Journal articles on the topic 'Turbomachinery measurements'
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1
INOUE, Masahiro, and Masato FURUKAWA. "Measurements of Flow Field in Turbomachinery." Journal of the Society of Mechanical Engineers 89, no. 814 (1986): 1020–26. http://dx.doi.org/10.1299/jsmemag.89.814_1020.
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Choi, Jong-Soo. "Discharge flow measurements of a centrifugal turbomachinery." KSME Journal 8, no. 2 (June 1994): 152–60. http://dx.doi.org/10.1007/bf02953264.
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Camp, T. R., and H. W. Shin. "Turbulence Intensity and Length Scale Measurements in Multistage Compressors." Journal of Turbomachinery 117, no. 1 (January 1, 1995): 38–46. http://dx.doi.org/10.1115/1.2835642.
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This paper describes the measurement and processing of turbulence data from multistage low-speed compressors. Measurements were made at the same relative positions in three four-stage compressors, each having different levels of the design stage loading coefficient. A new method of data processing to calculate turbulence intensities and integral length scales is outlined. Using this method, integral length scales have been measured in turbomachinery flows for the first time. It is shown how the turbulence intensity and integral length scale vary with position in the blade passage, with changing flow coefficient and with the value of the design stage loading coefficient. The results have been used to specify representative inlet conditions for experimental rigs and to improve the application of CFD turbulence models to turbomachinery modeling.
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Kadambi, J. R., R. D. Quinn, and M. L. Adams. "Turbomachinery Blade Vibration and Dynamic Stress Measurements Utilizing Nonintrusive Techniques." Journal of Turbomachinery 111, no. 4 (October 1, 1989): 468–74. http://dx.doi.org/10.1115/1.3262295.
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The vibration of large turbomachinery blading is well known to be one of the most important design factors in modern turbomachinery. Typically, blade vibration is dominated by the unsteady flow phenomena and the interaction effects set up by vibration of blades within a high-velocity compressible fluid medium. This paper addresses the feasibility of developing an in-service noninterference measuring/monitoring system for steam turbine and gas turbine jet engine blade vibrations and stresses. The major purpose of such a measurement system is to provide a technically feasible, cost-effective means to isolate potential turbine and fan blade failures before they occur; thus minimizing costly machinery failure and risk of injury. The techniques that are examined include magnetic, inductive, optical, and laser and acoustic Doppler measurement methods. It appears likely that the most feasible and promising approach would include use of a few properly chosen measurement points on the blading in combination with use of advanced finite-element computational techniques and vibration modal methods. The modal analysis, performed experimentally and/or computationally, is especially useful in converting vibration measurements to the desired dynamic stresses.
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Behr, Thomas, Anestis I. Kalfas, and Reza S. Abhari. "A probabilistic uncertainty evaluation method for turbomachinery probe measurements." E3S Web of Conferences 345 (2022): 02001. http://dx.doi.org/10.1051/e3sconf/202234502001.
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The paper presents a probabilistic uncertainty evaluation method described in the Guide to the Expression of Uncertainty in Measurement (GUM) [1] and its application to the field of Turbomachinery probe measurement techniques. All sources of uncertainties contributing to a measurement result are expressed in terms of probability distributions. Consequently, the overall standard uncertainty of the result can be calculated using the Gaussian error propagation formula. The result of the uncertainty evaluation yields the most probable value of the measurand and describes its distribution in terms of standard or extended uncertainties. A pneumatic five-hole-probe measurement technique has been chosen to show the principle of the probabilistic uncertainty evaluation method. The complete signal chain including the probe calibration, the modeling and the application in the turbine has been included in the analysis. The overall uncertainties of the measured flow angles and flow total and static pressures are presented as a function of the flow Mach number. In addition, the contribution of the individual sources of uncertainty to the overall standard uncertainty is shown. Based on this break down of uncertainties optimization options of the measurement chain are suggested.
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Gossweiler, C. R., P. Kupferschmied, and G. Gyarmathy. "On Fast-Response Probes: Part 1—Technology, Calibration, and Application to Turbomachinery." Journal of Turbomachinery 117, no. 4 (October 1, 1995): 611–17. http://dx.doi.org/10.1115/1.2836579.
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A system for fast-response probe measurements in turbomachine flows has been developed and tested. The system has been designed for 40 kHz bandwidth and used with various in-house built probes accommodating up to four piezoresistive pressure transducers. The present generation of probes works accurately up to several bar pressure and 120°C temperature. The probes were found to be quite robust. The use of a miniature pressure transducer placed in the head of a probe showed that a precise packaging technique and a careful compensation of errors can considerably improve the accuracy of the pressure measurement. Methods for aerodynamic probe calibration and off-line data evaluation are briefly presented. These aimed, e.g., in the case of a four-hole probe, at measuring the velocity fluctuations as characterized by yaw, pitch, total pressure, and static pressure and at deriving mean values and spectral or turbulence parameters. Applications of the measuring system to turbomachinery flow in a radial compressor and to a turbulent pipe flow demonstrate the performance of the measuring system.
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Firoozian, R., and R. Stanway. "Modelling and Control of Turbomachinery Vibrations." Journal of Vibration and Acoustics 110, no. 4 (October 1, 1988): 521–27. http://dx.doi.org/10.1115/1.3269560.
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The authors describe an integrated approach to the modelling and active control of lateral vibrations in turbomachinery. Starting with consideration of the control of multiple rotor bending modes, the generation of a state vector from available measurements using an observer is discussed together with the effect on stability of employing a controller of reduced order. The various points are illustrated in an extended case study which also compares the active schemes with one involving a simple passive damper.
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Tisserant, D., and F. A. E. Breugelmans. "Rotor Blade-to-Blade Measurements Using Particle Image Velocimetry." Journal of Turbomachinery 119, no. 2 (April 1, 1997): 176–81. http://dx.doi.org/10.1115/1.2841096.
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The study of turbomachinery flow fields requires detailed experimental data. The rotating parts of turbomachines greatly limit the measurement techniques that can be used. Particle Image Velocimetry (PIV) appears to be a suitable tool to investigate the blade-to-blade flow in a rotor. The facility is a subsonic axial-flow compressor. The experimental apparatus enables the recording of a double-exposed photograph in a circumferential plane located at 85 percent of the blade height. The illumination plane has an axial direction and is provided by a pulsed ruby laser. The tracers used are submicron glycerine oil droplets. Data are processed by Young’s fringes method. Measurements were performed at 3000, 4500, and 6000 rpm with velocities in the range of 30 to 70 m/s. Steady operating conditions are chosen in such a way that the effect of radial velocity on PIV measurements can be neglected. Experimental problems encountered included homogeneous seeding of the flow field and laser light scattering from blade surfaces. The uncertainty affecting the velocity determination corresponds to 2 percent of the measured value. For a given set of operating conditions, 10 PIV pictures are recorded. The periodic flow field is approximated by averaging the experimental data point by point. Upstream and downstream velocity triangles are confirmed by measurements obtained from pressure probes. PIV measurement results were found to be similar to those of a blade-to-blade potential-flow calculation.
