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Sample records for stage stator vane

  1. Numerical Investigation: Effect of Stator Vanes on Turbocharger Turbine Performance

    Directory of Open Access Journals (Sweden)

    Ganesh Yadagiri Rapolu

    2014-01-01

    Full Text Available With reduced turbo lag and better transient response, the introduction of VTG stator guide vanes improved turbocharger performance at all the engine operating conditions. The VTG system accelerates and maneuvers exhaust gas flow to the turbine. Favorable flow conditions at turbine inlet created by vane shape improve turbine performance. At lower engine speed, it is observed that the pressure drop across vane system influences overall efficiency. Whereas at higher speed, the pressure drop and guide vane exit flow angle are found to determine the turbine efficiency. Successful practical operation of VTG system also depends on its ability to smoothly open and close the vanes at different gas loads. Stator vane shape greatly influences the smooth operability/controllability of vane system. In the present work, 3 symmetric vanes with different T/C ratios and 2 asymmetric vanes are analyzed. The effect of geometric changes is studied from overall turbine performance as well as VTG system performance perspective. It is observed that symmetric vanes cause higher pressure drop at lower speeds leading to lower efficiency irrespective of the vane width. It is also observed that the pressure drop characteristics and vane exit flow angle are better with the asymmetric vanes, whereas the controllability of symmetric vanes is found to be superior. Analysis methodology is presented for achieving the best compromise between performance and controllability by the modification of vane geometric parameters through CFD simulations.

  2. Stochastic Behaviour of Mistuned Stator Vane Sectors: An Industrial Application

    Directory of Open Access Journals (Sweden)

    A.C. Sall

    2012-01-01

    Full Text Available Stator vanes which are found in axial compressors are subject to vibratory fatigue. Their division into monoblock sectors makes the prediction of their vibratory behaviour difficult by deterministic methods due to the loss of the cyclic symmetry properties and also to a high sensitivity to mistuning. The purpose is to present a robust calculation strategy based on a stochastic modelisation of the structure. The methodology has been developed first on a simplified model and then applied to an industrial case. Polynomial chaos based results are in good agreement with reference Monte Carlo simulations.

  3. The Off-Design Performance Simulation of Marine Gas Turbine Based on Optimum Scheduling of Variable Stator Vanes

    Directory of Open Access Journals (Sweden)

    Zhitao Wang

    2017-01-01

    Full Text Available As one of the antisurge techniques, the adjusting scheme of VSV under off-design conditions has a significant impact on the performance of gas turbines. In this paper, the one-dimensional characteristic of the compressor calculation program is embedded into the zero-dimensional overall gas turbine model, which replaces the original compressor characteristic module. Based on the assembling relationship of the actual components of the marine gas turbine, the architecture of the modular model library is designed, and an integrated simulation platform of marine gas turbine is developed by using MATLAB/GUI software. The influence of the first 3 rows of variable stator vanes of the 9-stage axial compressor working alone on the performance of the compressor at different speeds and different angles was analyzed by the HARIKA compressor characteristic calculation program. Taking the economics and stability of the gas turbine as the optimization objective, the optimization of the first three-stage stator vanes regulation schemes under different working conditions was carried out. The steady-state performance parameters under each working condition of gas turbine of power generation with or without variable stator vane mode were calculated. The study results can provide references for the adjusting scheme of VSV under gas turbine off-design conditions operating process.

  4. The Optimization of Four-Stage Low Pressure Turbine with Outlet Guide Vane

    Science.gov (United States)

    Matveev, V.; Baturin, O.; Popov, G.

    2018-01-01

    The goal of the research was to improve efficiency of four-stage low-pressure turbine with outlet guide vane (LPT) at the design point by optimization the shape of all turbine stator vanes and the stagger angles of all rotor blades. The LPT mathematical model was created by using NUMECA FineTurbo software. Several constraints were imposed the mass flow rate through the LPT and the total pressure ratio at the design point may vary within ±0.5% from the original. Parameters of the stator blade shape and rotor blades stagger angles were obtained. This new geometry of the LPT blades produce a 0.8% increase in efficiency at the design point.

  5. Study of controlled diffusion stator blading. 1. Aerodynamic and mechanical design report

    Science.gov (United States)

    Canal, E.; Chisholm, B. C.; Lee, D.; Spear, D. A.

    1981-01-01

    Pratt & Whitney Aircraft is conducting a test program for NASA in order to demonstrate that a controlled-diffusion stator provides low losses at high loadings and Mach numbers. The technology has shown great promise in wind tunnel tests. Details of the design of the controlled diffusion stator vanes and the multiple-circular-arc rotor blades are presented. The stage, including stator and rotor, was designed to be suitable for the first-stage of an advanced multistage, high-pressure compressor.

  6. Surface Temperature Measurements from a Stator Vane Doublet in a Turbine Engine Afterburner Flame Using a YAG:Tm Thermographic Phosphor

    Science.gov (United States)

    Eldridge, J. I.; Walker, D. G.; Gollub, S. L.; Jenkins, T. P.; Allison, S. W.

    2015-01-01

    Luminescence-based surface temperature measurements were obtained from a YAG:Tm-coated stator vane doublet exposed to the afterburner flame of a J85 test engine at University of Tennessee Space Institute (UTSI). The objective of the testing was to demonstrate that reliable surface temperatures based on luminescence decay of a thermographic phosphor producing short-wavelength emission could be obtained from the surface of an actual engine component in a high gas velocity, highly radiative afterburner flame environment. YAG:Tm was selected as the thermographic phosphor for its blue emission at 456 nm (1D23F4 transition) and UV emission at 365 nm (1D23H6 transition) because background thermal radiation is lower at these wavelengths, which are shorter than those of many previously used thermographic phosphors. Luminescence decay measurements were acquired using a probe designed to operate in the afterburner flame environment. The probe was mounted on the sidewall of a high-pressure turbine vane doublet from a Honeywell TECH7000 turbine engine coated with a standard electron-beam physical vapor deposited (EB-PVD) 200-m-thick TBC composed of yttria-stabilized zirconia (YSZ) onto which a 25-m-thick YAG:Tm thermographic phosphor layer was deposited by solution precursor plasma spray (SPPS). Spot temperature measurements were obtained by measuring luminescence decay times at different afterburner power settings and then converting decay time to temperature via calibration curves. Temperature measurements using the decays of the 456 and 365 nm emissions are compared. While successful afterburner environment measurements were obtained to about 1300C with the 456 nm emission, successful temperature measurements using the 365 nm emission were limited to about 1100C due to interference by autofluorescence of probe optics at short decay times.

  7. Effects of vane/blade ratio and spacing on fan noise, volume 1

    Science.gov (United States)

    Gliebe, P. R.; Kantola, R. A.

    1983-01-01

    The noise characteristics of a high-speed fan were studied. The experimental investigation was carried out on a 50.8 cm (20 in.) diameter scale model fan stage in an anechoic chamber with an inflow turbulence control screen installed. The forty-four blade rotor was tested with forty-eight vane and eighty-six vane stator rows, over a range of aixal rotor-stator spacings from 0.5 to 2.3 rotor tip chords. A two-dimensional strip theory model of rotor-stator interaction noise was employed to predict the measured tone power level trends, and good overall agreement with measured trends was obtained.

  8. An intracooling system for a novel two-stage sliding-vane air compressor

    Science.gov (United States)

    Murgia, Stefano; Valenti, Gianluca; Costanzo, Ida; Colletta, Daniele; Contaldi, Giulio

    2017-08-01

    Lube-oil injection is used in positive-displacement compressors and, among them, in sliding-vane machines to guarantee the correct lubrication of the moving parts and as sealing to prevent air leakage. Furthermore, lube-oil injection allows to exploit lubricant also as thermal ballast with a great thermal capacity to minimize the temperature increase during the compression. This study presents the design of a two-stage sliding-vane rotary compressor in which the air cooling is operated by high-pressure cold oil injection into a connection duct between the two stages. The heat exchange between the atomized oil jet and the air results in a decrease of the air temperature before the second stage, improving the overall system efficiency. This cooling system is named here intracooling, as opposed to intercooling. The oil injection is realized via pressure-swirl nozzles, both within the compressors and inside the intracooling duct. The design of the two-stage sliding-vane compressor is accomplished by way of a lumped parameter model. The model predicts an input power reduction as large as 10% for intercooled and intracooled two-stage compressors, the latter being slightly better, with respect to a conventional single-stage compressor for compressed air applications. An experimental campaign is conducted on a first prototype that comprises the low-pressure compressor and the intracooling duct, indicating that a significant temperature reduction is achieved in the duct.

  9. Effects of Stator Shroud Injection on the Aerodynamic Performance of a Single-Stage Transonic Axial Compressor

    International Nuclear Information System (INIS)

    Dinh, Cong-Truong; Ma, Sang-Bum; Kim, Kwang Yong

    2017-01-01

    In this study, stator shroud injection in a single-stage transonic axial compressor is proposed. A parametric study of the effect of stator shroud injection on aerodynamic performances was conducted using the three-dimensional Reynolds-averaged Navier-Stokes equations. The curvature, length, width, and circumferential angle of the stator shroud injector and the air injection mass flow rate were selected as the test parameters. The results of the parametric study show that the aerodynamic performances of the single-stage transonic axial compressor were improved by stator shroud injection. The aerodynamic performances were the most sensitive to the injection mass flow rate. Further, the total pressure ratio and adiabatic efficiency were the maximum when the ratio of circumferential angle was 10%.

  10. Effects of Stator Shroud Injection on the Aerodynamic Performance of a Single-Stage Transonic Axial Compressor

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, Cong-Truong; Ma, Sang-Bum; Kim, Kwang Yong [Inha Univ., Incheon (Korea, Republic of)

    2017-01-15

    In this study, stator shroud injection in a single-stage transonic axial compressor is proposed. A parametric study of the effect of stator shroud injection on aerodynamic performances was conducted using the three-dimensional Reynolds-averaged Navier-Stokes equations. The curvature, length, width, and circumferential angle of the stator shroud injector and the air injection mass flow rate were selected as the test parameters. The results of the parametric study show that the aerodynamic performances of the single-stage transonic axial compressor were improved by stator shroud injection. The aerodynamic performances were the most sensitive to the injection mass flow rate. Further, the total pressure ratio and adiabatic efficiency were the maximum when the ratio of circumferential angle was 10%.

  11. Laser anemometer measurements and computations for transonic flow conditions in an annular cascade of high turning core turbine vanes

    Science.gov (United States)

    Goldman, Louis J.

    1993-01-01

    An advanced laser anemometer (LA) was used to measure the axial and tangential velocity components in an annular cascade of turbine stator vanes operating at transonic flow conditions. The vanes tested were based on a previous redesign of the first-stage stator in a two-stage turbine for a high-bypass-ratio engine. The vanes produced 75 deg of flow turning. Tests were conducted on a 0.771-scale model of the engine-sized stator. The advanced LA fringe system employed an extremely small 50-micron diameter probe volume. Window correction optics were used to ensure that the laser beams did not uncross in passing through the curved optical access port. Experimental LA measurements of velocity and turbulence were obtained at the mean radius upstream of, within, and downstream of the stator vane row at an exit critical velocity ratio of 1.050 at the hub. Static pressures were also measured on the vane surface. The measurements are compared, where possible, with calculations from a three-dimensional inviscid flow analysis. Comparisons were also made with the results obtained previously when these same vanes were tested at the design exit critical velocity ratio of 0.896 at the hub. The data are presented in both graphical and tabulated form so that they can be readily compared against other turbomachinery computations.

  12. Laser anemometer measurements and computations in an annular cascade of high turning core turbine vanes

    Science.gov (United States)

    Goldman, Louis J.; Seasholtz, Richard G.

    1992-01-01

    An advanced laser anemometer (LA) was used to measure the axial and tangential velocity components in an annular cascade of turbine stator vanes designed for a high bypass ratio engine. These vanes were based on a redesign of the first-stage stator, of a two-stage turbine, that produced 75 degrees of flow turning. Tests were conducted on a 0.771 scale model of the engine size stator. The advanced LA fringe system was designed to employ thinner than usual laser beams resulting in a 50-micron-diameter probe volume. Window correction optics were used to ensure that the laser beams did not uncross in passing through the curved optical access port. Experimental LA measurements of velocity and turbulence were obtained both upstream, within, and downstream of the stator vane row at the design exit critical velocity ratio of 0.896 at the hub. Static pressures were also measured on the vane surface. The measurements are compared, where possible with calculations from a 3-D inviscid flow analysis. The data are presented in both graphic and tabulated form so that they may be readily used to compare against other turbomachinery computations.

  13. Analysis of the flow field into a two stages and double entry storage pump taking into account two geometries of stator blades

    International Nuclear Information System (INIS)

    Dunca, G; Isbasoiu, E C; Muntean, S

    2010-01-01

    The paper presents the 3D numerical analysis of the flow into a hydraulic passage of the two stages and double entry storage pump. One of the reasons for choosing this machinery was that, even from the beginning of its operation, high levels of noise and vibration were recorded. According to the literature, these can be considered as effects of the impeller-stator phenomenon. After only 100 hours of operation, the pump' first stator blades was bend and the second stator blades was broken. As a rehabilitation solution, 100 mm of the chord were cut from the stator blades, near the leading edge. After the rehabilitation, a decrease of the noise and vibration levels during pump operation was observed. In order to analyse the pump behaviour, three measurements campaigns were conducted, after the rehabilitation. Yet, the experimental results were not very conclusive. A more detailed experimental analysis on a real turbo machine is very difficult and expensive. Thus, in order to obtain more detailed information regarding the impeller-stator phenomenon inside the analysed pump, a numerical analysis was realized. The impeller-stator (between the first impeller and first stator as well as between second impeller and second stator) and stator-impeller (between the first stator and second impeller) interactions are taken into account with mixing interface method. The hydrodynamic field from the inlet to the outlet is obtained. As a result, the pressure rise and hydraulic efficiency are computed at best efficiency point. These values are validated against experimental data measured into the storage pump. Comparing the numerical results obtained for the two geometries of the stators, it can be seen that they have different behaviour during the pump's operation. It can be considered that, although the same geometry modification was realized for both the stators, the effects on the flow parameters are different, only for the second stator being possible to observe a net

  14. Analysis of the flow field into a two stages and double entry storage pump taking into account two geometries of stator blades

    Science.gov (United States)

    Dunca, G.; Muntean, S.; Isbasoiu, E. C.

    2010-08-01

    The paper presents the 3D numerical analysis of the flow into a hydraulic passage of the two stages and double entry storage pump. One of the reasons for choosing this machinery was that, even from the beginning of its operation, high levels of noise and vibration were recorded. According to the literature, these can be considered as effects of the impeller-stator phenomenon. After only 100 hours of operation, the pump' first stator blades was bend and the second stator blades was broken. As a rehabilitation solution, 100 mm of the chord were cut from the stator blades, near the leading edge. After the rehabilitation, a decrease of the noise and vibration levels during pump operation was observed. In order to analyse the pump behaviour, three measurements campaigns were conducted, after the rehabilitation. Yet, the experimental results were not very conclusive. A more detailed experimental analysis on a real turbo machine is very difficult and expensive. Thus, in order to obtain more detailed information regarding the impeller-stator phenomenon inside the analysed pump, a numerical analysis was realized. The impeller-stator (between the first impeller and first stator as well as between second impeller and second stator) and stator-impeller (between the first stator and second impeller) interactions are taken into account with mixing interface method. The hydrodynamic field from the inlet to the outlet is obtained. As a result, the pressure rise and hydraulic efficiency are computed at best efficiency point. These values are validated against experimental data measured into the storage pump. Comparing the numerical results obtained for the two geometries of the stators, it can be seen that they have different behaviour during the pump's operation. It can be considered that, although the same geometry modification was realized for both the stators, the effects on the flow parameters are different, only for the second stator being possible to observe a net

  15. Morphology of {gamma}' precipitates of nickel-based superalloy serviced as first stage high pressure turbine nozzle guide vane

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Nobuhiro; Nakada, Kouji; Kondo, Yoshihiro [National Defense Academy, Yokosuka, Kanagawa (Japan)

    2010-07-01

    The morphology of {gamma}' precipitates of the nickel-based superalloy serviced as the first stage high pressure turbine nozzle guide vane of the jet engine was examined. The aim of this work was to estimate the temperature and the stress distribution, and the stress direction of the vane in service. The vane was cut into four parts perpendicular to the longitudinal direction of the vane at 5, 25, 35 and 45mm from the root. These parts were designated as the root, 25mm, 35mm and tip parts. Microstructure observations by a FE-SEM were carried out on the forty-six portions at the vicinity of the interface between the coating layer and the matrix on the suction and pressure sides. At the root parts of the pressure and suction sides, most of the {gamma}' precipitates kept cuboidal in shape, and the secondary {gamma}' precipitates were observed in the {gamma} matrix channels. On the contrary, at the trailing edge side of the pressure and suction sides of the 25 and 35mm parts and at the leading edge of the pressure side of the tip part, well aligned rafted {gamma}/{gamma}' structures were appeared in the direction parallel to the surface at the vicinity of the interface of the vane. Furthermore, at the trailing edge of the pressure side of the middle parts, the rafted {gamma}/{gamma}' structures start to collapse. Consequently, the vane in service, at the trailing edge sides of the pressure side the 25 and 35mm parts were exposed to the highest temperature and stress conditions. And this microstructure evidence indicated that the multi-axial compressive stress parallel to the nozzle surface was expected to act on the vane in service. (orig.)

  16. On a two-dimensional mode-matching technique for sound generation and transmission in axial-flow outlet guide vanes

    Science.gov (United States)

    Bouley, Simon; François, Benjamin; Roger, Michel; Posson, Hélène; Moreau, Stéphane

    2017-09-01

    The present work deals with the analytical modeling of two aspects of outlet guide vane aeroacoustics in axial-flow fan and compressor rotor-stator stages. The first addressed mechanism is the downstream transmission of rotor noise through the outlet guide vanes, the second one is the sound generation by the impingement of the rotor wakes on the vanes. The elementary prescribed excitation of the stator is an acoustic wave in the first case and a hydrodynamic gust in the second case. The solution for the response of the stator is derived using the same unified approach in both cases, within the scope of a linearized and compressible inviscid theory. It is provided by a mode-matching technique: modal expressions are written in the various sub-domains upstream and downstream of the stator as well as inside the inter-vane channels, and matched according to the conservation laws of fluid dynamics. This quite simple approach is uniformly valid in the whole range of subsonic Mach numbers and frequencies. It is presented for a two-dimensional rectilinear-cascade of zero-staggered flat-plate vanes and completed by the implementation of a Kutta condition. It is then validated in sound generation and transmission test cases by comparing with a previously reported model based on the Wiener-Hopf technique and with reference numerical simulations. Finally it is used to analyze the tonal rotor-stator interaction noise in a typical low-speed fan architecture. The interest of the mode-matching technique is that it could be easily transposed to a three-dimensional annular cascade in cylindrical coordinates in a future work. This makes it an attractive alternative to the classical strip-theory approach.

  17. Sliding vane geometry turbines

    Science.gov (United States)

    Sun, Harold Huimin; Zhang, Jizhong; Hu, Liangjun; Hanna, Dave R

    2014-12-30

    Various systems and methods are described for a variable geometry turbine. In one example, a turbine nozzle comprises a central axis and a nozzle vane. The nozzle vane includes a stationary vane and a sliding vane. The sliding vane is positioned to slide in a direction substantially tangent to an inner circumference of the turbine nozzle and in contact with the stationary vane.

  18. On the study of wavy leading-edge vanes to achieve low fan interaction noise

    Science.gov (United States)

    Tong, Fan; Qiao, Weiyang; Xu, Kunbo; Wang, Liangfeng; Chen, Weijie; Wang, Xunnian

    2018-04-01

    The application of wavy leading-edge vanes to reduce a single-stage axial fan noise is numerically studied. The aerodynamic and acoustic performance of the fan is numerically investigated using a hybrid unsteady Reynolds averaged Navier-Stokes (URANS)/acoustic analogy method (Goldstein equations). First, the hybrid URANS/Goldstein method is developed and successfully validated against experiment results. Next, numerical simulations are performed to investigate the noise reduction effects of the wavy leading-edge vanes. The aerodynamic and acoustic performance is assessed for a fan with vanes equipped with two different wavy leading-edge profiles and compared with the performance of conventional straight leading-edge vanes. Results indicate that a fan with wavy leading-edge vanes produces lower interaction noise than the baseline fan without a significant loss in aerodynamic performance. In fact, it is demonstrated that wavy leading-edge vanes have the potential to lead to both aerodynamic and acoustic improvements. The two different wavy leading-edge profiles are shown to successfully reduce the fan tone sound power level by 1.2 dB and 4.3 dB, respectively. Fan efficiency is also improved by about 1% with one of the tested wavy leading-edge profiles. Large eddy simulation (LES) is also performed for a simplified fan stage model to assess the effects of wavy leading-edge vanes on the broadband fan noise. Results indicate that the overall sound power level of a fan can be reduced by about 4 dB with the larger wavy leading-edge profile. Finally, the noise reduction mechanisms are investigated and analysed. It is found that the wavy leading-edge profiles can induce significant streamwise vorticity around the leading-edge protuberances and reduce pressure fluctuations (especially at locations of wavy leading-edge hills) and unsteady forces on the stator vanes. The underlying mechanism of the reduced pressure fluctuations is also discussed by examining the magnitude

  19. Influence of Upstream and Downstream Compressor Stators on Rotor Exit Flow Field

    Directory of Open Access Journals (Sweden)

    Nicole L. Key

    2014-01-01

    Full Text Available Measurements acquired at the rotor exit plane illuminate the interaction of the rotor with the upstream vane row and the downstream vane row. The relative phase of the upstream and downstream vane rows is adjusted using vane clocking so that the effect of the upstream propagating potential field from the downstream stator can be distinguished from the effects associated with the wakes shed from the upstream stator. Unsteady absolute flow angle information shows that the downstream potential field causes the absolute flow angle to increase in the vicinity of the downstream stator leading edge. The presence of Stator 1 wake is also detected at this measurement plane using unsteady total pressure data. The rotor wakes are measured at different circumferential locations across the vane passage, and the influence of Stator 1 wake on the suction side of the rotor wake is evident. Also, the influence of the downstream stator is detected on the pressure side of the rotor wake for a particular clocking configuration. Understanding the role of the surrounding vane rows on rotor wake development will lead to improved comparison between experimental data and results from computational models.

  20. Study of blade aspect ratio on a compressor front stage aerodynamic and mechanical design report

    Science.gov (United States)

    Burger, G. D.; Lee, D.; Snow, D. W.

    1979-01-01

    A single stage compressor was designed with the intent of demonstrating that, for a tip speed and hub-tip ratio typical of an advanced core compressor front stage, the use of low aspect ratio can permit high levels of blade loading to be achieved at an acceptable level of efficiency. The design pressure ratio is 1.8 at an adiabatic efficiency of 88.5 percent. Both rotor and stator have multiple-circular-arc airfoil sections. Variable IGV and stator vanes permit low speed matching adjustments. The design incorporates an inlet duct representative of an engine transition duct between fan and high pressure compressor.

  1. Effect of Modifications to Induction System on Altitude Performance of V-1710-93 Engine III : Use of Parabolic Rotating Guide Vanes and NACA Designed Auxiliary-stage Inlet Elbow and Interstage Duct

    Science.gov (United States)

    Standahar, Ray M; Mccarty, James S

    1947-01-01

    Bench runs of a modified V-1710-93 engine equipped with a two-stage supercharger, interstage carburetor, aftercooler assembly, and backfire screens have been made at a simulated altitude of 29,000 feet to determine the effect of several induction-system modifications on the engine and supercharger performance. The standard guide vanes on the auxiliary- and engine-stage superchargers were replaced by rotating guide vanes with a parabolic blade profile. The auxiliary-stage inlet elbow and interstage duct were replaced with new units of NACA design. These modifications were made one at a time and data were obtained after each change to determine the effect of each modification. All runs were made at a constant engine speed of 3000 rpm at a simulated altitude of 29,000 feet and all changes in engine power were made by varying the speed of the auxiliary-stage supercharger.

  2. Mixing vane grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Galbraith, K.P.

    1978-01-01

    An improved mixing vane grid spacer having enhanced flow mixing capability by virtue of mixing vanes being positioned at welded intersecting joints of the spacer wherein each mixing vane has an opening or window formed therein substantially directly over the welded joint to provide improved flow mixing capability is described. Some of the vanes are slotted, depending on their particular location in the spacers. The intersecting joints are welded by initially providing consumable tabs at and within each window, which are consumed during the welding of the spacer joints

  3. Rumsansning mellem vane og oplevelse

    DEFF Research Database (Denmark)

    Reeh, Henrik

    2004-01-01

    Walter Benjamin, Steen Eiler Rasmussen, arkitektur, sansning, vane, taktilitet, oplevelse, erfaring, Rom......Walter Benjamin, Steen Eiler Rasmussen, arkitektur, sansning, vane, taktilitet, oplevelse, erfaring, Rom...

  4. Structural Stator Spacers

    DEFF Research Database (Denmark)

    Rasmussen, Peter Omand; Andreasen, Jens H.; Pijanowski, J. M.

    2001-01-01

    This paper presents a powerful new design aspect to reduce acoustic noise and vibration of electro-magnetic origin for electrical machines, by introducing improved slot wedges referred to as "Structural Stator Spacers". These spacers, by using a very stiff dielectric and non magnetic material, a ...

  5. Optimization of submerged vane parameters

    Indian Academy of Sciences (India)

    H Sharma

    experimentally obtained the optimum vane sizes and recommended that it can be used for vane design. This ..... lift produced around the hydro-foil. More is .... energy. The reason behind this drop is that the vortices separate from the vane, which is acting as source of tur- bulence generation is now far away from the vortices.

  6. Sideload vanes for fluid pump

    Science.gov (United States)

    Erler, Scott R. (Inventor); Dills, Michael H. (Inventor); Rodriguez, Jose L. (Inventor); Tepool, John Eric (Inventor)

    2010-01-01

    A fluid pump assembly includes a rotatable component that can be rotated about an axis and a static vane assembly located adjacent to the rotatable component. The static vane assembly includes a circumferential surface axially spaced from the rotatable component, and one or more vanes extending from the circumferential surface toward the rotatable component. The one or more vanes are configured to produce a radial load on the rotatable component when the rotatable component is rotating about the axis and a fluid is present between the static vane assembly and the rotatable component.

  7. Wind vanes in the antiquity

    Science.gov (United States)

    Lindgrén, S.; Neumann, J.

    1983-06-01

    Mesopotamia: An Akkadian tablet, the original of which was incised between about 1800 and 1600 B.C., makes explicit mention of a wind vane. Further three Sumero-Akkadian “dictionaries” have three different names for the single Akkadian name for wind vane. Since the latest period of flourishing of the Sumerian civilization took place between about 2 100 and 2000 B.C., wind vanes must have been in use in ancient Mesopotamia already about 4000 years ago, i.e. about 2000 years before the Chinese and Greeks had wind vanes. The Mesopotamian wind vanes were made of wood. China: It appears from the old Chinese literature that streamers were in use about the 2nd century B.C. in China for wind vanes. Shortly thereafter, a wind vane in the shape of a bird made of bronze is mentioned in the literature. Greece: The wind vane in the shape of a triton that was fixed, according to Vitruvius, to the top of the Tower of Winds at Athens, must have disappeared before A.D. 1436. Roman Empire: According to a passage in Dio Chrysostom's writtings, streamers appear to have been used for wind vanes. What seems to be the first wind vane in the shape of a cock, was erected in the 2nd century A.D. on the top of the mausoleum of the Flavians, in a North African province of the Roman Empire.

  8. Gas turbine vane platform element

    Science.gov (United States)

    Campbell, Christian X [Oviedo, FL; Schiavo, Anthony L [Oviedo, FL; Morrison, Jay A [Oviedo, FL

    2012-08-28

    A gas turbine CMC shroud plate (48A) with a vane-receiving opening (79) that matches a cross-section profile of a turbine vane airfoil (22). The shroud plate (48A) has first and second curved circumferential sides (73A, 74A) that generally follow the curves of respective first and second curved sides (81, 82) of the vane-receiving opening. Walls (75A, 76A, 77A, 78A, 80, 88) extend perpendicularly from the shroud plate forming a cross-bracing structure for the shroud plate. A vane (22) may be attached to the shroud plate by pins (83) or by hoop-tension rings (106) that clamp tabs (103) of the shroud plate against bosses (105) of the vane. A circular array (20) of shroud plates (48A) may be assembled to form a vane shroud ring in which adjacent shroud plates are separated by compressible ceramic seals (93).

  9. Capacity control of rotary vane apparatus

    International Nuclear Information System (INIS)

    Roberts, R. W.

    1985-01-01

    A capacity control arrangement for a rotary vane fluid displacement apparatus, such as a rotary vane compressor, having a vane retaining means that normally engages and retains the vanes in their retracted or nonworking position within the rotor defined guide slits of such rotary vane compressor. The retaining means are actuated to the vane-disengaged position by hydraulic control fluid which is communicated to the retaining means in response to an external parameter sensed by a control means

  10. Optimization of submerged vane parameters

    Indian Academy of Sciences (India)

    Submerged vanes are airfoils which are in general placed at certain angle with respect to the flow direction in a channel to induce artificial circulations downstream. By virtue of these artificially generated circulations, submerged vanes were utilized to protect banks of rivers against erosion, to control shifting of rivers, to avoid ...

  11. Measurement and calculation of nozzle guide vane end wall heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, N.W.; Rose, M.G.; Coupland, J. [Rolls-Royce plc, Derby (United Kingdom); Jones, T.V. [Univ. of Oxford, Derby (United Kingdom). Dept. of Engineering Science

    1999-04-01

    A three-dimensional steady viscous finite volume pressure correction method for the solution of the Reynolds-averaged Navier-Stokes equations has been used to calculate the heat transfer rates on the end walls of a modern High Pressure Turbine first-stage stator. Surface heat transfer rates have been calculated at three conditions and compared with measurements made on a model of the vane tested in annular cascade in the Isentropic Light Piston Facility at DERA, Pyestock. The NGV Mach numbers, Reynolds numbers, and geometry are fully representative of engine conditions. Design condition data have previously been presented by Harvey and Jones (1990). Off-design data are presented here for the first time. In the areas of highest heat transfer, the calculated heat transfer rates are shown to be within 20% of the measured values at all three conditions. Particular emphasis is placed on the use of wall functions in the calculations with which relatively coarse grids (of around 140,000 nodes) can be used to keep computational run times sufficiently low for engine design purposes.

  12. High-loading, 1800 ft/sec tip speed transonic compressor fan stage. 1: Aerodynamic and mechanical design

    Science.gov (United States)

    Morris, A. L.; Halle, J. E.; Kennedy, E. E.

    1972-01-01

    A single stage fan with a tip speed of 1800 ft/sec (548.6m/sec) and hub/tip ratio of 0.5 was designed to produce a pressure ratio of 2.285:1 with an adiabatic efficiency of 84.0%. The design flow per inlet annulus area is 38.7 lbm/sq ft-sec (188.9KG/sqm-sec). Rotor blades have modified multiple-circular-arc and precompression airfoil sections. The stator vanes have multiple-circular-arc airfoil sections.

  13. Turbofan gas turbine engine with variable fan outlet guide vanes

    Science.gov (United States)

    Wood, Peter John (Inventor); Zenon, Ruby Lasandra (Inventor); LaChapelle, Donald George (Inventor); Mielke, Mark Joseph (Inventor); Grant, Carl (Inventor)

    2010-01-01

    A turbofan gas turbine engine includes a forward fan section with a row of fan rotor blades, a core engine, and a fan bypass duct downstream of the forward fan section and radially outwardly of the core engine. The forward fan section has only a single stage of variable fan guide vanes which are variable fan outlet guide vanes downstream of the forward fan rotor blades. An exemplary embodiment of the engine includes an afterburner downstream of the fan bypass duct between the core engine and an exhaust nozzle. The variable fan outlet guide vanes are operable to pivot from a nominal OGV position at take-off to an open OGV position at a high flight Mach Number which may be in a range of between about 2.5-4+. Struts extend radially across a radially inwardly curved portion of a flowpath of the engine between the forward fan section and the core engine.

  14. Performance of an Active Noise Control System for Fan Tones Using Vane Actuators

    Science.gov (United States)

    Sutliff, Daniel L.; Curtis, Alan R. D.; Heidelberg, Laurence J.; Remington, Paul J.

    2000-01-01

    An Active Noise Control (ANC) system for ducted fan noise was built that uses actuators located in stator vanes. The custom designed actuators A,ere piezoelectric benders manufactured using THUNDER technology. The ANC system was tested in the NASA Active Noise Control Fan rig. A total of 168 actuators in 28 stator vanes were used (six per vane). Simultaneous inlet and exhaust acoustic power level reductions were demonstrated for a fan modal structure that contained two radial modes in each direction. Total circumferential mode power levels were reduced by up to 9 dB in the inlet and 3 dB in the exhaust. The corresponding total 2BPF tone level reductions were by 6 dB in the inlet and 2 dB in the exhaust. Farfield sound pressure level reductions of up to 17 dB were achieved at the peak mode lobe angle. The performance of the system was limited by the constraints of the power amplifiers and the presence of control spillover. Simpler control/actuator systems using carefully selected subsets of the full system and random simulated failures of up to 7% of the actuators were investigated. (The actuators were robust and none failed during the test). Useful reductions still occurred under these conditions.

  15. Transonic Axial Splittered Rotor Tandem Stator Stage

    Science.gov (United States)

    2016-12-01

    you provided. Andria Holmes, thank you for our weekly sports discussions and all the help you provided. Dr. Platzer, thank you for sharing your...vertical Z direction. The extruder works in the same manner as a hot glue gun tip. Electrical coils heat the tip of the extruder and melt the plastic...change of enthalpy, equation 4, is equated to the product of the specific heat capacity at constant pressure and the change of temperature between

  16. Flow characteristics of guide vane of diffuser pump by PIV measurement

    International Nuclear Information System (INIS)

    Kim, J. H.; Lee, Young Ho; Choi, J. W.; Kim, M. Y.; Lee, H.

    2000-01-01

    The present experimental study is focused on the application of multi-point simultaneous measurement by PIV(Particle Image Velocimetry) to guide vane region within a diffuser pump. Various different kinds of clearance were selected as experimental conditions. Optimized cross correlation identification to obtain velocity vectors was implemented with direct calculation of correlation coefficients. Fine optical setup important in PIV performance is arranged for the accurate PIV measurement of high-speed complex flow. Various flow patterns are represented quantitatively at the stator passages

  17. Unsteady adjoint for large eddy simulation of a coupled turbine stator-rotor system

    Science.gov (United States)

    Talnikar, Chaitanya; Wang, Qiqi; Laskowski, Gregory

    2016-11-01

    Unsteady fluid flow simulations like large eddy simulation are crucial in capturing key physics in turbomachinery applications like separation and wake formation in flow over a turbine vane with a downstream blade. To determine how sensitive the design objectives of the coupled system are to control parameters, an unsteady adjoint is needed. It enables the computation of the gradient of an objective with respect to a large number of inputs in a computationally efficient manner. In this paper we present unsteady adjoint solutions for a coupled turbine stator-rotor system. As the transonic fluid flows over the stator vane, the boundary layer transitions to turbulence. The turbulent wake then impinges on the rotor blades, causing early separation. This coupled system exhibits chaotic dynamics which causes conventional adjoint solutions to diverge exponentially, resulting in the corruption of the sensitivities obtained from the adjoint solutions for long-time simulations. In this presentation, adjoint solutions for aerothermal objectives are obtained through a localized adjoint viscosity injection method which aims to stabilize the adjoint solution and maintain accurate sensitivities. Preliminary results obtained from the supercomputer Mira will be shown in the presentation.

  18. Analysis of Pressure Pulsation Induced by Rotor-Stator Interaction in Nuclear Reactor Coolant Pump

    Directory of Open Access Journals (Sweden)

    Xu Zhang

    2017-01-01

    Full Text Available The internal flow of reactor coolant pump (RCP is much more complex than the flow of a general mixed-flow pump due to high temperature, high pressure, and large flow rate. The pressure pulsation that is induced by rotor-stator interaction (RSI has significant effects on the performance of pump; therefore, it is necessary to figure out the distribution and propagation characteristics of pressure pulsation in the pump. The study uses CFD method to calculate the behavior of the flow. Results show that the amplitudes of pressure pulsation get the maximum between the rotor and stator, and the dissipation rate of pressure pulsation in impellers passage is larger than that in guide vanes passage. The behavior is associated with the frequency of pressure wave in different regions. The flow rate distribution is influenced by the operating conditions. The study finds that, at nominal flow, the flow rate distribution in guide vanes is relatively uniform and the pressure pulsation amplitude is the smallest. Besides, the vortex shedding or backflow from the impeller blade exit has the same frequency as pressure pulsation but there are phase differences, and it has been confirmed that the absolute value of phase differences reflects the vorticity intensity.

  19. A Novel Numerical Approach for Generation and Propagation of Rotor-Stator Interaction Noise

    Science.gov (United States)

    Patel, Krishna

    As turbofan engine designs move towards bypass ratios ≥12 and corresponding low pressure ratios, fan rotor blade tip Mach numbers are reduced, leading to rotor-stator interaction becoming an important contributor to tonal fan noise. For future aircraft configurations employing boundary layer ingestion, non-uniform flow enters the fan. The impact of such non-uniform flows on the generation and propagation of rotor-stator interaction tones has yet to be assessed. In this thesis, a novel approach is proposed to numerically predict the generation and propagation of rotor-stator interaction noise with distorted inflow. The approach enables a 42% reduction in computational cost compared to traditional approaches employing a sliding interface between the rotor and stator. Such an interface may distort rotor wakes and can cause non-physical acoustic wave reflections if time steps are not sufficiently small. Computational costs are reduced by modelling the rotor using distributed, volumetric body forces. This eliminates the need for a sliding interface and thus allows a larger time step size. The force model responds to local flow conditions and thus can capture the effects of long-wavelength flow distortions. Since interaction noise is generated by the incidence of the rotor wakes onto the stator vanes, the key challenge is to produce the wakes using a body force field since the rotor blades are not directly modelled. It is shown that such an approach can produce wakes by concentrating the viscous forces along streamtubes in the last 15% chord. The new approach to rotor wake generation is assessed on the GE R4 fan from NASA's Source Diagnostic Test, for which the computed overall aerodynamic performance matches the experiment to within 1%. The rotor blade wakes are generated with widths in excellent agreement and depths in fair agreement with the experiment. An assessment of modal sound power levels computed in the exhaust duct indicates that this approach can be used

  20. Brittle Materials Design High Temperature Gas Turbine Stator Vane Development and Static Rig Tests. Volume 2

    Science.gov (United States)

    1976-12-01

    of this analysis. Analogous to the practice of crowning steel rollers (blending large radii to taper the ends), 0.250 inch edge radii were introduced...Materials 59 A cursory review of low conductivity materials indicated that reaction sintered silicon nitride or high density stabilized zirconia would

  1. Numerical Investigation of Compressor Non-Synchronous Vibration with Full Annulus Rotor-Stator Interaction

    Science.gov (United States)

    Espinal, Daniel

    circumferentially averaged parameters like total pressure ratio, NSV is observed to have an effect, particularly at radial locations above 70% span. Therefore, to achieve similar or better total pressure ratio a design with a smaller loading of the upper blade span and a higher loading of the mid blade spans should be considered. A fully-conservative sliding interface boundary condition (BC) is implemented with phase-lag capabilities using the Direct Store method for single-passage simulations. Also Direct Store phase-lag was applied to the circumferential BCs to enforce longer disturbance wavelengths. The unsteady simulation using single-blade-passage with periodic BC for an inlet guide vane (IGV)-rotor configuration captures a 2291 Hz NSV excitation frequency and an IGV-rotor-stator configuration predicts a 2365 Hz NSV excitation frequency with a significantly higher amplitude above 90% span. This correlates closely to the predicted NSV excitation frequency of 2439 Hz for the full-annulus configuration. The two-blade-row configuration exhibits the same vortex structures captured in the full-annulus study. The three-blade-row configuration only captures a tip vortex shedding at the leading edge, which can be attributed to the reflective nature of the BCs causing IGV-rotor-stator interactions to be augmented, becoming dominant and shifting NSV excitation response to engine order regime. Phase-lag simulations with a Nodal Diameter (ND) of 5 is enforced for the circumferential BCs for the three-blade-row configuration, and the results exactly matched the frequency response and flow structures of the periodic simulation, illustrating the small effect that phase-lag has on strongly periodic flow disturbances. A ND of 7 is enforced at the sliding interface, however the NSV excitation completely disappears and only the wake propagation from IGV-Rotor-Stator interactions are captured. Rotor blade passage exhibits a circumferentially travelling vortex similar to those observed in the full

  2. Flow control in axial fan inlet guide vanes by synthetic jets

    Directory of Open Access Journals (Sweden)

    Wurst P.

