream stator row on the secondary flow of the rotor has been detected. The geometry data of the one-and-1/2-stage turbine will be available to the public domain for validation and improvement of numerical tools. NOMENCLATURE c Absolute flow velocity