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Wadia, A. R., and B. F. Beacher. "Three-Dimensional Relief in Turbomachinery Blading." Journal of Turbomachinery 112, no. 4 (October 1, 1990): 587–96. http://dx.doi.org/10.1115/1.2927697.
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The leading edge region of turbomachinery blading in the vicinity of the endwalls is typically characterized by an abrupt increase in the inlet flow angle and a reduction in total pressure associated with endwall boundary layer flow. Conventional two-dimensional cascade analysis of the airfoil sections at the endwalls indicates large leading edge loadings, which are apparently detrimental to the performance. However, experimental data exist that suggest that cascade leading edge loading conditions are not nearly as severe as those indicated by a two-dimensional cascade analysis. This discrepancy between two-dimensional cascade analyses and experimental measurements has generally been attributed to inviscid three-dimensional effects. This article reports on two and three-dimensional calculations of the flow within two axial-flow compressor stators operating near their design points. The computational results of the three-dimensional analysis reveal a significant three-dimensional relief near the casing endwall that is absent in the two-dimensional calculations. The calculated inviscid three-dimensional relief at the endwall is substantiated by airfoil surface static pressure measurements on low-speed research compressor blading designed to model the flow in the high-speed compressor. A strong spanwise flow toward the endwall along the leading edge on the suction surface of the airfoil is responsible for the relief in the leading edge loading at the endwall. This radial migration of flow results in a more uniform spanwise loading compared to that predicted by two-dimensional calculations.
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Kim, Namhyo, and David L. Rhode. "Refined Turbulence Modeling for Swirl Velocity in Turbomachinery Seals." International Journal of Rotating Machinery 9, no. 6 (2003): 451–59. http://dx.doi.org/10.1155/s1023621x03000447.
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A generalized new form of the rotation-sensitive source term coefficient previously proposed by Bardina and colleagues as an extension of the standardk-εturbulence model was developed. The proposal made by Bardina and colleagues focused on rotating flows without significant turbulence generation, and the result was a negative-valued constant coefficient. The new functional form developed here for the coefficient has global as well as local dependence. The new model predictions of laser Doppler anemometry measurements of swirling flows in labyrinth seals were compared with the swirl distribution measurements and with the standardk-εmodel (i.e., no rotation source term) predictions. It was found that for the labyrinth seal cases for which detailed measurements are available, the standardk-εmodel gives unsatisfactory predictions, whereas the new model gives significantly improved predictions.
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Reinhardt, A. K., J. R. Kadambi, and R. D. Quinn. "Laser Vibrometry Measurements of Rotating Blade Vibrations." Journal of Engineering for Gas Turbines and Power 117, no. 3 (July 1, 1995): 484–88. http://dx.doi.org/10.1115/1.2814121.
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One of the most important design factors in modern turbomachinery is the vibration of turbomachinery blading. There is a need for developing an in-service, noncontacting, noninterfering method for the measurement and monitoring of gas turbine, jet engine, and steam turbine blade vibrations and stresses. Such a technique would also be useful for monitoring rotating helicopter blades. In the power generation industry, blade failures can result in millions of dollars of downtime. The measurement of blade vibrations and dynamic stresses is an important guide for preventive maintenance, which can be a major contributor to the availability of steam turbine, gas turbine, and helicopter operations. An experiment is designed to verify the feasibility of such a vibration monitoring system using the reference beam on-axis laser-Doppler technique. The experimental setup consists of two flat, cantilever blades mounted on a hub attached to the shaft of a dc motor. The motor rests on a linear bearing permitting motion only in the direction of the motor shaft. The motor and blade assembly is then excited via an electrodynamic shaker at the first natural frequency of the blades. The resulting blade vibration is then detected using a laser vibrometer. The vibration frequencies and amplitudes of the two rotating blades are successfully measured.
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Boerner, Marcel, Martin Bitter, and Reinhard Niehuis. "On the challenge of five-hole-probe measurements at high subsonic Mach numbers in the wake of transonic turbine cascades." Journal of the Global Power and Propulsion Society 2 (October 8, 2018): JPRQQM. http://dx.doi.org/10.22261/jgpps.jprqqm.
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Five-hole-probes are common use in turbomachinery flow investigations, even though, inserting a probe into a flow field inevitably induces perturbations to the flow which can falsify the measurement results, especially when exposed to transonic flows. The objective of the investigations presented here is to evaluate the Mach number measurements of a five-hole-probe (5HP) in the wake flow of a transonic turbine cascade at engine relevant Reynolds numbers by comparing them to the results of particle image velocimetry (PIV). Furthermore, PIV measurements were performed with inserted probe to investigate the influence of the probe on the wake flow field. Together with a sensitivity study of 5HP measurements in flow regimes close to Ma = 1, the results demonstrate how the measurement uncertainty can be improved in high subsonic flow regimes.
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Chasoglou, Alexandros C., Michel Mansour, Anestis I. Kalfas, and Reza S. Abhari. "A novel 4-sensor fast-response aerodynamic probe for non-isotropic turbulence measurement in turbomachinery flows." Journal of the Global Power and Propulsion Society 2 (May 17, 2018): UALS07. http://dx.doi.org/10.22261/jgpps.uals07.
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Abstract In modern computational studies for turbomachinery applications, time, length scales and isotropy of turbulent structures are important for representative modelling. To this end, experimental data are essential to validate the numerical tools. The current article presents the development and application of a newly designed 4-sensor Fast Response Aerodynamic Probe (FRAP-4S) enabling time-resolved measurement of the three-dimensional unsteady flow velocity vector in turbomachines. The miniature multi-sensor probe demonstrates a 4 mm probe-tip. In the first part of this article the design, manufacturing and calibration results of the FRAP-4S are presented in detail. To assess the newly developed probe accuracy, comparison against traditional instrumentation developed at the Laboratory for Energy Conversion is also provided. In the second part of this work, measurements are performed at the rotor exit of a one-and-a-half stage, unshrouded and highly-loaded axial turbine configuration. The results showed increased level of unsteadiness and turbulence levels with peak-to-peak fluctuation from 5 to 35%. More importantly, in some regions stream-wise unsteadiness was found to be ten times higher, compared to the cross-wise components, an indication of the high degree of anisotropy.
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Tanaka, Keizo, Anestis I. Kalfas, and Howard P. Hodson. "Development of single sensor fast response pressure probes." E3S Web of Conferences 345 (2022): 01004. http://dx.doi.org/10.1051/e3sconf/202234501004.