    2013-04-01

    Full Text Available Tested high pressure axial flow fan with hub/tip ratio of 0.70 and external diameter of 600 mm consisted of inlet guide vanes (IGV, rotor and stator blade rows. Fan peripheral velocity was 47 m/s. Air volume flow rate was changed by turning of rear part of the inlet guide vanes. At turning of 20 deg the flow was separated on the IGV profiles. The synthetic jets were introduced through radial holes in machine casing in the location before flow separation origin. Synthetic jet actuator was designed with the use of a speaker by UT AVCR. Its membrane had diameter of 63 mm. Excitation frequency was chosen in the range of 500 Hz – 700 Hz. Synthetic jets favourably influenced separated flow on the vane profiles in the distance of (5 – 12 mm from the casing surface. The reduction of flow separation area caused in the region near the casing the decrease of the profile loss coefficient approximately by 20%.

  3. Stator Fault Modelling of Induction Motors

    DEFF Research Database (Denmark)

    Thomsen, Jesper Sandberg; Kallesøe, Carsten

    2006-01-01

    In this paper a model of an induction motor affected by stator faults is presented. Two different types of faults are considered, these are; disconnection of a supply phase, and inter-turn and turn-turn short circuits inside the stator. The output of the derived model is compared to real measurem......In this paper a model of an induction motor affected by stator faults is presented. Two different types of faults are considered, these are; disconnection of a supply phase, and inter-turn and turn-turn short circuits inside the stator. The output of the derived model is compared to real...... measurements from a specially designed induction motor. With this motor it is possible to simulate both terminal disconnections, inter-turn and turn-turn short circuits. The results show good agreement between the measurements and the simulated signals obtained from the model. In the tests focus...

  4. Shaft MisalignmentDetectionusing Stator Current Monitoring

    OpenAIRE

    Alok Kumar Verma, Somnath Sarangi and M.H. Kolekar

    2013-01-01

    This paper inspects the misaligned of shaft by usingdiagnostic medium such as current and vibration.Misalignments in machines can cause decrease inefficiency and in the long-run it may cause failurebecause of unnecessary vibration, stress on motor,bearings and short-circuiting in stator and rotorwindings.In this study, authors investigate the onsetof instability on a shaft mounted on journal bearings.Shaft displacement and stator current samples duringmachine run up under misaligned condition...

  5. Stator Fault Modelling of Induction Motors

    DEFF Research Database (Denmark)

    Thomsen, Jesper Sandberg; Kallesøe, Carsten

    2006-01-01

    In this paper a model of an induction motor affected by stator faults is presented. Two different types of faults are considered, these are; disconnection of a supply phase, and inter-turn and turn-turn short circuits inside the stator. The output of the derived model is compared to real...... is on the phase currents and the star point voltage as these signals are often used for fault detection....

  6. Stay vane and wicket gate relationship study

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2005-01-19

    This report evaluates potential environmental and performance gains that can be achieved in a Kaplan turbine through non-structural modifications to stay vane and wicket gate assemblies. This summary is based primarily on data and conclusions drawn from models and studies of Lower Granite Dam. Based on this investigation, the study recommends (1) a proof of concept at Lower Granite Dam to establish predicted improvements for the existing turbine and to further refine the stay vane wicket gate designs for fish passage; and (2) consideration of the stay vane wicket gate systems in any future turbine rehabilitation studies.

  7. Three component laser anemometer measurements in an annular cascade of core turbine vanes with contoured end wall

    Science.gov (United States)

    Goldman, Louis J.; Seasholtz, Richard G.

    1988-01-01

    The three mean velocity components were measured in a full-scale annular turbine stator cascade with contoured hub end wall using a newly developed laser anemometer system. The anemometer consists of a standard fringe configuration using fluorescent seed particles to measure the axial and tangential components. The radial component is measured with a scanning confocal Fabry-Perot interferometer. These two configurations are combined in a single optical system that can operate simultaneously in a backscatter mode through a single optical access port. Experimental measurements were obtained both within and downstream of the stator vane row and compared with calculations from a three-dimensional inviscid computer program. In addition, detailed calibration procedures are described that were used, prior to the experiment, to accurately determine the laser beam probe volume location relative to the cascade hardware.

  8. Numerical study of pressure fluctuations in different guide vanes' opening angle in pump mode of a pump turbine

    International Nuclear Information System (INIS)

    Sun, Y K; Zuo, Z G; Liu, S H; Wu, Y L; Liu, J T

    2012-01-01

    A numerical model based on a pumped storage power station was built to develop the numerical simulation, to analyze the pressure fluctuations in a pump turbine in different guide vanes' opening angle. The different guide vanes' opening angles were simulated using the SST k-ω turbulence model and SIMPLEC Pressure-Velocity coupling scheme. The pressure sensor were placed in mainly three positions, they are: bottom ring between runner and the wicket gates, downstream and left side in the draft tube cone below the runner. All the peak to peak values of pressure fluctuation meet signal probability of 97%. The frequency is gained by Fast Fourier Transform. The pressure fluctuations in different positions of the model in pump condition were showed when the guide vanes' opening angels were different. The simulation results confirmed the results gained in model tests. The results show that pressure fluctuations in design opening angle were much lower than those in off design opening angle. The main source of pressure fluctuations between runner and guide vanes is rotor stator interaction. While a lower frequency is the main frequency of the pressure fluctuation in draft tube.

  9. 2012 SRNL-EM VANE RHEOLOGY RESULTS

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, E.; Marzolf, A.; Hera, K.

    2012-08-31

    The vane method has been shown to be an effective tool in measuring the yield stress of both settled and mixed slurries in laboratory bench scale conditions in supporting assessments of both actual and simulant waste slurries. The vane has also been used to characterize dry powders and granular solids, the effect of non-cohesive solids with interstitial fluids and used as a guide to determine if slip is present in the geometries typically used to perform rheological flow curve measurements. The vane has been extensively characterized for measuring the shear strength in soils in both field and laboratory studies. The objectives for this task are: Fabricate vane instrument; Bench top testing to further characterize the effect of cohesive, non-cohesive, and blends of cohesive/non-cohesive simple simulants; Data from measurement of homogenized and settled bed of Kaolin sludge and assessment of the technology. In this document, the assessment using bench scale measurements of non-cohesive materials (beads) and cohesive materials (kaolin) is discussed. The non-cohesive materials include various size beads and the vane was assessed for depth and deaeration (or packing) via tapping measurements. For the cohesive (or non-Newtonian) materials, flow curves and yield stress measurements are performed using the vane and this data is compared to the traditional concentric cylinder flow curve measurement. Finally, a large scale vane was designed, fabricated, and tested with the cohesive (or non-Newtonian) materials to determine how a larger vane performs in measuring the yield stress and flow curve of settled cohesive solids.

  10. Solar energy system with wind vane

    Science.gov (United States)

    Grip, Robert E

    2015-11-03

    A solar energy system including a pedestal defining a longitudinal axis, a frame that is supported by the pedestal and that is rotateable relative to the pedestal about the longitudinal axis, the frame including at least one solar device, and a wind vane operatively connected to the frame to urge the frame relative to the pedestal about the longitudinal axis in response to wind acting on the wind vane.

  11. An Algorithm for Induction Motor Stator Flux Estimation

    Directory of Open Access Journals (Sweden)

    STOJIC, D. M.

    2012-08-01

    Full Text Available A new method for the induction motor stator flux estimation used in the sensorless IM drive applications is presented in this paper. Proposed algorithm advantageously solves problems associated with the pure integration, commonly used for the stator flux estimation. An observer-based structure is proposed based on the stator flux vector stationary state, in order to eliminate the undesired DC offset component present in the integrator based stator flux estimates. By using a set of simulation runs it is shown that the proposed algorithm enables the DC-offset free stator flux estimated for both low and high stator frequency induction motor operation.

  12. Control rod drive mechanism stator loss of coolant test

    International Nuclear Information System (INIS)

    Besel, L.; Ibatuan, R.

    1977-04-01

    This report documents the stator loss of coolant test conducted at HEDL on the lead unit Control Rod Drive Mechanism (CRDM) in February, 1977. The purpose of the test was to demonstrate scram capability of the CRDM with an uncooled stator and to obtain a time versus temperature curve of an uncooled stator under power. Brief descriptions of the test, hardware used, and results obtained are presented in the report. The test demonstrated that the CRDM could be successfully scrammed with no anomalies in both the two-phase and three-phase stator winding hold conditions after the respective equilibrium stator temperatures had been obtained with no stator coolant

  13. Advanced Low-Noise Research Fan Stage Design

    Science.gov (United States)

    Neubert, Robert; Bock, Larry; Malmborg, Eric; Owen-Peer, William

    1997-01-01

    This report describes the design of the Advanced Low-Noise Research Fan stage. The fan is a variable pitch design, which is designed at the cruise pitch condition. Relative to the cruise setting, the blade is closed at takeoff and opened for reverse thrust operation. The fan stage is a split flow design with fan exit guide vanes (FEGVs) and core stators. The fan stage design is combined with a nacelle and engine core duct to form a powered fan/nacelle subscale model. This model is intended for use in combined aerodynamic, acoustic, and structural testing in a wind tunnel. The fan has an outer diameter of 22 in. and a hub-to-tip of 0.426 in., which allows the use of existing NASA fan and cowl force balance and rig drive systems. The design parameters were selected to permit valid acoustic and aerodynamic comparisons with the Pratt & Whitney (P&W) 17- and 22-in. rigs previously tested under NASA contract. The fan stage design is described in detail. The results of the design axisymmetric and Navier-Stokes aerodynamic analysis are presented at the critical design conditions. The structural analysis of the fan rotor and attachment is included. The blade and attachment are predicted to have adequate low-cycle fatigue life and an acceptable operating range without resonant stress or flutter. The stage was acoustically designed with airfoil counts in the FEGV and core stator to minimize noise. A fan/FEGV tone analysis developed separately under NASA contract was used to determine the optimum airfoil counts. The fan stage was matched to the existing nacelle, designed under the previous P&W low-noise contract, to form a fan/nacelle model for wind tunnel testing. It is an axisymmetric nacelle for convenience in testing and analysis. Previous testing confirmed that the nacelle performed as required at various aircraft operating conditions.

  14. A study of generator performance with linear permanent magnet in various coil configuration and rotor-stator geometry

    Science.gov (United States)

    Asy'ari, Hasyim; Sarjito, Prasetio, Septian Heri

    2017-04-01

    The aim of the research work describe in this paper was to design and optimize a permanent magnet linear generator for renewable energy power plants. It is cover of first stage of designing stator and rotor permanent magnet linear generator. Stator design involves determining dimensions, number of slots, diameter of wire, and the number of winding in each slot. The design of the rotor includes rotor manufacture of PVC pipe material, 10 pieces of permanent magnet type ferrite 271 mikroweber, and resin. The second stage was to assemble the stator and rotor that has been done in the first stage to be a permanent magnet linear generator. The third stage was to install a permanent magnet linear generator with induction motors. Further stage was to test performance of a permanent magnet linear generator by utilizing of induction motor as a prime mover experimentally. In this study, permanent magnet linear generator with a rotor consists of five pairs of permanent magnets. The stator consists of 6 slots of the stator frame, each slot mounted stator coil of 200, 300, 400, 500, and 800 windings, and dimensions of wire used was 0.4 mm. The stator frame was made from acrylic. Results of the experiment that, permanent magnet linear generator when no load was able to generate a DC voltage of 14.5 volts at 300 rpm, and at the output of the linear generator when it is connected to the DC fan as a load only generated of 6.7 volts. It concludes that permanent magnet linear generator output can be used as an input device hybrid system. Data obtained from this experiment in laboratory scale can be developed in a larger scale by varying the type of magnet being used, the number of windings, and the speed used to generate more power.

  15. Precision Model for Microwave Rotary Vane Attenuator

    DEFF Research Database (Denmark)

    Guldbrandsen, Tom

    1979-01-01

    A model for a rotary vane attenuator is developed to describe the attenuator reflection and transmission coefficients in detail. All the parameters of the model can be measured in situ, i.e., without diassembling any part. The tranmission errors caused by internal reflections are calculated from ...

  16. Study and Control of a Radial Vaned Diffuser Stall

    Directory of Open Access Journals (Sweden)

    Aurélien Marsan

    2012-01-01

    Full Text Available The aim of the present study is to evaluate the efficiency of a boundary layer suction technique in case of a centrifugal compressor stage in order to extend its stable operating range. First, an analysis of the flow pattern within the radial vaned diffuser is presented. It highlights the stall of the diffuser vanes when reaching a low massflow. A boundary layer separation in the hub-suction side corner grows when decreasing the massflow from the nominal operating point to the surge and finally leads to a massive stall. An aspiration strategy is investigated in order to control the stall. The suction slot is put in the vicinity of the saddle that originates the main separating skin-friction line, identified thanks to the analysis of the skin-friction pattern. Several aspiration massflow rates are tested, and two different modelings of the aspiration are evaluated. Finally, an efficient control is reached with a removal of only 0,1% of the global massflow and leads—from a steady-state calculations point of view—to an increase by 40% of the compressor operating range extent.

  17. Rotor/stator unsteady calculation

    Energy Technology Data Exchange (ETDEWEB)

    Denis, C.; Dejean, F. [Electricite de France, 78 - Chatou (France). Direction des Etudes et Recherches

    1997-12-31

    The flow prediction involves the use of the three-dimensional Navier-Stokes solver N3S-NATUR. This compressible and turbulent finite volume / finite element code is able to perform multi-domain steady and now unsteady calculations through the external coupling module CALCIUM. The later is based on PVM (Parallel Virtual Machine). The originality of the method is the use of this external coupling module in such a way that each domain is computed with its own N3S code. Of course, a turbomachinery stage flow is always unsteady because of the rotor. When dealing with steady computations, the principal assumption is that the flow is steady relative to each domain individually and that each domain can communicate via mixing planes. These planes introduce circumferential averaging of the flow properties but preserve quite general radial variations. For unsteady calculations, the same method is used but without any circumferential averaging. Here, two fixed and three rotating blades are taken into account which involves the use of five different N3S-NATUR codes (one code for one blade). Of course, in order to perform such a calculation without any hypothesis, all the blades have to be modelled. Actually, such a calculation is done for a turbine stage of 23 fixed and 37 rotating blades (VEGA 2 turbine). In order to perform such a calculation in a realistic time, 60 processors of a parallel architecture computer are used. (authors)

  18. Heat transfer in rotor/stator cavity

    Science.gov (United States)

    Tuliszka-Sznitko, Ewa; Majchrowski, Wojciech; Kiełczewski, Kamil

    2011-12-01

    In the paper we analyze the results of DNS/LES of the flow with heat transfer in the rotor/stator cavity. The rotor and the outer cylinder are heated. Computations have been performed for wide range of Reynolds numbers and aspect ratios. Computations are based on the efficient pseudo-spectral Chebyshev-Fourier method. In LES we used a Lagrangian dynamic subgrid-scale model of turbulence. Analysis allowed to check the influence of the aspect ratio and Reynolds number on the statistics and the structure of the flow. We analyzed all six Reynolds stress tensor components, turbulent fluctuations, three turbulent heat fluxes and different structural parameters which can be useful for modeling purposes. The distributions of Nusselt numbers obtained for different Re and aspect rations along disks are given. We also investigated influence of thermal Rosssby number as well as distributions of temperature along heated disk on statistics. Computations have shown that turbulence is mostly concentrated in the stator boundary layer with a maximum at the junction between the stator and the outer cylinder. The results are compared to the experimental and numerical data taken from literature.

  19. Reconstruction of the Switched Reluctance Motor Stator

    Science.gov (United States)

    El-Kharashi, Eyhab; Hassanien, Hany M.

    2012-01-01

    The paper re-designs the conventional 6/8 switched reluctance motor (SRM) by a particular way to minimize the losses. The flux loops are shortened by making each two stator teeth incorporated in one magnetic circuit only. Subsequently the flux does not cross in some iron parts of the stator core backs. These unused iron sections are taken off consequently the iron losses decreased. Now the stator consists of three separated sections and they are fixed inside non-magnetic cylinder. The copper losses also are decreased because less copper windings are used to produce the same amount of the output torque as the flux paths become short then the flux density increases. The analysis and comparison of the 6/8 SRM before and after the re-design process are presented. A m files Matlab software is used to simulate the dynamic performance. Then the paper proceeds to examine different control techniques to the new design. The hysteresis and PI controllers are used as classical method to control the SRM. Then the artificial neural network (ANN) is used to test the new control techniques.

  20. Vane shear test for cohesionless soils

    Science.gov (United States)

    Park, Sung-Sik; An, Zhou; Ye, Sung-Ryol; Lee, Sae-Byeok; Chae, Kyung-Hyeon

    2015-04-01

    The vane shear test (VST) is a simple and rapid testing method for determining the undrained shear strength of cohesive soils. It has not been applied for granular soils because the failure surface was irregular and hardly determined due to their cohesionless property. In this study, the VST was used to determine the shear strength of cohesionless soils such as sand. A small laboratory vane with 5 cm in diameter and 10 cm in height was inserted into sand within pressurized cell. When the vane rotates within sand, a failure surface can be assumed to be cylindrical shape because the sand is pressurized with loading frame. Dry Nakdong River sand was prepared for loose and dense conditions in the cell and the axial pressure of 50, 100, and 200 kPa was applied on the surface of sand. The relationship between measured torque and resistant force along cylindrical shape due to friction of sand was derived and the internal friction angle of sand was determined for loose and dense conditions. It was possible for the VST to determine the shear strength of sand under confined condition.

  1. Improvement of Energy Density in Single Stator Interior Permanent Magnet Using Double Stator Topology

    Directory of Open Access Journals (Sweden)

    Raja Nor Firdaus

    2014-01-01

    Full Text Available The paper presents the energy density improvement using magnetic circuit analysis of the interior permanent magnet motor. The leakage flux from the conventional structure is improved with modified magnetic circuit to improve the energy and thereby the torque value. This is approached with a double stator structure design. The proposed structure is investigated with two design variations, namely, the double stator with thin pole shoe and the double stator with thick pole shoe motors. Variations in the mechanical parameters of the all the developed models are analyzed through the finite element analysis tool. In all investigations the magnetic source is fixed in both the permanent magnet volume and coil magnetomotive force, respectively, as 400 mm3 per each pole and 480 Ampere turns per pole. From the analysis the best fit magnetic structure based on the torque characteristics is derived and is fabricated for the same volume as that of the conventional structure for performance evaluations. It is found out that there is improvement on the motor constant square density for the proposed improved magnetic circuit through the best fit double stator with thick pole shoe by about 83.66% greater than that of the conventional structure.

  2. Experimental study of the efficiency of steam injection on wet-steam turbine stator blade cascade

    Science.gov (United States)

    Khomyakov, S. V.; Alexeev, R. A.; Gavrilov, I. Y.; Gribin, V. G.; Tishchenko, A. A.; Tishchenko, V. A.; Popov, V. V.

    2017-11-01

    Currently, in order to decrease the negative effects caused by the presence of a discrete phase in the flow path of steam turbines stages operating in wet-steam area, different technical solutions are apply. These methods reduce the number of coarse droplets and wetness of working medium. The implementation of erosion reduction methods requires modifying surfaces of flow path, which can significantly affect the efficiency of the steam turbine. For example application of intrachanel moisture removing and steam injection needs changes of the stator blades surfaces. This article is a part of researches cycle about the efficiency of steam injection on the stator blade surface as the main method of coarse liquid particles diameters reduction in the last stages of high-power steam turbines. The paper presents the results of the analysis and comparison of experimental research unmodified profile to the profile of the stator blade changed by injection slot. The comparison of the profile losses considered blades is present. The analysis of the experimental results showed the feasibility and efficiency of this method of coarse liquid particles diameters reduction in the last stages of high-power steam turbines.

  3. Numerical Investigations of the Influence of Unsteady Vane Trailing Edge Shock Wave on Film Cooling Effectiveness of Rotor Blade Leading Edge

    Science.gov (United States)

    Wang, Yufeng; Cai, Le; Wang, Songtao; Zhou, Xun

    2018-04-01

    Unsteady numerical simulations of a high-load transonic turbine stage have been carried out to study the influences of vane trailing edge outer-extending shockwave on rotor blade leading edge film cooling performance. The turbine stage used in this paper is composed of a vane section and a rotor one which are both near the root section of a transonic high-load turbine stage. The Mach number is 0.94 at vane outlet, and the relative Mach number is above 1.10 at rotor outlet. Various positions and oblique angles of film cooling holes were investigated in this research. Results show that the cooling efficiency on the blade surface of rotor near leading edge is significantly affected by vane trailing edge outer-extending shockwave in some cases. In the cases that film holes are close to leading edge, cooling performance suffers more from the sweeping vane trailing edge outer-extending shockwave. In addition, coolant flow ejected from oblique film holes is harder to separate from the blade surface of rotor, and can cover more blade area even under the effects of sweeping vane trailing edge shockwave. As a result, oblique film holes can provide better film cooling performance than vertical film holes do near the leading edge on turbine blade which is swept by shockwaves.

  4. Design and analysis of full pitch winding and concentrated stator ...

    Indian Academy of Sciences (India)

    the winding, (ii) low cogging torque and permanent magnet (PM) weight. The basic machine configuration is an 8 salient pole rotor and 6 salient pole stator with concentrated windings. Permanent Magnets are fixed to the stator pole. Figure 1 shows this machine configuration. FRM for low-speed servo drive application was ...

  5. Design and analysis of full pitch winding and concentrated stator ...

    Indian Academy of Sciences (India)

    The flux reversal machine (FRM) is a doubly-salient stator permanent magnet machine with flux linkage reversal in the stator concentrated winding. The existing machines at low speed, low power (2·4 kW, 300 rpm) range are not economical. FRM topology is best suited for this application. An attempt has been made to ...

  6. A novel thermally driven rotor-vane/pressure-exchange ejector refrigeration system with environmental benefits and energy efficiency

    International Nuclear Information System (INIS)

    Hong, W.J.; Alhussan, Khaled; Zhang Hongfang; Garris, Charles A.

    2004-01-01

    The latest results of an ongoing coordinated experimental and computational program on the design and performance of a novel supersonic rotor-vane/pressure-exchange ejector for thermally driven ejector refrigeration systems are presented. For the supersonic rotor-vane/pressure-exchange ejector, careful management of the entropy rise through the oblique shocks and boundary layers is required for obtaining an advance in ejector performance. Since the invention of this new ejector is quite recent, understanding its aerodynamics, with the consequent optimization of performance, is in the formative stage. This paper shows how the supersonic aerodynamics is managed to provide the desirable flow induction characteristics through computational study and, in parallel, experimental results including flow visualization showing actual behavior with different-shaped rotor vanes. The importance of the existence of the tail part with a long expansion ramp, the sharp leading edge such as knife-edge, the proper height of leading edges, for the overall shape of rotor vane, were observed. Also the larger spin-angle rotor vane produces better flow induction and mixing between primary flow and secondary flow

  7. Liquid oxygen/liquid hydrogen boost/vane pump for the advanced orbit transfer vehicles auxiliary propulsion system

    Science.gov (United States)

    Gluzek, F.; Mokadam, R. G.; To, I. H.; Stanitz, J. D.; Wollschlager, J.

    1979-01-01

    A rotating, positive displacement vane pump with an integral boost stage was designed to pump saturated liquid oxygen and liquid hydrogen for auxiliary propulsion system of orbit transfer vehicle. This unit is designed to ingest 10% vapor by volume, contamination free liquid oxygen and liquid hydrogen. The final pump configuration and the predicted performance are included.

  8. Gas turbine row #1 steam cooled vane

    Science.gov (United States)

    Cunha, Frank J.

    2000-01-01

    A design for a vane segment having a closed-loop steam cooling system is provided. The vane segment comprises an outer shroud, an inner shroud and an airfoil, each component having a target surface on the inside surface of its walls. A plurality of rectangular waffle structures are provided on the target surface to enhance heat transfer between each component and cooling steam. Channel systems are provided in the shrouds to improve the flow of steam through the shrouds. Insert legs located in cavities in the airfoil are also provided. Each insert leg comprises outer channels located on a perimeter of the leg, each outer channel having an outer wall and impingement holes on the outer wall for producing impingement jets of cooling steam to contact the airfoil's target surface. Each insert leg further comprises a plurality of substantially rectangular-shaped ribs located on the outer wall and a plurality of openings located between outer channels of the leg to minimize cross flow degradation.

  9. Study on casing treatment and stator matching on multistage fan

    Science.gov (United States)

    Wu, Chuangliang; Yuan, Wei; Deng, Zhe

    2017-10-01

    Casing treatments are required for expanding the stall margin of multi-stage high-load turbofans designed with high blade-tip Mach numbers and high leakage flow. In the case of a low mass flow, the casing treatment effectively reduces the blockages caused by the leakage flow and enlarges the stall margin. However, in the case of a high mass flow, the casing treatment affects the overall flow capacity of the fan, the thrust when operating at the high speeds usually required by design-point specifications. Herein, we study a two-stage high-load fan with three-dimensional numerical simulations. We use the simulation results to propose a scheme that enlarges the stall margin of multistage high-load fans without sacrificing the flow capacity when operating with a large mass flow. Furthermore, a circumferential groove casing treatment is used and adjustments are made to the upstream stator angle to match the casing treatment. The stall margin is thus increased to 16.3%, with no reduction in the maximum mass flow rate or the design thrust performance.

  10. Motor stator using corner scraps for additional electrical components

    Science.gov (United States)

    Hsu, John S.; Su, Gui-Jia; Adams, Donald J.; Nagashima, James M.; Stancu, Constantin; Carlson, Douglas S.; Smith, Gregory S.

    2004-03-16

    A method for making a motor and auxiliary devices with a unified stator body comprises providing a piece of material (10) having an area larger than a cross section of the stator (11), removing material from the piece of material (10) to form a pattern for a cross section of a core (11) for the stator, and removing material from the piece of material (10) outside the cross section of the core of the stator (11) to allow positioning of cores (22, 23, 24) for supporting windings (25, 26, 27) of least one additional electromagnetic device, such as a transformer (62) in a dc-to-dc converter (61, 62) that provides a low. voltage dc output. An article of manufacture made according to the invention is also disclosed and apparatus made with the method and article of manufacture are also disclosed.

  11. Performance of a vane driven-gear pump

    Science.gov (United States)

    Heald, R H

    1921-01-01

    Given here are the results of a test conducted in a wind tunnel on the performance of a vane-driven gear pump used to pump gasoline upward into a small tank located within the upper wing from which it flows by gravity to the engine carburetor. Information is given on the efficiency of the pump, the head resistance of the vanes, the performance and characteristics of the unit with and without housing about the vanes, the pump performance when motor driven, and resistance and power characteristics.

  12. Introduction on KPS's maintenance experience of the swirl vane assemblies of primary separators for SG model F in Korea

    International Nuclear Information System (INIS)

    Kim, Yong tae

    2003-01-01

    Recently, we had experienced to replace the Swirl Vane Assemblies of primary moisture separator for SG model F in Korea because of serious degradation (Thinning) in carbon steel swirl vane blades and carbon steel separator barrel wall adjacent to swirl vane blades. When the symptom was observed by us at the first time on the swirl vane assemblies, there were small or a bit clear erosion / or corrosion marks on the edge regions of the blades but within 3 cycles of operation, we found that those marks became holes which penetrated the most of swirl vane assemblies and even more seriously, some parts of the assemblies were worn-out. Therefore, we concluded that the speed of degradation would be very rapid and serious from the beginning stage. It had been assumed that these kinds of thinning problems would be due to FAC(Flow Accelerated Corrosion) because the plants having these problems are using a highly concentrated hydrazine for the water treatment of secondary side which lead to reduce the oxygen and pH in the water. What are more serious reasons will be that the swirl vane assemblies are very weak to FAC because they were made by a low concentrated chromium carbon steel and the assemblies would have to be under the operation conditions of the highly turbulent steam-water mixed fluid with the operating temperature of higher than 280 .deg. C. Potentially, the damaged swirl vane assemblies of the primary moisture separator may create bad influences for the plant operation because it may cause the rupture of SG Tubes and over-exceed fluid influx onto the turbine and etc. KPS had successfully performed the replacement of the degraded swirl vane assemblies through our own planning and preparation. This was the unique case in all over the world and I would like to introduce you about our unique repair experience to prepare an expected future situation as we see the similar problems in other model F SGs operating in Korea

  13. Installation Effects on Heat Transfer Measurements for a Turbine Vane

    National Research Council Canada - National Science Library

    Polanka, Marc

    2003-01-01

    ...). This turbine vane was instrumented with two types of heat flux gauges. The first was a thin film Upilex gauge design wrapped over the full airfoil surface, while the second consisted of Pyrex insert type gauges...

  14. Installation Effects on Heat Transfer Measurements for a Turbine Vane

    National Research Council Canada - National Science Library

    Polanka, Marc

    2003-01-01

    .... This suggested a potential change in the flowfield for one of the gauge types. Interrogation of the vane surface metrology showed depressions in the epoxy filler between the Pyrex insert and the metal airfoil...

  15. Turbocharger with variable nozzle having vane sealing surfaces

    Science.gov (United States)

    Arnold, Philippe [Hennecourt, FR; Petitjean, Dominique [Julienrupt, FR; Ruquart, Anthony [Thaon les Vosges, FR; Dupont, Guillaume [Thaon les Vosges, FR; Jeckel, Denis [Thaon les Vosges, FR

    2011-11-15

    A variable nozzle for a turbocharger includes a plurality of vanes rotatably mounted on a nozzle ring and disposed in a nozzle flow path defined between the nozzle ring and an opposite nozzle wall. Either or both of the faces of the nozzle ring and nozzle wall include(s) at least one step that defines sealing surfaces positioned to be substantially abutted by airfoil surfaces of the vanes in the closed position of the vanes and to be spaced from the airfoil surfaces in positions other than the closed position. This substantial abutment between the airfoil surfaces and the sealing surfaces serves to substantially prevent exhaust gas from leaking past the ends of the airfoil portions. At the same time, clearances between the nozzle ring face and the end faces of the airfoil portions can be sufficiently large to prevent binding of the vanes under all operating conditions.

  16. Bed erosion control at 60 degree river confluence using vanes

    Science.gov (United States)

    Wuppukondur, Ananth; Chandra, Venu

    2017-04-01

    Confluences are common occurrences along natural rivers. Hydrodynamics at the confluence is complex due to merging of main and lateral flows with different characteristics. Bed erosion occurs at the confluence due to turbulence and also secondary circulation induced by centrifugal action of the lateral flow. The eroded sediment poses various problems in the river ecosystem including river bank failure. Reservoirs are majorly affected due to sediment deposition which reduces storage capacity. The bed erosion also endangers stability of pipeline crossings and bridge piers. The aim of this experimental study is to check the performance of vanes in controlling bed erosion at the confluence. Experiments are performed in a 600 confluence mobile bed model with a non-uniform sediment of mean particle size d50 = 0.28mm. Discharge ratio (q=ratio of lateral flow discharge to main flow discharge) is maintained as 0.5 and 0.75 with a constant average main flow depth (h) of 5cm. Vanes of width 0.3h (1.5cm) and thickness of 1 mm are placed along the mixing layer at an angle of 150, 300 and 600(with respect to main flow) to perform the experiments. Also, two different spacing of 2h and 3h (10cm and 15cm) between the vanes are used for conducting the experiments. A digital point gauge with an accuracy of ±0.1mm is used to measure bed levels and flow depths at the confluence. An Acoustic Doppler Velocitimeter (ADV) with a frequency of 25Hz and accuracy of ±1mm/s is used to measure flow velocities. Maximum scour depth ratio Rmax, which is ratio between maximum scour depth (Ds) and flow depth (h), is used to present the experimental results.From the experiments without vanes, it is observed that the velocities are increasing along the mixing layer and Rmax=0.82 and 1.06, for q=0.5 and 0.75, respectively. The velocities reduce with vanes since roughness increases along the mixing layer. For q=0.5 and 0.75, Rmax reduces to 0.62 and 0.7 with vanes at 2h spacing, respectively. Similarly

  17. Mechanical support of a ceramic gas turbine vane ring

    Science.gov (United States)

    Shi, Jun; Green, Kevin E.; Mosher, Daniel A.; Holowczak, John E.; Reinhardt, Gregory E.

    2010-07-27

    An assembly for mounting a ceramic turbine vane ring onto a turbine support casing comprises a first metal clamping ring and a second metal clamping ring. The first metal clamping ring is configured to engage with a first side of a tab member of the ceramic turbine vane ring. The second metal clamping ring is configured to engage with a second side of the tab member such that the tab member is disposed between the first and second metal clamping rings.

  18. The influence of the vane on the lubrication characteristics between the vane and the rolling piston of a rotary compressor

    International Nuclear Information System (INIS)

    Cho, Ihn Sung; Jung, Jae Youn

    2006-01-01

    The rolling piston type rotary compressor has been widely used for refrigeration and air -conditioning systems due to its compactness and high-speed operation. The present analysis is part of a research program directed toward maximizing the advantages of refrigerant compressors. The study of lubrication characteristics in the critical sliding component is essential for the design of refrigerant compressors. Therefore, theoretical investigation of the lubrication characteristics of a rotary compressor being used for refrigeration and air-conditioning systems was investigated. The Newton-Raphson method was used for a partial elastohydrodynamic lubrication analysis between the vane and the rolling piston of a rotary compressor. The results demonstrated that the vane thickness and the center line position of the vane significantly influenced the friction force and the energy loss between the vane and the rolling piston

  19. A lightweight, biological structure with tailored stiffness: The feather vane.

    Science.gov (United States)

    Sullivan, Tarah N; Pissarenko, Andreï; Herrera, Steven A; Kisailus, David; Lubarda, Vlado A; Meyers, Marc A

    2016-09-01

    The flying feathers of birds are keratinous appendages designed for maximum performance with a minimum weight penalty. Thus, their design contains ingenious combinations of components that optimize lift, stiffness, aerodynamics, and damage resistance. This design involves two main parts: a central shaft that prescribes stiffness and lateral vanes which allows for the capture of air. Within the feather vane, barbs branch from the shaft and barbules branch from barbs, forming a flat surface which ensures lift. Microhooks at the end of barbules hold barbs tightly together, providing the close-knit, unified structure of the feather vane and enabling a repair of the structure through the reattachment of un-hooked junctions. Both the shaft and barbs are lightweight biological structures constructed of keratin using the common motif of a solid shell and cellular interior. The cellular core increases the resistance to buckling with little added weight. Here we analyze the detailed structure of the feather barb and, for the first time, explain its flexural stiffness in terms of the mechanics of asymmetric foam-filled beams subjected to bending. The results are correlated and validated with finite element modeling. We compare the flexure of single barbs as well as arrays of barbs and find that the interlocking adherence of barbs to one another enables a more robust structure due to minimized barb rotation during deflection. Thus, the flexure behavior of the feather vane can be tailored by the adhesive hooking between barbs, creating a system that mitigates damage. A simplified three-dimensional physical model for this interlocking mechanism is constructed by additive manufacturing. The exceptional architecture of the feather vane will motivate the design of bioinspired structures with tailored and unique properties ranging from adhesives to aerospace materials. Despite its importance to bird flight, literature characterizing the feather vane is extremely limited. The feather

  20. Stator Flux Observer for Induction Motor Based on Tracking Differentiator

    Directory of Open Access Journals (Sweden)

    Dafang Wang

    2013-01-01

    Full Text Available Voltage model is commonly used in direct torque control (DTC for flux observing of asynchronous motor. In order to improve low-speed and dynamic performance of the voltage model, a modified low-pass filter (LPF algorithm is proposed. Firstly, the tracking differentiator is brought in to modulate the measured stator current, which suppresses the measurement noise, and then amplitude and phase compensation is made towards the stator electromotive force (EMF, after which the stator flux is obtained through a low-pass filter. This method can eliminate the dynamic error of flux filtered by LPF and improve low-speed performance. Experimental results demonstrate effectiveness and improved dynamic performance of such method.

  1. Automated Cable Preparation for Robotized Stator Cable Winding

    Directory of Open Access Journals (Sweden)

    Erik Hultman

    2017-04-01

    Full Text Available A method for robotized cable winding of the Uppsala University Wave Energy Converter generator stator has previously been presented and validated. The purpose of this study is to present and validate further developments to the method: automated stand-alone equipment for the preparation of the winding cables. The cable preparation consists of three parts: feeding the cable from a drum, forming the cable end and cutting the cable. Forming and cutting the cable was previously done manually and only small cable drums could be handled. Therefore the robot cell needed to be stopped frequently. The new equipment was tested in an experimental robot stator cable winding setup. Through the experiments, the equipment was validated to be able to perform fully automated and robust cable preparation. Suggestions are also given on how to further develop the equipment with regards to performance, robustness and quality. Hence, this work represents another important step towards demonstrating completely automated robotized stator cable winding.

  2. Welding fixture for joining bar-wound stator conductors

    Energy Technology Data Exchange (ETDEWEB)

    De Souza, Urban J.; Rhoads, Frederick W.; Hanson, Justin

    2017-09-12

    A fixture assembly for welding a plurality of stator wire end pairs may include an anvil, a movable clamp configured to translate between an unclamped state and a clamped state, a first grounding electrode, and a second grounding electrode. The movable clamp may be configured to urge the plurality of stator wire ends against the anvil when in the clamped state. The moveable clamp includes a separator feature that generally extends toward the anvil. Each of the first grounding electrode and second grounding electrodes may be configured to translate between a clamped state and an unclamped state. When in the clamped state, each of the first and second grounding electrodes is configured to urge a pair of the plurality of stator wire end pairs against the separator feature.

  3. Stator Core Fault Diagnosis in Induction Motor Using Adaptive Observer

    Directory of Open Access Journals (Sweden)

    Hailiang HOU

    2014-09-01

    Full Text Available This document presents a method of on-line fault diagnosis for iron core of induction motor stator based on adaptive observer. Due to the equivalent resistance is directly affected by the stator core fault, while the iron loss is considered in the series iron loss model of the induction motor, so we can determine the core fault state by identifying equivalent iron consumption resistance. In this paper, Matlab LMI toolbox is employed to calculate the feedback gain matrix of adaptive observer, which can makes up the deficiency of other method such as pole assignment. Finally, the experimental results confirm the validity of the proposed approach.

  4. Pressure Drop Test of Hybrid Mixing Vane Spacer Grid

    Energy Technology Data Exchange (ETDEWEB)

    Oh, D. S.; Chang, S. K.; Kim, B. D.; Chun, S. Y.; Chun, T. H

    2007-08-15

    The pressure loss test has been accomplished in the test section containing 5x5 rod bundle with a length of 2 m including 3 spacer grids. The test has been performed for the 5 kinds of spacer grids to compare the pressure loss characteristics: 1. Plain spacer grid which has the same body of the Hybrid but without vane (Plain), 2. Hybrid Vane spacer grid (Hybrid), 3. Hybrid-SC spacer grid which is constructed with coined, chamfered strip and is fabricated by spot welding, 4. Hybrid-LC spacer grid which is constructed with coined, chamfered strip and is fabricated by line welding along intersection line, 5. Westinghouse spacer grid with split vane (Plus-7). The pressure loss coefficient of the Plain, Hybrid, Hybrid-SC, Hybrid-LC, and Plus-7 spacer grid is 0.93, 1.15, 1.02, 1.04, and 1.08, respectively.