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Multi-sensor fast response pressure probes are often used in turbomachinery investigations. However, the size of multi-sensor probes are often larger than is ideal. This paper describes the development of a single sensor pressure probe that has sufficient sensitivity for the measurements of unsteady 3D flow fields in turbomachines. Because there is only one sensor, the probe can be made much smaller than previous designs. Several types of probe were designed and tested using largescale models in a wind tunnel. Both the steady state and the dynamic response have been investigated. The relationship between the shape of the probe and its yaw and pitch sensitivity has been investigated through measurements of the pressure distribution on the large-scale models and through visualizations of the flow. Dambach and Hodson [3] proposed a new method of data reduction for a single sensor pressure probe. In that work, a single sensor pressure probe with the shape of a triangular prism was fabricated and tested with success in a radial flow turbine where the flow field was mainly 2D. The probe was shown to have only yaw sensitivity while pitch sensitivity is also important in the survey of three dimensional turbomachinery flows. In this paper, the model probes were used to assess the pitch sensitivity of single sensor pressure probes. All the probes have the sensing face at the end of a radially mounted stem so that they can be used for inter bladerow measurements. Through the steady state measurements, the dependency of pitch sensitivity on (1) the shape of the probe stem (e.g., Square, Circular, and Triangular) and (2) the angle of the slanted sensing face at the tip of the probe were investigated. Having assessed all the designs based on the steady state experiments, the dynamic behaviour of selected designs was investigated. The results indicate that a slanted face and appropriate probe tip design can be used to increase the pitch sensitivity of the single sensor probe to acceptable levels.
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Hasmatuchi, Vlad, Alin Bosioc, Sébastien Luisier, and Cécile Münch-Alligné. "A Dynamic Approach for Faster Performance Measurements on Hydraulic Turbomachinery Model Testing." Applied Sciences 8, no. 9 (August 21, 2018): 1426. http://dx.doi.org/10.3390/app8091426.
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During the design and optimization of hydraulic turbomachines, the experimental evaluation of hydraulic performances beyond the best efficiency point and for off-design conditions remains essential to validate the simulation process and to finalize the development. In this context, an alternative faster method to measure the efficiency of hydraulic turbomachines using a dynamic approach has been investigated. The so-called “sliding-gate” dynamic measurement method has been adapted and implemented on the hydraulic test rig of the HES-SO Valais//Wallis, Sion, Switzerland. This alternative approach, particularly gainful for small-hydro for which the investment devoted to development is limited, has been successfully assessed on two cases for drinking water networks energy recovery. A 2.65 kW double-regulated laboratory prototype of a tubular axial micro-turbine with two independent variable speed counter-rotating runners and a 11 kW multi-stage centrifugal pump-as-turbine (PAT) with variable speed have been selected. The hydraulic efficiency results obtained by dynamic measurements are compared to the ones obtained by the classical steady point-by-point method. This dynamic method, suitable not only for hydraulic machinery, allows: (i) reducing significantly (up to 10×) the time necessary to draw the complete efficiency characteristics of a hydraulic machine; (ii) rapidly detecting the hydrodynamic instabilities within the operating range of the machine.
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Heath, Steve. "A New Technique for Identifying Synchronous Resonances Using Tip-Timing." Journal of Engineering for Gas Turbines and Power 122, no. 2 (January 3, 2000): 219–25. http://dx.doi.org/10.1115/1.483198.
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Non-contact measurement of vibration at turbomachinery rotor blade tips using blade tip-timing has become an industry-standard procedure. Current research focuses on analysis methods for interpretation of the measured vibration data from a limited number of probes. The methods are classified by the form of the vibration they can identify. Identification of asynchronous response amplitude and frequency is well documented. Whilst a method for identifying maximum synchronous resonance amplitude has existed since the early 1970s, there is no published evidence of a method for directly identifying frequency or engine order using a small number of probes. This paper presents a new analysis method for identifying synchronous resonance engine order using two tip-timing vibration measurements. The measurements are made at different locations on the turbomachinery casing using a minimum of two probes. A detailed description of the method and results from its practical application are given. The potential of the method to identify the amplitude and frequency of close modes, not possible with current methods, is demonstrated. The effect of blade mistuning on the accuracy of the method is investigated. Existing synchronous response analysis methods and the new method presented here give the response amplitude and frequency after the resonance has been traversed. Real-time identification of synchronous response amplitude and frequency would allow tip-timing to be used as a safety monitor of all blades. Real-time methods, their limitations and practical application are discussed. The future use of tip-timing as the dominant vibration measurement system is discussed with reference to experience on measurements made solely with tip-timing on assemblies with undefined vibration characteristics. [S0742-4795(00)02602-8]
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Michaud, Mathias, Petro Jr Milan, and Huu Duc Vo. "Low-Cost Rotating Experimentation in Compressor Aerodynamics Using Rapid Prototyping." International Journal of Rotating Machinery 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/8518904.
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With the rapid evolution of additive manufacturing, 3D printed parts are no longer limited to display purposes but can also be used in structural applications. The objective of this paper is to show that 3D prototyping can be used to produce low-cost rotating turbomachinery rigs capable of carrying out detailed flow measurements that can be used, among other things, for computational fluid dynamics (CFD) code validation. A fully instrumented polymer two-stage axial-mixed flow compressor test rig was designed and fabricated with stereolithography (SLA) technology by a team of undergraduate students as part of a senior-year design course. Experiments were subsequently performed on this rig to obtain both the overall pressure rise characteristics of the compressor and the stagnation pressure distributions downstream of the blade rows for comparison with CFD simulations. In doing so, this work provides a first-of-a-kind assessment of the use of polymer additive technology for low-cost rotating turbomachinery experimentation with detailed measurements.
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Hacks, Alexander Johannes, and Dieter Brillert. "Turbomachine Operation with Magnetic Bearings in Supercritical Carbon Dioxide Environment." International Journal of Turbomachinery, Propulsion and Power 7, no. 2 (June 14, 2022): 18. http://dx.doi.org/10.3390/ijtpp7020018.
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In the sCO2-HeRo project, the Chair of Turbomachinery at the University of Duisburg-Essen developed, built and tested a turbomachine with an integral design in which the compressor, generator and turbine are housed in a single hermetic casing. However, ball bearings limited operation because their lubricants were incompatible with supercritical CO2 (sCO2) and they had to operate in gaseous CO2 instead. To overcome this problem, the turbomachine was redesigned built and tested in the sCO2-4-NPP project. Instead of ball bearings, magnetic bearings are now used to operate the turbomachine with the entire rotor in sCO2. This paper presents the revised design, focusing on the usage of magnetic bearings. It also investigates whether the sCO2 limits the operating range. Test runs show that increasing the density and rotational speed results in greater deflection of the rotor and greater forces on the bearings. Measurements are also analyzed with respect to influence of the density increase on the destabilizing forces in the rotor–stator cavities. The conclusion is that for the operation of the turbomachine, the control parameters of the magnetic bearings must be adjusted not only to the rotor speed, but also to the fluid density. This enabled successful operation of the turbomachine, which reached a speed of about 40,000 rpm during initial tests in CO2.
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Jonsson, Isak, Valery Chernoray, and Radheesh Dhanasegaran. "Infrared Thermography Investigation of Heat Transfer on Outlet Guide Vanes in a Turbine Rear Structure." International Journal of Turbomachinery, Propulsion and Power 5, no. 3 (September 1, 2020): 23. http://dx.doi.org/10.3390/ijtpp5030023.
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Aerothermal heat transfer measurements in fluid dynamics have a relatively high acceptance of uncertainty due to the intricate nature of the experiments. The large velocity and pressure gradients present in turbomachinery application add further complexity to the measurement procedure. Recent method and manufacturing development has addressed some of the primary sources of uncertainty in these heat transfer measurements. However, new methods have so far not been applied in a holistic approach for heat transfer studies. This gap is bridged in the present study where a cost-effective and highly accurate method for heat transfer measurements is implemented, utilising infrared thermography technique (IRT) for surface temperature measurement. Novel heat transfer results are obtained for the turbine rear sturcture (TRS), at engine representative conditions for three different outlet guide vane (OGV) blade loading and at Reynolds Number of 235000. In addition to that, an extensive description of the implementation and error mitigation is presented.
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Brozowski, L. A., T. V. Ferguson, and L. Rojas. "Impeller Flow Field Laser Velocimeter Measurements." International Journal of Rotating Machinery 2, no. 3 (1996): 149–59. http://dx.doi.org/10.1155/s1023621x96000024.
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Development of Computational Fluid Dynamics (CFD) computer codes for complex turbomachinery affords a complete three-dimensional (3-D) flow field description. While significant improvements in CFD have been made due to improvements in computers, numerical algorithms, and physical modeling, a limited experimental database for pump CFD code validation exists.Under contract (NAS8-38864) to the National Aeronautics and Space Administration (NASA) at Marshall Space Flight Center (MSFC) a test program was undertaken at Rocketdyne to obtain benchmark data for typical rocket engine pump geometry. Nonintrusive velocity data were obtained with a laser two-focus velocimeter. Extensive laser surveys at the inlet and discharge of a Rocketdyne-designed impeller were performed. Static pressures were measured at key locations to provide boundary conditions for CFD code validation.
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Franken, Arnoud R. C., and Paul C. Ivey. "Enhancing Flow Field Measurements Through Adaptive Multidimensional Data Sampling." Journal of Engineering for Gas Turbines and Power 128, no. 3 (September 6, 2005): 518–24. http://dx.doi.org/10.1115/1.2135822.
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A way to gain insight into the flow field conditions in turbomachinery is by carrying out a series of point measurements in a cross section of the flow, for example, with a miniature multihole pressure probe. A problem commonly encountered in situations like these is the selection of a suitable measurement grid layout and density for obtaining all essential information in a cost-effective and timely manner. In order to achieve the latter, a novel adaptive multidimensional data sampling technique has been developed at Cranfield University. This paper describes the underlying principles of this technique, the algorithms utilized, and the results obtained during its successful application to data sets of two different flow fields in a high-speed research compressor.
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Kidd, S. R., J. S. Barton, and J. D. C. Jones. "Demonstration of optical fiber probes for high bandwidth thermal measurements in turbomachinery." Journal of Lightwave Technology 13, no. 7 (July 1995): 1335–39. http://dx.doi.org/10.1109/50.400679.
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Ainsworth, R. W., J. L. Allen, and J. J. M. Batt. "The Development of Fast Response Aerodynamic Probes for Flow Measurements in Turbomachinery." Journal of Turbomachinery 117, no. 4 (October 1, 1995): 625–34. http://dx.doi.org/10.1115/1.2836581.
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The advent of a new generation of transient rotating turbine simulation facilities, where engine values of Reynolds and Mach number are matched simultaneously together with the relevant rotational parameters for dimensional similitude (Dunn et al., 1988; Epstein and Guenette, 1984; Ainsworth et al., 1988), has provided the stimulus for developing improved instrumentation for investigating the aerodynamic flows in these stages. Much useful work has been conducted in the past using hot-wire and laser anemometers. However, hot-wire anemometers are prone to breakage in the high-pressure flows required for correct Reynolds numbers. Furthermore, some laser techniques require a longer run-time than these transient facilities permit, and generally yield velocity information only, giving no data on loss production. Advances in semiconductor aerodynamic probes are beginning to fulfill this perceived need. This paper describes advances made in the design, construction, and testing of two and three-dimensional fast response aerodynamic probes, where semiconductor pressure sensors are mounted directly on the surface of the probes, using techniques that have previously been successfully used on the surface of rotor blades (Ainsworth et al., 1991). These are to be used to measure Mach number and flow direction in compressible unsteady flow regimes. In the first section, a brief review is made of the sensor and associated technology that has been developed to permit a flexible design of fast response aerodynamic probe. Following this, an extensive program of testing large-scale aerodynamic models of candidate geometries for suitable semiconductor scale probes is described, and the results of these discussed. The conclusions of these experiments, conducted for turbine representative mean and unsteady flows, yielded new information for optimizing the design of the small-scale semiconductor probes, in terms of probe geometry, sensor placement, and aerodynamic performance. Details are given of a range of wedge and pyramid semiconductor probes constructed, and the procedures used in calibrating and making measurements with them. Differences in performance are discussed, allowing the experimenter to choose an appropriate probe for the particular measurement required. Finally, the application of prototype semiconductor probes in a transient rotor experiment at HP turbine representative conditions is described, and the data so obtained are compared with CFD solutions of the unsteady viscous flow-field.
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Brodersen, S., and D. Wulff. "Measurements of the Pressure and Velocity Distribution in Low-Speed Turbomachinery by Means of High-Frequency Pressure Transducers." Journal of Turbomachinery 114, no. 1 (January 1, 1992): 100–107. http://dx.doi.org/10.1115/1.2927972.
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The flow in a low-speed, single-state compressor with a very high blade loading has been measured using a two-probe arrangement. The measuring technique and data reduction procedure described have been especially adjusted for application in low-speed turbomachinery. Those machines show only small pressure fluctuations in the flow downstream of the rotor, for which specific requirements concerning the measuring technique have been taken into account. The probes used contain unsteady pressure transducers and simulate an unsteady multisensor pressure probe. This technique proves to be suitable for applications in low-speed turbomachinery. The measurements are based on phase-locked ensemble averages of multiple samples, where the data are acquired using a simple and convenient experimental setup. This allows the velocity and pressure distribution of the flow to be determined in rotor coordinates. The results show the flow field and the loss distribution of an aero-dynamically highly loaded rotor at design flow rate.
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Magkoutas, Konstantinos, Theofilos Efstathiadis, and Anestis Kalfas. "Experimental investigation of geometry effects and performance of five-hole probe in measuring jets in crossflow." E3S Web of Conferences 345 (2022): 01005. http://dx.doi.org/10.1051/e3sconf/202234501005.
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Vortical and shear flows are common in turbomachinery. Multi-hole pressure probes are used in turbomachinery flows in order to provide robust and accurate measurements of both pressure and velocity components. In this study, two different miniature five-hole probes are designed and fabricated, both with a cobra shape. The probe tip was 1.45 mm and it was maintained in that size for the length of the cobra shape formation, providing very close proximity to the solid boundaries and reduced flow blockage. The difference among the probes corresponded to the head geometry, as the one probe was formed with a pyramid tip shape, while the other was maintained with a flat shape. The calibration process was carried out in an open-circuit suction wind tunnel for the range of ±32⁰ in yaw and pitch direction. The results showed that the pyramid probe exhibits a high flow angle spatial sensitivity and a reliable measurement range of ±28⁰ in yaw and pitch direction. The flat probe provided unexpected well angle sensitivity and reliable measurements data despite the fact that it is of a very simple form. The pyramid probe showed superior performance. In particular, the pyramid probe offers 12.5% wider operating range. In order to prove the effectiveness of the pyramid probe, measurements were obtained in a jet in cross flow. In order to evaluate the performance of the probe, further, a surface fit model was employed to produce ideal calibration coefficients. These were used to redefine the magnitude of the velocities in the measured flow domain. The accuracy in measurements was assessed, comparing the velocities produced by the two variants of pressure coefficients. The results indicate that the pyramid probe operates reliably in a very large range of constantly changing velocity vector, which occurs in jet in cross flow.