  5. The wave vane - A device to measure the breaker angle

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Nayak, B.U.; Anand, N.M.

    with the shoreline at the wave vane is equal to the breaker angle as the wave vane is installed very close to breaker zone. Repeating the procedure, the breaker angles for a required duration can be estimated. FIELD TEST A 4 km long beach near Karwar on the west... in Table 1. Ob- servations on breaker angles were made for 20 minutes duration every day. The average breaker angle computed based on the 20 minute observation is presented in Table 1. A directional wave rider buoy was deployed at 16 m water depth...

  6. Influence of blockage effect on measurement by vane anemometers

    Directory of Open Access Journals (Sweden)

    Sluse Jan

    2017-01-01

    Full Text Available The article deals with influence of blockage effect caused by vane anemometer in the wind tunnel by measurement via this anemometer. The influences will be represented by correction coefficient. The first part of this article is focused on the design of the impeller of vane anemometers. The impellers are printed on 3D printer with variable parameters. The anemometer is fixed in an open section of the wind tunnel with closed loop and the velocity profile is measured by Laser Doppler velocimetry (LDV in front and behind it for all impellers. The experimental data are compared with the numerical simulation in OpenFOAM. The results are correction coefficients.

  7. Model based defect detection for free stator of ultrasonic motor

    DEFF Research Database (Denmark)

    Amini, Rouzbeh; Mojallali, Hamed; Izadi-Zamanabadi, Roozbeh

    2007-01-01

    In this paper, measurements of admittance magnitude and phase are used to identify the complex values of equivalent circuit model for free stator of an ultrasonic motor. The model is used to evaluate the changes in the admittance and relative changes in the values of equivalent circuit elements. ...

  8. Torque characteristics of double-stator permanent magnet synchronous machines

    Directory of Open Access Journals (Sweden)

    Awah Chukwuemeka Chijioke

    2017-12-01

    Full Text Available The torque profile of a double-stator permanent magnet (PM synchronous machine of 90 mm stator diameter having different rotor pole numbers as well as dual excitation is investigated in this paper. The analysis includes a comparative study of the machine’s torque and power-speed curves, static torque and inductance characteristics, losses and unbalanced magnetic force. The most promising flux-weakening potential is revealed in 13- and 7-rotor pole machines. Moreover, the machines having different rotor/stator (Nr/Ns pole combinations of the form Nr = Ns ± 1 have balanced and symmetric static torque waveforms variation with the rotor position in contrast to the machines having Nr = Ns ± 2. Further, the inductance results of the analyzed machines reveal that the machines with odd rotor pole numbers have better fault-tolerant capability than their even rotor pole equivalents. A prototype of the developed double-stator machine having a 13-pole rotor is manufactured and tested for verification.

  9. Analysis of induction machines with combined stator windings

    Czech Academy of Sciences Publication Activity Database

    Schreier, Luděk; Bendl, Jiří; Chomát, Miroslav

    2015-01-01

    Roč. 60, č. 2 (2015), s. 155-171 ISSN 0001-7043 R&D Projects: GA ČR GA13-35370S Institutional support: RVO:61388998 Keywords : induction machines * symmetrical components * combined stator winding Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  10. Thermal modeling of a mini rotor-stator system

    NARCIS (Netherlands)

    Dikmen, E.; van der Hoogt, Peter; de Boer, Andries; Aarts, Ronald G.K.M.; Jonker, Jan B.

    2009-01-01

    In this study the temperature increase and heat dissipation in the air gap of a cylindrical mini rotor stator system has been analyzed. A simple thermal model based on lumped parameter thermal networks has been developed. With this model the temperature dependent air properties for the fluid-rotor

  11. Systematic modeling for free stators of rotary - Piezoelectric ultrasonic motors

    DEFF Research Database (Denmark)

    Mojallali, Hamed; Amini, Rouzbeh; Izadi-Zamanabadi, Roozbeh

    2007-01-01

    An equivalent circuit model with complex elements is presented in this paper to describe the free stator model of traveling wave piezoelectric motors. The mechanical, dielectric and piezoelectric losses associated with the vibrator are considered by introducing the imaginary part to the equivalent...... the measurements of a recently developed piezoelectric motor and a well known USR60....

  12. Stator insulation systems for medium voltage PWM drives fed motors

    International Nuclear Information System (INIS)

    Gao, G.; Chen, W.

    2005-01-01

    This paper presents the partial results of a research project that studied the impact of medium voltage PWM ASD (adjustable speed drives) on motor stator insulation system. The findings from this study/ investigation have aided designers to improve the robustness of the insulation system used for ASD-fed motors, based on accelerated laboratory tests. (author)

  13. Stator winding service life analysis of wet winding motor RCP

    International Nuclear Information System (INIS)

    Yeoh Eingyee; Li Linsen; Wang Ziguan; Shen Feng

    2017-01-01

    The reactor coolant pump type RUV of KSB is specially designed for the Westinghouse AP1000 reactor. It is hermetically sealed, wet winding motor pump. This wet winding motor concept has higher efficiency as compared to a canned motor since there are no eddy current losses, but this makes the stator cable insulator face the challenge of degradation by γ-irradiation in coolant. Radiation dose at the RUV is evaluated in interest from the material degradation point of view and the service life of stator winding in RUV is preliminarily analyzed. The values obtained are less than the dose rate and the dose which change the mechanical properties of the insulator material. According to the preliminary analysis, it can be concluded that the degradation of cable insulator of stator winding by γ-irradiation in coolant is negligible for the 60 years' service life of reactor coolant pump. This result also ensures crosslinked polyethylene used as cable insulator of stator winding is reliable in reactor coolant pump. (author)

  14. Numerical Analysis and Geometry Optimisation of Vertical Vane of Room Air-conditioner

    Directory of Open Access Journals (Sweden)

    Al-Obaidi Abdulkareem Sh. Mahdi

    2018-01-01

    Full Text Available Vertical vanes of room air-conditioners are used to control and direct cold air. This paper aims to study vertical vane as one of the parameters that affect the efficiency of dissipating cold air to a given space. The vertical vane geometry is analysed and optimised for lower production cost using CFD. The optimised geometry of the vertical vane should have the same or increased efficiency of dissipating cold air and have lesser mass compared to the existing original design. The existing original design of vertical vane is simplified and analysed by using ANSYS Fluent. Efficiency of wind direction is define as how accurate the direction of airflow coming out from vertical vane. In order to calculate the efficiency of wind direction, 15° and 30° rotation of vertical vane inside room air-conditioner are simulated. The efficiency of wind direction for 15° rotation of vertical vane is 57.81% while efficiency of wind direction for 30° rotation of vertical vane is 47.54%. The results of the efficiency of wind direction are used as base reference for parametric study. The parameters investigated for optimisation of vertical vane are focused at length of long span, tip chord and short span. The design of 15% decreased in vane surface area at tip chord is the best optimised design of vertical vane because the efficiency of wind direction is the highest as 60.32%.

  15. Measuring Undrained Shear Strength using CPT and Field Vane

    DEFF Research Database (Denmark)

    Luke, Kirsten

    1992-01-01

    This paper presents the results of CPT's and Field Vane tests from two small test areas with different soils, Glacial Till and Yoldia Clay. An average of Nk = qt/cv for the Yoldia Clay is 7.7 with a standard deviation of 0.7. The average of Nk for the Glacial Till is 9.7 with a standard deviation...

  16. Solar updraft power generator with radial and curved vanes

    Science.gov (United States)

    Hafizh, Hadyan; Hamsan, Raziff; Zamri, Aidil Azlan Ahmad; Keprawi, Mohamad Fairuz Mohamad; Shirato, Hiromichi

    2018-02-01

    Solar radiation is the largest source of energy available on earth and the solar updraft power generator (SUPG) is a renewable energy facility capable of harnessing its abundant power. Unlike the conventional wind turbines that harness natural wind in the atmosphere and often encounter with the intermittent issue or even complete cut-off from airflow, the SUPG creates artificial wind as a result of solar-induced convective flows. However, the SUPG has an inherent low total efficiency due to the conversion of thermal energy into pressure energy. Acknowledging the low efficiency and considering its potential as a renewable energy facility, the current work aims to increase the total efficiency by installing a series of guide walls inside the collector. Two types of guide walls were used i.e. radial and curved vanes. The result with curved vanes showed that the updraft velocity is higher compare to those without vanes. About 18% and 64% improvement of updraft velocity and mechanical power were attained respectively. Furthermore, it was observed that the role of radial vanes configuration was more to produce a smooth updraft velocity profile rather than increasing the total efficiency.

  17. Optimization of pre-swirl stators based on CFD for a chemical product carrier

    Directory of Open Access Journals (Sweden)

    HAN Cong

    2017-01-01

    Full Text Available The viscous self-propulsion flow fields of a model-scaled 55k DWT chemical product carrier fitted with a rudder-bulb-fin and a pre-swirl stator are numerically simulated based on the CFD general code FLUENT. The energy saving effects of stators are evaluated through the increase of propulsive efficiency. It is found that the computed changing tendencies of almost all self-propulsion factors after being equipped with a stator are the same as in the experiments, such as a decreased revolution rate, increased thrust deduction and mean wake. A wake energy analysis is also conducted to verify the energy-saving effects of stators, and it shows that the stator decreases the flow of kinetic energy behind the propeller through its contra-propeller pre-swirl. Next, an optimization of pre-swirl stators is conducted by CFD. Aside from the prototype stator, three modified stators are designed and the self-propulsion characteristics with these stators are also numerically simulated. The increase order of the evaluated energy-saving effects of these modified stators is seen to be the same as in the design idea. The case with the highest propulsive efficiency shows the largest increase of Ktotal before the propeller and the largest decrease of Ktotal behind the propeller relative to cases without stators.

  18. Evaluation of stator core loss of high speed motor by using thermography camera

    Science.gov (United States)

    Sato, Takeru; Enokizono, Masato

    2018-04-01

    In order to design a high-efficiency motor, the iron loss that is generated in the motor should be reduced. The iron loss of the motor is generated in a stator core that is produced with an electrical steel sheet. The iron loss characteristics of the stator core and the electrical steel sheet are agreed due to a building factor. To evaluate the iron loss of the motor, the iron loss of the stator core should be measured more accurately. Thus, we proposed the method of the iron loss evaluation of the stator core by using a stator model core. This stator model core has been applied to the surface mounted permanent magnet (PM) motors without windings. By rotate the permanent magnet rotor, the rotating magnetic field is generated in the stator core like a motor under driving. To evaluate the iron loss of the stator model core, the iron loss of the stator core can be evaluated. Also, the iron loss can be calculated by a temperature gradient. When the temperature gradient is measured by using thermography camera, the iron loss of entire stator core can be evaluated as the iron loss distribution. In this paper, the usefulness of the iron loss evaluation method by using the stator model core is shown by the simulation with FEM and the heat measurement with thermography camera.

  19. Active Flow Control in a Radial Vaned Diffuser for Surge Margin Improvement: A Multislot Suction Strategy

    Directory of Open Access Journals (Sweden)

    Aurélien Marsan

    2017-01-01

    Full Text Available This work is the final step of a research project that aims at evaluating the possibility of delaying the surge of a centrifugal compressor stage using a boundary-layer suction technique. It is based on Reynolds-Averaged Navier-Stokes numerical simulations. Boundary-layer suction is applied within the radial vaned diffuser. Previous work has shown the necessity to take into account the unsteady behavior of the flow when designing the active flow control technique. In this paper, a multislot strategy is designed according to the characteristics of the unsteady pressure field. Its implementation results in a significant increase of the stable operating range predicted by the unsteady RANS numerical model. A hub-corner separation still exists further downstream in the diffuser passage but does not compromise the stability of the compressor stage.

  20. Cooling Strategies for Vane Leading Edges in a Syngas Environment Including Effects of Deposition and Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Ames, Forrest [Univ. of North Dakota, Grand Forks, ND (United States); Bons, Jeffrey [Univ. of North Dakota, Grand Forks, ND (United States)

    2014-09-30

    The Department of Energy has goals to move land based gas turbine systems to alternate fuels including coal derived synthetic gas and hydrogen. Coal is the most abundant energy resource in the US and in the world and it is economically advantageous to develop power systems which can use coal. Integrated gasification combined cycles are (IGCC) expected to allow the clean use of coal derived fuels while improving the ability to capture and sequester carbon dioxide. These cycles will need to maintain or increase turbine entry temperatures to develop competitive efficiencies. The use of coal derived syngas introduces a range of potential contaminants into the hot section of the gas turbine including sulfur, iron, calcium, and various alkali metals. Depending on the effectiveness of the gas clean up processes, there exists significant likelihood that the remaining materials will become molten in the combustion process and potentially deposit on downstream turbine surfaces. Past evidence suggests that deposition will be a strong function of increasing temperature. Currently, even with the best gas cleanup processes a small level of particulate matter in the syngas is expected. Consequently, particulate deposition is expected to be an important consideration in the design of turbine components. The leading edge region of first stage vanes most often have higher deposition rates than other areas due to strong fluid acceleration and streamline curvature in the vicinity of the surface. This region remains one of the most difficult areas in a turbine nozzle to cool due to high inlet temperatures and only a small pressure ratio for cooling. The leading edge of a vane often has relatively high heat transfer coefficients and is often cooled using showerhead film cooling arrays. The throat of the first stage nozzle is another area where deposition potentially has a strongly adverse effect on turbine performance as this region meters the turbine inlet flow. Based on roughness

  1. Sparse Reconstruction for Temperature Distribution Using DTS Fiber Optic Sensors with Applications in Electrical Generator Stator Monitoring

    Science.gov (United States)

    Bazzo, João Paulo; Pipa, Daniel Rodrigues; da Silva, Erlon Vagner; Martelli, Cicero; Cardozo da Silva, Jean Carlos

    2016-01-01

    This paper presents an image reconstruction method to monitor the temperature distribution of electric generator stators. The main objective is to identify insulation failures that may arise as hotspots in the structure. The method is based on temperature readings of fiber optic distributed sensors (DTS) and a sparse reconstruction algorithm. Thermal images of the structure are formed by appropriately combining atoms of a dictionary of hotspots, which was constructed by finite element simulation with a multi-physical model. Due to difficulties for reproducing insulation faults in real stator structure, experimental tests were performed using a prototype similar to the real structure. The results demonstrate the ability of the proposed method to reconstruct images of hotspots with dimensions down to 15 cm, representing a resolution gain of up to six times when compared to the DTS spatial resolution. In addition, satisfactory results were also obtained to detect hotspots with only 5 cm. The application of the proposed algorithm for thermal imaging of generator stators can contribute to the identification of insulation faults in early stages, thereby avoiding catastrophic damage to the structure. PMID:27618040

  2. Sparse Reconstruction for Temperature Distribution Using DTS Fiber Optic Sensors with Applications in Electrical Generator Stator Monitoring

    Directory of Open Access Journals (Sweden)

    João Paulo Bazzo

    2016-09-01

    Full Text Available This paper presents an image reconstruction method to monitor the temperature distribution of electric generator stators. The main objective is to identify insulation failures that may arise as hotspots in the structure. The method is based on temperature readings of fiber optic distributed sensors (DTS and a sparse reconstruction algorithm. Thermal images of the structure are formed by appropriately combining atoms of a dictionary of hotspots, which was constructed by finite element simulation with a multi-physical model. Due to difficulties for reproducing insulation faults in real stator structure, experimental tests were performed using a prototype similar to the real structure. The results demonstrate the ability of the proposed method to reconstruct images of hotspots with dimensions down to 15 cm, representing a resolution gain of up to six times when compared to the DTS spatial resolution. In addition, satisfactory results were also obtained to detect hotspots with only 5 cm. The application of the proposed algorithm for thermal imaging of generator stators can contribute to the identification of insulation faults in early stages, thereby avoiding catastrophic damage to the structure.

  3. Design and Performance Improvement of AC Machines Sharing a Common Stator

    Science.gov (United States)

    Guo, Lusu

    With the increasing demand on electric motors in various industrial applications, especially electric powered vehicles (electric cars, more electric aircrafts and future electric ships and submarines), both synchronous reluctance machines (SynRMs) and interior permanent magnet (IPM) machines are recognized as good candidates for high performance variable speed applications. Developing a single stator design which can be used for both SynRM and IPM motors is a good way to reduce manufacturing and maintenance cost. SynRM can be used as a low cost solution for many electric driving applications and IPM machines can be used in power density crucial circumstances or work as generators to meet the increasing demand for electrical power on board. In this research, SynRM and IPM machines are designed sharing a common stator structure. The prototype motors are designed with the aid of finite element analysis (FEA). Machine performances with different stator slot and rotor pole numbers are compared by FEA. An 18-slot, 4-pole structure is selected based on the comparison for this prototype design. Sometimes, torque pulsation is the major drawback of permanent magnet synchronous machines. There are several sources of torque pulsations, such as back-EMF distortion, inductance variation and cogging torque due to presence of permanent magnets. To reduce torque pulsations in permanent magnet machines, all the efforts can be classified into two categories: one is from the design stage, the structure of permanent magnet machines can be optimized with the aid of finite element analysis. The other category of reducing torque pulsation is after the permanent magnet machine has been manufactured or the machine structure cannot be changed because of other reasons. The currents fed into the permanent magnet machine can be controlled to follow a certain profile which will make the machine generate a smoother torque waveform. Torque pulsation reduction methods in both categories will be

  4. Numerical method for calculation of 3D viscous turbomachine flow taking into account stator/rotor unsteady interaction

    Energy Technology Data Exchange (ETDEWEB)

    Rusanov, A.V.; Yershov, S.V. [Institute of Mechanical Engineering Problems of National Academy of Sciences of Ukraine Kharkov (Ukraine)

    1997-12-31

    The numerical method is suggested for the calculation of the 3D periodically unsteady viscous cascade flow evoked by the aerodynamics interaction of blade rows. Such flow is described by the thin-layer Reynolds-averaged unsteady Navier-Stokes equations. The turbulent effects are simulated with the modified Baldwin-Lomax turbulence model. The problem statement allows to consider an unsteady flow through either a single turbo-machine stage or a multi stage turbomachine. The sliding mesh techniques and the time-space non-oscillatory square interpolation are used in axial spacings to calculate the flow in a computational domain that contains the reciprocally moving elements. The gasdynamical equations are integrated numerically with the implicit quasi-monotonous Godunov`s type ENO scheme of the second or third order of accuracy. The suggested numerical method is incorporated in the FlowER code developed by authors for calculations of the 3D viscous compressible flows through multi stage turbomachines. The numerical results are presented for unsteady turbine stage throughflows. The method suggested is shown to simulate qualitatively properly the main unsteady cascade effects in particular the periodically blade loadings, the propagation of stator wakes through rotor blade passage and the unsteady temperature flowfields for stages with cooled stator blades. (author) 21 refs.

  5. Stator iron loss of tubular permanent-magnet machines \\ud

    OpenAIRE

    Amara, Y.; Wang, J.B.; Howe, D.

    2005-01-01

    While methods of determining the iron loss in rotating permanent-magnet (PM) machines have been investigated extensively, the study of iron loss in linear machines is relatively poorly documented. This paper describes a simple analytical method to predict flux density waveforms in discrete regions of the laminated stator of a tubular PM machine, and employs an established iron loss model to determine the iron loss components, on both no load and on load. Analytical predictions are compared wi...

  6. Partial discharge as a stator winding evaluation tool

    International Nuclear Information System (INIS)

    Maughan, C.V.

    2005-01-01

    This paper has been prepared to illustrate the value of partial discharge (PD) testing in assessing the condition of stator windings on operating generators and motors. The database of one particular PD system vendor was chosen for this study because of the magnitude of data accumulated by this company over the last 15 years. It was felt that sufficient data had been accumulated to allow useful statistical analysis of the capabilities of PD testing. The PD detection technology used by Iris has been installed on about 6000 generators and motors, and has inspection information from about 3600 machines. On these 3600 generators and motors, PD has successfully identified 209 potential problems that were verified by inspection to be present. In most cases, moderate corrective maintenance permitted return of the equipment to service without major repairs. An estimate of the actual number of avoided failures was not possible from the available reports. But it is clear that many potentially serious stator winding failures were avoided as a result of removal of these machines from service because of high PD readings. No attempt has been made in the paper to provide technical background or details of the PD test/analysis processes. There are numerous technical papers and industry guides; the interested reader is referred to IEEE 1434, EPRI Reports, and other documents in the Bibliography. While this paper is based somewhat narrowly on data from only one company, there are several other companies involved in PD testing and evaluation. As described below in this paper, these companies have also been successful in identifying stator winding problems through the use of PD equipment. Clearly, PD testing is a useful tool in monitoring and assessing the condition of stator windings, as well as other associated electrical equipment in the power plant. Because of the power of PD testing, it is expected that the use of PD monitoring will continue to expand at a significant rate in

  7. Effect of Guide Vane Clearance Gap on Francis Turbine Performance

    Directory of Open Access Journals (Sweden)

    Ravi Koirala

    2016-04-01

    Full Text Available Francis turbine guide vanes have pivoted support with external control mechanism, for conversion of pressure to kinetic energy and to direct them to runner vanes. This movement along the support is dependent on variation of load and flow (operating conditions. Small clearance gaps between facing plates and the upper and lower guide vane tips are available to aid this movement, through which leakage flow occurs. This secondary flow disturbs the main flow stream, resulting performance loss. Additionally, these increased horseshoe vortex, in presence of sand, when crosses through the gaps, both the surfaces are eroded. This causes further serious effect on performance and structural property by increasing gaps. This paper discusses the observation of the severity in hydropower plants and effect of clearance gaps on general performance of the Francis turbine through computational methods. It also relates the primary result with the empirical relation for leakage flow prediction. Additionally, a possible method to computationally estimate thickness depletion has also been presented. With increasing clearance gap, leakage increases, which lowers energy conversion and turbine efficiency along with larger secondary vortex.

  8. A three dimensional model of a vane rheometer

    International Nuclear Information System (INIS)

    Nazari, Behzad; Moghaddam, Ramin Heidari; Bousfield, Douglas

    2013-01-01

    Highlights: • FEM was used to calculate the isothermal flow parameters in a vane geometry. • Velocity, pressure and then stress fields were obtained. • Using total stress, shaft torque was calculated to compare with experimental data. • A modified cell Reynolds number and power number were used to study flow pattern. • A comparison between 2D and 3D modeling was done based on calculated torques. -- Abstract: Vane type geometries are often used in rheometers to avoid slippage between the sample and the fixtures. While yield stress and other rheological properties can be obtained with this geometry, a complete analysis of this complex flow field is lacking in the literature. In this work, a finite element method is used to calculate the isothermal flow parameters in a vane geometry. The method solves the mass and momentum continuity equations to obtain velocity, pressure and then stress fields. Using the total stress numerical data, we calculated the torque applied on solid surfaces. The validity of the computational model was established by comparing the results to experimental results of shaft torque at different angular velocities. The conditions where inertial terms become important and the linear relationship between torque and stress are quantified with dimensionless groups. The accuracy of a two dimensional analysis is compared to the three dimensional results

  9. The Modeling and Simulation of Thermal Analysis at Hydro Generator Stator Winding Insulation

    Directory of Open Access Journals (Sweden)

    Mihaela Raduca

    2006-10-01

    Full Text Available This paper presents the modelling and simulation of thermal analysis at hydro generator stator winding. The winding stator is supplied at high voltage of 11 kV for high power hydro generator. To present the thermal analysis for stator winding is presented at supply of coil by 11 kV, when coil is heat and thermal transfer in insulation at ambient temperature.

  10. An experimental study of water absorption characteristics for generator stator winding insulation

    International Nuclear Information System (INIS)

    Lee, D. S.; Bae, Y. C.; Kim, H. S.; Kim, Y. H.; Lee, H.

    2004-01-01

    Leaking water coolant into stator electrical insulation is a growing concern for the aging water-cooled generator since leaks in the generator water-cooled stator winding can affect machine availability and insulation life. But a domestic techniques of such field are insufficient and depend wholly on GE or TOSHIBA technique. Therefore this paper introduces measuring principle and developed measuring system, which has been used to detecting wet absorption. We accomplished the experiment with a stator promotion of virtue which is used in actual power plant. Also, experimental method of generator stator winding, which is investigated into wet absorption test

  11. Impulsive Control of the Rotor-Stator Rub Based on Phase Characteristic

    Directory of Open Access Journals (Sweden)

    Jieqiong Xu

    2014-01-01

    Full Text Available An impulsive control method is proposed to eliminate the rotor-stator rubbing based on the phase characteristic. The relation between the vibration energy and the phase difference suggests the starting point for controlling the rotor-stator rubbing by implementing impulse. When the contact between the rotor and the stator occurs, the impulse is implemented in x-direction and y-direction several times to avoid the rotor-stator rubbing. The practical feasibility of this approach is investigated by numerical simulations.

  12. Experimental Study on Series Operation of Sliding Vane Pump and Centrifugal Pump

    OpenAIRE

    Tao Li; Weiming Zhang; Ming Jiang; Zhengyang Li

    2013-01-01

    A platform for sliding vane pump and centrifugal pump tests is installed to study the series operation of them under different characteristics of pipeline. Firstly, the sliding vane pump and the centrifugal pump work independently, and the performance is recorded. Then, the two types of pumps are combined together, with the sliding vane pump acting as the feeding pump. Comparison is made between the performance of the independently working pump and the performance of series operation pump. Re...

  13. Broadband Noise of Fans - With Unsteady Coupling Theory to Account for Rotor and Stator Reflection/Transmission Effects

    Science.gov (United States)

    Hanson, Donald B.

    2001-01-01

    This report examines the effects on broadband noise generation of unsteady coupling between a rotor and stator in the fan stage of a turbofan engine. Whereas previous acoustic analyses treated the blade rows as isolated cascades, the present work accounts for reflection and transmission effects at both blade rows by tracking the mode and frequency scattering of pressure and vortical waves. The fan stage is modeled in rectilinear geometry to take advantage of a previously existing unsteady cascade theory for 3D perturbation waves and thereby use a realistic 3D turbulence spectrum. In the analysis, it was found that the set of participating modes divides itself naturally into "independent mode subsets" that couple only among themselves and not to the other such subsets. This principle is the basis for the analysis and considerably reduces computational effort. It also provides a simple, accurate scheme for modal averaging for further efficiency. Computed results for a coupled fan stage are compared with calculations for isolated blade rows. It is found that coupling increases downstream noise by 2 to 4 dB. Upstream noise is lower for isolated cascades and is further reduced by including coupling effects. In comparison with test data, the increase in the upstream/downstream differential indicates that broadband noise from turbulent inflow at the stator dominates downstream noise but is not a significant contributor to upstream noise.

  14. Theoretical morphology and development of flight feather vane asymmetry with experimental tests in parrots.

    Science.gov (United States)

    Feo, Teresa J; Prum, Richard O

    2014-06-01

    Asymmetry in flight feather vane width is a major functional innovation associated with the evolution of flight in the ancestors of birds. However, the developmental and morphological basis of feather shape is not simple, and the developmental processes involved in vane width asymmetry are poorly understood. We present a theoretical model of feather morphology and development that describes the possible ways to modify feather development and produce vane asymmetry. Our model finds that the theoretical morphospace of feather shape is redundant, and that many different combinations of parameters could be responsible for vane asymmetry in a given feather. Next, we empirically measured morphological and developmental model parameters in asymmetric and symmetric feathers from two species of parrots to identify which combinations of parameters create vane asymmetry in real feathers. We found that both longer barbs, and larger barb angles in the relatively wider trailing vane drove asymmetry in tail feathers. Developmentally, longer barbs were the result of an offset of the radial position of the new barb locus, whereas larger barb angles were produced by differential expansion of barbs as the feather unfurls from the tubular feather germ. In contrast, the helical angle of barb ridge development did not contribute to vane asymmetry and could be indicative of a constraint. This research provides the first comprehensive description of both the morphological and developmental modifications responsible for vane asymmetry within real feathers, and identifies key steps that must have occurred during the evolution of vane asymmetry. © 2014 Wiley Periodicals, Inc.

  15. Numerical analysis and experiment research on fluid orbital performance of vane type propellant management device

    International Nuclear Information System (INIS)

    Hu, Q; Li, Y; Pan, H L; Liu, J T; Zhuang, B T

    2015-01-01

    Vane type propellant management device (PMD) is one of the key components of the vane-type surface tension tank (STT), and its fluid orbital performance directly determines the STT's success or failure. In present paper, numerical analysis and microgravity experiment study on fluid orbital performance of a vane type PMD were carried out. By using two-phase flow model of volume of fluid (VOF), fluid flow characteristics in the tank with the vane type PMD were numerically calculated, and the rules of fluid transfer and distribution were gotten. A abbreviate model test system of the vane type PMD is established and microgravity drop tower tests were performed, then fluid management and transmission rules of the vane type PMD were obtained under microgravity environment. The analysis and tests results show that the vane type PMD has good and initiative fluid orbital management ability and meets the demands of fluid orbital extrusion in the vane type STT. The results offer valuable guidance for the design and optimization of the new generation of vane type PMD, and also provide a new approach for fluid management and control in space environment

  16. Enhanced Boiling-Metal Cooling Of Vanes Exposed To Hot Gases

    Science.gov (United States)

    Osofsky, I. B.

    1995-01-01

    Incorporation of automatic, self-powered jet pumps proposed to enhance boiling-liquid-metal cooling of vanes exposed to hot gases. In original intended application, vanes and probes thrust-vector-control devices inserted in supersonic flows of hot gases in rocket-engine nozzles; this cooling concept also applicable to vanes and blades in high-performance turbine engines. In further improvement, additional axial and transverse slots added to coolant passages in vane or probe and to coolant reservoir. Slots reduce stresses caused by thermal expansion and contraction of solid coolant.

  17. Free Stator Modeling of a Traveling Wave Ultrasonic Motor

    DEFF Research Database (Denmark)

    Izadi-Zamanabadi, Roozbeh; Helbo, Jan; Mojallali, Hamed

    2005-01-01

    elements. It is shown that the calculation of the circuit parameters from the complex elastic, dielectric and piezoelectric material constants is straightforward and the model accuracy is verified with simulation around the important frequencies suitable for motor controller design purposes.......An equivalent circuit method describing the free stator of piezoelectric motor is presented in this paper, while the circuit elements have complex values. The mechanical, dielectric and piezoelectric losses associated with the vibrator are accounted for by the imaginary components of the circuit...

  18. Toward Understanding Tip Leakage Flows in Small Compressor Cores Including Stator Leakage Flow

    Science.gov (United States)

    Berdanier, Reid A.; Key, Nicole L.

    2017-01-01

    The focus of this work was to provide additional data to supplement the work reported in NASA/CR-2015-218868 (Berdanier and Key, 2015b). The aim of that project was to characterize the fundamental flow physics and the overall performance effects due to increased rotor tip clearance heights in axial compressors. Data have been collected in the three-stage axial research compressor at Purdue University with a specific focus on analyzing the multistage effects resulting from the tip leakage flow. Three separate rotor tip clearances were studied with nominal tip clearance gaps of 1.5 percent, 3.0 percent, and 4.0 percent based on a constant annulus height. Overall compressor performance was previously investigated at four corrected speedlines (100 percent, 90 percent, 80 percent, and 68 percent) for each of the three tip clearance configurations. This study extends the previously published results to include detailed steady and time-resolved pressure data at two loading conditions, nominal loading (NL) and high loading (HL), on the 100 percent corrected speedline for the intermediate clearance level (3.0 percent). Steady detailed radial traverses of total pressure at the exit of each stator row are supported by flow visualization techniques to identify regions of flow recirculation and separation. Furthermore, detailed radial traverses of time-resolved total pressures at the exit of each rotor row have been measured with a fast-response pressure probe. These data were combined with existing three-component velocity measurements to identify a novel technique for calculating blockage in a multistage compressor. Time-resolved static pressure measurements have been collected over the rotor tips for all rotors with each of the three tip clearance configurations for up to five loading conditions along the 100 percent corrected speedline using fast-response piezoresistive pressure sensors. These time-resolved static pressure measurements reveal new knowledge about the

  19. Dynamic performance of doubly-fed induction generator stator flux during consecutive grid voltage variations

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Chen, Zhe; Wu, Xiaojie

    2015-01-01

    For the grid-connected doubly-fed induction generator (DFIG)-based wind turbine, because of the stator connected to the grid directly, the stator flux easily suffers from the effects of grid voltage variations, such as grid disturbances and grid faults. Moreover, since the magnetic field is excited...

  20. Optimal Design of Stator Interior Permanent Magnet Machine with Minimized Cogging Torque for Wind Power Application

    DEFF Research Database (Denmark)

    Chen, Zhe; Zhang, Jianzhong; Cheng, Ming

    2008-01-01

    This paper proposes a new approach to minimize the cogging torque of a stator interior permanent magnet (SIPM) machine. The optimization of stator slot gap and permanent magnet is carried out and the cogging torque ripple is analyzed by using finite element analysis. Experiments on a prototype...

  1. Stator Current Harmonic Reduction in a Novel Half Quasi-Z-Source Wind Power Generation System

    Directory of Open Access Journals (Sweden)

    Shoudao Huang

    2016-09-01

    Full Text Available The generator stator current gets distorted with unacceptable levels of total harmonic distortion (THD because impedance-source wind power generation systems use three-phase diode rectifiers. The stator current harmonics will cause increasing losses and torque ripple, which reduce the efficiency and stability of the system. This paper proposes a novel half quasi-Z-source inverter (H-qZSI for grid-connected wind power generation systems, which can reduce the generator stator current harmonics a great deal. When H-qZSI operates in the shoot-through zero state, the derivative of the generator stator current is only determined by the instantaneous value of the generator stator voltage, so the nonlinear relationship between generator stator current and stator voltage is improved compared with the traditional impedance-source inverter. Theoretically, it is indicated that the stator current harmonics can be reduced effectively by means of the proposed H-qZSI. Finally, simulation and experimental results are given to verify the theoretical analysis.

  2. Sensorless Control of a Six-Phase Induction Motors Drive Using FOC in Stator Flux Reference Frame

    OpenAIRE

    G. R. Arab Markadeh; J. Soltani; N. R. Abjadi; M. Hajian

    2009-01-01

    In this paper, a direct torque control - space vector modulation (DTC-SVM) scheme is presented for a six-phase speed and voltage sensorless induction motor (IM) drive. The decoupled torque and stator flux control is achieved based on IM stator flux field orientation. The rotor speed is detected by on-line estimating of the rotor angular slip speed and stator vector flux speed. In addition, a simple method is introduced to estimate the stator resistance. Moreover in this control...

  3. The Screw-Conveyor Vane Design for Piece-Wise Construction ...

    African Journals Online (AJOL)

    Such a method of manufacture is beyond the resources of a general-purpose metal workshop that may require the odd spiral vane once in a while and can neither afford the time nor the cost of ordering from abroad. In this article the method of six blanks which the author has developed for the building up of the vane ...

  4. Wind Vanes in Ancient Mesopotamia, About 2000-1500 B.C..

    Science.gov (United States)

    Neumann, J.; Parpola, S.

    1983-10-01

    A search made of the Sumerian and Akkadian literature for indications of the possible existence of wind vanes in the ancient Mesopotamian civilizations resulted in two discoveries. First, in one Akkadian fable, originally written between about 1800 and 1600 B.C., mention was made of a wind vane. It follows from the context of the fable that the vane was made of wood, while the name of the vane suggests that it was in the shape of a bird. Second, three Sumero-Akkadian vocabularies of this period give three different Sumerian names for the single Akkadian name for vane. The Sumerian names appear to be genuine Sumerian terms and not translations of the Akkadian term. All three Sumerian names suggest that the vanes were made of wood; one of the three may possibly indicate that the vane was made in the form of either a fish (shark?) or a mythological water monster. Since the Sumerian culture flourished before about 2000 B.C. (the Ur III dynasty ruled from about 2100to 2000 B.C.), it seems that in the ancient Mesopotamian civilizations there were wind vanes about 4000 years ago, i.e., about 2000 years earlier than reported in ancient China and classical Greece.

  5. Dynamic Model of Contact Interface between Stator and Rotor

    Directory of Open Access Journals (Sweden)

    ZengHui Zhao

    2013-01-01

    Full Text Available Based on the equivalent principle, a linear spring contact model was established for the friction layer between stator and rotor. Different contact conditions were described by a distance index δ. Detailed analysis of the nonlinear contact behavior especially the static and dynamic slipping was carried on using a space-time equation. A contact deflection angle was proposed to quantitatively express the influence of friction force on the output performance. A more precision simulation model was established based on the theoretical analysis, and influences of different preload pressures and elastic modulus Em of friction layer on output performance were analyzed. The results showed the simulation results had very good consistency with experimental results, and the model could well reflect the output characteristics of contact interface.

  6. Improving the reliability of stator insulation system in rotating machines

    International Nuclear Information System (INIS)

    Gupta, G.K.; Sedding, H.G.; Culbert, I.M.

    1997-01-01

    Reliable performance of rotating machines, especially generators and primary heat transport pump motors, is critical to the efficient operation on nuclear stations. A significant number of premature machine failures have been attributed to the stator insulation problems. Ontario Hydro has attempted to assure the long term reliability of the insulation system in critical rotating machines through proper specifications and quality assurance tests for new machines and periodic on-line and off-line diagnostic tests on machines in service. The experience gained over the last twenty years is presented in this paper. Functional specifications have been developed for the insulation system in critical rotating machines based on engineering considerations and our past experience. These specifications include insulation stress, insulation resistance and polarization index, partial discharge levels, dissipation factor and tip up, AC and DC hipot tests. Voltage endurance tests are specified for groundwall insulation system of full size production coils and bars. For machines with multi-turn coils, turn insulation strength for fast fronted surges in specified and verified through tests on all coils in the factory and on samples of finished coils in the laboratory. Periodic on-line and off-line diagnostic tests were performed to assess the condition of the stator insulation system in machines in service. Partial discharges are measured on-line using several techniques to detect any excessive degradation of the insulation system in critical machines. Novel sensors have been developed and installed in several machines to facilitate measurements of partial discharges on operating machines. Several off-line tests are performed either to confirm the problems indicated by the on-line test or to assess the insulation system in machines which cannot be easily tested on-line. Experience with these tests, including their capabilities and limitations, are presented. (author)

  7. Robust stator resistance identification of an IM drive using model reference adaptive system

    International Nuclear Information System (INIS)

    Madadi Kojabadi, Hossein; Abarzadeh, Mostafa; Aghaei Farouji, Said

    2013-01-01

    Highlights: ► We estimate the stator resistance and rotor speed of the IM. ► We proposed a new quantity to estimate the speed and stator resistance of IM. ► The proposed algorithm is robust to rotor resistance variations. ► We estimate the IM speed and stator resistance simultaneously to avoid speed error. - Abstract: Model reference adaptive system (MRAS) based robust stator resistance estimator for sensorless induction motor (IM) drive is proposed. The MRAS is formed with a semi-active power quantity. The proposed identification method can be achieved with on-line tuning of the stator resistance with robustness against rotor resistance variations. Stable and efficient estimation of IM speed at low region will be guaranteed by simultaneous identification of IM speed and stator resistance. The stability of proposed stator resistance estimator is checked through Popov’s hyperstability theorem. Simulation and experimental results are given to highlight the feasibility, the simplicity, and the robustness of the proposed method.

  8. Dual stator dynamics in the Shewanella oneidensis MR-1 flagellar motor.

    Science.gov (United States)

    Paulick, Anja; Delalez, Nicolas J; Brenzinger, Susanne; Steel, Bradley C; Berry, Richard M; Armitage, Judith P; Thormann, Kai M

    2015-06-01

    The bacterial flagellar motor is an intricate nanomachine which converts ion gradients into rotational movement. Torque is created by ion-dependent stator complexes which surround the rotor in a ring. Shewanella oneidensis MR-1 expresses two distinct types of stator units: the Na(+)-dependent PomA4 B2 and the H(+)-dependent MotA4 B2. Here, we have explored the stator unit dynamics in the MR-1 flagellar system by using mCherry-labeled PomAB and MotAB units. We observed a total of between 7 and 11 stator units in each flagellar motor. Both types of stator units exchanged between motors and a pool of stator complexes in the membrane, and the exchange rate of MotAB, but not of PomAB, units was dependent on the environmental Na(+)-levels. In 200 mM Na(+), the numbers of PomAB and MotAB units in wild-type motors was determined to be about 7:2 (PomAB:MotAB), shifting to about 6:5 without Na(+). Significantly, the average swimming speed of MR-1 cells at low Na(+) conditions was increased in the presence of MotAB. These data strongly indicate that the S. oneidensis flagellar motors simultaneously use H(+) and Na(+) driven stators in a configuration governed by MotAB incorporation efficiency in response to environmental Na(+) levels. © 2015 John Wiley & Sons Ltd.

  9. Measurements of a in 2-stage axial turbine with shrouded bladings. Influence of open and closed shroud cavities on the flowfield in a 2-stage turbine with shrouded bladings. Final report; GuD-Kraftwerk - 500 MW auf einer Welle (AG Turbo II). Vorhaben 2.1.7A: 3-D-instationaere Schaufelgitter-Interaktionen in 2-stufigen Turbinenbeschaufelungen mit Deckband-Kavitaeten. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, D.; Tuemmers, C.; Bouzidi, F.

    2003-06-01

    The flow in a multi-stage turbine is characterised by complex steady and unsteady 3D - flow phenomena such as rotor-stator interactions or secondary flow phenomena like the passage - or the vortex. The unsteady flow field itself is influenced by different parameters, like the blade geometry, the flow in the shroud cavities or the relative position of the guide vanes respectively the rotating blades among each other (clocking). Understanding the basic mechanism relating development and propagation of secondary flow phenomena is key to reducing the aerodynamic losses. The aim of this project was the investigation of the influence of open and closed shroud cavities, blade geometry, axial blade distance, relative positions of the guide vanes and the rotor blades to each other (clocking) and the operating conditions on the flow losses, related by the interaction between the guide vanes and the rotor blades. These influences are analysed by coupled experimental and numerical investigation on a two-stage test turbine. The test turbine is built up in a modular way, so that different bladings (a basis- and an optimised blading) and different endwall, rotor and hub geometries can be investigated. For the numerical investigations the in-house Navier-Stockes - solver CHT-flow has been used. The comparison of the basis blading and the optimised blading shows that due to the design of the optimised blading the secondary flow regions at the hub and the tip could have been reduced significantly. Thus, a radially homogeneous flow field and therefore an increased efficiency could be achieved for the optimised blading. Further numerical and experimental investigations showed that due to opened shroud cavities the boundary layer at the hub and the tip has been increased. This leads to a displacement of the secondary flows from the endwalls towards the middle of the channel. Furthermore additional losses are induced, leading to an overall decrease in efficiency. Investigations

  10. A dynamic model of the piezoelectric traveling wave rotary ultrasonic motor stator with the finite volume method.

    Science.gov (United States)

    Renteria Marquez, I A; Bolborici, V

    2017-05-01

    This manuscript presents a method to model in detail the piezoelectric traveling wave rotary ultrasonic motor (PTRUSM) stator response under the action of DC and AC voltages. The stator is modeled with a discrete two dimensional system of equations using the finite volume method (FVM). In order to obtain accurate results, a model of the stator bridge is included into the stator model. The model of the stator under the action of DC voltage is presented first, and the results of the model are compared versus a similar model using the commercial finite element software COMSOL Multiphysics. One can observe that there is a difference of less than 5% between the displacements of the stator using the proposed model and the one with COMSOL Multiphysics. After that, the model of the stator under the action of AC voltages is presented. The time domain analysis shows the generation of the traveling wave in the stator surface. One can use this model to accurately calculate the stator surface velocities, elliptical motion of the stator surface and the amplitude and shape of the stator traveling wave. A system of equations discretized with the finite volume method can easily be transformed into electrical circuits, because of that, FVM may be a better choice to develop a model-based control strategy for the PTRUSM. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. FEM-based Analysis of a Hybrid Synchronous Generator with Skewed Stator Slots

    Directory of Open Access Journals (Sweden)

    MUNTEANU, A.

    2011-11-01

    Full Text Available The paper presents a simulation study of a hybrid synchronous generator (dual excitation system - permanent magnets and electromagnets with skewed stator slots. The main goal is to establish if the skewing of the slots brings a significant improvement of the air-gap flux density and of the induced stator voltage. The skewness angle is the parameter in discussion. The study is based on finite element method analysis. Due to the particular geometry of the stator slots, a multilayer approach is employed.

  12. Electrical machines and assemblies including a yokeless stator with modular lamination stacks

    Science.gov (United States)

    Qu, Ronghai; Jansen, Patrick Lee; Bagepalli, Bharat Sampathkumar; Carl, Jr., Ralph James; Gadre, Aniruddha Dattatraya; Lopez, Fulton Jose

    2010-04-06

    An electrical machine includes a rotor with an inner rotor portion and an outer rotor portion, and a double-sided yokeless stator. The yokeless stator includes modular lamination stacks and is configured for radial magnetic flux flow. The double-sided yokeless stator is concentrically disposed between the inner rotor portion and the outer rotor portion of the electrical machine. Examples of particularly useful embodiments for the electrical machine include wind turbine generators, ship propulsion motors, switch reluctance machines and double-sided synchronous machines.

  13. Pre-Swirl Stator and Propeller Design for Varying Operating Conditions

    DEFF Research Database (Denmark)

    Saettone, Simone; Regener, Pelle Bo; Andersen, Poul

    2016-01-01

    blades ahead of the propeller.This paper describes the hydrodynamic design of apre-swirl stator with radially variable pitch, paired with aconventional propeller. The aim is to achieve the highest possible effciency in various operating conditions, and to avoid effciency penalties in off-design operation.......To investigate the propeller and stator designs and configurations in different operating conditions, the computationally inexpensive vortex-lattice method is used a sa first step to optimize the geometry in an initial parameter study. Then the flow over hull, stator and propelleris simulated in a CFD...

  14. YiXing pump turbine guide vane vibrations: Problem reso lution with advanced CFD analysis

    Science.gov (United States)

    Nennemann, B.; Parkinson, É.

    2010-08-01

    During commissioning of YiXing pump turbine (Jiangsu province, China) by - at the time - GE Energy Hydro a number of guide vane vibration issues occurred. An investigation was launched to determine the root causes of these vibration incidents including analysis of site measurement data from the incidents and a Computation Fluid Dynamics (CFD) study. Several interesting hydro-dynamic phenomena were discovered during the course of this investigation, notably circumferentially synchronized and amplified von Karman vortices at the guide vane trailing edges in pump mode, unexpected flow attachment to the guide vane trailing edge pump mode resulting in bi-stable flow conditions and a self-excited torsion mode flutter vibration. The latter two phenomena explain the vibration incidents at site. The CFD study helped in identifying and quantifying the geometric parameters that influence torsion mode flutter and therefore enabled a targeted modification of the guide vane profile that is stable with respect to self-excitation. Between May 2009 and April 2010 the modified guide vanes were - now by Andritz Hydro Ltd. - installed in all 4 units of the YiXing pumped storage plant and proved to be successful in eliminating the vibration problems. Opening and closing sequences of the guide vanes - including pump start from closed guide vanes and transition from pump to synchronous condenser operation - could be implemented as required by the contract.

  15. Interaction of impeller and guide vane in a series-designed axial-flow pump

    International Nuclear Information System (INIS)

    Kim, S; Choi, Y S; Lee, K Y; Kim, J H

    2012-01-01

    In this paper, the interaction of the impeller and guide vane in a series-designed axial-flow pump was examined through the implementation of a commercial CFD code. The impeller series design refers to the general design procedure of the base impeller shape which must satisfy the various flow rate and head requirements by changing the impeller setting angle and number of blades of the base impeller. An arc type meridional shape was used to keep the meridional shape of the hub and shroud with various impeller setting angles. The blade angle and the thickness distribution of the impeller were designed as an NACA airfoil type. In the design of the guide vane, it was necessary to consider the outlet flow condition of the impeller with the given setting angle. The meridional shape of the guide vane were designed taking into consideration the setting angle of the impeller, and the blade angle distribution of the guide vane was determined with a traditional design method using vane plane development. In order to achieve the optimum impeller design and guide vane, three-dimensional computational fluid dynamics and the DOE method were applied. The interaction between the impeller and guide vane with different combination set of impeller setting angles and number of impeller blades was addressed by analyzing the flow field of the computational results.

  16. Turbine blade and vane heat flux sensor development, phase 2

    Science.gov (United States)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1985-01-01

    The development of heat flux sensors for gas turbine blades and vanes and the demonstration of heat transfer measurement methods are reported. The performance of the heat flux sensors was evaluated in a cylinder in cross flow experiment and compared with two other heat flux measurement methods, the slug calorimeter and a dynamic method based on fluctuating gas and surface temperature. Two cylinders, each instrumented with an embedded thermocouple sensor, a Gardon gauge, and a slug calorimeter, were fabricated. Each sensor type was calibrated using a quartz lamp bank facility. The instrumented cylinders were then tested in an atmospheric pressure combustor rig at conditions up to gas stream temperatures of 1700K and velocities to Mach 0.74. The test data are compared to other measurements and analytical prediction.

  17. Control of sediment entry into an intake canal by using submerged vanes

    Science.gov (United States)

    Sruthi, T. K.; Ranjith, K. B.; Chandra, Venu

    2017-08-01

    River flow which is entering into an intake canal carries lot of sediment due to centrifugal action at river-intake junction and results in various problems. The present work aims to control sediment entry into an intake canal by modifying flow pattern using submerged vanes. Experiments are conducted in a 57.5 cm wide rectangular laboratory model filled with sediment, d50=0.28mm, for a constant discharge of 0.025m3/s and flow depth (H) of 8cm. A rigid bed trapezoidal channel (side slopes, 1H: 1V) of bed width 15 cm, diverting at an angle of 45° from river model is used as an intake channel. Submerged vanes of width 0.18H and 1mm thick are arranged in single and double rows at a spacing (Vs) of 8cm and 12cm. The angle of attack (θ) of vane with respect to flow direction in river model varies as 15°, 300 and 450. A total of seven vanes are arranged as a crest of wave with a central vane height of 0.625 H and decreasing gradually to 0.438H on either side. In single row vane arrangement, for `Vs'=8 cm and `θ'=15°, 30° and 450, the sediment entry (S) reduces to 43%, 47% and 57% of sediment entry without vanes (So) and it is 40%, 44% and 48% of `So' for `Vs'= 12cm. Further `S' reduces to 38%, 39% and 47% of `So', by adding a second row of vanes at a lateral spacing and `Vs' of 8cm. It is observed that `S' decreases with an increase of `Vs' as well as with addition of a second row of vanes and increases with an increase of `θ'.

  18. Vane fabrication for the proof-of-principle radio-frequency quadrupole accelerator

    International Nuclear Information System (INIS)

    Williams, S.W.; Potter, J.M.

    1981-01-01

    The electrodes for the Proof-of-Principle (POP) Radio-Frequency Quadrupole (RFQ) accelerator were machined on a numerically controlled, three-axis, vertical mill. These pole tips, or vanes, were prepared for, and used, in the successful demonstration of RFQ practicality at Los Alamos National Laboratory in February 1980. The data set that described the vanes contained about 10 million bits of tool position data. The vanes were cut from OFHC copper blanks. The tolerances achieved were approximately +- 0.005 cm. The design and manufacturing procedures are described

  19. Powerful Swirl Generation of Flow-driven Rotating Mixing Vane for Enhancing CHF

    International Nuclear Information System (INIS)

    Seo, Han; Seo, Seok Bin; Heo, Hyo; Bang, In Cheol

    2014-01-01

    Mixing vanes are utilized to improve CHF and heat transfer performance in the rod bundle during normal operation. Experimental measurement of the swirling flow from a split vane pair was conducted using particle image velocimetry (PIV) and boroscope. The lateral velocity fields show that the swirling flow was initially centered in the subchannel and the computational fluid dynamics (CFD) analysis was performed based on the experiment. To visualize flow patterns in the 5Χ5 subchannel using PIV, matching the refraction between the working fluid and the structure was considered and the experiment aimed to develop the experimental data for providing fundamental information of the CFD analysis. The fixed split vane is the main mixing inducer in the fuel assembly. In a heat exchanger research, propeller type swirl generates at several pitch ratios and different blades angles were used to enhance heat transfer rate. Significant improvements of the heat transfer rate using the propellers were confirmed due to creation of tangential flow. In the present study, the mixing effect of rotation vane which has a shape of propeller was studied using PIV. A split vane was considered in the experiment to show the effect of rotation vane. Vertical and horizontal flow analyses were conducted to show the possible use of rotation vane in a subchannel. In the present work, the study of flow visualization using three types of vanes is conducted to show the mixing effect. The vertical flow and the horizontal flow distributions were analyzed in the two experimental facilities. For the vertical flow facility, flow distributions, flow profiles, and the turbulence kinetic energy are analyzed at the centerline of the channel. The results show that the rotation vane has the highest flow and turbulence kinetic intensity at the centerline of the channel. For the horizontal flow facility, the results indicate that lateral flow of the rotation vane is generated and maintained along with the flow

  20. Permanent magnet motor drives with switched stator windings

    Energy Technology Data Exchange (ETDEWEB)

    Nipp, E.

    1999-06-01

    Permanent magnet (PM) motors are today regarded as an interesting solution for a wide range of inverter-fed variable-speed drives. The generally increased interest in these motors has led to many investigations on their feasibility for vehicle propulsion. Consequently, they are also of interest for traction applications which led to the research project that is presented in this thesis. The most important advantages that are expected in comparison to the state of the art asynchronous motors are lower losses and a higher torque density. Often the field weakening speed range is important, but difficult to obtain with PM machines because the inductance in the direction of the magnetization tends to be low. An alternative can be to switch different coils groups of the stator winding into different configurations. This is the central topic of this thesis. Various aspects of the design of PM motor drives are considered with special attention to the requirements for the application of the switched winding concept. The studies were thereby limited to the inner rotor, radial flux topology. It was found that two winding parts per phase, implying four different winding connections, is the only interesting solution. An advantage of switched windings is that the internal voltage of the machine will never exceed the maximum inverter output, which increases the operation safety. Furthermore the machine design can uncompromisingly be optimized for operation below base speed, which means low inductances implying a large air gap length and thick magnets. A problem with switched windings is that circulating currents can occur. To diminish them, a 2/3 magnet covering of the pole surface must be chosen in combination with a non-salient rotor. Moreover it was found that the eddy current losses in the magnets can reach non-negligible levels and must be considered when designing a drive system. The major drawback of switched stator windings is probably the occurrence of torque

  1. On the interaction of a fan stator and acoustic treatments using the transfer element method

    International Nuclear Information System (INIS)

    Wang Xiaoyu; Sun Xiaofeng

    2010-01-01

    In the present investigation, a theoretical model is suggested to study the interaction of a fan stator and acoustic treatments using the transfer element method. Firstly, the solution of an acoustic field caused by a fan stator in an infinite duct is extended to that in a finite domain with all knowns and unknowns on the interface plane. Secondly, the related numerical results for an annular cascade are compared with the data obtained by directly solving an integral equation based on the blade boundary condition, which have good agreement with each other. Finally, more emphasis is placed on studying how a fan stator interacts with both upstream and downstream acoustic treatments. It is found that the interaction has an important influence on sound attenuation. In addition, optimal sound attenuation will depend on the combined design of both acoustic treatment and the fan stator. (invited paper)

  2. Enhanced control of DFIG wind turbine based on stator flux decay compensation

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Deng, Fujin; Chen, Zhe

    2016-01-01

    For the doubly-fed induction generator (DFIG)- based wind energy conversion system (WECS), the decaying flux and negative flux are the main reasons to cause the DFIG rotor overcurrent, during grid faults. The stator decaying flux characteristics versus the depth and instant of the stator voltage...... variation are analyzed firstly. On the basis of the stator flux performances, the enhanced control strategy is proposed to limit the decaying flux approximately into zero in half fundamental period by changing the stator voltage drop and recovery mode, and consequently the rotor transient current pulse...... is significantly reduced during grid faults. The experimental results based on the 7.5 kW DFIG setup is carried to validate the correctness and feasibility of the proposed strategy. Dynamic voltage restorer (DVR) can be one of the applications. With the proposed strategy, the DVR only works in a half fundamental...

  3. Investigation of slot discharge on a 239 MVA hydro generator stator winding

    Energy Technology Data Exchange (ETDEWEB)

    Li, S.; Hong, W. [BC Hydro and Power Authority, Vancouver, BC (Canada)

    2009-07-01

    This paper discussed a slot discharge investigation conducted on a 239 MVA generator stator winding. The generator in which the winding was located had experienced core split distortion, stator winding phase-to-phase failures, winding failures during Hipot testing, and high partial discharge (PD) activity. The results of on-line PD testing data were evaluated. The stator winding was subjected to visual inspections, bar dissections, and failure mechanism analyses. Eleven winding bars were removed from the stator slots in order to assess groundwall insulation conditions and identify the cause of the slot discharge activity. It was determined that the root cause of the slot discharge was a loose, non-uniform bar in the slot. The vibrating bar caused the semi-conductive coating to wear out and degraded the armour tape. Results of the study demonstrated the importance of on-line PD monitoring for detecting slot PD activity. 4 refs., 3 tabs., 11 figs.

  4. System and method for preventing stator permanent magnet demagnetization during vacuum pressure impregnation

    Science.gov (United States)

    Raminosoa, Tsarafidy; Alexander, James Pellegrino; EL-Refaie, Ayman Mohamed Fawzi

    2017-06-06

    A permanent magnet electrical machine includes a stator having conductive windings wound thereon and one or more permanent magnets embedded in the stator. A magnetic keeper element is positioned on the stator so as to form a magnetic flux path with the permanent magnets, with the magnetic keeper element closing the magnetic flux path of the permanent magnets by providing a low reluctance flux path to magnetic flux generated by the permanent magnets. A vacuum pressure impregnation (VPI) process is performed on the stator to increase a thermal conductivity of the windings, with the VPI process including a curing step that is performed at a selected temperature. The magnetic keeper element sets an operating point of the permanent magnets to an internal flux density level above a demagnetization threshold associated with the selected temperature at which the curing step is performed.

  5. Nonlinear Dynamics and Chaos of a Nonsmooth Rotor-Stator System

    Directory of Open Access Journals (Sweden)

    André Brandão

    2017-01-01

    Full Text Available Rotor systems have wide applications in industries, including aero engines, turbo generators, and gas turbines. Critical behaviors promoted by the system unbalance and the contact between rotor and stator lead to important nonlinearities on system dynamics. This paper investigates the complex behavior presented by a rotor-stator system’s dynamics due to intermittent contact. A four-degree-of-freedom Jeffcott nonsmooth rotor/stator system is used to describe the rotor behavior, while a viscoelastic suspended rigid cylinder represents the stator. Numerical simulations are carried out showing rich dynamics that include periodic, quasiperiodic, and chaotic responses. Special attention is dedicated to chaotic behavior and the calculation of Lyapunov exponents is employed as a diagnostic tool.

  6. Study on the vibration displacement distribution of a circular ultrasonic motor stator.

    Science.gov (United States)

    Ri, Chol-Su; Kim, Myong-Jin; Kim, Chol-Su; Im, Song-Jin

    2015-05-01

    In this paper is presented a theoretical consideration on the stator's displacement distribution, which is one of the most important problems in defining the structure of a circular ultrasonic motor stator. The results are compared with ones obtained utilizing a holographic interferometer, a laser vibrometer and FEM (finite element method) simulation. They are in good agreement with each other. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Rotational hysteresis and eddy current losses in electrical motor stators under non-conventional supply

    International Nuclear Information System (INIS)

    Bottauscio, Oriano.; Canova, Aldo; Chiampi, Mario; Repetto, Maurizio

    2003-01-01

    The magnetic analysis of stators of electrical motors is performed through an innovative 2D finite element formulation that takes into account the effects of eddy currents within the laminations by means of a generalized constitutive relationship also including vector hysteresis. This approach is applied to a deep estimation of magnetic flux distribution and magnetic losses in stator of induction motors supplied by high-frequency sinusoidal or six-step voltage sources

  8. Special MV cable for long stator winding application Transrapid Shanghai; Cable MT special pour enroulements de stator long sur le train Transrapid de Shanghai

    Energy Technology Data Exchange (ETDEWEB)

    Buethe, H.; Le Dren, S.; Steinbrink, D.; Zamzow, P.E. [Nexans Industries GmbH and Co KG (Germany)

    2003-07-01

    The long stator winding of the Transrapid represents the most innovative high speed MAGLEV technology application for a special rubber MV cable with formerly unequaled mechanical and electrical requirements. For the first time, we are able to provide details about this special MV cable solution, using high quality rubber compounds for conductor insulation and semiconductive outer sheath with gliding coating for the long stator winding of the Transrapid Shanghai propulsion system, and to report that the high demands and specifications of the whole system were fulfilled. (authors)

  9. A Kalman Filter Based Technique for Stator Turn-Fault Detection of the Induction Motors

    Science.gov (United States)

    Ghanbari, Teymoor; Samet, Haidar

    2017-11-01

    Monitoring of the Induction Motors (IMs) through stator current for different faults diagnosis has considerable economic and technical advantages in comparison with the other techniques in this content. Among different faults of an IM, stator and bearing faults are more probable types, which can be detected by analyzing signatures of the stator currents. One of the most reliable indicators for fault detection of IMs is lower sidebands of power frequency in the stator currents. This paper deals with a novel simple technique for detecting stator turn-fault of the IMs. Frequencies of the lower sidebands are determined using the motor specifications and their amplitudes are estimated by a Kalman Filter (KF). Instantaneous Total Harmonic Distortion (ITHD) of these harmonics is calculated. Since variation of the ITHD for the three-phase currents is considerable in case of stator turn-fault, the fault can be detected using this criterion, confidently. Different simulation results verify high performance of the proposed method. The performance of the method is also confirmed using some experiments.

  10. Physics-based MDAO tool for CMC blades and vanes conceptual design, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed work will develop a reliability analysis tool consistent with conceptual-level design for ceramic matrix composite (CMC) turbine blades and vanes. The...

  11. Study of Flow Deformation around Wind-Vane Mounted Three-Dimensional Hot-Wire Probes

    DEFF Research Database (Denmark)

    Rømer Rasmussen, K.; Larsen, Søren Ejling; Jørgensen, F. E.

    1981-01-01

    Open wind tunnel tests on several different sensor systems consisting of triaxial hot-wire probes mounted on wind vanes (DISA and Riso vanes) have shown that flow deformation around the hot-wire sensor introduces errors in the measured velocity components. Though changes in the horizontal...... components proved to be negligible, flow deformation resulted in an overestimation of the vertical component from 1.1 to 1.5, depending on the direction of the vertical component. Turbulence and mean value data were adjusted by use of a linear correction derived from the wind tunnel tests. Wind vane...... construction must strike a compromise between minor flow disturbance and sufficient probe support. The final version of the DISA vane resulted in an acceptable vertical correction of about 10%....

  12. Suction Side Roughness Effects on Film Cooling Heat Transfer on a Turbine Vane

    National Research Council Canada - National Science Library

    Rutledge, James

    2004-01-01

    An experimental study was conducted in a simulated three vane linear cascade to determine the effects of surface roughness and film cooling on the heat transfer coefficient distribution in the region...

  13. Unsteady diffuser vane pressure and impeller wake measurements in a centrifugal pump

    Science.gov (United States)

    Arndt, N.; Acosta, A. J.; Brennen, C. E.; Caughey, T. K.

    1987-01-01

    Unsteady surface pressure measurements on a vaned diffuser of a centrifugal pump, and wake measurements of the flow exiting a centrifugal impeller into a vaneless diffuser are presented. Frequency spectra and ensemble averages are given for the unsteady measurements. Two different impellers were used, the pump impeller of the HPOTP (High Pressure Oxygen Turbopump) of the SSME (Space Shuttle Main Engine) and a two-dimensional impeller. The magnitude of the unsteady total pressure measured in the stationary frame at the impeller exit was found to be of the same order of magnitude as the total pressure rise across the pump. The magnitude of the unsteady diffuser vane pressures was observed to be significantly different on suction and pressure side of the vane, attaining its largest value on the suction side the leading edge while decreasing along the vane.

  14. Engineering diagnostics for vortex-induced stay vanes cracks in a Francis turbine

    Science.gov (United States)

    D'Agostini Neto, Alexandre; Gissoni, Humberto, Dr.; Gonçalves, Manuel, Dr.; Cardoso, Rogério; Jung, Alexander, Dr.; Meneghini, Julio, Prof.

    2016-11-01

    Despite the fact that vortex-induced vibration (VIV) in hydraulic turbines components (especially in stay vanes) is a well-known phenomenon, it still remains challenging for operation and maintenance teams in several power plants around the world. Since the first publication of a similar problem in 1967, literature shows that at least 27 other turbines witnessed strong stay vane vibrations associated with vortex shedding. Recurrent stay vane cracks in a 250 MW Francis turbine in Brazil motivated an engineering study involving prototype measurements, structural and Computational Fluid Dynamics (CFD) analysis in order to determine a proper geometry modification that could eliminate the periodic vortex wake generated at the stay vanes trailing edge. First cracks appeared in 1978 just after the machine was put into operation. A study published in 1982 associated these cracks with dynamic excitations caused by the water flow at high flow conditions. New stay vane profiles were proposed and executed as well as improved welding recommendations. Cracks however, continued to appear requiring welding repairs roughly every two years. Although Voith Hydro was not the original equipment manufacturer for these units, the necessary information was available to study the issue and propose and execute new stay vane profiles. This paper details the approach taken for the study. First, indirect vibration measurements were used to determine vibration frequencies to help to characterize the affected mode shapes. These results were compared to finite element (FE) calculations. Strain gage measurements performed afterwards confirmed the conclusions of this analysis. Next, transient CFD calculations were run to reproduce the measured phenomenon and to serve as a basis for a new stay vane geometry. This modification was then implemented in the actual turbine stay vanes. A new set of indirect vibration measurements indicated the effectiveness of the proposed solution. Final confirmation

  15. Modification of the trailing edges of the large stay vanes and their influence on dynamic stresses

    Science.gov (United States)

    Gajić, A.; Manzalović, P.; Predić, Z.

    2010-08-01

    In the purpose of discovering causes of high vibrations and long cracks on stay vanes of the turbines at HPP "Iron Gate I" measuring of stresses in the upper zone and in the lower zone along the stay ring are completed. Investigations performed some 20 years ago, in order to find out the excitation of vibrations, included measurements of the pressure along the trailing edge and stresses on stay vanes. The main frequency was about 36 Hz, which is very close to the natural frequencies of some stay vanes. It was concluded that there were two excitations, one belonging to Karman vortexes and the other to attack flow of the guide vanes, both with very close frequencies, causing beating oscillations. Modification of the stay vanes was made by grinding of the convex part of the trailing edges until half-circular concave of the same radius of 25 mm was reached. On site measurements performed at one unit, with original and modified trailing edge, with the same measuring devices, at the same measuring points and at the nearly same operating regimes. Influence of the modification on the static and dynamic stresses of the stay vanes, as well as their frequencies of the oscillations, is shown in the paper.

  16. Numerical modelling of multi-vane expander operating conditions in ORC system

    Science.gov (United States)

    Rak, Józef; Błasiak, Przemysław; Kolasiński, Piotr

    2017-11-01

    Multi-vane expanders are positive displacement volumetric machines which are nowadays considered for application in micro-power domestic ORC systems as promising alternative to micro turbines and other volumetric expanders. The multi-vane expander features very simple design, low gas flow capacity, low expansion ratios, an advantageous ratio of the power output to the external dimensions and are insensitive to the negative influence of the gas-liquid mixture expansion. Moreover, the multi-vane expander can be easily hermetically sealed, which is one of the key issues in the ORC system design. A literature review indicates that issues concerning the application of multi-vane expanders in such systems, especially related to operating of multi-vane expander with different low-boiling working fluids, are innovative, not fully scientifically described and have the potential for practical implementation. In this paper the results of numerical investigations on multi-vane expander operating conditions are presented. The analyses were performed on three-dimensional numerical model of the expander in ANSYS CFX software. The numerical model of the expander was validated using the data obtained from the experiment carried out on a lab test-stand. Then a series of computational analysis were performed using expanders' numerical model in order to determine its operating conditions under various flow conditions of different working fluids.

  17. Performance Analysis of The Effect on Insertion Guide Vanes For Rectangular Elbow 900 Cross Section

    Directory of Open Access Journals (Sweden)

    Setyo Nugroho

    2016-12-01

    Full Text Available The use of elbow or curved pipe in the installation of piping has a loss of pressure (pressure drop which could lead the power of pump that drive the fluid and decrease the energy efficiency of the system. The pressure drop is caused by the curved shape of the elbow that cause pressure on the outer wall (outter larger and blocking off the pace of the fluid, and flow pressure losses caused by friction, flow separation and secondary flow. A method that can be used to reduce flow separation and pressure loss in the elbow is by the insertion guide vane. The test model in the form of rectangular elbow 900  with a radius ratio (rc/Dh = 1.1249 without using a guide vane and number of guide vane insertion one until three guide vanes. With Reynolds number ReDh ≈ 8.6 × 104. The velocity inlet is uniform, the measured variable is static pressure. Static pressure was measured using an inclined manometer. With variation the number of guide vane gives a more effect on the value of pressure drop, the largest pressure drop until 123.35% compared to that without guide vane. The velocity distribution profile on the outlet side becomes more uniform. The magnitude of this pressure drop occurs as a result of the increased flow friction and its secondary flow become smaller.

  18. Experimental Investigation on Design Enhancement of Axial Fan Using Fixed Guide Vane

    Science.gov (United States)

    Munisamy, K. M.; Govindasamy, R.; Thangaraju, S. K.

    2015-09-01

    Airflow passes through the rotating blade in an axial flow fan will experience a helical flow pattern. This swirling effect leads the system to experience swirl energy losses or pressure drop yet reducing the total efficiency of the fan system. A robust tool to encounter this air spin past the blade is by introducing guide vane to the system. Owing to its importance, a new approach in designing outlet guide vane design for a commercial usage 1250mm diameter axial fan with a 30° pitch angle impeller has been introduced in this paper. A single line metal of proper curvature guide vane design technique has been adopted for this study. By choosing fan total efficiency as a target variable to be improved, the total and static pressure on the design point were set to be constraints. Therefore, the guide vane design was done based on the improvement target on the static pressure in system. The research shows that, with the improvement in static pressure by 29.63% through guide vane installation, the total fan efficiency is increased by 5.12%, thus reduces the fan power by 5.32%. Good agreement were found, that when the fan total efficiency increases, the power consumption of the fan is reduced. Therefore, this new approach of guide vane design can be applied to improve axial fan performance.

  19. Study on effects of mixing vane grids on coolant temperature distribution by subchannel analysis

    International Nuclear Information System (INIS)

    Mao, H.; Yang, B.W.; Han, B.

    2016-01-01

    Mixing vane grids (MVG) have great influence on coolant temperature field in the rod bundle. The MVG could enhance convective heat transfer between the fuel rod wall and the coolant, and promote inter-subchannel mixing at the same time. For the influence of the MVG on convective heat transfer enhancement, many experiments have been done and several correlations have been developed based on the experimental data. However, inter-subchannel mixing promotion caused by the MVG is not well estimated in subchannel analysis because the information of mixing vanes is totally missing in most subchannel codes. This paper analyzes the influence of mixing vanes on coolant temperature distribution using the improved MVG model in subchannel analysis. The coolant temperature distributions with the MVG are analyzed, and the results show that mixing vanes lead to a more uniform temperature distribution. The performances of split vane grids under different power conditions are evaluated. The results are compared with those of spacer grids without mixing vanes and some conclusions are obtained.

  20. Numerical and experimental study of the leakage flow in guide vanes with different hydrofoils

    Directory of Open Access Journals (Sweden)

    Sailesh Chitrakar

    2017-07-01

    Full Text Available Clearance gaps between guide vanes and cover plates of Francis turbines tend to increase in size due to simultaneous effect of secondary flow and erosion in sediment affected hydropower plants. The pressure difference between the two sides of the guide vane induces leakage flow through the gap. This flow enters into the suction side with high acceleration, disturbing the primary flow and causing more erosion and losses in downstream turbine components. A cascade rig containing a single guide vane passage has been built to study the effect of the clearance gap using pressure sensors and PIV (Particle Image Velocimetry technique. This study focuses on developing a numerical model of the test rig, validating the results with experiments and investigating the behavior of leakage flow numerically. It was observed from both CFD and experiment that the leakage flow forms a passage vortex, which shifts away from the wall while travelling downstream. The streamlines contributing to the formation of this vortex have been discussed. Furthermore, the reference guide vane with symmetrical hydrofoil has been compared with four cambered profiles, in terms of the guide vane loading and the consequent effect on the leakage flow. A dimensionless term called Leakage Flow Factor (Lff has been introduced to compare the performances of hydrofoils. It is shown that the leakage flow and its effect on increasing losses and erosion can be minimized by changing the pressure distribution over the guide vane.

  1. Numerical modelling of multi-vane expander operating conditions in ORC system

    Directory of Open Access Journals (Sweden)

    Rak Józef

    2017-01-01

    Full Text Available Multi-vane expanders are positive displacement volumetric machines which are nowadays considered for application in micro-power domestic ORC systems as promising alternative to micro turbines and other volumetric expanders. The multi-vane expander features very simple design, low gas flow capacity, low expansion ratios, an advantageous ratio of the power output to the external dimensions and are insensitive to the negative influence of the gas-liquid mixture expansion. Moreover, the multi-vane expander can be easily hermetically sealed, which is one of the key issues in the ORC system design. A literature review indicates that issues concerning the application of multi-vane expanders in such systems, especially related to operating of multi-vane expander with different low-boiling working fluids, are innovative, not fully scientifically described and have the potential for practical implementation. In this paper the results of numerical investigations on multi-vane expander operating conditions are presented. The analyses were performed on three-dimensional numerical model of the expander in ANSYS CFX software. The numerical model of the expander was validated using the data obtained from the experiment carried out on a lab test-stand. Then a series of computational analysis were performed using expanders' numerical model in order to determine its operating conditions under various flow conditions of different working fluids.

  2. Speed Sensorless Direct Torque Control of a PMSM Drive using Space Vector Modulation Based MRAS and Stator Resistance Estimator

    OpenAIRE

    A. Ameur; B. Mokhtari; N. Essounbouli; L. Mokrani

    2012-01-01

    This paper presents a speed sensorless direct torque control scheme using space vector modulation (DTC-SVM) for permanent magnet synchronous motor (PMSM) drive based a Model Reference Adaptive System (MRAS) algorithm and stator resistance estimator. The MRAS is utilized to estimate speed and stator resistance and compensate the effects of parameter variation on stator resistance, which makes flux and torque estimation more accurate and insensitive to parameter variation. ...

  3. Journal bearings design for a novel revolving vane compressor

    Energy Technology Data Exchange (ETDEWEB)

    Tan, K.M.; Ooi, K.T. [Thermal and Fluids Division, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2011-01-15

    This paper presents the theoretical details of the journal bearing design for Revolving Vane (RV) rotary type compressor. The mathematical models, force analysis, and the theoretical design analysis for the dynamically loaded journal bearing of the compressor are presented. The variations of the minimum oil film thickness and the maximum film pressure developed are shown and the influences of design parameters, compressor configurations, and operating conditions on the journal bearing performance are described. For an air-conditioning compressor of 1.5 kW cooling capacity, the lowest minimum oil film thickness for lower and upper journal bearings is 6.6 {mu}m and 4.3 {mu}m respectively, when the cylinder is simply supported and the rotor is cantilever-supported. The lowest minimum oil film thickness for the journal bearing, which supports the cylinder, reduces to 4.0 {mu}m if the cantilever-type support is used. Besides that, a short-fat configuration of RV compressor is favorable in the interest of lowering bearing forces. (author)

  4. Exergy Analysis of the Revolving Vane Compressed Air Engine

    Directory of Open Access Journals (Sweden)

    Alison Subiantoro

    2016-01-01

    Full Text Available Exergy analysis was applied to a revolving vane compressed air engine. The engine had a swept volume of 30 cm3. At the benchmark conditions, the suction pressure was 8 bar, the discharge pressure was 1 bar, and the operating speed was 3,000 rev·min−1. It was found that the engine had a second-law efficiency of 29.6% at the benchmark conditions. The contributors of exergy loss were friction (49%, throttling (38%, heat transfer (12%, and fluid mixing (1%. A parametric study was also conducted. The parameters to be examined were suction reservoir pressure (4 to 12 bar, operating speed (2,400 to 3,600 rev·min−1, and rotational cylinder inertia (0.94 to 2.81 g·mm2. The study found that a higher suction reservoir pressure initially increased the second-law efficiency but then plateaued at about 30%. With a higher operating speed and a higher cylinder inertia, second-law efficiency decreased. As compared to suction pressure and operating speed, cylinder inertia is the most practical and significant to be modified.

  5. Test procedure for use of the shear vane in tanks 103-SY, 103-AN, and 103-AW

    International Nuclear Information System (INIS)

    LeClair, M.D.; Waters, E.

    1995-01-01

    This is a record copy of a test procedure for application of the full-scale shear vane to underground waste tanks at Hanford. The introduction of the report provides background information on the development and proof-testing of the shear vane, as well as information about its current location. The document was originally prepared in 1988, and the work as shelved temporarily for lack of funds. Activities to utilize the shear vane will be expedited by use of this information

  6. Coolant pressure and airflow distribution in a strut-supported transpiration-cooled vane for a gas turbine engine

    Science.gov (United States)

    Kaufman, A.; Poferl, D. J.; Richards, H. T.

    1972-01-01

    An analysis to predict pressure and flow distribution in a strut-supported wire-cloth vane was developed. Results were compared with experimental data obtained from room-temperature airflow tests conducted over a range of vane inlet airflow rates from 10.7 to 40.4 g/sec (0.0235 to 0.0890 lb/sec). The analytical method yielded reasonably accurate predictions of vane coolant flow rate and pressure distribution.

  7. A Comparison of Hyporheic Transport at a Cross-Vane Structure and Natural Riffle.

    Science.gov (United States)

    Smidt, Samuel J; Cullin, Joseph A; Ward, Adam S; Robinson, Jesse; Zimmer, Margaret A; Lautz, Laura K; Endreny, Theodore A

    2015-01-01

    While restoring hyporheic flowpaths has been cited as a benefit to stream restoration structures, little documentation exists confirming that constructed restoration structures induce comparable hyporheic exchange to natural stream features. This study compares a stream restoration structure (cross-vane) to a natural feature (riffle) concurrently in the same stream reach using time-lapsed electrical resistivity (ER) tomography. Using this hydrogeophysical approach, we were able to quantify hyporheic extent and transport beneath the cross-vane structure and the riffle. We interpret from the geophysical data that the cross-vane and the natural riffle induced spatially and temporally unique hyporheic extent and transport, and the cross-vane created both spatially larger and temporally longer hyporheic flowpaths than the natural riffle. Tracer from the 4.67-h injection was detected along flowpaths for 4.6 h at the cross-vane and 4.2 h at the riffle. The spatial extent of the hyporheic zone at the cross-vane was 12% larger than that at the riffle. We compare ER results of this study to vertical fluxes calculated from temperature profiles and conclude significant differences in the interpretation of hyporheic transport from these different field techniques. Results of this study demonstrate a high degree of heterogeneity in transport metrics at both the cross-vane and the riffle and differences between the hyporheic flowpath networks at the two different features. Our results suggest that restoration structures may be capable of creating sufficient exchange flux and timescales of transport to achieve the same ecological functions as natural features, but engineering of the physical and biogeochemical environment may be necessary to realize these benefits. © 2014, National Ground Water Association.