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Hamed, A., and T. P. Kuhn. "Effects of Variational Particle Restitution Characteristics on Turbomachinery Erosion." Journal of Engineering for Gas Turbines and Power 117, no. 3 (July 1, 1995): 432–40. http://dx.doi.org/10.1115/1.2814115.
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This paper presents the results of an investigation to determine the effects of variational particle rebounding models on surface impacts and blade erosion patterns in gas turbines. The variance in the particle velocities after the surface impacts are modeled based on the experimental measurements using Laser-Doppler Velocimetry (LDV) under varying flow conditions. The probabilistic particle trajectory computations simulate the experimental variance in the particle restitution characteristics using cumulative distribution functions and random sampling techniques. The results are presented for the particle dynamics through a gas turbine flow field and are compared to those obtained with deterministic rebound models based on experimental mean values.
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Farrell, K. J., and M. L. Billet. "A Correlation of Leakage Vortex Cavitation in Axial-Flow Pumps." Journal of Fluids Engineering 116, no. 3 (September 1, 1994): 551–57. http://dx.doi.org/10.1115/1.2910312.
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Tip clearance flow in turbomachinery can lead to losses in efficiency and stall margin. In liquid handling turbomachinery, the vortical flow field, formed from the interaction of the leakage flow with the through-flow, is subject to cavitation. Furthermore, this flow field is complex and not well understood. A correlation of variables which predict the vortex minimum pressure has been formulated. Measurements of the important variables for this correlation have been made on a high Reynolds number (3 × 106) axial-flow test rig. The correlation has been applied to the measured data and other data sets from the literature with good agreement. An optimum tip clearance has been theoretically identified as experiments have shown. Observations of cavitation indicate a second vortex originating along the suction side trailing edge.
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Kwanka, K. "Improving the Stability of Labyrinth Gas Seals." Journal of Engineering for Gas Turbines and Power 123, no. 2 (March 1, 1997): 383–87. http://dx.doi.org/10.1115/1.1359772.
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The flow through labyrinth seals of turbomachinery generates forces which can cause self-excited vibrations of the rotor above the stability limit. The stability limit is reached at a specific rotating speed or power. The continuous growth of power density and rotating speed necessitates an exact prediction of the stability limit of turbomachinery. Usually the seal forces are described with dynamic coefficients. A new, easy-to-handle identification procedure uses the stability behavior of a flexible rotor to determine the dynamic coefficients. Systematic measurements with a great number of labyrinth seal geometries lead to reasonable results and demonstrate the accuracy and sensitivity of the procedure. A comparison of the various methods used to minimize the excitation indicates which seal is more stable and will thus improve the dynamic behavior of the rotor.
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Ruiz, C., D. Post, and R. Czarnek. "Moire´ Interferometric Study of Dovetail Joints." Journal of Applied Mechanics 52, no. 1 (March 1, 1985): 109–14. http://dx.doi.org/10.1115/1.3168978.
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High sensitivity Moire´ interferometry has been applied to the study of dovetail joints as found in turbomachinery. Without physical measurements, the true contact conditions cannot be known. The benefits to be gained when coupled with a finite element stress analysis are discussed. It is concluded that Moire´ interferometry is of great potential in the study of fixed mechanical joints.
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Witkowski, Dariusz, Damian Obidowski, Piotr Reorowicz, Daniel Jodko, and Krzysztof Jozwik. "Particle Image Velocimetry Tests on Pediatric 45-cc and 30-cc Ventricle Assist Devices: Effects of Heart Rate on VAD Operation." International Journal of Artificial Organs 40, no. 10 (August 7, 2017): 558–62. http://dx.doi.org/10.5301/ijao.5000618.
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Background This study investigated flow analysis inside pediatric ventricle assist devices (VADs) designed and manufactured at the Foundation for Cardiac Surgery Development (FRK), Zabrze, Poland. The main goal of the experiment was to define the minimal heart rate admissible in clinical practice. Methods The flow was directed by mechanical, single-disc valves developed at the Lodz University of Technology, Institute of Turbomachinery in Lodz, Poland. VAD operation conditions under different heart rates were analyzed. Measurements were performed on Religa PED pediatric VADs (45 cm3 and 30 cm3) with a particle image velocimetry (PIV) system. Results Due to the PIV method used, the measurements were made without interference of the measuring system onto the flow structure in the investigated channel, as the measurement procedure is noninvasive. During the investigations conducted in different measurement planes, the majority of the flow volume in the chamber was observable. Conclusions The measurements at different heart rates demonstrated a significant influence of this parameter on the flow nature in the heart ventricle. Additionally, it was found that the heart rate affected the operation of heart valves in the VAD.
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Heath, S., and M. Imregun. "A Survey of Blade Tip-Timing Measurement Techniques for Turbomachinery Vibration." Journal of Engineering for Gas Turbines and Power 120, no. 4 (October 1, 1998): 784–91. http://dx.doi.org/10.1115/1.2818468.
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This paper aims at providing a comparative survey of current analysis methods for the interpretation of vibration data measured at turbomachinery rotor blade tips using optical laser probes. The methods are classified by the form of the vibration that they attempt to identify, namely, asynchronous and synchronous with respect to rotor speed. The performance of the various techniques is investigated by using both actual assembly measurements and simulated response data. In the latter case, synchronous vibration data are obtained via a multidegree-of-freedom numerical simulator that includes the structural and geometric properties of the bladed-disk assembly, the external forcing terms, and the characteristics of the optical probe. When using experimental data, the results of the tip timing analysis are compared to those obtained from standard strain-gauge tests and the relative merits of the two approaches are discussed with emphasis on the effects of blade mistuning. Existing industry standard, tip-timing analysis techniques are found to exhibit a number of inherent limitations and suggestions were made to address these deficiencies. A detailed tip-timing case study for a steam turbine rotor is presented in some detail, and other potential application areas are explored. Of particular note is the introduction of a new indirect analysis method for identifying the characteristics of synchronous vibration modes using measurements from two probes. Finally, new avenues for future analysis methods and further developments in tip-timing systems are also discussed.
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Povey, Thomas, and Guillermo Paniagua. "Method to improve precision of rotating inertia and friction measurements in turbomachinery applications." Mechanical Systems and Signal Processing 30 (July 2012): 323–29. http://dx.doi.org/10.1016/j.ymssp.2012.01.025.