  8. Partial Stator Overlap in a Linear Generator for Wave Power: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Anna E. Frost

    2017-11-01

    Full Text Available This paper presents a study on how the power absorption and damping in a linear generator for wave energy conversion are affected by partial overlap between stator and translator. The theoretical study shows that the electrical power as well as the damping coefficient change quadratically with partial stator overlap, if inductance, friction and iron losses are assumed independent of partial stator overlap or can be neglected. Results from onshore experiments on a linear generator for wave energy conversion cannot reject the quadratic relationship. Measurements were done on the inductance of the linear generator and no dependence on partial stator overlap could be found. Simulations of the wave energy converter’s operation in high waves show that entirely neglecting partial stator overlap will overestimate the energy yield and underestimate the peak forces in the line between the buoy and the generator. The difference between assuming a linear relationship instead of a quadratic relationship is visible but small in the energy yield in the simulation. Since the theoretical deduction suggests a quadratic relationship, this is advisable to use during modeling. However, a linear assumption could be seen as an acceptable simplification when modeling since other relationships can be computationally costly.

  9. Evaluation of effect of low opening operation on increasing wear of bearing bushings of guide vanes used in hydropower plants

    International Nuclear Information System (INIS)

    Kim, Jong Sung; Kim, Se Na

    2012-01-01

    A guide vane plays a key role in controlling the flow rate of water supplied to the turbine of a hydropower plant. It has been reported that guide vane bearing bushings are subjected to considerable wear, which requires them to be maintained. An ancillary service such as frequency control and black start causes cyclic low opening operation of the guide vanes. It is empirically well known that such operation increases the wear rate of the guide vane bearing bushing. In this study, the effect of low opening operation on the increasing wear of the guide vane bearing bushing is quantitatively assessed via finite element flow analysis, finite element stress analysis, and relative wear evaluation. As a result of the assessment, it is identified that the pressure applied on the guide vane surface increases and the contact length between the outer surface of the guide vane stem and the inner surface of the bearing bushing decreases with a decrease in the opening of the guide vane. In addition, low opening of the guide vanes results in an increase in the relative wear owing to the generation of high contact pressure on the bearing bushing surfaces

  10. Using Stator Blades in Accessory Tracts of Hermetic Pumps

    Directory of Open Access Journals (Sweden)

    V. A. Cheryomushkin

    2017-01-01

    Full Text Available Centrifugal pumps are the most extensive class of dynamic hydraulic machines, which are commonly used. So-called hermetic pumps, which possess a number of calculation and design features, stand apart among these machines. Rather complicated task is to calculate internal tracts of the hermetic pump, which are used to cool and lubricate its units. The article is concerned with this calculation, namely, the study of the hollow flow. In designing the hermetic pump, when simulating the flow through the accessory tracts, a so-called “lock” effect was detected between the rotor end and the side cover. This effect is caused by a macro-vortex formed in the hollow, which resulted in a significant pressure drop at the inlet of the shaft opening. Such a pressure drop leads to reducing fluid flow through the accessory tracts, which can cause overheating and failure of the engine and bearing units. In view of the large width of the hollow under consideration, to describe theoretically its flow is difficult. Therefore, a numerical simulation is the most accurate way to determine the impact degree of the macro-vortex on the flow process. The article shows a mathematical model used in computer modeling. Presents the images of a flowing part of the accessory tracts and the computation mesh. Also, gives the models to construct a mesh and the boundary conditions desirable to provide hydrodynamic calculation. Then, describes the possible ways to eliminate the “block” effect, i.e. to set an additional impeller, completely change the configuration of a flowing part of the internal tracts, as well as to add the stator blades to the side cover. The latter option was chosen, as the most optimal in terms of labor intensity and manufacturability. Further, to compare the nature of the flow with the blades and without them the article shows pressure distribution fields, vectors of velocity, and turbulent kinetic energy values. All the results obtained, including

  11. Thrust Reduction of Magnetic Levitation Vehicle Driven by Long Stator Linear Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Wan-Tsun Tseng

    2013-01-01

    Full Text Available The propulsion technology of long stator linear synchronous motors is used to drive high-speed maglev trains. The linear synchronous motor stator is divided into sections placed on guideway. The electric power supplies to stator sections in which the train just passes in change-step mode for long-distance operation. However, a thrust drop will be caused by change-step machinery for driving magnetic vehicle. According to the train speed and vehicle data, the change-step mode has three types of operation, namely premature commutation, simultaneous commutation, and late commutation. Each type of operation has a different thrust drop which can be affected by several parameters such as jerk, running speed, motor section length, and vehicle data. This paper focuses on determining the thrust drop of the change-step mode. The study results of this paper can be used to improve the operation system of high-speed maglev trains.

  12. A Design Study of Dual-Stator Permanent Magnet Brushless DC Motor

    Directory of Open Access Journals (Sweden)

    Yanliang Xu

    2013-11-01

    Full Text Available Dual-stator permanent magnet brushless DC Motor (DSBLDC features high efficiency and torque-density. As DSBLDC could operate in various states according to different winding connection modes, it is fully qualified for electric vehicle (EV drive. Unfortunately, due to the particular dual-stator structure, this kind of motor is difficult to be designed by available design methods. However, this paper demonstrates that a DSBLDC with series magnetic circuit structure can be regarded as being consisted of two independent BLDCs, i.e. an inner-rotor BLDC and an outer-rotor BLDC. Thus, the DSBLDC can be divided into two single-stator BLDCs. Based on this demonstration, the design method is verified by finite element analysis (FEA, and the basic design steps are given. Furthermore, experimental results of the prototype motor have verified the correction of the method, which also indicates that the motor with superior performance is adapted to EV drive.

  13. Stator Current Harmonic Control with Resonant Controller for Doubly Fed Induction Generator

    DEFF Research Database (Denmark)

    Liu, Changjin; Blaabjerg, Frede; Chen, Wenjie

    2012-01-01

    Voltage harmonics in the grid can introduce stator current harmonics in a doubly fed induction generator (DFIG) wind turbine system, which may potentially impact the generated power quality. Therefore, wind turbine current controllers need to be designed to eliminate the impact of grid voltage...... harmonics, especially low-order harmonics. This paper proposes a stator current harmonic suppression method using a sixth-order resonant controller to eliminate negative sequence fifth- and positive sequence seventh-order current harmonics. A stator current harmonic control loop is added to the conventional...... rotor current control loop for harmonic suppression. The overall control scheme is implemented in dq frame. Based on a mathematical model of the DFIG control system, the effects on system stability using the resonant controller, an analysis of the steady-state error, and the dynamic performance...

  14. On the Rotor to Stator Contact Dynamics with Impacts and Friction - Theoretical and Experimental Study

    DEFF Research Database (Denmark)

    Lahriri, Said

    The contact between a rotor and its stator can in some cases be considered as a serious malfunction that may lead to catastrophic failure. This major threat arises normally from full annular dry friction backward whirl and whip motion where the rotor runs and rubs at a high frequency on the inner...... of the friction coefficient behavior.......The contact between a rotor and its stator can in some cases be considered as a serious malfunction that may lead to catastrophic failure. This major threat arises normally from full annular dry friction backward whirl and whip motion where the rotor runs and rubs at a high frequency on the inner...... surface of the stator, and thereby traversing the full extent of the clearance. Normal and friction forces are exerted on the rotor at each impact and rubs. These particular forces can sustain the rotor in a persistent backward dry whirl or whip motion. In that case, the friction force plays a significant...

  15. Synthesis and evaluation of molecular rotors with large and bulky tert-butyldiphenylsilyloxy-substituted trityl stators.

    Science.gov (United States)

    Arcos-Ramos, Rafael; Rodríguez-Molina, Braulio; Romero, Margarita; Méndez-Stivalet, J Manuel; Ochoa, María Eugenia; Ramírez-Montes, Pedro I; Santillan, Rosa; Garcia-Garibay, Miguel A; Farfán, Norberto

    2012-08-17

    The search for voluminous stators that may accommodate large rotator units and speed rotational dynamics in the solid state led us to investigate a simple and efficient method for the synthesis of molecular rotors with tert-butyldiphenylsilyl-protected (TBDPS) triphenylmethyl stators. Additionally, solid state characterization of these systems with two-, four-, and six-TBDPS groups provided us with a description of their crystallinity and thermal stability. Among them, molecular rotor 7c with the largest and most symmetric stator resulting from six peripheral silyl groups showed the best tendency to crystallize, and the study of its isotopologue 7c-d(4) by solid state (2)H NMR revealed a 2-fold motion of the 1,4-diethynylphenylene-d(4) rotator in the kHz regime.

  16. A Very Low-Speed Sensorless Induction Motor Drive with Online Stator Resistance identification scheme

    Directory of Open Access Journals (Sweden)

    M. Zaky

    2008-03-01

    Full Text Available Recently, speed sensorless control of induction motor drives received great attention to avoid the different problems associated with direct speed sensors. However, low speed operation with robustness against parameter variations remains an area of research for sensorless systems. Stator resistance is of greatest importance for good operation of speed sensorless systems in low speed region. In this paper, a sliding mode current observer for an induction motor is presented. An estimation algorithm based on this observer in conjunction with Popov's hyper-stability theory is proposed to calculate the speed and stator resistance independently. The proposed speed observer with parallel stator resistance identification is firstly verified by simulation. Experimental results are included as well to demonstrate the good performance of the proposed observer and estimation algorithms at low speed.

  17. Control of a Dual-Stator Flux-Modulated Motor for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Xinhua Guo

    2016-07-01

    Full Text Available This paper presents the control strategies for a novel dual-stator flux-modulated (DSFM motor for application in electric vehicles (EVs. The DSFM motor can be applied to EVs because of its simple winding structure, high reliability, and its use of two stators and rotating modulation steels in the air gap. Moreover, it outperforms conventional brushless doubly-fed machines in terms of control performance. Two stator-current-oriented vector controls with different excitation in the primary winding, direct and alternating current excitation, are designed, simulated, and evaluated on a custom-made DSFM prototype allowing the decoupled control of torque. The stable speed response and available current characteristics strongly validate the feasibility of the two control methods. Furthermore, the proposed control methods can be employed in other applications of flux-modulated motors.

  18. Design and numerical investigation of swirl recovery vanes for the Fokker 29 propeller

    Directory of Open Access Journals (Sweden)

    Wang Yangang

    2014-10-01

    Full Text Available Swirl recovery vanes (SRVs are a set of stationary vanes located downstream from a propeller, which may recover some of the residual swirl from the propeller, hoping for an improvement in both thrust and efficiency. The SRV concept design for a scaled version representing the Fokker 29 propeller is performed in this paper, which may give rise to a promotion in propulsive performance of this traditional propeller. Firstly the numerical strategy is validated from two aspects of global quantities and the local flow field of the propeller compared with experimental data, and then the exit flow together with the development of propeller wake is analyzed in detail. Three kinds of SRV are designed with multiple circular airfoils. The numerical results show that the swirl behind the propeller is recovered significantly with Model V3, which is characterized by the highest solidity along spanwise, for various working conditions, and the combination of rotor and vane produced 5.76% extra thrust at the design point. However, a lower efficiency is observed asking for a better vane design and the choice of a working point. The vane position is studied which shows that there is an optimum range for higher thrust and efficiency.

  19. Simulation of flow pattern at rectangular lateral intake with different dike and submerged vane scenarios

    Directory of Open Access Journals (Sweden)

    Hojat Karami

    2017-07-01

    Full Text Available A comprehensive understanding of the sediment behavior at the entrance of diversion channels requires complete knowledge of three-dimensional (3D flow behavior around such structures. Dikes and submerged vanes are typical structures used to control sediment entrainment in the diversion channel. In this study, a 3D computational fluid dynamic (CFD code was calibrated with experimental data and used to evaluate flow patterns, the diversion ratio of discharge, the strength of secondary flow, and dimensions of the vortex inside the channel in various dike and submerged vane installation scenarios. Results show that the diversion ratio of discharge in the diversion channel is dependent on the width of the flow separation plate in the main channel. A dike perpendicular to the flow with a narrowing ratio of 0.20 doubles the ratio of diverted discharge in addition to reducing suspended sediment input to the basin, compared with a no-dike situation, by creating the outer arch conditions. A further increase in the narrowing ratio decreases the diverted discharge. In addition, increasing the longitudinal distance between consecutive vanes (Ls increases the velocity gradient between the vanes and leads to a more severe erosion of the bed, near the vanes.

  20. Evaluating transient performance of servo mechanisms by analysing stator current of PMSM

    Science.gov (United States)

    Zhang, Qing; Tan, Luyao; Xu, Guanghua

    2018-02-01

    Smooth running and rapid response are the desired performance goals for the transient motions of servo mechanisms. Because of the uncertain and unobservable transient behaviour of servo mechanisms, it is difficult to evaluate their transient performance. Under the effects of electromechanical coupling, the stator current signals of a permanent-magnet synchronous motor (PMSM) potentially contain the performance information regarding servo mechanisms in use. In this paper, a novel method based on analysing the stator current of the PMSM is proposed for quantifying the transient performance. First, a vector control model is constructed to simulate the stator current behaviour in the transient processes of consecutive speed changes, consecutive load changes, and intermittent start-stops. It is discovered that the amplitude and frequency of the stator current are modulated by the transient load torque and motor speed, respectively. The stator currents under different performance conditions are also simulated and compared. Then, the stator current is processed using a local means decomposition (LMD) algorithm to extract the instantaneous amplitude and instantaneous frequency. The sample entropy of the instantaneous amplitude, which reflects the complexity of the load torque variation, is calculated as a performance indicator of smooth running. The peak-to-peak value of the instantaneous frequency, which defines the range of the motor speed variation, is set as a performance indicator of rapid response. The proposed method is applied to both simulated data in an intermittent start-stops process and experimental data measured for a batch of servo turrets for turning lathes. The results show that the performance evaluations agree with the actual performance.

  1. Patterns of the Rotor-over-Stator Rolling under Change in the Damping Components

    Science.gov (United States)

    Shatokhin, V. F.

    2018-03-01

    As experimental studies show, the rubbing of the rotor against the structure usually excites harmonics of different frequencies. In high-frequency regions, the power of the vibration signal appears to be considerable. The rotor—supports—stator system is in an unstable equilibrium state during the contact interaction between the rotor and the stator. The forces exerted on the rotor facilitate the excitation of the asynchronous rolling and its damping. The forces have been determined that facilitate the excitation of the progressive and retrograde rotor precession. The consideration of these forces in the algorithm for modeling the rotor-over-stator rolling development allows investigation of the impact of the components of the above forces on the behavior of the rotor system. The initial excitation—disturbance of the normal operation—of the rotor and subsequent unsteady oscillations of it result from sudden imbalance in the second span. The results of numerical modeling of the rubbing in the second span and the rotor-over-stator rolling upon change in the damping components of secondary (gyroscopic) components b ij ( i ≠ j) of the damping matrix are presented for the rotor on three bearing-supports considering the synergetic effect of the forces of various types exerted on the rotor. It is shown that change in one of the parameters of the excitation forces leads to ambiguity of the pattern (manifestation form) of the asynchronous rotor-over-stator rolling and proves the existence of more than one states towards which the rotor—supports—stator system tends. In addition to the rolling with a constant rotor—stator contact, oscillations of the rotor develop in the direction perpendicular to the common trajectory of the precession motion of the rotor's center with transition to the vibro-impact motion mode. The oscillations of the rotor tend towards the symmetry center of the system (the stator bore center). The reason is the components of the stiffness

  2. A Novel Modular-Stator Outer-Rotor Flux-Switching Permanent-Magnet Motor

    OpenAIRE

    Jing Zhao; Yun Zheng; Congcong Zhu; Xiangdong Liu; Bin Li

    2017-01-01

    A novel modular-stator outer-rotor flux-switching permanent-magnet (MSOR-FSPM) motor is proposed and studied in this paper. Structure, operation and design principles of the MSOR-FSPM motor are introduced and analyzed. Considering that the combination of different pole number and slot number has a great influence on the motor performance, the optimum rotor pole number for the 12-stator-slot MSOR-FSPM motor is researched to obtain good performance and make full use of the space in the MSOR-FSP...

  3. Comparison of electromagnetic performance of brushless motors having magnets in stator and rotor

    Science.gov (United States)

    Hua, Wei; Cheng, Ming; Zhu, Z. Q.; Zhao, Wenxiang; Kong, Xiangxin

    2008-04-01

    The electromagnetic performance of two permanent magnet brushless motors, viz., flux-switching magnet (FSPM) and surface-mounted motors, in which concentrated stator windings are employed but the magnets are located in the stator and the rotor, respectively, is investigated by the finite element analysis. The significant differences in topologies and static characteristics are highlighted. The results show that both motors exhibit sinusoidal back-emf waveform and the FSPM motor exhibits not only larger airgap flux density, higher torque per copper loss, but also higher torque ripple due to cogging torque.

  4. Incipient Stator Insulation Fault Detection of Permanent Magnet Synchronous Wind Generators Based on Hilbert–Huang Transformation

    DEFF Research Database (Denmark)

    Wang, Chao; Liu, Xiao; Chen, Zhe

    2014-01-01

    Incipient stator winding fault in permanent magnet synchronous wind generators (PMSWGs) is very difficult to be detected as the fault generated variations in terminal electrical parameters are very weak and chaotic. This paper simulates the incipient stator winding faults at different degree...

  5. Digital signal processing control of induction machine`s torque and stator flux utilizing the direct stator flux field orientation method

    Energy Technology Data Exchange (ETDEWEB)

    Seiz, Julie Burger [Union College, Schenectady, NY (United States)

    1997-04-01

    This paper presents a review of the Direct Stator Flux Field Orientation control method. This method can be used to control an induction motor`s torque and flux directly and is the application of interest for this thesis. This control method is implemented without the traditional feedback loops and associated hardware. Predictions are made, by mathematical calculations, of the stator voltage vector. The voltage vector is determined twice a switching period. The switching period is fixed throughout the analysis. The three phase inverter duty cycle necessary to control the torque and flux of the induction machine is determined by the voltage space vector Pulse Width Modulation (PWM) technique. Transient performance of either the flux or torque requires an alternate modulation scheme which is also addressed in this thesis. A block diagram of this closed loop system is provided. 22 figs., 7 tabs.

  6. Test of a Supersonic Axial Compressor Stage Incorporating Splitter Vanes in the Rotor

    Science.gov (United States)

    1975-06-01

    n pa a tt.9fl Mfln%!4.OU d.4’t% i 4d’ V~~t .cru. .ý alpea a a* . &n,6 8.2 N .4N6 SIP b. Sfl-.4 V`.4Ŕ.4A) -’ 40.al r.N at9 ’l~~.7tt~4 % b-j t9%. %r4ft...1 lia aC %.# to1 up IN 3# Wi 0 3 W i 41C2 UP W = -) ~U W %L’ *j %0 W P J ) 0) %0 0 I WU U) 40 ) &V’ %V At9 ’ %AP 4) 4) W WA %V’ %A L V %V %P D %P%0

  7. Cone Factors from Field Vane and Triaxial Tests in Danish Soils

    DEFF Research Database (Denmark)

    Luke, Kirsten

    1996-01-01

    Six Danish cohesive soils are investigated using Cone Penetration Test (CPT) to estimate the undrained shear strength, cu. Field vane tests and consolidated triaxial tests are used to estimate cu for the six soils. The tested soils all come up with cone factors very close to 10 when using cu from...... the triaxial tests whereas cone factors ranging from 7 to 11 are estimated by using measurements from field vane tests. A strong correlation between the cone factor, Nkt and the friction ratio, fR is obtained when the cone factor is estimated from vane tests. This relation, which is obtained using only the six...... thoroughly investigated soils, is tested on data from other Danish and international sites. Likewise the constant cone factor of Nkt = 10 obtained from the triaxial tests is evaluated and compared with cone factors obtained from triaxial tests in other countries....

  8. A new stator-flux orientation strategy for flux-switching permanent magnet motor based on current-hysteresis control

    Science.gov (United States)

    Hua, Wei; Cheng, Ming; Lu, Wei; Jia, Hongyun

    2009-04-01

    A stator-flux orientation strategy based on current hysteresis for the flux-switching permanent magnet (FSPM) motor is proposed, in which the stator-PM FSPM motor is considered as a conventional rotor-PM surface-mounted motor and an equivalent rotor-orientated dq-axes synchronous reference frame is built although there are actually no rotary magnetic motive force produced by the stator magnets in the FSPM motor. Based on the proposed model, a vector-control strategy with current hysteresis for the FSPM motor drive is investigated and implemented on a dSPACE-based platform, and both the simulated and experimental results validate the effectiveness. It should be emphasized that the proposed stator-flux orientation strategy can be applied to other stator-PM machines (including doubly salient and flux-reversal PM machines) and other control methods (including space-vector pulsed-width-modification and direct torque control).

  9. System and method for monitoring and controlling stator winding temperature in a de-energized AC motor

    Science.gov (United States)

    Lu, Bin [Kenosha, WI; Luebke, Charles John [Sussex, WI; Habetler, Thomas G [Snellville, GA; Zhang, Pinjia [Atlanta, GA; Becker, Scott K [Oak Creek, WI

    2011-12-27

    A system and method for measuring and controlling stator winding temperature in an AC motor while idling is disclosed. The system includes a circuit having an input connectable to an AC source and an output connectable to an input terminal of a multi-phase AC motor. The circuit further includes a plurality of switching devices to control current flow and terminal voltages in the multi-phase AC motor and a controller connected to the circuit. The controller is configured to activate the plurality of switching devices to create a DC signal in an output of the motor control device corresponding to an input to the multi-phase AC motor, determine or estimate a stator winding resistance of the multi-phase AC motor based on the DC signal, and estimate a stator temperature from the stator winding resistance. Temperature can then be controlled and regulated by DC injection into the stator windings.

  10. Study of turbine and guide vanes integration to enhance the performance of cross flow vertical axis wind turbine

    Science.gov (United States)

    Wibowo, Andreas; Tjahjana, Dominicus Danardono Dwi Prija; Santoso, Budi; Situmorang, Marcelinus Risky Clinton

    2018-02-01

    The main purpose of this study is to investigate the best configuration between guide vanes and cross flow vertical axis wind turbine with variation of several parameters including guide vanes tilt angle and the number of turbine and guide vane blades. The experimental test were conducted under various wind speed and directions for testing cross flow wind turbine, consisted of 8, 12 and 16 blades. Two types of guide vane were developed in this study, employing 20° and 60° tilt angle. Both of the two types of guide vane had three variations of blade numbers which had same blade numbers variations as the turbines. The result showed that the configurations between 60° guide vane with 16 blade numbers and turbine with 16 blade numbers had the best configurations. The result also showed that for certain configuration, guide vane was able to increase the power generated by the turbine significantly by 271.39% compared to the baseline configuration without using of guide vane.

  11. Design and experimental validation of the inlet guide vane system of a mini hydraulic bulb-turbine

    Energy Technology Data Exchange (ETDEWEB)

    Ferro, L.M.C. [Department of Mechanical Engineering, Escola Superior de Tecnologia de Setubal, Polytechnic Institute of Setubal, Campus do IPS, Estefanilha, 2910-761 Setubal (Portugal); IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais,1049-001 Lisboa (Portugal); Gato, L.M.C.; Falcao, A.F.O. [IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, Av. Rovisco Pais,1049-001 Lisboa (Portugal)

    2010-09-15

    The paper presents a fast design method for the inlet guide vanes of low-cost mini hydraulic bulb turbines. The guide vanes are positioned between two conical surfaces with a common vertex and have constant thickness distribution, except close to the leading and the trailing edges. The conical-walled inlet guide vane row is designed using a quasi-three-dimensional calculation method, by prescribing the angular-momentum distribution along the span at the outlet section of the guide vanes. The meridional through-flow is computed by a streamline curvature method and the blade-to-blade flow by a singularity surface method. The stagger angle and the vane camber are computed to fulfil the required design circulation and zero-incidence flow at the leading edge. The final vane shape is a single-curvature surface with straight leading and trailing edges. To validate the design method, a conical-walled inlet guide vane row nozzle-model with six fixed vanes was designed, manufactured and tested in an airflow rig. Traversing measurements along the circumferential and radial directions were made with a five-hole probe. The experimental results are compared with the prescribed design conditions and with numerical results from the three-dimensional inviscid and viscous flow computed with the FLUENT code. (author)

  12. Analytical solution for the electrical properties of a radio-frequency quadrupole (RFQ) with simple vanes

    International Nuclear Information System (INIS)

    Lancaster, H.

    1982-01-01

    Although the SUPERFISH program is used for calculating the design parameters of an RFQ structure with complex vanes, an analytical solution for electrical properties of an RFQ with simple vanes provides insight into the parametric behavior of these more complicated resonators. The fields in an inclined plane wave guide with proper boundary conditions match those in one quadrant of an RFQ. The principle of duality is used to exploit the solutions to a radial transmission line in solving the field equations. Calculated are the frequency equation, frequency sensitivity factors, electric field, magnetic field, stored energy (U), power dissipation, and quality factor

  13. Turbulent Coolant Dispersion in the Wake of a Turbine Vane Trailing Edge

    Science.gov (United States)

    2015-01-01

    Burlet, and D.L. Sondak. A survey of hot streak experiments and simulations. International Journal of Turbo and Jet Engines, 16(1):1–16, March 1999...dis- persion of film coolant in a turbine vane cascade”. Proceedings of ASME Turbo Expo 2014 (GT2014-25484). Additional excerpts are from Yapa SD...turbulent dis- persion of film coolant in a turbine vane cascade”. Proceedings of ASME Turbo Expo 2014 (GT2014-25484). Section 2.5 is a reformatted

  14. Effects of the friction coefficient on the torque characteristics of a hydraulic cam-rotor vane motor

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Qiankun; Wang, Xuyong; Yuan, Fan; Chen, Liang Shen; Tao, Jian Feng [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai (China); Miao, Zhong Hua [School of Mechatronic Engineering and Automation, Shanghai University, Shanghai (China)

    2016-08-15

    The friction coefficient between the vane and the slot is one of the most critical factors that affects the performance of a continuous rotary hydraulic cam-rotor vane motor. To study the effects of this coefficient on the torque characteristics of the motor, the mathematical model for the normal force and the disturbing torque between the cam rotors and the vanes of the motor was established by analyzing the forces exerted on the vanes. The mathematical model was simulated with MATLAB, and simulation results show that an increase in the friction coefficient would simultaneously decrease the normal force and increase the disturbing torque, which would negatively affect the performance of the motor. Further experimental research indicated that the low-speed performance of the hydraulic cam-rotor motor was significantly improved when the friction coefficient was reduced by controlling the parallelism tolerance, flatness and roughness between the vanes and the slots.

  15. An electrostatic lower stator axial-gap polysilicon wobble motor part I: Design and modeling

    NARCIS (Netherlands)

    Legtenberg, R.; Legtenberg, Rob; Berenschot, Johan W.; van Baar, J.J.J.; Elwenspoek, Michael Curt

    This paper presents design issues and a theoretical model of electrostatically driven axial-gap polysilicon wobble motors. The motor design benefits from large axial rotor-to-stator overlap and large gear ratios, and motor designs with rotor radii of 50 and 100 μm are capable of generating torques

  16. An electrostatic lower stator axial-gap polysilicon wobble motor part II: Fabrication and performance

    NARCIS (Netherlands)

    Legtenberg, R.; Legtenberg, Rob; Berenschot, Johan W.; van Baar, J.J.J.; Elwenspoek, Michael Curt

    This paper presents the fabrication and first performance characteristics of electrostatically driven axial-gap polysilicon wobble motors. The fabrication is based on a four mask process using polysilicon surface-micromachining techniques. Three twelve-stator-pole wobble motor designs have been

  17. Detection of Stator Winding Fault in Induction Motor Using Fuzzy Logic with Optimal Rules

    Directory of Open Access Journals (Sweden)

    Hamid Fekri Azgomi

    2013-04-01

    Full Text Available Induction motors are critical components in many industrial processes. Therefore, swift, precise and reliable monitoring and fault detection systems are required to prevent any further damages. The online monitoring of induction motors has been becoming increasingly important. The main difficulty in this task is the lack of an accurate analytical model to describe a faulty motor. A fuzzy logic approach may help to diagnose traction motor faults. This paper presents a simple method for the detection of stator winding faults (which make up 38% of induction motor failures based on monitoring the line/terminal current amplitudes. In this method, fuzzy logic is used to make decisions about the stator motor condition. In fact, fuzzy logic is reminiscent of human thinking processes and natural language enabling decisions to be made based on vague information. The motor condition is described using linguistic variables. Fuzzy subsets and the corresponding membership functions describe stator current amplitudes. A knowledge base, comprising rule and data bases, is built to support the fuzzy inference. Simulation results are presented to verify the accuracy of motor’s fault detection and knowledge extraction feasibility. The preliminary results show that the proposed fuzzy approach can be used for accurate stator fault diagnosis.

  18. A Study on generator stator cooling water flow reduction phenomena at Kori unit 3 and 4

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Chul Un; Kim, Bum Nyun; Jun, Hwang Yong; Kim, Yong Gak; Lee, Sun Ki; Han, Sin Won; Park, Kwang Kyu; Kim, Wang Bae; Han, Jung Ran [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Hwang, Il Soon; Park, Goon Cherl; Park, Byung Gi; Kang, Bo Sun; Min, Seung Kee; Jung, Jin Oh; Oh, Seung Min; Lee, Na Young; Park, Won Suk [Electrical Engineering and Science Research Institute (Korea, Republic of)

    1995-12-31

    This research activities include the followings. To analyze the cause of flow reduction of Kori unit 3 and 4 and evaluate the chemical cleaning method and procedures. To identify the factors causing flow reduction experimentally by simulation experiments for stator cooling systems of Kori unit 3 and 4. To establish the operation guide for the prevention of flow reduction (author). 43 refs., 128 figs.

  19. A traveling wave ultrasonic motor with a metal/polymer-matrix material compound stator

    Science.gov (United States)

    Li, Jinbang; Liu, Shuo; Zhou, Ningning; Yu, Aibing; Cui, Yuguo; Chen, Pengfei

    2018-01-01

    This study proposes a traveling wave ultrasonic motor with a metal/polymer-matrix material compound stator. The stator is composed of a metal ring and polymer-matrix teeth. The resonance frequency of the stator with different structural dimensions was analyzed by the finite element method. From the results, the structure parameters of the metal ring were obtained. The effects of the density and elastic modulus of the tooth material on the resonance frequency were also investigated. A viscoelastic contact model was built to explore the contact state between the compound stator and rotor. Considering the density, elastic modulus and tribological properties, the tooth material was prepared by a molding process. The load-torque and efficiency-torque characteristics of the motor with different tooth thicknesses were measured under different preloads using a preload controlled ultrasonic motor test device. The maximum no-load speed of the motor was about 85 r min-1 with a tooth thickness of 3 mm and a preload of 100 N, the maximum stall torque of the motor was about 0.5 N · m with a tooth thickness of 4 mm and a preload of 125 N, and a maximum efficiency of about 5.5% occurred with a tooth thickness of 4 mm, a preload of 100 N and a torque of 0.3 N · m. The main merits of the proposed ultrasonic motor are low cost, light weight, high processing efficiency and long life.

  20. Robust method for stator current reconstruction from DC link in a ...

    African Journals Online (AJOL)

    Using the switching signals and dc link current, this paper presents a new algorithm for the reconstruction of stator currents of an inverter-fed, three-phase induction motor drive. Unlike the classical and improved methods available in literature, the proposed method is neither based on pulse width modulation pattern ...

  1. Comparative study of different analytical approaches for modelling the transmission of sound waves through turbomachinery stators

    NARCIS (Netherlands)

    Behn, Maximilian; Tapken, Ulf; Puttkammer, Peter; Hagmeijer, Rob; Thouault, Nicolas

    2016-01-01

    The present study is dealing with the analytical modelling of sound transmission through turbomachinery stators. Two-dimensional cascade models are applied in combination with a newly proposed impedance model to account for the effect of flow deflection on the propagation of acoustic modes in

  2. Frequencies in the Vibration Induced by the Rotor Stator Interaction in a Centrifugal Pump Turbine

    DEFF Research Database (Denmark)

    Rodriguez, Cristian; Egusquiza, Eduard; Santos, Ilmar

    2007-01-01

    The highest vibration levels in large pump turbines are, in general, originated in the rotor stator interaction (RSI). This vibration has specific characteristics that can be clearly observed in the frequency domain: harmonics of the moving blade passing frequency and a particular relationship am...

  3. Optimized design of resonant controller for stator current harmonic compensation in DFIG wind turbine systems

    DEFF Research Database (Denmark)

    Liu, Changjin; Chen, Wenjie; Blaabjerg, Frede

    2012-01-01

    This paper presents an analytical method to optimize the parameters of resonant controller which is used in a Doubly-Fed Induction Generator (DFIG). In the DFIG control system, the fundamental current loop is controlled by PI-controllers, and the stator harmonic current loop is controlled...

  4. Calculation and analysis of generator limiting regimes with respect to stator end core heating

    Directory of Open Access Journals (Sweden)

    Kostić Miloje

    2015-01-01

    Full Text Available A new simplified procedure for defining the limiting operating regimes on the generator capability curve, with respect to stator end core heating, is proposed and described in this paper. First of all, a simplified analysis of axial flux leakage that penetrates into the end plates of the stator is carried out and the corresponding power losses are calculated. Then the analysis of measured point temperature increases over the stator end core, and a qualitative and quantitative overview of the effects, are presented. A simplified procedure for defining the limiting regime with regard to the heating stator end core, which is illustrated for the case of an operating diagram for a given generator of apparent power of 727 MVA (B2 is also described. The given limiting line constructed using this method is similar to the appropriate line constructed on the basis of complex and lengthy factory and on-site tests performed by the manufacturer and the user. According to the results and the check, the proposed method has been proved and the application of the simplified procedure can be recommended for use along with other procedures, at least when it comes to similar synchronous generators in Serbia's Electric Power Industry.

  5. Modeling of a Switched Reluctance Motor under Stator Winding Fault Condition

    DEFF Research Database (Denmark)

    Chen, Hao; Han, G.; Yan, Wei

    2016-01-01

    A new method for modeling stator winding fault with one shorted coil in a switched reluctance motor (SRM) is presented in this paper. The method is based on artificial neural network (ANN), incorporated with a simple analytical model in electromagnetic analysis to estimate the flux...

  6. Analysis of Properties of Induction Machine with Combined Parallel Star-Delta Stator Winding

    Czech Academy of Sciences Publication Activity Database

    Schreier, Luděk; Bendl, Jiří; Chomát, Miroslav

    2017-01-01

    Roč. 113, č. 1 (2017), s. 147-153 ISSN 0239-3646 R&D Projects: GA ČR(CZ) GA16-07795S Institutional support: RVO:61388998 Keywords : induction machine * parallel combined stator winding Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Electrical and electronic engineering

  7. Effects of Endwall Geometry and Stacking on Two-Stage Supersonic Turbine Performance

    Science.gov (United States)

    Dorney, Daniel J.; Griffin, Lisa W.; Huber, Frank W.; Sondak, Douglas L.; Turner, Jim (Technical Monitor)

    2002-01-01

    The drive towards high-work turbines has led to designs which can be compact, transonic, supersonic, counter rotating, or use a dense drive gas. These aggressive designs can lead to strong secondary flows and airfoil flow separation. In many cases the secondary and separated flows can be minimized by contouring the hub/shroud endwalls and/or modifying the airfoil stacking. In this study, three-dimensional unsteady Navier-Stokes simulations were performed to study three different endwall shapes between the first-stage vanes and rotors, as well as two different stackings for the first-stage vanes. The predicted results indicate that changing the stacking of the first-stage vanes can significantly impact endwall separation (and turbine performance) in regions where the endwall profile changes.

  8. Experimental Investigation of Turbine Vane Heat Transfer for Alternative Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Nix, Andrew Carl [West Virginia Univ., Morgantown, WV (United States)

    2015-03-23

    The focus of this program was to experimentally investigate advanced gas turbine cooling schemes and the effects of and factors that contribute to surface deposition from particulate matter found in coal syngas exhaust flows on turbine airfoil heat transfer and film cooling, as well as to characterize surface roughness and determine the effects of surface deposition on turbine components. The program was a comprehensive, multi-disciplinary collaborative effort between aero-thermal and materials faculty researchers and the Department of Energy, National Energy Technology Laboratory (NETL). The primary technical objectives of the program were to evaluate the effects of combustion of syngas fuels on heat transfer to turbine vanes and blades in land-based power generation gas turbine engines. The primary questions to be answered by this investigation were; What are the factors that contribute to particulate deposition on film cooled gas turbine components? An experimental program was performed in a high-temperature and pressure combustion rig at the DOE NETL; What is the effect of coal syngas combustion and surface deposition on turbine airfoil film cooling? Deposition of particulate matter from the combustion gases can block film cooling holes, decreasing the flow of the film coolant and the film cooling effectiveness; How does surface deposition from coal syngas combustion affect turbine surface roughness? Increased surface roughness can increase aerodynamic losses and result in decreased turbine hot section efficiency, increasing engine fuel consumption to maintain desired power output. Convective heat transfer is also greatly affected by the surface roughness of the airfoil surface; Is there any significant effect of surface deposition or erosion on integrity of turbine airfoil thermal barrier coatings (TBC) and do surface deposits react with the TBC in any way to decrease its thermal insulating capability? Spallation and erosion of TBC is a persistent problem in

  9. Assessment of Soft Vane and Metal Foam Engine Noise Reduction Concepts

    Science.gov (United States)

    Jones, Michael G.; Parrott, Tony L.; Sutliff, Daniel L.; Hughes, Chris

    2009-01-01

    Two innovative fan-noise reduction concepts developed by NASA are presented - soft vanes and over-the-rotor metal foam liners. Design methodologies are described for each concept. Soft vanes are outlet guide vanes with internal, resonant chambers that communicate with the exterior aeroacoustic environment via a porous surface. They provide acoustic absorption via viscous losses generated by interaction of unsteady flows with the internal solid structure. Over-the-rotor metal foam liners installed at or near the fan rotor axial plane provide rotor noise absorption. Both concepts also provide pressure-release surfaces that potentially inhibit noise generation. Several configurations for both concepts are evaluated with a normal incidence tube, and the results are used to guide designs for implementation in two NASA fan rigs. For soft vanes, approximately 1 to 2 dB of broadband inlet and aft-radiated fan noise reduction is achieved. For over-the-rotor metal foam liners, up to 3 dB of fan noise reduction is measured in the low-speed fan rig, but minimal reduction is measured in the high-speed fan rig. These metal foam liner results are compared with a static engine test, in which inlet sound power level reductions up to 5 dB were measured. Brief plans for further development are also provided.

  10. Relationship of the Vane Kindergarten Test and Wechsler Preschool and Primary Scale of Intelligence

    Science.gov (United States)

    Scherr, S. S.; And Others

    1973-01-01

    Vane Kindergarten Test and WPPSI scores of 33 kindergarten children were compared. Obtained results suggest that the VKT is promising method to assess intelligence in a reasonably brief period of time and provides results comparable to those of the more time-consuming WPPSI. (Author)

  11. Methodology of Computer-Aided Design of Variable Guide Vanes of Aircraft Engines

    Science.gov (United States)

    Falaleev, Sergei V.; Melentjev, Vladimir S.; Gvozdev, Alexander S.

    2016-01-01

    The paper presents a methodology which helps to avoid a great amount of costly experimental research. This methodology includes thermo-gas dynamic design of an engine and its mounts, the profiling of compressor flow path and cascade design of guide vanes. Employing a method elaborated by Howell, we provide a theoretical solution to the task of…

  12. Analysis of swirl recovery vanes for increased propulsive efficiency in tractor propeller aircraft

    NARCIS (Netherlands)

    Veldhuis, L.L.M.; Stokkermans, T.C.A.; Sinnige, T.; Eitelberg, G.