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Fenyvesi, Bence, and Csaba Horváth. "Identification of Turbomachinery Noise Sources via Processing Beamforming Data Using Principal Component Analysis." Periodica Polytechnica Mechanical Engineering 66, no. 1 (December 22, 2021): 32–50. http://dx.doi.org/10.3311/ppme.18555.
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Complex turbomachinery systems produce a wide range of noise components. The goal is to identify noise source categories, determine their characteristic noise patterns and locations. Researchers can then use this information to quantify the impact of these noise sources, based on which new design guidelines can be proposed. Phased array microphone measurements processed with acoustic beamforming technology provide noise source maps for pre-determined frequency bands (i.e., bins) of the investigated spectrum. However, multiple noise generation mechanisms can be active in any given frequency bin. Therefore, the identification of individual noise sources is difficult and time consuming when using conventional methods, such as manual sorting. This study presents a method for combining beamforming with Principal Component Analysis (PCA) methods in order to identify and separate apart turbomachinery noise sources with strong harmonics. The method is presented through the investigation of Counter-Rotating Open Rotor (CROR) noise sources. It has been found that the proposed semi-automatic method was able to extract even weak noise source patterns that repeat throughout the data set of the beamforming maps. The analysis yields results that are easy to comprehend without special prior knowledge and is an effective tool for identifying and localizing noise sources for the acoustic investigation of various turbomachinery applications.
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Cumpsty, N. A., and J. H. Horlock. "Averaging Nonuniform Flow for a Purpose." Journal of Turbomachinery 128, no. 1 (February 1, 2005): 120–29. http://dx.doi.org/10.1115/1.2098807.
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Averaging nonuniform flow is important for the analysis of measurements in turbomachinery and gas turbines; more recently an important need for averaging arises with results of computational fluid dynamics (CFD). In this paper we show that there is a method for averaging which is “correct,” in the sense of preserving the essential features of the nonuniform flow, but that the type of averaging which is appropriate depends on the application considered. The crucial feature is the decision to retain or conserve those quantities which are most important in the case considered. Examples are given to demonstrate the appropriate methods to average nonuniform flows in the accounting for turbomachinery blade row performance, production of thrust in a nozzle, and mass flow capacity in a choked turbine. It is also shown that the numerical differences for different types of averaging are, in many cases, remarkably small.
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Bühler, Johannes, Sebastian Leichtfuß, Heinz-Peter Schiffer, Thomas Lischer, and Simon Raabe. "Surge Limit Prediction for Automotive Air-Charged Systems." International Journal of Turbomachinery, Propulsion and Power 4, no. 4 (October 1, 2019): 34. http://dx.doi.org/10.3390/ijtpp4040034.
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Compressor surge has been investigated and predicted since the early days of turbomachinery research. Experimental testing of turbomachinery applications is still needed to determine whether stable compressor operation is possible in the expected application regime. Measuring compressor maps and operating ranges on hot gas test stands is common. The test benches are designed and optimized to ensure ideal inflow and outflow conditions as well as low measurement uncertainty. Compressor maps are used to match turbocharger and application. However, a shift in surge limit, caused by the piping system or application, can only be adequately addressed with full engine tests. Ideal measurements use the corresponding piston engine in the charged-air system. This can only take place in the development process, when surge detection is unfavorable from an economic perspective. The surge model for turbochargers presented here is an extension of the Greitzer’s surge model, which considers the effect of inlet throttling. Application components, such as air filters, pipe elbows and flow straighteners, reduce pressure in front of the compressor and flow conditions might differ from those in laboratory testing. Experimental results gathered from the hot gas test stand at TU Darmstadt indicate strong variation in surge limit, influenced by inlet throttling. An extension to the surge model is developed to explain the observed phenomena. The model was validated using extensive experimental variations and matches the experienced surge limit shift. Additional measurements with a piston engine downstream of the turbocharger demonstrated the validity of the surge model. The results also show that surge is a system-dependent phenomenon, influenced by compressor aerodynamics and boundary conditions.
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Gerolymos, G. A., and I. Vallet. "Robust Implicit Multigrid Reynolds-Stress Model Computation of 3D Turbomachinery Flows." Journal of Fluids Engineering 129, no. 9 (March 31, 2007): 1212–27. http://dx.doi.org/10.1115/1.2754320.
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The purpose of this paper is to present a numerical methodology for the computation of complex 3D turbomachinery flows using advanced multiequation turbulence closures, including full seven-equation Reynolds-stress transport models. The flow equations are discretized on structured multiblock grids, using an upwind biased (O[ΔxH3]MUSCL reconstruction) finite-volume scheme. Time integration uses a local dual-time-stepping implicit procedure, with internal subiterations. Computational efficiency is achieved by a specific approximate factorization of the implicit subiterations, designed to minimize the computational cost of the turbulence transport equations. Convergence is still accelerated using a mean-flow-multigrid full-approximation-scheme method, where multigrid is applied only on the mean-flow variables. Speed-ups of a factor 3 are obtained using three levels of multigrid (fine plus two coarser grids). Computational examples are presented using two Reynolds-stress models, and also a baseline k−ε model, for various turbomachinery configurations, and compared to available experimental measurements.
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Bryanston-Cross, P. J., C. E. Towers, T. R. Judge, D. P. Towers, S. P. Harasgama, and S. T. Hopwood. "The Application of Particle Image Velocimetry (PIV) in a Short-Duration Transonic Annular Turbine Cascade." Journal of Turbomachinery 114, no. 3 (July 1, 1992): 504–9. http://dx.doi.org/10.1115/1.2929173.
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A series of experiments have been performed to demonstrate the application of Particle Image Velocimetry (PIV) to turbomachinery flows. The tests were performed at transonic speeds on a fully annular engine size turbine nozzle guide vane. The vane cascade was installed in a short-duration Isentropic Light Piston Cascade (ILPC) test facility operating with high inlet turbulence levels. The technique has been shown to map the whole flow field with a resolution of 0.5 mm. The quality of the results obtained is not significantly affected by local turbulence rates. The accuracy of the measurements is put at around 4 percent of absolute velocity and is limited by the quality of the image on the film plane. The velocities derived from the PIV images have been compared with predictions from a three-dimensional viscous numerical calculation. It is shown that the experimental and predicted results are in good agreement. It is considered that this technique has considerable potential in application to turbomachinery flow field diagnostics.
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Provenza, Andrew J., Gerald T. Montague, Mark J. Jansen, Alan B. Palazzolo, and Ralph H. Jansen. "High Temperature Characterization of a Radial Magnetic Bearing for Turbomachinery." Journal of Engineering for Gas Turbines and Power 127, no. 2 (April 1, 2005): 437–44. http://dx.doi.org/10.1115/1.1807413.
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Open loop, experimental force and power measurements of a radial, redundant-axis, magnetic bearing at temperatures to 1000°F (538°C) and rotor speeds to 15,000 rpm along with theoretical temperature and force models are presented in this paper. The experimentally measured force produced by a single C-core circuit using 22A was 600 lb (2.67 kN) at room temperature and 380 lb (1.69 kN) at 538°C. These values were compared with force predictions based on a one-dimensional magnetic circuit analysis and a thermal analysis of gap growth as a function of temperature. The analysis showed that the reduction of force at high temperature is mostly due to an increase in radial gap due to test conditions, rather than to reduced core permeability. Tests under rotating conditions showed that rotor speed has a negligible effect on the bearing’s static force capacity. One C-core required approximately 340 W of power to generate 190 lb (845 N) of magnetic force at 538°C, however the magnetic air gap was much larger than at room temperature. The data presented are after bearing operation for eleven total hours at 538°C and six thermal cycles.
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Bornassi, S., T. M. Berruti, C. M. Firrone, and G. Battiato. "Vibration parameters identification of turbomachinery rotor blades under transient condition using Blade Tip-Timing measurements." Measurement 183 (October 2021): 109861. http://dx.doi.org/10.1016/j.measurement.2021.109861.
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Uzol, O., D. Brzozowski, Y. C. Chow, J. Katz, and C. Meneveau. "A database of PIV measurements within a turbomachinery stage and sample comparisons with unsteady RANS." Journal of Turbulence 8 (January 2007): N10. http://dx.doi.org/10.1080/14685240601142867.
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Liu, Zhibo, Fajie Duan, Guangyue Niu, Ling Ma, Jiajia Jiang, and Xiao Fu. "An Improved Circumferential Fourier Fit (CFF) Method for Blade Tip Timing Measurements." Applied Sciences 10, no. 11 (May 26, 2020): 3675. http://dx.doi.org/10.3390/app10113675.
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Rotating blade vibration measurements are very important for any turbomachinery research and development program. The blade tip timing (BTT) technique uses the time of arrival (ToA) of the blade tip passing the casing mounted probes to give the blade vibration. As a non-contact technique, BTT is necessary for rotating blade vibration measurements. The higher accuracy of amplitude and vibration frequency identification has been pursued since the development of BTT. An improved circumferential Fourier fit (ICFF) method is proposed. In this method, the ToA is not only dependent on the rotating speed and monitoring position, but also on blade vibration. Compared with the traditional circumferential Fourier fit (TCFF) method, this improvement is more consistent with reality. A 12-blade assembly simulator and experimental data were used to evaluate the ICFF performance. The simulated results showed that the ICFF performance is comparable to TCFF in terms of EO identification, except the lower PSR or more number probes that have a more negative effect on ICFF. Besides, the accuracy of amplitude identification is higher for ICFF than TCFF on all test conditions. Meanwhile, the higher accuracy of the reconstruction of ICFF was further verified in all measurement resonance analysis.
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Baumann, Markus, Christian Koch, and Stephan Staudacher. "Application of Neural Networks and Transfer Learning to Turbomachinery Heat Transfer." Aerospace 9, no. 2 (January 20, 2022): 49. http://dx.doi.org/10.3390/aerospace9020049.
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Model-based predictive maintenance using high-frequency in-flight data requires digital twins that can model the dynamics of their physical twin with high precision. The models of the twins need to be fast and dynamically updatable. Machine learning offers the possibility to address these challenges in modeling the transient performance of aero engines. During transient operation, heat transferred between the engine’s structure and the annulus flow plays an important role. Diabatic performance modeling is demonstrated using non-dimensional transient heat transfer maps and transfer learning to extend turbomachinery transient modeling. The general form of such a map for a simple system similar to a pipe is reproduced by a Multilayer Perceptron neural network. It is trained using data from a finite element simulation. In a next step, the network is transferred using measurements to model the thermal transients of an aero engine. Only a limited number of parameters measured during selected transient maneuvers is needed to generate suitable non-dimensional transient heat transfer maps. With these additional steps, the extended performance model matches the engine thermal transients well.
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Chen, Peter Y. P., Ningsheng Feng, Eric J. Hahn, and Wenlong Hu. "Recent Developments in Turbomachinery Modeling for Improved Balancing and Vibration Response Analysis." Journal of Engineering for Gas Turbines and Power 127, no. 3 (June 24, 2005): 646–53. http://dx.doi.org/10.1115/1.1850942.
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Present day turbogenerator installations are statically indeterminate rotor-bearing-foundation systems utilizing nonlinear hydrodynamic bearings. For optimal balancing and diagnostic purposes it is important to be able to correctly predict the system vibration behavior over the operating speed range. Essential aspects of this involve identifying the unbalance state, identifying appropriate dynamic foundation parameters, and identifying the system configuration state (relative location of the support bearings). This paper shows that, provided the system response is periodic at some speeds over the operating range and appropriate rotor and bearing housing motion measurements are made, it is possible, in principle, to satisfactorily achieve the above identifications without relying on the Reynolds equation for evaluating bearing forces. Preliminary results indicate that the identifications achieved promise to be superior to identification approaches that use the Reynolds equation.
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Olasek, Krzysztof, Maciej Karczewski, Michal Lipian, Piotr Wiklak, and Krzysztof Józwik. "Wind tunnel experimental investigations of a diffuser augmented wind turbine model." International Journal of Numerical Methods for Heat & Fluid Flow 26, no. 7 (September 5, 2016): 2033–47. http://dx.doi.org/10.1108/hff-06-2015-0246.
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Purpose A solution to increase the energy production rate of the wind turbine is proposed by forcing more air to move through the turbine working section. This can be achieved by equipping the rotor with a diffusing channel ended with a brim (diffuser augmented wind turbine – DAWT). The purpose of this paper is to design an experimental stand and perform the measurements of velocity vector fields through the diffuser and power characteristic of the wind turbine. Design/methodology/approach The experiments were carried out in a small subsonic wind tunnel at the Institute of Turbomachinery, Lodz University of Technology. An experimental stand design process as well as measurement results are presented. Model size sensitivity study was performed at the beginning. The experimental campaign consisted of velocity measurements by means of particle image velocimetry (PIV) and pneumatic pitot probe as well as torque and rotational velocity measurements. Findings Characteristics (power coefficient vs tip speed ratio) of the bare and shrouded wind turbine were obtained. The results show an increase in the wind turbine power up to 70-75 per cent by shrouding the rotor with a diffuser. The mechanisms responsible for such a power increase were well explained by the PIV and pneumatic measurement results revealing the nature of the flow through the diffuser. Research limitations/implications Experimental stand for wind turbine rotor testing is of a preliminary character. Most optimal methodology for obtaining power characteristic should be determined now. Presented results can serve as good input for choice of stable and reliable control system of wind turbine operational parameters. Practical implications A 3 kW DAWT is being developed at the Institute of Turbomachinery, Lodz University of Technology. Aim of the study is to design a compact and smart wind turbine optimised for low wind speed conditions. Developed wind turbine has a potential to be used as an effective element within a net of distributed generation, e.g. for domestic use. Originality/value Research carried out is the continuation of theoretical study began in 1970s. It was also inspired by practical solutions proposed by Japanese researchers few years ago. Presented paper is the summary of work devoted to optimisation of the DAWT for wind conditions in the region. Original solution has been applied, e.g. for experimental stand design (3D printing application).