    2016-01-01

    In this paper we address a preliminary assessment of the performance effects of swirl recovery vanes (SRVs) in a installed and uninstalled tractor propeller arrangement. A numerical analysis was performed on a propeller and a propeller-wing configuration after the SRVs were optimized first in a

  13. Improvement of wells turbine performance by means of 3D guide vanes; Sanjigen annai hane ni yoru wells turbine seino no kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Takao, M.; Kim, T.H. [Saga University, Saga (Japan); Setoguchi, T. [Saga University, Saga (Japan). Faculty of Science and Engineering; Inoue, M. [Kyushu University, Fukuoka (Japan). Faculty of Engineering

    2000-02-25

    Performance of a Wells turbine was improved by equipping 3D guide vanes before and behind a rotor. For further improvement, 3D guide vanes have been proposed in this paper. The performance of the Wells turbine with 2D and 3D guide vanes have been investigated experimentally by model testing under steady flow conditions. Then, the running and starting characteristics in irregular ocean waves have been obtained by a computer simulation. As a result, it is found that both of the running and starting characteristics of the Wells turbine with 3D guide vanes are superior to those of the turbine with 2D guide vanes. (author)

  14. Study on flow pattern and separation performance of air–water swirl-vane separator

    International Nuclear Information System (INIS)

    Xiong, Zhenqin; Lu, Mingchao; Wang, Minglu; Gu, Hanyang; Cheng, Xu

    2014-01-01

    Highlights: • A small-scale swirl-vane type steam separator is studied using air–water mixture. • The flow pattern inside the swirl-vane separator is analyzed. • Separation efficiency and pressure drop is experimentally obtained. • Separation efficiency is affected significantly by micro scale water droplets. • The separation efficiency predicted agrees well with the experimental results. - Abstract: Two-phase mixture has a complicated separating process inside a swirl-vane separator which plays an important role in assuring a low wetness of the steam to turbine. To understand the flow pattern inside the swirl-vane separator and analyze the separation performance, a simplified swirl-vane steam separator made of transparent acrylic resin is studied by experiment in which the mixture of air and water is used as the working fluids. Experimental results reveal that the separation efficiency of the separator strongly depends on the flow pattern and the water velocity. The separation efficiency in the annular flow is higher than that of the mist flow and the churn flow. The pressure drop is mainly affected by the air flow rate and the water droplet diameter. Furthermore, a numerical model assuming water as sphere droplets and neglecting its deformation is developed to simulate the separator with Euler two-phase model and RSM turbulence model. It is founded that although the separation efficiency is not sensitive to the size of the big water droplets, it is affected significantly by the micro scale water droplets. By assuming that 94% water droplet equals the Sauter mean diameter and the other 6% is 0.4 times of the Sauter mean diameter, the separation efficiency predicted agrees well with the experimental results for the studied case

  15. Assessment of Stage 35 With APNASA

    Science.gov (United States)

    Celestina, Mark L.; Mulac, Richard

    2009-01-01

    An assessment of APNASA was conducted at NASA Glenn Research Center under the Fundamental Aeronautics Program to determine their predictive capabilities. The geometry selected for this study was Stage 35 which is a single stage transonic compressor. A speedline at 100% speed was generated and compared to experimental data at 100% speed for two turbulence models. Performance of the stage at 100% speed and profiles of several key aerodynamic parameters are compared to the survey data downstream of the stator in this report. In addition, hub leakage was modeled and compared to solutions without leakage and the available experimental data.

  16. Untersuchung des Stroemungsverhaltens von hochbelasteten ungekuehlten Niederdruck-Turbinengittern unter Berucksichtigung der Rotor-Stator Interaktion (Examination of Flow Behavior of Highly Loaded Uncooled Low-Pressure Turbine Grids with Regard to Rotor-Stator Interaction)

    National Research Council Canada - National Science Library

    Brunner, Stefan

    2000-01-01

    ... the typical Mach and Reynolds number combinations. After an introduction on the influence of rotor-stator interaction on the profile border layers in turbo machines, a trial construction ensues in a High-Speed Grid Wind Canal (HSGWC...

  17. Experimental Evaluation of Turning Vane Designs for High-speed and Coupled Fan-drive Corners of 0.1-scale Model of NASA Lewis Research Center's Proposed Altitude Wind Tunnel

    Science.gov (United States)

    Gelder, Thomas F.; Moore, Royce D.; Shyne, Rickey J.; Boldman, Donald R.

    1987-01-01

    Two turning vane designs were experimentally evaluated for the fan-drive corner (corner 2) coupled to an upstream diffuser and the high-speed corner (corner 1) of the 0.1 scale model of NASA Lewis Research Center's proposed Altitude Wind Tunnel. For corner 2 both a controlled-diffusion vane design (vane A4) and a circular-arc vane design (vane B) were studied. The corner 2 total pressure loss coefficient was about 0.12 with either vane design. This was about 25 percent less loss than when corner 2 was tested alone. Although the vane A4 design has the advantage of 20 percent fewer vanes than the vane B design, its vane shape is more complex. The effects of simulated inlet flow distortion on the overall losses for corner 1 or 2 were small.

  18. Turbofan noise generation. Volume 1: Analysis

    Science.gov (United States)

    Ventres, C. S.; Theobald, M. A.; Mark, W. D.

    1982-01-01

    Computer programs were developed which calculate the in-duct acoustic modes excited by a fan/stator stae operating at subsonic tip speed. Three noise source mechanisms are included: (1) sound generated by the rotor blades interacting with turbulence ingested into, or generated within, the inlet duct; (2) sound generated by the stator vanes interacting with the turbulent wakes of the rotors blades; and (3) sound generated by the stator vanes interacting with the mean velocity deficit wakes of the rotor blades. The fan/stator stage is modeled as an ensemble of blades and vanes of zero camber and thickness enclosed within an infinite hard-walled annular duct. Turbulence drawn into or generated within the inlet duct is modeled as nonhomogeneous and anisotropic random fluid motion, superimposed upon a uniform axial mean flow, and convected with that flow. Equations for the duct mode amplitudes, or expected values of the amplitudes, are derived.

  19. A low-temperature high-sensitivity torsion balance magnetometer with in situ stator adjustment

    Science.gov (United States)

    Matthews, A. J.; Usher, A.; Williams, C. D. H.

    2004-08-01

    Torsion balance magnetometry can be used as a versatile probe of two-dimensional electron systems. We have developed a highly sensitive magnetometer, utilizing capacitive proximity detection of the rotor position, for use at temperatures below 10 mK. The instrument incorporates two piezo-electric linear motors to enable the stator positions to be adjusted in situ at base temperature. The magnetometer responsivity is inversely proportional to the square of the rotor-stator separation and the novel linear motor technique, accompanied by effective vibration isolation and optimized capacitance bridge electronics, achieves a resolution 6.5×10-12 N m Hz-1/2. This resolution, together with the low temperatures attainable, allows for experiments that probe the family of quantum fluid states responsible for the fractional quantum Hall effect, even at filling factors greater than one.

  20. Rotor speed estimation for indirect stator flux oriented induction motor drive based on MRAS scheme

    Directory of Open Access Journals (Sweden)

    Youssef Agrebi

    2007-09-01

    Full Text Available In this paper, a conventional indirect stator flux oriented controlled (ISFOC induction motor drive is presented. In order to eliminate the speed sensor, an adaptation algorithm for tuning the rotor speed is proposed. Based on the model reference adaptive system (MRAS scheme, the rotor speed is tuned to obtain an exact ISFOC induction motor drive. The reference and adjustable models, developed in stationary stator reference frame, are used in the MRAS scheme to estimate induction rotor peed from measured terminal voltages and currents. The IP gains speed controller and PI gains current controller are calculated and tuned at each sampling time according to the new estimated rotor speed. The proposed algorithm has been tested by numerical simulation, showing the capability of driving active load; and stability is preserved. Experimental results obtained with a general-purpose 1-kW induction machine are presented showing the effectiveness of the proposed approach in terms of dynamic performance.

  1. Dual stator winding variable speed asynchronous generator: optimal design and experiments

    International Nuclear Information System (INIS)

    Tutelea, L N; Deaconu, S I; Popa, G N

    2015-01-01

    In the present paper is carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behavior in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings to optimal design using a Matlab code. Issue is limited to three phase range of double stator winding cage-induction generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA]. (paper)

  2. Doubly Fed Induction Generator System Resonance Active Damping through Stator Virtual Impedance

    DEFF Research Database (Denmark)

    Song, Yipeng; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    (positive capacitor or negative inductor) into the stator branch through stator current feedforward control. The effectiveness of the DFIG system active damping control is verified by a 7.5 kW experimental down-scaled DFIG system, and simulation results of a commercial 2 MW DFIG system is provided as well....... converters/loads. This paper analyzes and explains first the HFR phenomenon between the DFIG system and a parallel compensated weak network (series RL + shunt C). Then on the basis of the DFIG system impedance modeling, an active damping control strategy is introduced by inserting a virtual impedance...... Frequency Resonance (HFR) due to the impedance interaction between the DFIG system and the weak grid network whose impedance is comparative large. Thus, it is important to implement an active damping for the HFR in order to ensure a safe and reliable operation of both the DFIG system and the grid connected...

  3. An investigation of a flow field in one and half axial turbine stage

    Science.gov (United States)

    Němec, Martin; Jelínek, Tomáš; Milčák, Petr

    2017-09-01

    An investigation of one and half axial turbine stage configuration was carried out in a closed-loop wind tunnel. The investigation was addressed to that impact how the previous stage outlet flow field influences a flow structures in the next stator in steam multistage turbines. The detailed measurement behind the rotor and the second stator was performed with a pneumatic probes to gain a useful data for an impact analysis. Various rotor shroud clearances were also tested to capture the shroud outlet flow field influences.

  4. THE DIAGNOSTICS OF INDUCTION MOTORS ROTOR BAR BREAKS BASED ON THE ANALYSIS OF ELECTROMOTIVE FORCE IN THE STATOR WINDINGS

    Directory of Open Access Journals (Sweden)

    M.V. Zagirnyak

    2014-12-01

    Full Text Available A method for diagnostics of the induction motor rotor bar breaks, based on the wavelet-analysis of the electromotive force induced in the stator windings in the rundown mode is developed. A method for decomposition of the electromotive force of the stator winding phase to the electromotive force signals of the active sides of winding coils using Z-transformation theory is developed. The effectiveness of the proposed diagnostic method was experimentally confirmed.

  5. Characteristics of Hybrid Type Switched Reluctance Motor with Salient Pole Stator

    Science.gov (United States)

    Oyama, Jun; Higuchi, Tsuyoshi; Abe, Takashi; Koga, Takahiro

    In this paper, we propose a new Hybrid type SRM with salient pole stator, which has a pair of permanent magnets attached symmetrically between the iron poles of the rotor. The paper describes experimental results of not only basic characteristics of the Hybrid SRM but also characteristics with current control loop under optimized advanced firing angle and cut-off angle. Considerable improvement of machine performance, especially efficiency and power factor, in the Hybrid SRM over conventional VR type SRM is confirmed.

  6. Microcontroller based Stator Winding Resistance Determination of Induction Motor Drive on Temperature Variations

    OpenAIRE

    Siraj Ahmed T; Sukhdeo Sao; K.S.R Anjaneyulu

    2014-01-01

    In this paper an experiment has been conducted to determine the online stator winding resistance of an induction motor, in industries as well as domestic purpose induction motors is largely utilized, as it has both applications of variable and constant torque operation nature. The major requirement of an electric drive system is its independent control of torque and speed; this is achieved in DC motor Drive but has more disadvantages. With the help of fast acting switching devices it is possi...

  7. The Generated Power of Multipole Induction Generator with Secondary Winding on the Stator

    OpenAIRE

    Diļevs, G; Jākobsons, E

    2009-01-01

    This paper posses the construction of induction generator, which has the ability to operate at a low rotation speed. This generator can be applied for directly driven turbine without using the gearbox. The generator is multi pole with all of the windings placed on the stator. Rotor is tooth-like and has no windings on it. Primary winding is three phase, secondary winding is two phase.

  8. Punching influence on magnetic properties of the stator teeth of an induction motor

    International Nuclear Information System (INIS)

    Kedous-Lebouc, A.; Cornut, B.; Perrier, J.C.; Manfe, Ph.; Chevalier, Th.

    2003-01-01

    In order to study the effects of punching of electrical steel sheets, a suitable geometrical structure able to characterize the stator teeth behavior of an induction motor is proposed and validated. The influence of the punching on a fully processed M330-65A is then characterized. A spectacular degradation of loss and B(H) curves is observed. This leads to a perceptible increase of the no-load machine current

  9. Operating experience gained during the copper oxide plugging incident in Koeberg unit 1 generator stator

    International Nuclear Information System (INIS)

    Mellor, S.P.; Matthee, F.W.

    2002-01-01

    In June 1999 Koeberg's unit 1 started to experience adverse operating conditions which were later ascribed to blockages in the hollow conductors of the generator stator. These blockages were attributed to copper oxide plugs which developed progressively during the following year and culminated in reduced power operation. Many attempts were made to address the plugging by implementing various off-line and on-line cleaning processes. Subsequent to a successful on-line cleaning operation, the unit was returned to full power and the chemistry regime for the stator cooling water system was changed to allow for operation at an elevated pH. This paper discusses Koeberg's experience with copper oxide blockages, describes the initial indications of the problem and the impact on the operating parameters. The remainder of the paper focuses on the actions taken to address the deteriorating situation and the different cleaning methods implemented to remove the copper oxide deposits. The paper concludes with the current status of the unit 1 generator stator and the lessons learned during the resolution of this problem. (authors)

  10. Operating experience gained during the copper oxide plugging incident in Koeberg unit 1 generator stator

    Energy Technology Data Exchange (ETDEWEB)

    Mellor, S.P.; Matthee, F.W. [ESKOM, Koeberg Nuclear Power Station (South Africa)

    2002-07-01

    In June 1999 Koeberg's unit 1 started to experience adverse operating conditions which were later ascribed to blockages in the hollow conductors of the generator stator. These blockages were attributed to copper oxide plugs which developed progressively during the following year and culminated in reduced power operation. Many attempts were made to address the plugging by implementing various off-line and on-line cleaning processes. Subsequent to a successful on-line cleaning operation, the unit was returned to full power and the chemistry regime for the stator cooling water system was changed to allow for operation at an elevated pH. This paper discusses Koeberg's experience with copper oxide blockages, describes the initial indications of the problem and the impact on the operating parameters. The remainder of the paper focuses on the actions taken to address the deteriorating situation and the different cleaning methods implemented to remove the copper oxide deposits. The paper concludes with the current status of the unit 1 generator stator and the lessons learned during the resolution of this problem. (authors)

  11. Investigation of Stator and Rotor Slits’ Effects to the Torque and Efficiency of an Induction Motor

    Directory of Open Access Journals (Sweden)

    Serdal ARSLAN

    2017-02-01

    Full Text Available Induction machines have a simple structure and are popular due to their wide range of use, however they have limited power factor and efficiency. Although the working principles of inductions machines have not changed for years, the materials and geometric structures used have undergone significant changes. In this study, slits were applied in the middle of the rotor teeth, rotor-stator teeth and stator teeth of a 7.5 kW induction motor. For these three situations, the torque ripple, iron losses, copper losses, inductance, phase current and voltage inducted in the windings and flux change were analyzed associated with the change in the slit width and slit height. Due to the fact that it is difficult to analytically calculate the slitted models created, they were analyzed by software which uses the finite elements method. The stator-rotor slitted structure determined as the optimum (the one with highest efficiency and the original motor were compared with 2D and 3D analyses. According to this comparison, a decrease in torque rupture and loss of copper is observed. The motor’s torque increased by 27%, and efficiency increased by 4%.

  12. On the Flow Behavior in Rotor-Stator System with Superposed Flow

    Directory of Open Access Journals (Sweden)

    Roger Debuchy

    2008-01-01

    Full Text Available The flow between a rotor and a stator at high Reynolds number and small Ekman number is divided into three domains, two boundary layers adjacent to the discs separated by a central core. In the present work, a simple theoretical approach provides analytical solutions for the radial distribution of the core swirl ratio valid for a rotor-stator system with a superposed radial inflow rate. At first, the flow in the rotor boundary layer is assumed to behave as expressed by Owen and Rogers (1989 in the case of a turbulent flow on a rotating single disc. On the stator side, a necessary compensation flow rate must take place according to the conservation of mass. It is found that this compensation flow rate cannot be estimated with a good accuracy using the hypotheses of a stationary disc in a rotating fluid by Owen and Rogers (1989. Thus, two innovative weighting functions are tested, leading to new analytical laws relating the core swirl ratio K to the coefficient of flow rate Cqr introduced by Poncet et al. (2005. The adequacy between the theoretical solutions and numerous results of the literature is clearly improved and the discussion allows a better understanding of the flow behavior.

  13. Design and analysis of a radial diffuser in a single-stage centrifugal pump

    Directory of Open Access Journals (Sweden)

    Ming-Gao Tan

    2016-01-01

    Full Text Available Radial diffusers can improve the flow uniformity in pumps and affect the hydraulic performance of centrifugal pumps directly. The diffusion coefficient d is an important parameter in fluid machinery but it has seldom been used in the diffuser design of single-stage centrifugal pumps. To improve the design method of radial diffuser use in centrifugal pumps, the diffusion coefficient was introduced into the design of radial diffusers based on a single-arc hydraulic design method and it was found that the vane outlet angle, vane outlet thickness and vane number have a significant impact on the design results. A single-stage centrifugal pump with a radial diffuser was selected as the research model. The inner flow was simulated using the commercial computational fluid dynamics (CFD program CFX and verified by experiment. The results indicate that the head and efficiency of the pump are best when the vane outlet angle is 6°. The flow area decreases and the flow velocity at radial diffuser outlet increase when the outlet thickness is greater than 2 mm. The hydraulic loss is minimum and the head and efficiency are better when the vane number is 8 at different flow rates. So, the optimal range of the diffusion coefficient for the model pump is around 1.6 to 2. The study indicates that it is feasible to design radial diffusers according to the diffusion coefficient.

  14. Numerical solution for the temperature distribution in a cooled guide vane blade of a radial gas turbine

    Science.gov (United States)

    Hosny, W. M.; Tabakoff, W.

    1977-01-01

    A two dimensional finite difference numerical technique is presented to determine the temperature distribution of an internal cooled blade of radial turbine guide vanes. A simple convection cooling is assumed inside the guide vane blade. Such cooling has relatively small cooling effectiveness at the leading edge and at the trailing edge. Heat transfer augmentation in these critical areas may be achieved by using impingement jets and film cooling. A computer program is written in FORTRAN IV for IBM 370/165 computer.

  15. Experimental evaluation of two turning vane designs for fan drive corner of 0.1-scale model of NASA Lewis Research Center's proposed altitude wind tunnel

    Science.gov (United States)

    Boldman, Donald R.; Moore, Royce D.; Shyne, Rickey J.

    1987-01-01

    Two turning vane designs were experimentally evaluated for corner 2 of a 0.1 scale model of the NASA Lewis Research Center's proposed Altitude Wind Tunnel (AWT). Corner 2 contained a simulated shaft fairing for a fan drive system to be located downstream of the corner. The corner was tested with a bellmouth inlet followed by a 0.1 scale model of the crossleg diffuser designed to connect corners 1 and 2 of the AWT. Vane A was a controlled-diffusion airfoil shape; vane B was a circular-arc airfoil shape. The A vanes were tested in several arrangements which included the resetting of the vane angle by -5 degrees or the removal of the outer vane. The lowest total pressure loss for vane A configuration was obtained at the negative reset angle. The loss coefficient increased slightly with the Mach number, ranging from 0.165 to 0.175 with a loss coefficient of 0.170 at the inlet design Mach number of 0.24. Removal of the outer vane did not alter the loss. Vane B loss coefficients were essentially the same as those for the reset vane A configurations. The crossleg diffuser loss coefficient was 0.018 at the inlet design Mach number of 0.33.

  16. An Empirical Model for Vane-Type Vortex Generators in a Navier-Stokes Code

    Science.gov (United States)

    Dudek, Julianne C.

    2005-01-01

    An empirical model which simulates the effects of vane-type vortex generators in ducts was incorporated into the Wind-US Navier-Stokes computational fluid dynamics code. The model enables the effects of the vortex generators to be simulated without defining the details of the geometry within the grid, and makes it practical for researchers to evaluate multiple combinations of vortex generator arrangements. The model determines the strength of each vortex based on the generator geometry and the local flow conditions. Validation results are presented for flow in a straight pipe with a counter-rotating vortex generator arrangement, and the results are compared with experimental data and computational simulations using a gridded vane generator. Results are also presented for vortex generator arrays in two S-duct diffusers, along with accompanying experimental data. The effects of grid resolution and turbulence model are also examined.

  17. NUMERICAL SIMULATION OF THE FLOW IN THE CENTRIFUGAL PUMP WITHIN VANE AND VANELESS DIFFUSER

    Directory of Open Access Journals (Sweden)

    K. Melih GÜLEREN

    2004-03-01

    Full Text Available In this study, the flow in a 5-bladed centrifugal pump within vaned and vaneless diffuser is analyzed numerically. The method contains of assumption as steady, incompressible and viscous flow solved according to 2-D Navier-Stokes equations relating finite volume technique. The pump used in this study runs at 890 rpm, its impeller diameter is approximately 20 cm and it has back-swept blade geometry. The jet-wake flow structures within the impeller and diffuser passages are investigated elaborately and in addition to this, the effects of vaned and vaneless diffuser of the pump are analyzed. The results are shown as velocity vectors, pressure and turbulent kinetic energy distributions in centrifugal pump, beside the performance curves. Moreover, the results are compared with available experimental data which is seen good agreement.

  18. Time-Frequency Characterization of Rotating Instabilities in a Centrifugal Pump with a Vaned Diffuser

    Directory of Open Access Journals (Sweden)

    G. Pavesi

    2008-01-01

    Full Text Available This paper presents acoustic and flowdynamic investigations of large-scale instabilities in a radial pump with a vaned diffuser. Pressure fluctuations were measured with transducers placed flush at the inlet duct, at the impeller discharge, and in the vane diffuser walls. Two impeller rotation speeds were analyzed in the study, at design, and at off-design flow rates. A spectral analysis was carried out on the pressure signals in frequency and in time-frequency domains to identified precursors, inception, and evolution of the pressure instabilities. The results highlighted the existence of a rotating pressure structure at the impeller discharge, having a fluid-dynamical origin and propagating both in the radial direction and inside the impeller. The experimental data were then compared with the results obtained with help of ANSYS CFX computer code; focusing on the changing flow field at part load. Turbulence was reproduced by DES model.

  19. Highly loaded multi-stage fan drive turbine: Performance of final three configurations

    Science.gov (United States)

    Cherry, D. G.; Thomas, M. W.

    1974-01-01

    Results for a three-stage highly loaded fan drive turbine follow-on test program are presented. The effects of combinations of tandem and leaned bladerows on three-stage turbine performance were tested. The three-stage turbine with a tandem stator in stage two exhibited a total-to-total efficiency of approximately 0.887 as compared to 0.886 for the plain blade turbine base case.

  20. Attenuation of Vane-Rotor Shock Interactions with Pulsating Coolant Flows

    Science.gov (United States)

    2012-03-01

    consists on, pulsating coolant blowing through the trailing edge of the airfoils . This paper presents an unprecedented experimental and numerical...A transonic turbine airfoil was experimentally and numerically tested to resolve the effects of pulsating cooling The model was tested at four Mach...interactions are one of the major sources of losses in supersonic airfoils . Additionally, vane shocks cause large pressure fluctuations that may result in

  1. Design optimization of a T mixing vane in nuclear fuel assembly

    International Nuclear Information System (INIS)

    Jung, Sang-Ho; Moon, Mi-Ae; Kim, Kwang-Yong

    2009-01-01

    The purposes of present work are to analyze the convective heat transfer with three-dimensional Reynolds-averaged Navier-Stokes analysis, and to optimize shape of the mixing vane using the analysis results. PLUS7 that is designed by KNF and Westinghouse is used as reference geometry. Shear stress transport turbulence model is used as a turbulence closure. Two bend angles of mixing vane are selected as design variable. The objective function is defined as a combination of inverse of heat transfer rate and friction loss. Response surface method is employed as an optimization technique. The calculation domains of 1x2 geometry are analyzed with translational and rotational periodic boundary conditions which take flow directions into account. The fluid flow and heat transfer characteristics have been explained through velocity vectors, streamlines and Nusselt numbers. The results show that the optimized geometry improves the heat transfer performance of the mixing vane with a relatively small pressure drop increment and has higher Critical Heat Flux. (author)

  2. Grid generation methodology and CFD simulations in sliding vane compressors and expanders

    Science.gov (United States)

    Bianchi, Giuseppe; Rane, Sham; Kovacevic, Ahmed; Cipollone, Roberto; Murgia, Stefano; Contaldi, Giulio

    2017-08-01

    The limiting factor for the employment of advanced 3D CFD tools in the analysis and design of rotary vane machines is the unavailability of methods for generation of computational grids suitable for fast and reliable numerical analysis. The paper addresses this challenge presenting the development of an analytical grid generation for vane machines that is based on the user defined nodal displacement. In particular, mesh boundaries are defined as parametric curves generated using trigonometrical modelling of the axial cross section of the machine while the distribution of computational nodes is performed using algebraic algorithms with transfinite interpolation, post orthogonalisation and smoothing. Algebraic control functions are introduced for distribution of nodes on the rotor and casing boundaries in order to achieve good grid quality in terms of cell size and expansion. In this way, the moving and deforming fluid domain of the sliding vane machine is discretized and the conservation of intrinsic quantities in ensured by maintaining the cell connectivity and structure. For validation of generated grids, a mid-size air compressor and a small-scale expander for Organic Rankine Cycle applications have been investigated in this paper. Remarks on implementation of the mesh motion algorithm, stability and robustness experienced with the ANSYS CFX solver as well as the obtained flow results are presented.

  3. Analysis of waves in the plasma guided by a periodical vane-type slow wave structure

    International Nuclear Information System (INIS)

    Wu, T.J.; Kou, C.S.

    2005-01-01

    In this study, the dispersion relation has been derived to characterize the propagation of the waves in the plasma guided by a periodical vane-type slow wave structure. The plasma is confined by a quartz plate. Results indicate that there are two different waves in this structure. One is the plasma mode that originates from the plasma surface wave propagating along the interface between the plasma and the quartz plate, and the other is the guide mode that originally travels along the vane-type slow wave structure. In contrast to its original slow wave characteristics, the guide mode becomes a fast wave in the low-frequency portion of the passband, and there exists a cut-off frequency for the guide mode. The vane-type guiding structure has been shown to limit the upper frequency of the passband of the plasma mode, compared with that of the plasma surface wave. In addition, the passband of the plasma mode increases with the plasma density while it becomes narrower for the guide mode. The influences of the parameters of the guiding structure and plasma density on the propagation of waves are also presented

  4. An experimental study on the effects of blade row interactions on aerodynamic loss mechanisms in a multistage compressor

    Science.gov (United States)

    Smith, Natalie Rochelle

    While the gas turbine engine has existed for nearly 80 years, much of the complex aerodynamics which governs compressor performance is still not well understood. The unsteady flow field consists of periodic blade row interactions from the wakes and potential fields of each blade and vane. Vane clocking is the relative circumferential indexing of adjacent vane rows with the same vane count, and it is one method to change blade row interactions. Though the potential of performance benefits with vane clocking is known, the driving flow physics have yet to be identified. This research examines the effects of blade row interactions on embedded stator total pressure loss and boundary layer transition in the Purdue 3-stage axial compressor. The inlet guide vane, Stator 1, and Stator 2 all have 44 vanes which enable vane clocking of the embedded stage, while the rotors have different blade counts producing amplitude modulation of the unsteady interactions. A detailed investigation of corrected conditions is presented to establish repeatable, compressor performance year-round in a facility utilizing ambient inlet conditions. Without proper humidity accounting of compressor corrected conditions and an understanding of the potential for inlet temperature changes to affect clearances due to thermal growth, measurements of small performance changes in detailed research studies could be indiscernible. The methodology and implementation of a powder-paint flow visualization technique along with the illuminated flow physics are presented in detail. This method assists in understanding the loss development in the compressor by highlighting stator corner separations and endwall flow patterns. Effects of loading condition, rotor tip clearance height, and stator wake and rotor tip leakage interactions are shown with this technique. Vane clocking effects on compressor performance were quantified for nine loading conditions and six clocking configurations - the largest vane clocking

  5. Experimental investigation of in-cylinder air flow to optimize number of helical guide vanes to enhance DI diesel engine performance using mamey sapote biodiesel

    Science.gov (United States)

    Kumar, A. Raj; Janardhana Raju, G.; Hemachandra Reddy, K.

    2018-03-01

    The current research work investigates the influence of helical guide vanes in to the intake runner of a D.I diesel engine operating by the high viscous Mamey Sapote biodiesel to enhance in-cylinder suction air flow features. Helical guide vanes of different number of vanes are produced from 3D printing and placed in the intake manifold to examine the air flow characteristics. Four different helical guide vane devices namely 3, 4, 5 and 6 vanes of the same dimensions are tested in a D.I diesel engine operating with Mamey Sapote biodiesel blend. As per the experimental results of engine performance and emission characteristics, it is found that 5 vanes helical guide vane swirl device exhibited in addition number of increased improvements such as the brake power and bake thermal efficiency by 2.4% and 8.63% respectively and the HC, NOx, Carbon monoxide and, Smoke densities are reduced by 15.62%, 4.23%, 14.27% and 9.6% at peak load operating conditions as collate with normal engine at the same load. Hence this investigation concluded that Helical Guide Vane Devices successfully enhanced the in-cylinder air flow to improve better addition of Mamey Sapote biodiesel with air leading in better performance of the engine than without vanes.

  6. Detailed Study of Closed Stator Slots for a Direct-Driven Synchronous Permanent Magnet Linear Wave Energy Converter

    Directory of Open Access Journals (Sweden)

    Erik Lejerskog

    2014-01-01

    Full Text Available The aim of this paper is to analyze how a permanent magnet linear generator for wave power behaves when the stator slots are closed. The usual design of stator geometry is to use open slots to maintain a low magnetic leakage flux between the stator teeth. By doing this, harmonics are induced in the magnetic flux density in the air-gap due to slotting. The closed slots are designed to cause saturation, to keep the permeability low. This reduces the slot harmonics in the magnetic flux density, but will also increase the flux leakage between the stator teeth. An analytical model has been created to study the flux through the closed slots and the result compared with finite element simulations. The outcome shows a reduction of the cogging force and a reduction of the harmonics of the magnetic flux density in the air-gap. It also shows a small increase of the total magnetic flux entering the stator and an increased magnetic flux leakage through the closed slots.

  7. Operation of a test bed axial-gap brushless dc rotor with a superconducting stator

    Science.gov (United States)

    McKeever, J. W.; Sohns, C. W.; Schwenterly, S. W.; Young, R. W., Sr.; Campbell, V. W.; Hickey, M. H.; Ott, G. W.; Bailey, J. M.

    A variable-speed axial-gap motor with a stator consisting of four liquid helium cooled superconducting electromagnets (two pole pairs) was built and proof tested up to 608 rpm in November 1990 as a tool for joint industry-laboratory evaluation of coils fabricated from high temperature oxide superconductors. A second rotor was fabricated with improved material, winding configuration, and wire type, and the drive system was modified to eliminate current spiking. The modified motor was characterized to design speed, 188 rad/s (1800 rpm), to acquire a performance baseline for future comparison with that of high temperature superconducting (HIS) wire. As it becomes commercially available, HTS wire will replace the low temperature electromagnet wire in a stator modified to control wire temperatures between 4 K and 77 K. Measurements of the superconducting electromagnetic field and locked rotor torque as functions of cryocurrent and dc current through two phases of the rotor, respectively, provided data to estimate power that could be developed by the rotor. Back emf and parasitic mechanical and electromagnetic drag torques were measured as functions of angular velocity to calculate actual rotor power developed and to quantify losses, which reduce the motor's efficiency. A detailed measurement of motor power at design speed confirmed the developed power equation. When subsequently operated at the 33-A maximum available rotor current, the motor delivered 15.3 kW (20.5 hp) to the load. In a final test, the cryostat was operated at 2500 A, 200 A below its critical current. At rotor design current of 60 A and 2500 A stator current, the extrapolated developed power would be 44.2 kW (59.2 hp) with 94% efficiency.

  8. Presentation and Performance Evaluation of a Novel Stator-Permanent-Magnet Hybrid Stepping Motor

    Directory of Open Access Journals (Sweden)

    Binglin Lu

    2017-05-01

    Full Text Available In this paper, a new type of hybrid stepping motor (HSM with permanent magnets (PMs embedded in the stator, namely the stator-permanent-magnet hybrid stepping motor (SHSM, is presented. It has the same operation principles as the traditional HSM, with a 2-D distributed magnetic field nature and superiorities such as simpler rotor structure, easier PM cooling, higher torque and power density, and higher power grade. Its structural topology and operation principles are initially presented. Then an investigation on the performance comparison between the HSM and the SHSM, in terms of PM flux density, PM torque, detent torque, positional holding accuracy, stator core saturation issue, PM flux leakage, and PM utilization rate is carried out theoretically to make an assessment of the performance superiorities of the SHSM. A prototype of a 2-phase 8-pole 50-rotor-tooth SHSM is fabricated and experimentally compared with the HSM by using finite element analysis (FEA to verify the motor’s operational feasibility and the theoretical analysis. The FEA and experimental results show that the proposed SHSM has performance advantages such as higher torque density, higher power grade, and higher pull-out torque, holding torque, and torque-speed property, although it has performance defects such as higher torque ripple and relatively lower positional holding accuracy in the open-loop operation than the conventional HSM. Consequently, this novel SHSM is more suitable for electromechanical energy conversion applications rather than positioning mechanisms, especially taking into account the open-loop control advantage.

  9. Detent torque from the soft magnetic stator stack of a hybrid stepper motor

    Science.gov (United States)

    Rajagopal, K. R.; Singh, Bhim; Singh, B. P.

    2003-05-01

    The residual magnetism present in the stator stack of a hybrid stepper motor, which will be of the last excited polarity, will develop a detent torque, similar to the static torque of the last excited phase, but with reduced excitation. The predominant component is fundamental. Even though this torque is the result of the stator excitation, it can be considered as a detent torque as it is available when the stator excitation is withdrawn. This detent torque is in addition to the inherent one due to the rotor permanent magnet, and it will be present until the next phase is switched ON. Once the excitation is removed from the second phase, because of the hysteresis the detent torque will be available, similar to the static torque profile for phase 2, but with less excitation. This means because of the hysteresis the detent torque follows the static torque of the phases. The magnitude of this detent torque will depend upon the level to which the phase was excited. Experiments have been carried out on a 0.5° hybrid stepper motor to study the effects of the excitation on the detent torque profiles. Harmonic analyses of the measured detent torque curves had been carried out and it is seen that the fundamental detent torque increases with the excitation and also follows the respective phases. Therefore, the residual flux density and the coercive force of the soft magnetic material used for the stator stack have to be as small as possible to get rid of this effect. Controlling a hybrid stepper motor by a suitable switching scheme for a given application requires the measured static torque profiles of the motor for all the phases at the exact working voltage (or voltages in case of a variable voltage supply) and detent torque profiles both before and after excitation. Harmonic spectrum of the measured static and detent torque profiles have to be accounted for while simulating stepping behavior of the motor, from which an appropriate switching scheme can be arrived at.

  10. Analysis of Pressure Pulsation Induced by Rotor-Stator Interaction in Nuclear Reactor Coolant Pump

    OpenAIRE

    Zhang, Xu; Wang, Pengfei; Ruan, Xiaodong; Xu, Zhongbin; Fu, Xin

    2017-01-01

    The internal flow of reactor coolant pump (RCP) is much more complex than the flow of a general mixed-flow pump due to high temperature, high pressure, and large flow rate. The pressure pulsation that is induced by rotor-stator interaction (RSI) has significant effects on the performance of pump; therefore, it is necessary to figure out the distribution and propagation characteristics of pressure pulsation in the pump. The study uses CFD method to calculate the behavior of the flow. Results s...

  11. Design of the robust synchronous generator stator voltage regulator based on the interval plant model

    Directory of Open Access Journals (Sweden)

    Stojić Đorđe

    2013-01-01

    Full Text Available In this paper a novel method for the stator voltage regulator of a synchronous generator based on the interval plant mode, is presented. Namely, it is shown in the literature that, in order to design a controller for the first-order compensator, the limited number of interval plants needs to be examined. Consequently, the intervals of the plant model parameter variations used to calculate the four extreme interval plants required for the sequential PI controller design are determined. The controller is designed using frequency-domain-based techniques, while its robust performance is examined using simulation tests.

  12. Core losses of an inverter-fed permanent magnet synchronous motor with an amorphous stator core under no-load

    Directory of Open Access Journals (Sweden)

    Nicolas Denis

    2016-05-01

    Full Text Available In this paper, an interior permanent magnet synchronous motor (IPMSM with a stator core made of amorphous magnetic material (AMM is presented. The IPMSM is driven by a voltage source three-phase inverter with classical pulse width modulation (PWM control. The core losses under no-load condition are measured by experiment and compared to an equivalent IPMSM with a stator core made of NO steel. Under these conditions, the core losses are influenced by the stator, rotor and magnet shapes but also by the PWM carrier signal that implies a high frequency harmonic in the magnetic flux density. It is demonstrated that the AMM can reduce the core losses by about 56 %.

  13. Development of Propulsion Inverter Control System for High-Speed Maglev based on Long Stator Linear Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Jeong-Min Jo

    2017-02-01

    Full Text Available In the case of a long-stator linear drive, unlike rotative drives for which speed or position sensors are a single unit attached to the shaft, these sensors extend along the guideway. The position signals transmitted from a maglev vehicle cannot meet the need of the real-time propulsion control in the on-ground inverter power substations. In this paper the design of the propulsion inverter control system with a position estimator for driving a long-stator synchronous motor in a high-speed maglev train is proposed. The experiments have been carried out at the 150 m long guideway at the O-song test track. To investigate the performance of the position estimator, the propulsion control system with, and without, the position estimator are compared. The result confirms that the proposed strategy can meet the dynamic property needs of the propulsion inverter control system for driving long-stator linear synchronous motors.

  14. Investigations on bending-torsional vibrations of rotor during rotor-stator rub using Lagrange multiplier method

    Science.gov (United States)

    Mokhtar, Md Asjad; Kamalakar Darpe, Ashish; Gupta, Kshitij

    2017-08-01

    The ever-increasing need of highly efficient rotating machinery causes reduction in the clearance between rotating and non-rotating parts and increase in the chances of interaction between these parts. The rotor-stator contact, known as rub, has always been recognized as one of the potential causes of rotor system malfunctions and a source of secondary failures. It is one of few causes that influence both lateral and torsional vibrations. In this paper, the rotor stator interaction phenomenon is investigated in the finite element framework using Lagrange multiplier based contact mechanics approach. The stator is modelled as a beam that can respond to axial penetration and lateral friction force during the contact with the rotor. It ensures dynamic stator contact boundary and more realistic contact conditions in contrast to most of the earlier approaches. The rotor bending-torsional mode coupling during contact is considered and the vibration response in bending and torsion are analysed. The effect of parameters such as clearance, friction coefficient and stator stiffness are studied at various operating speeds and it has been found that certain parameter values generate peculiar rub related features. Presence of sub-harmonics in the lateral vibration frequency spectra are prominently observed when the rotor operates near the integer multiple of its lateral critical speed. The spectrum cascade of torsional vibration shows the presence of bending critical speed along with the larger amplitudes of frequencies close to torsional natural frequency of the rotor. When m × 1/n X frequency component of rotational frequency comes closer to the torsional natural frequency, stronger torsional vibration amplitude is noticed in the spectrum cascade. The combined information from the stator vibration and rotor lateral-torsional vibration spectral features is proposed for robust rub identification.

  15. A Novel Modular-Stator Outer-Rotor Flux-Switching Permanent-Magnet Motor

    Directory of Open Access Journals (Sweden)

    Jing Zhao

    2017-07-01

    Full Text Available A novel modular-stator outer-rotor flux-switching permanent-magnet (MSOR-FSPM motor is proposed and studied in this paper. Structure, operation and design principles of the MSOR-FSPM motor are introduced and analyzed. Considering that the combination of different pole number and slot number has a great influence on the motor performance, the optimum rotor pole number for the 12-stator-slot MSOR-FSPM motor is researched to obtain good performance and make full use of the space in the MSOR-FSPM motor. The influences of rotor pole number on cogging torque, torque ripple and electromagnetic torque are analyzed and a 12-slot/10-pole MSOR-FSPM motor was chosen for further study. Then, several main parameters of the 12-slot/10-pole MSOR-FSPM motor were optimized to reduce the torque ripple. Finally, the utilization of permanent magnet (PM in the MSOR-FSPM motor and a conventional outer-rotor flux-switching permanent-magnet (COR-FSPM motor are compared and analyzed from the point of view of magnetic flux path, and verified by the finite element method (FEM. The FEM results show that the PM volume of MSOR-FSPM motor is only 54.04% of that in a COR-FSPM motor, but its average electromagnetic torque can reach more than 75% of the torque of COR-FSPM motor.

  16. Advanced single permanent magnet axipolar ironless stator ac motor for electric passenger vehicles

    Science.gov (United States)

    Beauchamp, E. D.; Hadfield, J. R.; Wuertz, K. L.

    1983-01-01

    A program was conducted to design and develop an advanced-concept motor specifically created for propulsion of electric vehicles with increased range, reduced energy consumption, and reduced life-cycle costs in comparison with conventional systems. The motor developed is a brushless, dc, rare-earth cobalt, permanent magnet, axial air gap inductor machine that uses an ironless stator. Air cooling is inherent provided by the centrifugal-fan action of the rotor poles. An extensive design phase was conducted, which included analysis of the system performance versus the SAE J227a(D) driving cycle. A proof-of-principle model was developed and tested, and a functional model was developed and tested. Full generator-level testing was conducted on the functional model, recording electromagnetic, thermal, aerodynamic, and acoustic noise data. The machine demonstrated 20.3 kW output at 1466 rad/s and 160 dc. The novel ironless stator demonstated the capability to continuously operate at peak current. The projected system performance based on the use of a transistor inverter is 23.6 kW output power at 1466 rad/s and 83.3 percent efficiency. Design areas of concern regarding electric vehicle applications include the inherently high windage loss and rotor inertia.

  17. Torque Characteristic Analysis of a Transverse Flux Motor Using a Combined-Type Stator Core

    Directory of Open Access Journals (Sweden)

    Xiaobao Yang

    2016-11-01

    Full Text Available An external rotor transverse flux motor using a combined-type stator core is proposed for a direct drive application in this paper. The stator core is combined by two kinds of components that can both be manufactured conveniently by generic laminated silicon steel used in traditional motors. The motor benefits from the predominance of low manufacturing cost and low iron loss by using a silicon-steel sheet. Firstly, the basic structure and operation principles of the proposed motor are introduced. Secondly, the expressions of the electromagnetic torque and the cogging torque are deduced by theoretical analysis. Thirdly, the basic characteristics such as permanent magnet flux linkage, no-load back electromotive force, cogging torque and electromagnetic torque are analyzed by a three-dimensional finite element method (3D FEM. Then, the influence of structure parameters on the torque density is investigated, which provides a useful foundation for optimum design of the novel motor. Finally, the torque density of the proposed motor is calculated and discussed, and the result shows that the proposed motor in this paper can provide considerable torque density by using few permanent magnets.

  18. Vane Pump Casing Machining of Dumpling Machine Based on CAD/CAM

    Science.gov (United States)

    Huang, Yusen; Li, Shilong; Li, Chengcheng; Yang, Zhen

    Automatic dumpling forming machine is also called dumpling machine, which makes dumplings through mechanical motions. This paper adopts the stuffing delivery mechanism featuring the improved and specially-designed vane pump casing, which can contribute to the formation of dumplings. Its 3D modeling in Pro/E software, machining process planning, milling path optimization, simulation based on UG and compiling post program were introduced and verified. The results indicated that adoption of CAD/CAM offers firms the potential to pursue new innovative strategies.

  19. Design and Comparison of a Novel Stator Interior Permanent Magnet Generator for Direct-Drive Wind Turbines

    DEFF Research Database (Denmark)

    Zhang, Johan Xi; Chen, Zhe; Cheng, M.

    2007-01-01

    A novel stator interior permanent magnet generator (SIPMG) is presented. A modular stator design is used for convenience in manufacture and maintenance. The generator has the advantages of rugged rotor and concentrated winding design whereas the torque ripple is smaller than that produced...... by a doubly salient machine. Several low-speed multi-pole SIPMGs are designed for direct-drive wind turbines with ratings from 3 to 10 MW. Comparisons between the SIPMG and rotor-surface-mounted permanent magnet synchronous generator (PMSG) show that the SIPMGs have about 120% torque density and 78% cost per...

  20. Compensation of negative sequence stator flux of doubly-fed induction generator using polar voltage control-based direct torque control under unbalanced grid voltage condition

    Directory of Open Access Journals (Sweden)

    Badrinarayan Bansilal Pimple

    2015-02-01

    Full Text Available This study proposes a polar voltage control-based direct torque control method to reduce the effects of unbalanced grid voltage on doubly-fed induction generator (DFIG-based wind turbine system. Under unbalanced grid voltage, the stator flux has a negative sequence component which leads to second harmonic pulsation in torque, stator active power, stator reactive power, stator current and rotor current. In the control scheme, the negative sequence rotor voltage vector is controlled to compensate the negative sequence stator flux by negative sequence rotor flux. Simulation study is carried out on a 2 MW DFIG system using MATLAB/SIMULINK. Feasibility of the proposed control strategy is experimentally verified on a 1.5 kW DFIG system.

  1. Experimental optimization of the vanes geometry for a variable geometry turbocharger (VGT) using a Design of Experiment (DoE) approach

    International Nuclear Information System (INIS)

    Hatami, M.; Cuijpers, M.C.M.; Boot, M.D.

    2015-01-01

    Highlights: • An optimization is performed for a variable geometry turbocharger (VGT) vane. • An experimental setup with different vanes design is designed. • Central composite design (CCD) is applied to reduce the cases and tests. • Results are compared to free space parameter (FSP) theory. - Abstract: In this paper, central composite design (CCD) based on Design of Experiment (DoE) is applied to obtain an optimal design of the vane geometry for a variable geometry turbine (VGT). The design is tested at four different pressure ratios (1.25, 1.5, 1.75 and 2.0) on a Garrett GT1541V turbocharger. Seventeen different cases for the inlet guide vanes are proposed. All cases, each having a unique combination of vane height, thickness, length and angle, has been produced via 3D printing. The goal of this study is to ascertain how vane geometry impacts turbine efficiency, so as to arrive at the ideal configuration for this specific turbine for the investigated range of operating conditions. As a main outcome, the results demonstrate that the applied vane angle has the strongest impact on the turbine efficiency, with smaller angles yielding the most favorable results. After CCD analysis, an optimized design for the vanes geometry with 76.31% efficiency (averagely in all pressures) is proposed. As a final step, all cases are analyzed from a free space parameter (FSP) perspective, with the theoretically optimal design (e.g., FSP < 5) corresponding nicely to the best experimental results.

  2. Investigations inside a vaned diffuser of a centrifugal pump at low flowrates.

    Science.gov (United States)

    Bayeul-Lainé, A. C.; Dupont, P.; Dazin, A.; Bois, G.

    2016-11-01

    This paper focuses on the unsteady flow behaviour inside the vaned diffuser of a radial flow pump model, operating at partial flowrates (0.387Qi, 0.584Qi and 0.766Qi where Qi is the impeller design flowrate).The effects of the leakage flows are taken into account in the analysis. PIV measurements have been performed at different hub to shroud planes inside one diffuser channel passage for a given speed of rotation, for several flowrates and different angular impeller positions. The performances and the static pressure rise of the diffuser were also measured using a three-holes probe in the same experimental conditions. The unsteady numerical simulations were carried out with Star CCM+ 10.02 code with and without leakage flow. The PIV measurements showed a high unsteadiness at very low flowrate which was confirmed by the numerical calculations. In previous studies it has been shown that the global performances, as the efficiencies are in good agreement between calculations and measurements. In this paper, a joint analysis of measurements and numerical calculations is proposed to improve the understanding of the flow behaviour in a vaned diffuser.

  3. Turbulence characteristics of the Bödewadt layer in a large enclosed rotor-stator system

    Science.gov (United States)

    Randriamampianina, Anthony; Poncet, Sébastien

    2006-05-01

    A three-dimensional (3D) direct numerical simulation is combined with a laboratory study to describe the turbulent flow in an enclosed annular rotor-stator cavity characterized by a large aspect ratio G =(b-a)/h=18.32 and a small radius ratio a /b=0.152, where a and b are the inner and outer radii of the rotating disk and h is the interdisk spacing. The rotation rate Ω under consideration is equivalent to the rotational Reynolds number Re =Ωb2/ν=9.5×104, where ν is the kinematic viscosity of the fluid. This corresponds to a value at which an experiment carried out at the laboratory has shown that the stator boundary layer is turbulent, whereas the rotor boundary layer is still laminar. Comparisons of the 3D computed solution with velocity measurements have given good agreement for the mean and turbulent fields. The results enhance evidence of weak turbulence at this Reynolds number, by comparing the turbulence properties with available data in the literature [M. Lygren and H. I. Andersson, J. Fluid Mech. 426, 297 (2001)]. An approximately self-similar boundary layer behavior is observed along the stator side. The reduction of the structural parameter a1 under the typical value 0.15 and the variation in the wall-normal direction of the different characteristic angles show that this boundary layer is three-dimensional. A quadrant analysis [H. S. Kang, H. Choi, and J. Y. Yoo, Phys. Fluids 10, 2315 (1998)] of conditionally averaged velocities is performed to identify the contributions of different events (ejections and sweeps) on the Reynolds shear stress producing vortical structures. The asymmetries observed in the conditionally averaged quadrant analysis are dominated by Reynolds stress-producing events in this Bödewadt layer. Moreover, case 1 vortices (with a positive wall induced velocity) are found to be the major source of generation of special strong events, in agreement with the conclusions of Lygren and Andersson [J. Fluid Mech. 426, 297 (2001)].

  4. MRAS speed estimator with fuzzy and PI stator resistance adaptation for sensorless induction motor drives using RT-lab

    Directory of Open Access Journals (Sweden)

    S. Mohan Krishna

    2016-09-01

    Full Text Available This paper presents a real-time simulation study of Model Reference Adaptive System based rotor speed estimator with parallel stator resistance adaptation mechanism for speed sensorless induction motor drive. Both, the traditional Proportional Integral and Fuzzy logic based control mechanisms are utilised for stator resistance adaptation, while, the rotor speed is estimated parallely by means of Proportional Integral based mechanism. The estimator's response to dynamic changes in Load perturbation and doubling of the nominal value of the actual stator resistance of the motor is observed. The superiority of the fuzzy based stator resistance adaptation in the Model Reference Adaptive System estimator is proved through results validated in real-time. The purpose of employing a fairly new real-time platform is to reduce the test and prototype time. The model is initially built using Matlab/Simulink blocksets and the results are validated in real time using RT-Lab. The RT-lab blocksets are integrated into the Simulink model and then executed in real-time using the OP-4500 target developed by Opal-RT. The real-time simulation results are observed in the workstation.

  5. Application of Boost Converter to Increase the Speed Range of Dual-stator Winding Induction Generator in Wind Power Systems

    DEFF Research Database (Denmark)

    Kavousi, Ayoub; Fathi, S. Hamid; Milimonfared, Jafar

    2018-01-01

    In this paper, a topology using a Dual-stator Winding Induction Generator (DWIG) and a boost converter is proposed for the variable speed wind power application. At low rotor speeds, the generator saturation limits the voltage of the DWIG. Using a boost converter, higher DC voltage can be produce...

  6. THE INFLUENCE OF POWER STATOR WINDINGS OF THE ASYNCHRONOUS TRACTION MOTORS FOR DYNAMIC WORKLOAD ELEMENTS OF TRACTION DRIVE LOCOMOTIVE

    Directory of Open Access Journals (Sweden)

    O. M. Bondarev

    2010-01-01

    Full Text Available The results of studies on determination of loading level of tractive drive elements in some operating conditions, when the values of frequencies of the change of feeding currents of stator windings are to be obtained in both subcritical and ultracritical zones for two types of the tractive gear are presented in the paper.

  7. Performance of a fractional dc electric motor equipped with plastic bonded Nd2Fe14B stator poles

    International Nuclear Information System (INIS)

    Nicolaides, G.K.; Atanassova, Y.K.; Ioannides, M.G.; Tsamakis, D.M.; Gamari-Seale, H.

    1997-01-01

    Injection molding Nd 2 Fe 14 B plastic bonded magnetic material is pressed into the form of cylindrical ring segments in order to investigate its performance when used in the manufacturing of stator poles of fractional power dc motors. Measurements of speed and armature current versus different load torques were performed. The experimental results obtained for stator poles made by three plastic bonded Nd 2 Fe 14 B magnetic materials of different densities, are compared to those results obtained by using a pair of typical barium ferrite stator poles. The torque versus speed curves, the obtained mechanical power versus speed and the efficiency of the motor as a function of the speed are presented. The torque speed data in high speeds follow a linear law, as is expected by theory, while at low speeds, below a crossover point, a deviation from this linearity appears. This is attributed to temperature effects. In this work it is shown that in the region of light loads and high speeds, at a certain speed, the injection molded Nd 2 Fe 14 B permanent magnet stators produce a higher electromagnetic torque, higher mechanical power, and higher efficiency than the barium ferrite ones. copyright 1997 American Institute of Physics

  8. Comparison of stator-mounted permanent-magnet machines based on a general power equation

    DEFF Research Database (Denmark)

    Chen, Zhe; Hua, Wei; Cheng, Ming

    2009-01-01

    The stator-mounted permanent-magnet (SMPM) machines have some advantages compared with its counterparts, such as simple rotor, short winding terminals, and good thermal dissipation conditions for magnets. In this paper, a general power equation for three types of SMPM machine is introduced first......, and then, power equations considering the specific topologies are derived. Based on these power equations, theoretical comparisons are carried out between various types of the SMPM machines. In all, eight topologies have been presented and benchmarked. It reveals that the flux switching permanent......-magnet (PM) machine owns higher power density than the flux reversal PM machine and the doubly salient PM machine under same outer diameter. The comparison based on the power equation has established a foundation for optimizing the SMPM machines....

  9. Numerical analysis of hydrodynamics in a rotor-stator reactor for biodiesel synthesis

    International Nuclear Information System (INIS)

    Wen, Zhuqing; Petera, Jerzy

    2016-01-01

    A rotor-stator spinning disk reactor for intensified biodiesel synthesis is described and numerically simulated. The reactor consists of two flat disks, located coaxially and parallel to each other with a gap ranging from 0.1 mm to 0.2 mm between the disks. The upper disk is located on a rotating shaft while the lower disk is stationary. The feed liquids, triglycerides (TG) and methanol are introduced coaxially along the center line of rotating disk and stationary disk, respectively. Fluid hydrodynamics in the reactor for synthesis of biodiesel from TG and methanol in the presence of a sodium hydroxide catalyst are simulated, using convection-diffusion-reaction species transport model by the CFD software ANSYS©Fluent v. 13.0. The effects of upper disk’s spinning speed, gap size and flow rates at inlets are evaluated.

  10. Modelling of BLDCM with a double 3-phase stator winding and back EMF harmonics

    Directory of Open Access Journals (Sweden)

    Drozdowski Piotr

    2015-03-01

    Full Text Available In this paper the mathematical model of the brushless DC motor (BLDCM with a double 3-phase stator winding is analysed. Both the 3-phase windings are mutually displaced by 30 electrical degree. Special care has been sacrificed to influence of higher harmonics of induced electromotive forces (EMF on electromagnetic torque and zero sequence voltages that may be used for sensorless control. The mathematical model has been presented in natural variables and, after transformation to symmetrical components, in a vector form. This allows, from one side, for formulating the equivalent circuit suitable for circuit oriented simulators (e.g.: Spice, SimPowerSystems of Simulink and, from the other point of view, for analysis of higher harmonics influence on control possibilities. These considerations have been illustrated with some results of four quadrant operation obtainded due to simulation at automatic control.

  11. Estimation of Stator Winding Faults in Induction Motors using an Adaptive Observer Scheme

    DEFF Research Database (Denmark)

    Kallesøe, C. S.; Vadstrup, P.; Rasmussen, Henrik

    2004-01-01

    This paper addresses the subject of inter-turn short circuit estimation in the stator of an induction motor. In the paper an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved in the short circuit...... and an expression of the current in the short circuit. Moreover the states of the motor are estimated, meaning that the magnetizing currents are made available even though a fault has happened in the motor. To be able to develop this observer, a model particular suitable for the chosen observer design, is also...... derived. The efficiency of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate inter-turn short circuit faults....

  12. Field-oriented control of five-phase induction motor with open-end stator winding

    Directory of Open Access Journals (Sweden)

    Listwan Jacek

    2016-09-01

    Full Text Available The mathematical model of the five-phase squirrel-cage induction motor and the system of the dual five-phase voltage source inverter have been presented. The control methods and control systems of the field-oriented control of the five-phase induction motor with an open-end stator winding are described. The structures of the direct fieldoriented control system (DFOC and the Indirect Field-oriented control system (IFOC with PI controllers in outer and inner control loops are analyzed. A method of space vector modulation used to control the system of the dual five-phase voltage source inverter has been discussed. The results of simulation studies of the field-oriented control methods are presented. Comparative analysis of the simulation results was carried out.

  13. Estimation of Stator Winding Faults in Induction Motors using an Adaptive Observer Scheme

    DEFF Research Database (Denmark)

    Kallesøe, C. S.; Vadstrup, P.; Rasmussen, Henrik

    2004-01-01

    and an expression of the current in the short circuit. Moreover the states of the motor are estimated, meaning that the magnetizing currents are made available even though a fault has happened in the motor. To be able to develop this observer, a model particular suitable for the chosen observer design, is also......This paper addresses the subject of inter-turn short circuit estimation in the stator of an induction motor. In the paper an adaptive observer scheme is proposed. The proposed observer is capable of simultaneously estimating the speed of the motor, the amount turns involved in the short circuit...... derived. The efficiency of the proposed observer is demonstrated by tests performed on a test setup with a customized designed induction motor. With this motor it is possible to simulate inter-turn short circuit faults....

  14. FEM analysis of an single stator dual PM rotors axial synchronous machine

    Science.gov (United States)

    Tutelea, L. N.; Deaconu, S. I.; Popa, G. N.

    2017-01-01

    The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors. The proposed topologies, the magneto-motive force analysis and quasi 3D-FEM analysis are the core of the paper.

  15. Rapid Optimization of Double-Stators Switched Reluctance Motor with Equivalent Magnetic Circuit

    Directory of Open Access Journals (Sweden)

    Wu-Sung Yao

    2017-10-01

    Full Text Available The primary objective for this paper is to create a methodology to rapidly optimize double-stators switched reluctance motor (DSSRM. An analytical model of equivalent magnetic circuits for the air gap reluctances of aligned and unaligned positions is proposed and the optimal operation point of the magneto-motive force (MMF can be determined. Genetic algorithm (GA integrated of the proposed equivalent magnetic circuit is developed for rapid optimization of DSSRM to reach the maximum of the ratio of torque to volume of DSSRM. Compared to conventional switched reluctance motor (SRM, an illustrated example of a 3-KW three-phase 12-Slot-8-Pole DSSRM is used to verify the efficiency of the proposed method. Simplified 2-D electromagnetic models are analyzed and simulated. Finally, results of the analytical calculations and the finite-element analysis (FEA are validated by the proposed motor to show the accuracy of the designed strategy.

  16. Novel model of stator design to reduce the mass of superconducting generators

    Science.gov (United States)

    Kails, Kevin; Li, Quan; Mueller, Markus

    2018-05-01

    High temperature superconductors (HTS), with much higher current density than conventional copper wires, make it feasible to develop very powerful and compact power generators. Thus, they are considered as one promising solution for large (10 + MW) direct-drive offshore wind turbines due to their low tower head mass. However, most HTS generator designs are based on a radial topology, which requires an excessive amount of HTS material and suffers from cooling and reliability issues. Axial flux machines on the other hand offer higher torque/volume ratios than the radial machines, which makes them an attractive option where space and transportation becomes an issue. However, their disadvantage is heavy structural mass. In this paper a novel stator design is introduced for HTS axial flux machines which enables a reduction in their structural mass. The stator is for the first time designed with a 45° angle that deviates the air gap closing forces into the vertical direction reducing the axial forces. The reduced axial forces improve the structural stability and consequently simplify their structural design. The novel methodology was then validated through an existing design of the HTS axial flux machine achieving a ∼10% mass reduction from 126 tonnes down to 115 tonnes. In addition, the air gap flux density increases due to the new claw pole shapes improving its power density from 53.19 to 61.90 W kg‑1. It is expected that the HTS axial flux machines designed with the new methodology offer a competitive advantage over other proposed superconducting generator designs in terms of cost, reliability and power density.

  17. Two-Stage Centrifugal Fan

    Science.gov (United States)

    Converse, David

    2011-01-01

    Fan designs are often constrained by envelope, rotational speed, weight, and power. Aerodynamic performance and motor electrical performance are heavily influenced by rotational speed. The fan used in this work is at a practical limit for rotational speed due to motor performance characteristics, and there is no more space available in the packaging for a larger fan. The pressure rise requirements keep growing. The way to ordinarily accommodate a higher DP is to spin faster or grow the fan rotor diameter. The invention is to put two radially oriented stages on a single disk. Flow enters the first stage from the center; energy is imparted to the flow in the first stage blades, the flow is redirected some amount opposite to the direction of rotation in the fixed stators, and more energy is imparted to the flow in the second- stage blades. Without increasing either rotational speed or disk diameter, it is believed that as much as 50 percent more DP can be achieved with this design than with an ordinary, single-stage centrifugal design. This invention is useful primarily for fans having relatively low flow rates with relatively high pressure rise requirements.

  18. Multi-scale thermodynamic analysis method for 2D SiC/SiC composite turbine guide vanes

    Directory of Open Access Journals (Sweden)

    Xin LIU

    2018-01-01

    Full Text Available Ceramic Matrix Composite (CMC turbine guide vanes possess multi-scale stress and strain with inhomogeneity at the microscopic scale. Given that the macroscopic distribution cannot reflect the microscopic stress fluctuation, the macroscopic method fails to meet the requirements of stress and strain analysis of CMC turbine guide vanes. Furthermore, the complete thermodynamic properties of 2D woven SiC/SiC-CMC cannot be obtained through experimentation. Accordingly, a method to calculate the thermodynamic properties of CMC and analyze multi-scale stress and strain of the turbine guide vanes should be established. In this study, the multi-scale thermodynamic analysis is investigated. The thermodynamic properties of Chemical Vapor Infiltration (CVI processed SiC/SiC-CMC are predicted by a Representative Volume Element (RVE model with porosity, leading to the result that the relative error between the calculated in-plane tensile modulus and the experimental value is 4.2%. The macroscopic response of a guide vane under given conditions is predicted. The relative error between the predicted strain on the trailing edge and the experimental value is 9.7%. The calculation of the stress distribution of micro-scale RVE shows that the maximum value of microscopic stress, which is located in the interlayer matrix, is more than 1.5 times that of macroscopic stress in the same direction and the microscopic stress distribution of the interlayer matrix is related to the pore distribution of the composite.

  19. Performance Enhancement of the In-Line Fan Equipped with the Guiding Vane and the Tail Body

    Directory of Open Access Journals (Sweden)

    Hung-Cheng Yen

    2014-02-01

    Full Text Available This integrated numerical and experimental study intends to enhance the performance of an in-line fan with the implement of the guiding vane and the tail body. At first the flow flied associated with the original in-line fan is simulated and analyzed within the framework of CFD code Fluent, in which the finite volume method is applied. Next, the guiding vane is constructed based on the calculated flow characteristics, and attached in the downstream of rotor to smoothen the flow pattern. An appropriate guiding vane with high-performance and low-noise features can be achieved after several design iterations. In addition, the tail body connected to the motor is introduced for further enhancing the fan performance by reducing the sizes of wake and reversed flow behind the hub. Thereafter, to manufacture the mockup for experimental verification, the modified fan with guiding vane is plotted in the CAD/CAM format for mockup fabrication via the rapid-prototype technique. Moreover, a set of relations correlating the performance and noise of this fan prototype are executed inside AMCA test chamber and semianechoic chamber, respectively. Consequently, the feasibility of design scheme and numerical system can be verified according to these experimental results. In summary, this work provides a systematic scheme for designing and analyzing the in-line fan.

  20. Effect of long time service exposure on microstructure and mechanical properties of gas turbine vanes made of IN939 alloy

    International Nuclear Information System (INIS)

    Jahangiri, M.R.; Abedini, M.

    2014-01-01

    Highlights: • Microstructure of service-exposed turbine vanes made of IN939 was investigated. • Mechanical properties of service-exposed alloy were also investigated. • Formation of M 23 C 6 films on GBs and degeneration of MCs are microstructural changes. • Despite its thermodynamic favorability, σ phase is not observed in microstructure. • Microstructural changes lead to a loss in tensile ductility and creep life. - Abstract: In the present study, the effects of long-term service exposure have been investigated on microstructure and mechanical properties of gas turbine vanes made of IN939 superalloy. The major microstructural changes for the investigated service-exposed vanes include the formation of continuous grain boundary carbides and the transformation (degeneration) of MC carbides located at the grain boundaries. The brittle σ phase, which is predicted to be stable on the basis of thermodynamic calculations, is not observed in the microstructure of service-exposed vanes. The microstructural changes during service lead to a loss in room temperature ductility as well as in creep properties of the alloy

  1. Preliminary Investigation on Turbulent Flow in Tight-lattice Rod Bundle with Twist-mixing Vane Spacer Grid

    International Nuclear Information System (INIS)

    Lee, Chiyoung; Kwack, Youngkyun; Park, Juyong; Shin, Changhwan; In, Wangkee

    2013-01-01

    Our research group has investigated the effect of P/D difference on the behavior of turbulent rod bundle flow without the mixing vane spacer grid, using PIV (Particle Image Velocimetry) and MIR (Matching Index of Refraction) techniques for tight lattice fuel rod bundle application. In this work, using the tight-lattice rod bundle with a twist-mixing vane spacer grid, the turbulent rod bundle flow is preliminarily examined to validate the PIV measurement and CFD (Computational Fluid Dynamics) simulation. The turbulent flow in the tight-lattice rod bundle with a twist-mixing vane spacer grid was preliminarily examined to validate the PIV measurement and CFD simulation. Both were in agreement with each other within a reasonable degree of accuracy. Using PIV measurement and CFD simulation tested in this work, the detailed investigations on the behavior of turbulent rod bundle flow with the twist-mixing vane spacer grid will be performed at various conditions, and reported in the near future

  2. Using a Swinging Vane Anemometer to Measure Airflow. Module 14. Vocational Education Training in Environmental Health Sciences.

    Science.gov (United States)

    Consumer Dynamics Inc., Rockville, MD.

    This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on using a swinging vane anemometer to measure airflow. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming each…

  3. 2.5 MeV CW 4-vane RFQ accelerator design for BNCT applications

    Science.gov (United States)

    Zhu, Xiaowen; Wang, Hu; Lu, Yuanrong; Wang, Zhi; Zhu, Kun; Zou, Yubin; Guo, Zhiyu

    2018-03-01

    Boron Neutron Capture Therapy (BNCT) promises a bright future in cancer therapy for its highly selective destruction of cancer cells, using the 10B +n→7Li +4 He reaction. It offers a more satisfactory therapeutic effect than traditional methods for the treatment of malignant brain tumors, head and neck cancer, melanoma, liver cancer and so on. A CW 4-vane RFQ, operating at 162.5 MHz, provides acceleration of a 20 mA proton beam to 2.5 MeV, bombarding a liquid lithium target for neutron production with a soft neutron energy spectrum. The fast neutron yield is about 1.73×1013 n/s. We preliminarily develop and optimize a beam shaping assembly design for the 7Li(p, n)7Be reaction with a 2.5 MeV proton beam. The epithermal neutron flux simulated at the beam port will reach up to 1 . 575 ×109 n/s/cm2. The beam dynamics design, simulation and benchmark for 2.5 MeV BNCT RFQ have been performed with both ParmteqM (V3.05) and Toutatis, with a transmission efficiency higher than 99.6% at 20 mA. To ease the thermal management in the CW RFQ operation, we adopt a modest inter-vane voltage design (U = 65 kV), though this does increase the accelerator length (reaching 5.2 m). Using the well-developed 3D electromagnetic codes, CST MWS and ANSYS HFSS, we are able to deal with the complexity of the BNCT RFQ, taking the contribution of each component in the RF volume into consideration. This allows us to optimize the longitudinal field distribution in a full-length model. Also, the parametric modeling technique is of great benefit to extensive modifications and simulations. In addition, the resonant frequency tuning of this RFQ is studied, giving the tuning sensitivities of vane channel and wall channel as -16.3 kHz/°C and 12.4 kHz/°C, respectively. Finally, both the multipacting level of this RFQ and multipacting suppressing in the coaxial coupler are investigated.

  4. Scale Effect Features During Simulation Tests of 3D Printer-Made Vane Pump Models

    Directory of Open Access Journals (Sweden)

    A. I. Petrov

    2015-01-01

    Full Text Available The article "Scale effect features during simulation tests of 3D printer-made vane pump models" discusses the influence of scale effect on translation of pump parameters from models, made with 3D-prototyping methods, to full-scale pumps. Widely spread now 3D-printer production of pump model parts or entire layouts can be considered to be the main direction of vane pumps modeling. This is due to the widespread development of pumps in different CAD-systems and the significant cost reduction in manufacturing such layouts, as compared to casting and other traditional methods.The phenomenon of scale effect in vane hydraulic machines, i.e. violation of similarity conditions when translating pump parameters from model to full-scale pumps is studied in detail in the theory of similarity. However, as the experience in the 3d-printer manufacturing of models and their testing gains it becomes clear that accounting large-scale effect for such models has a number of differences from the conventional techniques. The reason for this is the features of micro and macro geometry of parts made in different kinds of 3D-printers (extrusive, and powder sintering methods, ultraviolet light, etc..The article considers the converting features of external and internal mechanical losses, leakages, and hydraulic losses, as well as the specifics of the balance tests for such models. It also presents the basic conversion formulas describing the factors affecting the value of these losses. It shows photographs of part surfaces of models, manufactured by 3D-printer and subjected to subsequent machining. The paper shows results of translation from several pump models (layouts to the full-scale ones, using the techniques described, and it also shows that the error in translation efficiency does not exceed 1.15%. The conclusion emphasizes the importance of the balance tests of models to accumulate statistical data on the scale effect for pump layouts made by different 3D

  5. NASA Glenn/AADC Collaboration Optimized Erosion Coatings for Inlet Guide Vanes

    Science.gov (United States)

    Sutter, James K.; Leissler, George; Horan, Richard

    2002-01-01

    There is a need for lightweight, durable materials and structures to reduce the weight of propulsion systems. Polymer matrix composites (PMC's) are promising materials for aerospace applications because of their high strength-to-weight ratio relative to metals. Unfortunately, they are limited to applications where they are not exposed to hightemperature oxidizing atmospheres and/or particulates from ingested air. This is because oxidation and erosion occur on the surface, leading to weight loss, nodulation, and/or cracking on the surface, and a consequent decline of mechanical properties over time. Although prior research has shown that oxidation can be slowed when metallic or ceramic coatings are applied onto PMC's, there remains a need for erosion-resistant coatings that protect PMC's from high-velocity particulates in the engine flow path. These erosionresistant coatings could extend the life of polymer composites. Polymer composites are heavily damaged without an erosion-resistant coating because they are not as hard as metallic engine structures. The effectiveness and life of the coatings depends on their inherent properties as well as on the interaction between the coating and the PMC. Since polymers, in general, have high thermal expansion coefficients in comparison to metals and ceramics, failure of the coatings often occurs at this interface. The objective of this research is to develop strategies to improve this interface and tailor overlays for erosion resistance. The bondcoat, which was developed at the NASA Glenn Research Center, is composed of zinc blended with polyimides to improve the compatibility between the PMC and the overlay material. Initial coating trials at AADC produced vanes that had poor bonding between the overlay and bondcoats. Subsequently, Glenn successfully demonstrated that high-quality plasma-sprayed erosion coating systems could be applied to these guide vanes. Inlet guide vanes from AE 3007 engines fiber composites were coated

  6. Investigating the thermal hydraulic performance of spacer grid with mixing vanes using STAR-CCM+ and MATRA

    International Nuclear Information System (INIS)

    Agbodemegbe, V. Y.

    2014-07-01

    Enhancement of heat transfer for flow through rod bundles is linked to the extent and sustainability of mixing in the flow geometry. Spacer grids used as support for rod bundles in nuclear reactors, when attached with ditferent designs of mixing vanes promote turbulent mixing by inducing swirl or forced lateral convection that improves mixing within or between sub-channels. The improved turbulent mixing raises the margin of the onset of critical heat flux in light water reactors (LWR) and also ensures a higher fuel cycle economy. To optimize design of mixing vanes and performance of spacer grids with mixing vanes, computational fluid dynamic simulations arc carried out on new designs and validated experimentally prior to industrial application. In the present study, computational fluid dynamic simulation using STAR-CCM+ and sub-channel analysis with MATRA were performed for flow of water through a 5 X 5 rod bundle geometry for which the rod to rod pitch to diameter ratio was 1.33 and the wall to rod pitch to diameter ratio was 0.74. The two layer k-epsilon turbulence model with an all- y + automatic wall treatment function in STAR-CCM+ were adopted for an isothermal single phase flow through the geometry with imposed cyclic periodic and non-cyclic periodic interface boundary conditions. The objective was to primarily investigate the detail flow behavior in rod bundle in the presence of spacer grids with and without attached mixing vanes. Furthermore, the present study also investigated the extent of turbulent mixing and lateral mass flux induced by the mixing vanes through comparative analysis of parametric trends for spacer grid with and without mixing vanes. New models and empirical correlations for describing the mixing vanes effects were also developed. These semi-empirical correlations improved the prediction for lateral mass flux due to turbulence, fraction of flow diverted through gaps and cross-flow resistance coefficients. Validation of simulation results

  7. Influence of the Operational Wear of the Stator Parts of Shroud Seals on the Economic Efficiency of the Steam Turbines

    Science.gov (United States)

    Kostyuk, A. G.; Dmitriev, S. S.; Petrunin, B. N.; Gusev, A. A.

    2018-01-01

    During the operation of steam turbines under transient conditions, due to different thermal expansion of the stator and rotor parts in the radial and axial directions, the clearances fixed in the course of assembling the seals of the flow path change, which causes rubbing in the seals and the wear of the latter. This inevitably increases the leakages through the seals. A particularly large difference in the relative axial and radial displacements of the rotor and stator parts is observed during the turbine start-ups when the difference in their temperature expansion is maximal. Upon the turbine stops, the turbine shafting runs down freely, as a rule, passing through all critical speeds at which the amplitude of the shafting oscillations reach their peak values, which also leads to seizures in the seals and their wear and tear. The seizures in the seals may also be a consequence of the eccentricity between the rotor and stator caused by the thermal strain of the stator, incorrect choice of the clearances, floating-up of the rotor in the bearing, and many other factors. Recently, standard shroud labyrinth seals are being replaced in the steam turbines by seals with honeycomb stator inserts, the design of which allows the ridges to cut into the honeycomb surface without damaging the former, which allows fixing a radial clearance in the seals of 0.5 mm. On the honeycomb surface where the ridges touch it, grooves are cut through. The wear of the shroud seals reduces the efficiency of the steam turbines during the operation to the greatest degree. However, by the present there have been no exact quantitative data available on the change in the leakage through the worn-out honeycomb seals. The paper presents the results of comparative experimental studies on the flow and power characteristics of seal models with smooth and honeycomb stator parts for various degrees of their wear. The studies showed that the leakages through the worn-out stator parts of the honeycomb seals

  8. Influence of Prewhirl Regulation by Inlet Guide Vanes on Cavitation Performance of a Centrifugal Pump

    Directory of Open Access Journals (Sweden)

    Lei Tan

    2014-02-01

    Full Text Available The influence of prewhirl regulation by inlet guide vanes (IGVs on a centrifugal pump performance is investigated experimentally and numerically. The experimental results show that IGVs can obviously change the head and increase the efficiency of the tested centrifugal pump over a wide range of flow rates. Although the cavitation performance is degraded, the variation of the cavitation critical point is less than 0.5 m. Movement of the computed three-dimensional streamlines in suction pipe and impeller are analyzed in order to reveal the mechanism how the IGVs realize the prewhirl regulation. The calculated results show that the influence of IGVs on the cavitation performance of centrifugal pump is limited by a maximum total pressure drop of 1777 Pa, about 7.6% of the total pressure at the suction pipe inlet for a prewhirl angle of 24°.

  9. Morphological and thermal properties of PLA/OMMT nanocomposites prepared via vane extruder

    Science.gov (United States)

    Luo, Y.; Liu, H. Y.; Zhang, G. Z.; Qu, J. P.

    2017-06-01

    Polylactide/Organo-Montmorillonite (PLA/OMMT) Nanocomposites were prepared by melting extrusion using a novel vane extruder (VE), which can induce global elongational flow. In the study, the influence of different concentrations of the OMMT on the morphological and thermal properties were investigated. The morphology and structure of the nanocomposites were evaluated using Fourier Transform Infrared Spectroscopy (FTIR), the X-ray diffraction (XRD) and transmission electron microscopy (TEM) respectively, whereas the thermal behaviors and thermal stabilities were characterized using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) respectively. The results illustrate that PLA/OMMT nanocomposites displayed clear intercalation and/or exfoliation structures. Interestingly, increasing the clay content did not lead to the agglomeration of OMMT layers. Moreover, the presence of nanoclay decreased the enthalpy of crystallization of PLA/OMMT composites. Also, the melting temperatures of the nanocomposites were reduced by the addition of nanoclay.

  10. Extension of the Vane Pump-Grinder Technology to Manufacture Finely Dispersed Meat Batters.

    Science.gov (United States)

    Irmscher, Stefan B; Gibis, Monika; Herrmann, Kurt; Oechsle, Anja Maria; Kohlus, Reinhard; Weiss, Jochen

    2016-03-01

    A vane pump-grinder system was extended to enable the manufacture of finely dispersed emulsion-type sausages by constructing and attaching a high-shear homogenizer at the outlet. We hypothesized that the dispersing capabilities of the extended system may be improved to the point of facilitating meat-fat emulsification due to an overall increased volumetric energy input EV . Coarsely ground raw material mixtures were processed to yield meat batters at varying volume flow rates (10 to 60 L/min) and rotational rotor speeds of the homogenizer nrotor (1000 to 3400 rpm). The normalized torques acting on pump, grinder, and homogenizer motors were recorded and unit power consumptions were calculated. The structure of the manufactured meat batters and sausages were analyzed via image analysis. Key physicochemical properties of unheated and heated batters, that is, texture, water-binding, color, and solubilized protein were determined. The mean diameter d10 of the visible lean meat particles varied between 352 and 406 μm whereas the mean volume-surface diameter d32 varied between 603 and 796 μm. The lightness L* ranged from 66.2 to 70.7 and correlated with the volumetric energy input and product structure. By contrast, varying process parameters did not impact color values a* (approximately 11) and b* (approximately 8). Interestingly, water-binding and protein solubilization were not affected. An exponential process-structure relationship was identified allowing manufacturers to predict product properties as a function of applied process parameters. Raw material mixtures can be continuously comminuted, emulsified, and subsequently filled into casings using an extended vane pump-grinder. © 2016 Institute of Food Technologists®

  11. CFD Simulations of Supersonic Highly Swirling Flow Exiting a Turbine Vane Row Compared with Experimental Observations

    Science.gov (United States)

    West, Jeff S.; Richardson, Brian R.; Schmauch, Preston; Kenny, Robert J.