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Kiock, R., F. Lehthaus, N. C. Baines, and C. H. Sieverding. "The Transonic Flow Through a Plane Turbine Cascade as Measured in Four European Wind Tunnels." Journal of Engineering for Gas Turbines and Power 108, no. 2 (April 1, 1986): 277–84. http://dx.doi.org/10.1115/1.3239900.
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Reliable cascade data are esssential to the development of high-speed turbomachinery, but it has long been suspected that the tunnel environment influences the test results. This has now been investigated by testing one plane gas turbine rotor blade section in four European wind tunnels of different test sections and instrumentation. The Reynolds number of the transonic flow tests was Re2 = 8 × 105 based on exit flow conditions. The turbulence was not increased artificially. A comparison of results from blade pressure distributions and wake traverse measurements reveals the order of magnitude of tunnel effects.
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Mathioudakis, K., A. Papathanasiou, E. Loukis, and K. Papailiou. "Fast Response Wall Pressure Measurement as a Means of Gas Turbine Blade Fault Identification." Journal of Engineering for Gas Turbines and Power 113, no. 2 (April 1, 1991): 269–75. http://dx.doi.org/10.1115/1.2906558.
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The distortions of the pressure field around rotating blades of turbomachinery components due to alterations of their shape can be utilized for the identification of faults related to the blading. Measurement of the unsteady pressure field near the wall provides information on such flow and pressure distortions and can thus be used for diagnostic purposes. An experimental investigation of the compressor rotating blade pressure field of an industrial gas turbine has been undertaken, in order to demonstrate the feasibility of the abovementioned principle. Various realistic gas turbine blade faults have been examined. Application of the appropriate processing techniques demonstrates that unsteady pressure measurements can be used to identify the occurrence of minor blade faults (not traceable by standard techniques) as well as the kind of fault. The proposed methodology has the potential for being incorporated in a computerized engine health monitoring system.
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Pinarbasi, A., K. M. Guleren, and A. Ozturk. "Measurements of Reynolds stresses in centrifugal compressor vaned diffusers." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 222, no. 8 (August 1, 2008): 1487–503. http://dx.doi.org/10.1243/09544062jmes877.
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A phase lock loop sampling technique has been developed in order to perform detailed measurements for the flow field downstream of a turbomachinery rotor. Measurements have been carried out in the vaned diffuser of a low-speed centrifugal compressor using a triple hot wire anemometer. The phase lock loop technique employed in this work has provided a comprehensive representation of the complex three-dimensional unsteady flow in these diffusers. The diffuser vanes were found to have a significant influence on the flow in the vaneless space. The mixing out of the blade wakes is enhanced and accordingly the Reynolds stress levels drop rapidly between the impeller exit and the vane leading edge. The results provide an insight into the flow mechanisms responsible for the losses and hence can be used to develop better design strategies in the future. The flow also exhibits high levels of anisotropy, especially at the mid-vane positions. This suggests that basic Reynolds-averaged Navier—Stokes (RANS) models, including standard one- or two-equation models, might not be sufficient to accurately model the flow in centrifugal compressor diffusers.
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Buttsworth, D. R., T. V. Jones, and K. S. Chana. "Unsteady Total Temperature Measurements Downstream of a High-Pressure Turbine." Journal of Turbomachinery 120, no. 4 (October 1, 1998): 760–67. http://dx.doi.org/10.1115/1.2841787.
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An experimental technique for the measurement of flow total temperature in a turbine facility is demonstrated. Two thin film heat transfer gases located at the stagnation point of fused quartz substrates are operated at different temperatures in order to determine the flow total temperature. With this technique, no assumptions regarding the magnitude of the convective heat transfer coefficient are made. Thus, the probe can operate successfully in unsteady compressible flows of arbitrary composition and high free-stream turbulence levels without a heat transfer law calibration. The operation of the total temperature probe is first demonstrated using a small wind tunnel facility. Based on results from the small wind tunnel tests, it appears that the probe total temperature measurements are accurate to within ±1 K. Experiments using the probe downstream of a high-pressure turbine stage are than described. Both high and low-frequency components of the flow total temperature can be accurately resolved with the present technique. The probe measures a time-averaged flow total temperature that is in good agreement with thermocouple measurements made downstream of the rotor. Frequencies as high as 182 kHz have been detected in the spectral analysis of the heat flux signals from the total probe. Through comparison with fast-response aerodynamic probe measurements, it is demonstrated that the current measurement location, the total temperature fluctuations arise mainly due to the isentropic extraction of work by the turbine. The present total temperature probe is demonstrated to be an accurate, robust, fast-response device that is suitable for operation in a turbomachinery environment.
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Joslyn, H. D., and R. P. Dring. "Axial Compressor Stator Aerodynamics." Journal of Engineering for Gas Turbines and Power 107, no. 2 (April 1, 1985): 485–92. http://dx.doi.org/10.1115/1.3239754.
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Axisymmetric, through-flow calculations, currently the “backbone” of most multistage turbomachinery design systems, are being pushed to their limit. This is due to the difference between the complex, three-dimensional flows that actually occur in turbomachinery and the two-dimensional flow assumed in this type of analysis. To foster the development of design analyses that account more accurately for these three-dimensional effects, there is a need for detailed flow field data in a multistage environment. This paper presents a survey of the initial results from a detailed experimental study of the aerodynamics of the second stage of a large scale, two-stage axial compressor. Data were acquired over a range of flow coefficients. The data presented here are for the second stator and include airfoil and endwall flow visualization, and radial-circumferential traverse measurements presented in the form of fullspan contour plots of total pressure. Also presented are the spanwise distributions of total and static pressures, axial velocity, air angles, and blockage. The effect of increased loading on the growth of the hub corner stall and its impact on these parameters is discussed.
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Sundermeier, Stephan, Maximilian Passmann, Stefan aus der aus der Wiesche, and Eugeny Y. Kenig. "Flow in Pillow-Plate Channels for High-Speed Turbomachinery Heat Exchangers." International Journal of Turbomachinery, Propulsion and Power 7, no. 2 (March 22, 2022): 12. http://dx.doi.org/10.3390/ijtpp7020012.
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In numerous turbomachinery applications, e.g., in aero-engines with regenerators for improving specific fuel consumption (SFC), heat exchangers with low-pressure loss are required. Pil low-plate heat exchangers (PPHE) are a novel exchanger type and promising candidates for high-speed flow applications due to their smooth profiles avoiding blunt obstacles in the flow path. This work deals with the overall system behavior and gas dynamics of pillow-plate channels. A pillow-plate channel was placed in the test section of a blow-down wind tunnel working with dry air, and compressible flow phenomena were investigated utilizing conventional and focusing schlieren optics; furthermore, static and total pressure measurements were performed. The experiments supported the assumption that the system behavior can be described through a Fanno–Rayleigh flow model. Since only wavy walls with smooth profiles were involved, linearized gas dynamics was able to cover important flow features within the channel. The effects of the wavy wall structures on pressure drop and Mach number distribution within the flow path were investigated, and a good qualitative agreement with theoretical and numerical predictions was found. The present analysis demonstrates that pressure losses in pillow-plate heat exchangers are rather low, although their strong turbulent mixing enables high convective heat transfer coefficients.