    2011-01-01

    Marshall Space Flight Center (MSFC) has been heavily involved in developing the J2-X engine. The Center has been testing a Work Horse Gas Generator (WHGG) to supply gas products to J2-X turbine components at realistic flight-like operating conditions. Three-dimensional time accurate CFD simulations and analytical fluid analysis have been performed to support WHGG tests at MSFC. The general purpose CFD program LOCI/Chem was utilized to simulate flow of products from the WHGG through a turbine manifold, a stationary row of turbine vanes, into a Can and orifice assembly used to control the back pressure at the turbine vane row and finally through an aspirator plate and flame bucket. Simulations showed that supersonic swirling flow downstream of the turbine imparted a much higher pressure on the Can wall than expected for a non-swirling flow. This result was verified by developing an analytical model that predicts wall pressure due to swirling flow. The CFD simulations predicted that the higher downstream pressure would cause the pressure drop across the nozzle row to be approximately half the value of the test objective. With CFD support, a redesign of the Can orifice and aspirator plate was performed. WHGG experimental results and observations compared well with pre-test and post-test CFD simulations. CFD simulations for both quasi-static and transient test conditions correctly predicted the pressure environment downstream of the turbine row and the behavior of the gas generator product plume as it exited the WHGG test article, impacted the flame bucket and interacted with the external environment.

  12. An Experimental Investigation of the Flow Physics Associated With End Wall Losses and Large Rotor Tip Clearances as Found in the Rear Stages of a High Pressure Compressor

    Science.gov (United States)

    Berdanier, Reid A.; Key, Nicole L.

    2015-01-01

    measurements have also been used to calculate streamwise vorticity. Time-resolved static pressure measurements have been collected over the rotor tips for all rotors with each of the three tip clearance configurations for up to five loading conditions along the 100% corrected speedline using fast-response piezoresistive pressure sensors. These time-resolved static pressure measurements, as well as the time-resolved total pressures and velocities have helped to reveal a profound influence of the upstream stator vane on the size and shape of the rotor tip leakage flow. Finally, a novel particle image velocimetry (PIV) technique has been developed as a proof-of- concept. In contrast to PIV methods that have been typically been utilized for turbomachinery applications in the past, the method used for this study introduced the laser light through the same access window that was also used to image the flow. This new method addresses potential concerns related to the intrusive laser-introducing techniques that have typically been utilized by other authors in the past. Ultimately, the data collected for this project represent a unique data set which contributes to build a better understanding of the tip leakage flow field and its associated loss mechanisms. These data will facilitate future engine design goals leading to small blade heights in the rear stages of high pressure compressors and aid in the development of new blade designs which are desensitized to the performance penalties attributed to rotor tip leakage flows.

  13. Modelling of the travelling wave piezoelectric motor stator: an integrated review and new perspective

    Directory of Open Access Journals (Sweden)

    Rodríguez, H.

    2004-06-01

    Full Text Available Articles from different areas which are closely related to the modelling of the stator of travelling wave ultrasonic motors (TWUMs are reviewed in this work. Thus, important issues relevant to this problem are identified from the areas of vibration of annular plates, laminated plate theories, and modelling of piezoelectric transducers. From this integrated point of view, it becomes clear that there are some very important issues yet to be addressed in the modelling of TWUMs. Firstly, the influence of material properties and stator dimensions on output efficiency, electromechanical coupling coefficients (EMCC and maximum output energy is to be investigated in more detail. Secondly, the modelling of the electric potential field (by explicitly including the charge equation for TWUMs seems to be a must for better prediction of displacements and electric fields close to the resonance, as suggested by some recent works [1]. Moreover, the improvement of current models by using shear deformation (or higher order laminated plate theories (LPTs in conjunction with approximated methods of solution are discussed. In addition to analytical models, those works using Finite Element and Finite difference Methods (FEM and FDM for the modelling and simulation of the TWUM stator dynamics are reviewed.

    En este trabajo se realiza una revisión de los trabajos de investigación realizados en diversas áreas sobre el modelado del estátor de los motores ultrasónicos de onda viajera (TWUMs. Entre los problemas relevantes que se han estudiado podemos citar la vibración de placas anulares, las teorías de placas laminadas y el modelado de transductores piezoeléctricos. A raíz de este punto de vista integral se hace manifiesto que todavía quedan asuntos importantes que estudiar en el modelado de los TWUMs. En primer lugar, la influencia de las propiedades del material y las dimensiones del estátor en la eficiencia del motor, los coeficientes de acoplamiento

  14. Designing a Two-Phase BLDC Motor and Finite-Element Analysis of Stator Slots Structure Effects on the Motor Operation

    Directory of Open Access Journals (Sweden)

    Mehrdad Jafarboland

    2014-09-01

    Full Text Available Designing a two-phase brushless direct current motor (BLDC and analyzing effects of stator slots structure on the motor operation are main objectives of this paper. At first BLDC motor with three different structures for stator slots is designed by using RMxprt software and efficiency of BLDC motor for different structures in full-load condition has been presented, then the BLDC motor in different conditions by using Maxwell 3D software is designed and with finite element method is analyzed electromagnetically. The results of simulations show that by varying stator slots structure efficieny and operation of motor have changed significantly therefore with correct choosing of stator slots structure intersted operation can be found.

  15. Structure and Function of the Escherichia coli Tol-Pal Stator Protein TolR*

    Science.gov (United States)

    Wojdyla, Justyna A.; Cutts, Erin; Kaminska, Renata; Papadakos, Grigorios; Hopper, Jonathan T. S.; Stansfeld, Phillip J.; Staunton, David; Robinson, Carol V.; Kleanthous, Colin

    2015-01-01

    TolR is a 15-kDa inner membrane protein subunit of the Tol-Pal complex in Gram-negative bacteria, and its function is poorly understood. Tol-Pal is recruited to cell division sites where it is involved in maintaining the integrity of the outer membrane. TolR is related to MotB, the peptidoglycan (PG)-binding stator protein from the flagellum, suggesting it might serve a similar role in Tol-Pal. The only structure thus far reported for TolR is of the periplasmic domain from Haemophilus influenzae in which N- and C-terminal residues had been deleted (TolR(62–133), Escherichia coli numbering). H. influenzae TolR(62–133) is a symmetrical dimer with a large deep cleft at the dimer interface. Here, we present the 1.7-Å crystal structure of the intact periplasmic domain of E. coli TolR (TolR(36–142)). E. coli TolR(36–142) is also dimeric, but the architecture of the dimer is radically different from that of TolR(62–133) due to the intertwining of its N and C termini. TolR monomers are rotated ∼180° relative to each other as a result of this strand swapping, obliterating the putative PG-binding groove seen in TolR(62–133). We found that removal of the strand-swapped regions (TolR(60–133)) exposes cryptic PG binding activity that is absent in the full-length domain. We conclude that to function as a stator in the Tol-Pal complex dimeric TolR must undergo large scale structural remodeling reminiscent of that proposed for MotB, where the N- and C-terminal sequences unfold in order for the protein to both reach and bind the PG layer ∼90 Å away from the inner membrane. PMID:26354441

  16. Structure and function of the Escherichia coli Tol-Pal stator protein TolR.

    Science.gov (United States)

    Wojdyla, Justyna A; Cutts, Erin; Kaminska, Renata; Papadakos, Grigorios; Hopper, Jonathan T S; Stansfeld, Phillip J; Staunton, David; Robinson, Carol V; Kleanthous, Colin

    2015-10-30

    TolR is a 15-kDa inner membrane protein subunit of the Tol-Pal complex in Gram-negative bacteria, and its function is poorly understood. Tol-Pal is recruited to cell division sites where it is involved in maintaining the integrity of the outer membrane. TolR is related to MotB, the peptidoglycan (PG)-binding stator protein from the flagellum, suggesting it might serve a similar role in Tol-Pal. The only structure thus far reported for TolR is of the periplasmic domain from Haemophilus influenzae in which N- and C-terminal residues had been deleted (TolR(62-133), Escherichia coli numbering). H. influenzae TolR(62-133) is a symmetrical dimer with a large deep cleft at the dimer interface. Here, we present the 1.7-Å crystal structure of the intact periplasmic domain of E. coli TolR (TolR(36-142)). E. coli TolR(36-142) is also dimeric, but the architecture of the dimer is radically different from that of TolR(62-133) due to the intertwining of its N and C termini. TolR monomers are rotated ∼180° relative to each other as a result of this strand swapping, obliterating the putative PG-binding groove seen in TolR(62-133). We found that removal of the strand-swapped regions (TolR(60-133)) exposes cryptic PG binding activity that is absent in the full-length domain. We conclude that to function as a stator in the Tol-Pal complex dimeric TolR must undergo large scale structural remodeling reminiscent of that proposed for MotB, where the N- and C-terminal sequences unfold in order for the protein to both reach and bind the PG layer ∼90 Å away from the inner membrane. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Theoretical modelling, analysis and validation of the shaft motion and dynamic forces during rotor–stator contact

    DEFF Research Database (Denmark)

    Lahriri, Said; Santos, Ilmar

    2013-01-01

    This paper deals with the theoretical study of a horizontal shaft, partially levitated by a passive magnetic bearing, impacting its stator. Rigid body dynamics are utilised in order to describe the governing nonlinear equations of motion of the shaft interacting with a passive magnetic bearing...... and stator. Expressions for the restoring magnetic forces are derived using Biot Savart law for uniformed magnetised bar magnets and the contact forces are derived by use of a compliant contact force model. The theoretical mathematical model is verified with experimental results, and shows good agreements....... However, the simulated contact forces are higher in magnitude compared to the experimental results. The cause of this disagreement is addressed and shows that the formulation of the theoretical contact force model slightly overestimates the forces acting during a full annular backward whirl motion....

  18. Experimental measurements concerning the stator insulation partial discharge level of a hydro-generator of high power

    Science.gov (United States)

    Haţiegan, C.; Răduca, E.; Popescu, C.; Hamat, C. O.; Băra, A.; Anghel, D.; Pîrşan, D. A.

    2018-01-01

    The paper presents a determining and evaluating method from an experimental point of view of the partial discharges level from the insulation of the stator of a synchronous hydro-generator of high power that appear at different temperatures. The temperature is measured directly on the coil with placed thermo-resistant elements between the superior and inferior bars. Also, the level of partial discharges with the coil age in a cold state, at the temperature level of the surrounding environment from within the stator, but also in a warm state at different temperatures, is measured. Through this method there is created the possibility of highlighting some eventual degradations of the coil insulation of a hydro-generator.

  19. Fault Diagnosis System of Induction Motors Based on Neural Network and Genetic Algorithm Using Stator Current Signals

    Directory of Open Access Journals (Sweden)

    Tian Han

    2006-01-01

    Full Text Available This paper proposes an online fault diagnosis system for induction motors through the combination of discrete wavelet transform (DWT, feature extraction, genetic algorithm (GA, and neural network (ANN techniques. The wavelet transform improves the signal-to-noise ratio during a preprocessing. Features are extracted from motor stator current, while reducing data transfers and making online application available. GA is used to select the most significant features from the whole feature database and optimize the ANN structure parameter. Optimized ANN is trained and tested by the selected features of the measurement data of stator current. The combination of advanced techniques reduces the learning time and increases the diagnosis accuracy. The efficiency of the proposed system is demonstrated through motor faults of electrical and mechanical origins on the induction motors. The results of the test indicate that the proposed system is promising for the real-time application.

  20. Experimental verification of the effect of cable length on voltage distribution in stator winding of an induction motor under surge condition

    Energy Technology Data Exchange (ETDEWEB)

    Oyegoke, B.S. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Electromechanics

    1997-12-31

    This paper presents the results of surge distribution tests performed on a stator of a 6 kV induction motor. The primary aim of these tests was to determine the wave propagation properties of the machine winding fed via cables of different lengths. Considering the measured resorts, conclusions are derived regarding the effect of cable length on the surge distribution within the stator winding of an ac motor. (orig.) 15 refs.

  1. Diagnostics of induction motor based on spectral analysis of stator current signal with application of fuzzy classifier

    OpenAIRE

    A. Głowacz; W. Głowacz; A. Głowacz

    2010-01-01

    New implementation of diagnostics of imminent failure conditions of induction motor was presented. Software to recognize the current ofinduction motor was implemented. System of current recognition is based on a study of the frequency spectrum of stator current signal.Fuzzy classifier was applied. The studies were carried out for four imminent failure conditions of induction motor. The results confirm thatthe system can be useful for detecting damage and protect the engines.

  2. Diagnostics of induction motor based on spectral analysis of stator current signal with application of fuzzy classifier

    Directory of Open Access Journals (Sweden)

    A. Głowacz

    2010-07-01

    Full Text Available New implementation of diagnostics of imminent failure conditions of induction motor was presented. Software to recognize the current ofinduction motor was implemented. System of current recognition is based on a study of the frequency spectrum of stator current signal.Fuzzy classifier was applied. The studies were carried out for four imminent failure conditions of induction motor. The results confirm thatthe system can be useful for detecting damage and protect the engines.

  3. Prediction and Optimization of Key Performance Indicators in the Production of Stator Core Using a GA-NN Approach

    Science.gov (United States)

    Rajora, M.; Zou, P.; Xu, W.; Jin, L.; Chen, W.; Liang, S. Y.

    2017-12-01

    With the rapidly changing demands of the manufacturing market, intelligent techniques are being used to solve engineering problems due to their ability to handle nonlinear complex problems. For example, in the conventional production of stator cores, it is relied upon experienced engineers to make an initial plan on the number of compensation sheets to be added to achieve uniform pressure distribution throughout the laminations. Additionally, these engineers must use their experience to revise the initial plans based upon the measurements made during the production of stator core. However, this method yields inconsistent results as humans are incapable of storing and analysing large amounts of data. In this article, first, a Neural Network (NN), trained using a hybrid Levenberg-Marquardt (LM) - Genetic Algorithm (GA), is developed to assist the engineers with the decision-making process. Next, the trained NN is used as a fitness function in an optimization algorithm to find the optimal values of the initial compensation sheet plan with the aim of minimizing the required revisions during the production of the stator core.

  4. Feasibility of using PZT actuators to study the dynamic behavior of a rotating disk due to rotor-stator interaction.

    Science.gov (United States)

    Presas, Alexandre; Egusquiza, Eduard; Valero, Carme; Valentin, David; Seidel, Ulrich

    2014-07-07

    In this paper, PZT actuators are used to study the dynamic behavior of a rotating disk structure due to rotor-stator interaction excitation. The disk is studied with two different surrounding fluids-air and water. The study has been performed analytically and validated experimentally. For the theoretical analysis, the natural frequencies and the associated mode shapes of the rotating disk in air and water are obtained with the Kirchhoff-Love thin plate theory coupled with the interaction with the surrounding fluid. A model for the Rotor Stator Interaction that occurs in many rotating disk-like parts of turbomachinery such as compressors, hydraulic runners or alternators is presented. The dynamic behavior of the rotating disk due to this excitation is deduced. For the experimental analysis a test rig has been developed. It consists of a stainless steel disk (r = 198 mm and h = 8 mm) connected to a variable speed motor. Excitation and response are measured from the rotating system. For the rotating excitation four piezoelectric patches have been used. Calibrating the piezoelectric patches in amplitude and phase, different rotating excitation patterns are applied on the rotating disk in air and in water. Results show the feasibility of using PZT to control the response of the disk due to a rotor-stator interaction.

  5. Synthesis and Investigation of Algorithm for Estimation of Active Stator Resistance of Asynchronous Motor with Fixed Rotor

    Directory of Open Access Journals (Sweden)

    D. S. Odnolko

    2012-01-01

    Full Text Available The paper proposes an algorithm for online identification of active stator resistance. Algorithm synthesis has been developed on the basis of a recursive least squares method. The problem has been solved for induction motor model defined in the stationary stator frame α–β-coordinating system. An analysis of negative factors deteriorating the identifier operation has been made in the paper. The analysis has revealed the following: measured signals are noisy due to quantization and differentiation; dynamic model of an induction motor provides only approximate presentation about actual processes in the electromagnetic system of the machine. The paper presents results of  a system simulation while applying the proposed algorithm that confirm the fact that the estimated value of the active stator resistance tends to a true value with high accuracy. The identification test assumes a fixed rotor and nominal parameters uncertainty, but the flexible structure of the algorithm allows to use it as  for single-phase excitation so for full-phase control of the induction motor with freely rotating motor.

  6. Direct Torque Control with Full Order Stator Flux Observer for Dual-Three Phase Induction Motor Drives

    Science.gov (United States)

    Farina, Francesco; Bojoi, Radu; Tenconi, Alberto; Profumo, Francesco

    A Direct Torque Control (DTC) strategy for dual-three phase induction motor drives is discussed in this paper. The induction machine has two sets of stator three-phase windings spatially shifted by 30 electrical degrees with isolated neutral points. The proposed control strategy is based on Proportional Integral (PI) regulators implemented in the stator flux synchronous reference frame. To improve the flux estimation, an Adaptive Stator Flux Observer (ASFO) has been used. Doing so, besides a better flux estimation in contrast to open-loop flux estimators, it is possible to use the observed currents to compensate the inverter non-linear behavior (such as dead-time effects), improving the drive performance at low speed. This is particularly important for low voltage/high current applications, as the drive considered in this paper. The advantages of the discussed control strategy are: constant inverter switching frequency, good transient and steady-state performance and less distorted machine currents in contrast to DTC schemes with variable switching frequency. Experimental results are presented for a 10kW dual three-phase induction motor drive prototype.

  7. Analytical Calculation of Magnetic Field Distribution and Stator Iron Losses for Surface-Mounted Permanent Magnet Synchronous Machines

    Directory of Open Access Journals (Sweden)

    Zhen Tian

    2017-03-01

    Full Text Available Permanent-magnet synchronous machines (PMSMs are widely used in electric vehicles owing to many advantages, such as high power density, high efficiency, etc. Iron losses can account for a significant component of the total loss in permanent-magnet (PM machines. Consequently, these losses should be carefully considered during the PMSM design. In this paper, an analytical calculation method has been proposed to predict the magnetic field distribution and stator iron losses in the surface-mounted permanent magnet (SPM synchronous machines. The method introduces the notion of complex relative air-gap permeance to take into account the effect of slotting. The imaginary part of the relative air-gap permeance is neglected to simplify the calculation of the magnetic field distribution in the slotted air gap for the surface-mounted permanent-magnet (SPM machine. Based on the armature reaction magnetic field analysis, the stator iron losses can be estimated by the modified Steinmetz equation. The stator iron losses under load conditions are calculated according to the varying d-q-axis currents of different control methods. In order to verify the analysis method, finite element simulation results are compared with analytical calculations. The comparisons show good performance of the proposed analytical method.

  8. Feasibility of Using PZT Actuators to Study the Dynamic Behavior of a Rotating Disk due to Rotor-Stator Interaction

    Directory of Open Access Journals (Sweden)

    Alexandre Presas

    2014-07-01

    Full Text Available In this paper, PZT actuators are used to study the dynamic behavior of a rotating disk structure due to rotor-stator interaction excitation. The disk is studied with two different surrounding fluids—air and water. The study has been performed analytically and validated experimentally. For the theoretical analysis, the natural frequencies and the associated mode shapes of the rotating disk in air and water are obtained with the Kirchhoff-Love thin plate theory coupled with the interaction with the surrounding fluid. A model for the Rotor Stator Interaction that occurs in many rotating disk-like parts of turbomachinery such as compressors, hydraulic runners or alternators is presented. The dynamic behavior of the rotating disk due to this excitation is deduced. For the experimental analysis a test rig has been developed. It consists of a stainless steel disk (r = 198 mm and h = 8 mm connected to a variable speed motor. Excitation and response are measured from the rotating system. For the rotating excitation four piezoelectric patches have been used. Calibrating the piezoelectric patches in amplitude and phase, different rotating excitation patterns are applied on the rotating disk in air and in water. Results show the feasibility of using PZT to control the response of the disk due to a rotor-stator interaction.

  9. Electromagnetic Radial Forces in a Hybrid Eight-Stator-Pole, Six-Rotor-Pole Bearingless Switched-Reluctance Motor

    Science.gov (United States)

    Morrison, Carlos R.; Siebert, Mark W.; Ho, Eric J.

    2007-01-01

    Analysis and experimental measurement of the electromagnet force loads on the hybrid rotor in a novel bearingless switched-reluctance motor (BSRM) have been performed. A BSRM has the combined characteristics of a switched-reluctance motor and a magnetic bearing. The BSRM has an eight-pole stator and a six-pole hybrid rotor, which is composed of circular and scalloped lamination segments. The hybrid rotor is levitated using only one set of stator poles. A second set of stator poles imparts torque to the scalloped portion of the rotor, which is driven in a traditional switched reluctance manner by a processor. Analysis was done for nonrotating rotor poles that were oriented to achieve maximum and minimum radial force loads on the rotor. The objective is to assess whether simple one-dimensional magnetic circuit analysis is sufficient for preliminary evaluation of this machine, which may exhibit strong three-dimensional electromagnetic field behavior. Two magnetic circuit geometries, approximating the complex topology of the magnetic fields in and around the hybrid rotor, were employed in formulating the electromagnetic radial force equations. Reasonable agreement between the experimental results and the theoretical predictions was obtained with typical magnetic bearing derating factors applied to the predictions.

  10. A Comparison of Wind Readings from LIDAR, Hot Wire, and Propeller and Vane Anemometers over Time Periods Relevant to Fire Control Applications

    Science.gov (United States)

    2015-04-02

    Anemometers over Time Periods Relevant to Fire Control Applications 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...Distribution is unlimited 1 Aknowledgements The author wishes to express his gratitude to the ALAS-MC program for funding this effort...Propeller & Vane Anemometer at 0m Range Gate . 10 LIDAR Anemometer vs Propeller and Vane Anemometer at 400m /375m Range Gate ................. 11 Capturing

  11. Enhancing sediment distribution at the vicinity of power plant intakes using double rows of vanes and groins (Case study: New tebbin power plant

    Directory of Open Access Journals (Sweden)

    Sayed Mahgoub

    2013-12-01

    The study results showed that, in case of vanes absence, sediments with rates 1–2 m3/week were stuck within the sediment trap under the winter conditions. Also, the results indicated that the submerged vanes play an important role in preventing the sediment intrusion. Also, it was clear that using groins might lead to enhancing the sediment distribution at the intake vicinity.

  12. Tunneling of electrons via rotor–stator molecular interfaces: Combined ab initio and model study

    Energy Technology Data Exchange (ETDEWEB)

    Petreska, Irina, E-mail: irina.petreska@pmf.ukim.mk [Institute of Physics, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, PO Box 162, 1000 Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of); Ohanesjan, Vladimir [Institute of Physics, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, PO Box 162, 1000 Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of); Pejov, Ljupčo [Institute of Chemistry, Department of Physical Chemistry, Ss. Cyril and Methodius University, Arhimedova 5, P.O. Box 162, 1000 Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of); Kocarev, Ljupčo [Macedonian Academy of Sciences and Arts, Krste Misirkov 2, PO Box 428, 1000 Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of); Faculty of Computer Science and Engineering, Ss. Cyril and Methodius University, Skopje, Former Yugolav Republic of Macedonia, The (Macedonia, The Former Yugoslav Republic of)

    2016-07-01

    Tunneling of electrons through rotor–stator anthracene aldehyde molecular interfaces is studied with a combined ab initio and model approach. Molecular electronic structure calculated from first principles is utilized to model different shapes of tunneling barriers. Together with a rectangular barrier, we also consider a sinusoidal shape that captures the effects of the molecular internal structure more realistically. Quasiclassical approach with the Simmons’ formula for current density is implemented. Special attention is paid on conformational dependence of the tunneling current. Our results confirm that the presence of the side aldehyde group enhances the interesting electronic properties of the pure anthracene molecule, making it a bistable system with geometry dependent transport properties. We also investigate the transition voltage and we show that conformation-dependent field emission could be observed in these molecular interfaces at realistically low voltages. The present study accompanies our previous work where we investigated the coherent transport via strongly coupled delocalized orbital by application of Non-equilibrium Green’s Function Formalism.

  13. Root Cause Failure Analysis of Stator Winding Insulation failure on 6.2 MW hydropower generator

    Science.gov (United States)

    Adhi Nugroho, Agus; Widihastuti, Ida; Ary, As

    2017-04-01

    Insulation failure on generator winding insulation occurred in the Wonogiri Hydropower plant has caused stator damage since ase was short circuited to ground. The fault has made the generator stop to operate. Wonogiri Hydropower plant is one of the hydroelectric plants run by PT. Indonesia Power UBP Mrica with capacity 2 × 6.2 MW. To prevent damage to occur again on hydropower generators, an analysis is carried out using Root Cause Failure Analysis RCFA is a systematic approach to identify the root cause of the main orbasic root cause of a problem or a condition that is not wanted. There are several aspects to concerned such as: loading pattern and operations, protection systems, generator insulation resistance, vibration, the cleanliness of the air and the ambient air. Insulation damage caused by gradual inhomogeneous cooling at the surface of winding may lead in to partial discharge. In homogeneous cooling may present due to lattice hampered by dust and oil deposits. To avoid repetitive defects and unwanted condition above, it is necessary to perform major maintenance overhaul every 5000-6000 hours of operation.

  14. Detection of stator winding faults in induction motors using three-phase current monitoring.

    Science.gov (United States)

    Sharifi, Rasool; Ebrahimi, Mohammad

    2011-01-01

    The objective of this paper is to propose a new method for the detection of inter-turn short circuits in the stator windings of induction motors. In the previous reported methods, the supply voltage unbalance was the major difficulty, and this was solved mostly based on the sequence component impedance or current which are difficult to implement. Some other methods essentially are included in the offline methods. The proposed method is based on the motor current signature analysis and utilizes three phase current spectra to overcome the mentioned problem. Simulation results indicate that under healthy conditions, the rotor slot harmonics have the same magnitude in three phase currents, while under even 1 turn (0.3%) short circuit condition they differ from each other. Although the magnitude of these harmonics depends on the level of unbalanced voltage, they have the same magnitude in three phases in these conditions. Experiments performed under various load, fault, and supply voltage conditions validate the simulation results and demonstrate the effectiveness of the proposed technique. It is shown that the detection of resistive slight short circuits, without sensitivity to supply voltage unbalance is possible. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Modelling of rotor speed transient with shaft-to-stator contact

    International Nuclear Information System (INIS)

    Roques, S.

    2007-12-01

    This research thesis first reports the development of a one-dimensional model of a rotor where variables to be computed are the displacements of a beam in a three-dimensional space, and the rotor angular position. After a description of the industrial context (the turbo-alternator group which transforms the thermal energy into electrical energy within the secondary circuit of a nuclear plant), and starting with an energy formulation, the rotor movement equations are established for a speed transient. The second part deals with the contact mechanics and the time resolution of a rotor-stator interaction problem. Contactless speed transients on rotor simple models are then presented, where the equation enables the calculation of the shaft rotational speed. The author then explores interaction cases. The reliability of results is assessed by studying their evolution with respect to the time step. The convergence of different interesting quantities such as the rotor rotational speed, shaft line displacements, and stresses (bearings and contact) is shown

  16. Investigation on the Flow in a Rotor-Stator Cavity with Centripetal Through-Flow

    Directory of Open Access Journals (Sweden)

    Bo Hu

    2017-10-01

    Full Text Available Daily and Nece distinguished four flow regimes in an enclosed rotor-stator cavity, which are dependent on the circumferential Reynolds number and dimensionless axial gap width. A diagram of the different flow regimes including the respective mean profiles for both tangential and radial velocity was developed. The coefficients for the different flow regimes have also been correlated. In centrifugal pumps and turbines, the centripetal through-flow is quite common from the outer radius of the impeller to the impeller eye, which has a strong influence on the radial pressure distribution, axial thrust and frictional torque. The influence of the centripetal through-flow on the cavity flow with different circumferential Reynolds numbers and dimensionless axial gap width is not sufficiently investigated. It is also quite important to convert the 2D Daily and Nece diagram into 3D by introducing the through-flow coefficient. In order to investigate the impact of the centripetal through-flow, a test rig is designed and built up at the University of Duisburg-Essen. The design of the test rig is described. The impact of the above mentioned parameters on the velocity profile, pressure distribution, axial thrust and frictional torque are presented and analyzed in this paper. The 3D Daily and Nece diagram introducing the through-flow coefficient is also organized in this paper.

  17. The impact of inlet angle and outlet angle of guide vane on pump in reversal based hydraulic turbine performance

    International Nuclear Information System (INIS)

    Shi, F X; Yang, J H; Wang, X H; Zhang, R H; Li, C E

    2012-01-01

    In this paper, in order to research the impact of inlet angle and outlet angle of guide vane on hydraulic turbine performance, a centrifugal pump in reversal is adopted as turbine. A numerical simulation method is adopted for researching outer performance and flow field of turbine. The results show: inlet angle has a crucial role to turbine, to the same flow, there is a noticeable decline for the efficiency and head of turbine with the inlet angle increases. At the best efficiency point(EFP),to a same inlet angle, when the inlet angle greater than inlet angle, velocity circulation in guide vane outlet decreases, which lead the efficiency of turbine to reduce, Contrarily, the efficiency rises. With the increase of inlet angle and outlet angle, the EFP moves to the big flow area and the uniformity of pressure distribution becomes worse. The paper indicates that the inlet angle and outlet angle have great impact on the turbine performance, and the best combination exists for the inlet angle and outlet angle of the guide vane.

  18. Structure and Sound Absorption Properties of Spiral Vane Electrospun PVA/PEO Nanofiber Membranes

    Directory of Open Access Journals (Sweden)

    Huan Liu

    2018-02-01

    Full Text Available Noise pollution has become one of the four major pollution issues in the world and has drawn much attention recently. Controlling the sound source and using sound-absorbing materials reasonably is considered an effective way to reduce noise. Due to the high porosity and specific surface area, nanofibers membrane is widely used in the field of the sound absorption. Polyvinyl alcohol (PVA and Polyethylene oxide (PEO are both water-soluble polymers with good film-forming properties that can be mixed in any proportion. In this paper, nanofiber membranes were prepared by spiral vane electrospinning with different contents of PVA and PEO. The nanofibers membranes were characterized by Fourier Transform-Infrared (FT-IR, X-ray diffraction (XRD, 3D-M, and scanning electron microscopy (SEM. The sound absorption property of nanofibers membranes and the compositions (nanofiber membranes and needle punched non-woven fabric were tested with an impedance tube. The results demonstrate that the addition of PEO changed the morphological characteristics and construct of PVA, sound absorption properties had undergone great changes.

  19. Computational prediction of heat transfer to gas turbine nozzle guide vanes with roughened surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Guo, S.M.; Jones, T.V. [Univ. of Oxford (United Kingdom). Dept. of Engineering Science; Lock, G.D. [Univ. of Bath (United Kingdom). Dept. of Mechanical Engineering; Dancer, S.N. [Rolls-Royce PLC, Derby (United Kingdom)

    1998-04-01

    The local Mach number and heat transfer coefficient over the aerofoil surfaces and endwalls of a transonic gas turbine nozzle guide vane have been calculated. the computations were performed by solving the time-averaged Navier-Stokes equations using a fully three-dimensional computational code (CFDS), which is well established at Rolls-Royce. A model to predict the effects of roughness has been incorporated into CFDS and heat transfer levels have been calculated for both hydraulically smooth and transitionally rough surfaces. The roughness influences the calculations in two ways; first the mixing length at a certain height above the surface is increased; second the wall function used to reconcile the wall condition with the first grid point above the wall is also altered. The first involves a relatively straightforward shift of the origin in the van Driest damping function description, the second requires an integration of the momentum equation across the wall layer. A similar treatment applies to the energy equation. The calculations are compared with experimental contours of heat transfer coefficient obtained using both thin-film gages and the transient liquid crystal technique. Measurements were performed using both hydraulically smooth and roughened surfaces, and at engine-representative Mach and Reynolds numbers. The heat transfer results are discussed and interpreted in terms of surface-shear flow visualization using oil and dye techniques.

  20. Three-dimensional laser anemometer measurements in a linear turbine vane cascade

    Science.gov (United States)

    Zimmerman, D. R.

    Laser anemometer (LDA) measurements are presented which were made in a transparent test-section containing a linear cascade of four C3X turbine vanes. The velocity components corresponding to the 'axial' and 'circumferential' components were measured with the 0.4880 (blue) and 0.4765 micrometer (violet) wavelengths from an argon-ion laser. The blue and violet beams were transmitted through the transparent sidewalls. The 'radial' velocity component was measured with the 0.5145 micrometer (green) wavelength from the same laser. The green beams, aimed downstream through the inlet, were brought into position with a fiber optic cable and an optical train identical to the blue and violet optics. The three-color, six-beam, mutually-orthogonal LDA was brought to a common focal point. The optics were fixed in space and the test section was mounted on a milling machine. The data acquisition by three photomultipliers and three frequency counters was controlled by a coincidence timer and a microcomputer.

  1. Numerical Study of Compact Plate-Fin Heat Exchanger for Rotary-Vane Gas Refrigeration Machine

    Directory of Open Access Journals (Sweden)

    V. V. Trandafilov

    2017-10-01

    Full Text Available Plate-fin heat exchangers are widely used in refrigeration technique. They are popular because of their compactness and excellent heat transfer performance. Here we present a numerical model for the development, research and optimization of a plate-fin heat exchanger for a rotary-vane gas refrigeration machine. The method of analysis by graphic method of plate - fin heat exchanger is proposed. The model describes the effects of secondary parameters such as axial thermal conductivity through a metal matrix of the heat exchanger. The influence of geometric parameters and heat transfer coefficient is studied. Graphs of dependences of length, efficiency of a fin and pressure drop in a heat exchanger on the thickness of the fin and the number of fins per meter are obtained. To analyze the results of numerical simulation, the heat exchanger was designed in the Aspen HYSYS program. The simulation results show that the total deviation from the proposed numerical model is not more than 15%. 

  2. Film cooling modeling of a turbine vane with multiple configurations of holes

    Directory of Open Access Journals (Sweden)

    J.H. Liu

    2018-03-01

    Full Text Available Film cooling flow is important for gas turbine thermal protection. But it is difficult to predict the film cooling flow performances. The aim of this paper is to modeling the film cooling flow of a turbine vane with endwall film cooling, showerhead film cooling, and pressure/suction side film cooling simultaneously. Developing a method by adding endwall film cooling domain, the endwall film cooling flow can be simulated by CFD. This method can include heat transfer between flow and solid and capture the coolant details in the entering tubes. The conjugate heat transfer (CHT method was utilized for fluid-solid thermal transfer at interfaces. The results show that the highest film overall effectiveness occurred immediately downstream the holes. The distribution of overall effectiveness is relatively homogenous in the zones between holes row in the leading edge no matter considering solid conduction. Without solid thermal transfer, better lateral coverage downstream the holes can form due to higher density ratio. The overall effectiveness and temperature field are affected by solid conduction, but the aerodynamic performance keeps consistent. Single row of holes in endwall cannot form good coverage in the lateral direction, but the showerhead film cooling configuration can form a preferable coverage layer.

  3. A Study of Performance Output of a Multivane Air Engine Applying Optimal Injection and Vane Angles

    Directory of Open Access Journals (Sweden)

    Bharat Raj Singh

    2012-01-01

    Full Text Available This paper presents a new concept of the air engine using compressed air as the potential power source for motorbikes, in place of an internal combustion engine. The motorbike is proposed to be equipped with an air engine, which transforms the energy of the compressed air into mechanical motion energy. A mathematical model is presented here, and performance evaluation is carried out on an air-powered novel air turbine engine. The maximum power output is obtained as 3.977 kW (5.50 HP at the different rotor to casing diameter ratios, optimal injection angle 60°, vane angle 45° for linear expansion (i.e., at minimum air consumption when the casing diameter is kept 100 mm, at injection pressure 6 bar (90 psi and speed of rotation 2500 rpm. A prototype air engine is built and tested in the laboratory. The experimental results are also seen much closer to the analytical values, and the performance efficiencies are recorded around 70% to 95% at the speed of rotation 2500–3000 rpm.

  4. Effects of Radial Gap Ratio between Impeller and Vaned Diffuser on Performance of Centrifugal Compressors

    Directory of Open Access Journals (Sweden)

    Mohammadjavad Hosseini

    2017-07-01

    Full Text Available A high-performance centrifugal compressor is needed for numerous industry applications nowadays. The radial gap ratio between the impeller and the diffuser vanes plays an important role in the improvement of the compressor performance. In this paper, the effects of the radial gap ratio on a high-pressure ratio centrifugal compressor are investigated using numerical simulations. The performance and the flow field are compared for six different radial gap ratios and five rotational speeds. The minimal radial gap ratio was 1.04 and the maximal was 1.14. Results showed that reducing the radial gap ratio decreases the choke mass flow rate. For the tip-speed Mach number (impeller inlet with Mu < 1, the pressure recovery and the loss coefficients are not sensitive to the radial gap ratio. However, for Mu ≥ 1, the best radial gap ratio is 1.08 for the pressure recovery and the loss coefficients. Furthermore, the impeller pressure ratio and efficiency are reduced by increasing the radial gap ratio. Finally, the compressor efficiency was compared for different radial gap ratios. For Mu < 1, the radial gap ratio does not have noticeable effects. In comparison, the radial gap ratio of 1.08 has the best performance for Mu ≥ 1.

  5. Development of repair mechanism of FSX-414 based 1st stage nozzle of gas turbine

    Science.gov (United States)

    Rahman, Md. Tawfiqur

    2017-06-01

    This paper describes the failure mechanism and repair technology of 1st stage nozzle or vane of industrial gas turbine which is made of cobalt based super alloy FSX-414. 1st stage nozzles or vanes are important stationery components of gas turbine based power plant. Those are the parts of hot gas path components of gas turbine and their manufacturing process is casting. At present, it is widely accepted that gas turbine based combined cycle power plant is the most efficient and cost effective solution to generate electricity. One of the factors of high efficiency of this type of gas turbine is the increase of its turbine inlet temperature. As an effect of this factor and in conjunction with some other factors, the 1st stage nozzle of gas turbine operates under extremely high temperature and thermal stresses. As a result, the design lifetime of these components becomes limited. Furthermore, attention on nozzles or vanes is required in order to achieve their design lifetime. However, due to unfriendly operational condition and environmental effect, anytime failure can occur on these heat resistant alloy based components which may lead to severe damage of gas turbine. To mitigate these adverse effects, schedule maintenance is performed on a predetermined time interval of hot gas path components of gas turbine based power plant. This paper addresses common failures in gas turbine's 1st stage nozzles or vanes. Usually these are repaired by using ADH process but for several reasons ADH process is not used here. Hence the challenging task is performed using gas tungsten arc welding which is presented in this article systematically.

  6. Switching EKF technique for rotor and stator resistance estimation in speed sensorless control of IMs

    Energy Technology Data Exchange (ETDEWEB)

    Barut, Murat; Bogosyan, Seta [University of Alaska Fairbanks, Department of Electrical and Computer Engineering, Fairbanks, AK 99775 (United States); Gokasan, Metin [Istanbul Technical University, Electrical and Electronic Engineering Faculty, 34390 Istanbul (Turkey)

    2007-12-15

    High performance speed sensorless control of induction motors (IMs) calls for estimation and control schemes that offer solutions to parameter uncertainties as well as to difficulties involved with accurate flux/velocity estimation at very low and zero speed. In this study, a new EKF based estimation algorithm is proposed for the solution of both problems and is applied in combination with speed sensorless direct vector control (DVC). The technique is based on the consecutive execution of two EKF algorithms, by switching from one algorithm to another at every n sampling periods. The number of sampling periods, n, is determined based on the desired system performance. The switching EKF approach, thus applied, provides an accurate estimation of an increased number of parameters than would be possible with a single EKF algorithm. The simultaneous and accurate estimation of rotor, R{sub r}{sup '} and stator, R{sub s} resistances, both in the transient and steady state, is an important challenge in speed sensorless IM control and reported studies achieving satisfactory results are few, if any. With the proposed technique in this study, the sensorless estimation of R{sub r}{sup '} and R{sub s} is achieved in transient and steady state and in both high and low speed operation while also estimating the unknown load torque, velocity, flux and current components. The performance demonstrated by the simulation results at zero speed, as well as at low and high speed operation is very promising when compared with individual EKF algorithms performing either R{sub r}{sup '} or R{sub s} estimation or with the few other approaches taken in past studies, which require either signal injection and/or a change of algorithms based on the speed range. The results also motivate utilization of the technique for multiple parameter estimation in a variety of control methods. (author)

  7. Experimental investigation of the microscale rotor-stator cavity flow with rotating superhydrophobic surface

    Science.gov (United States)

    Wang, Chunze; Tang, Fei; Li, Qi; Wang, Xiaohao

    2018-03-01

    The flow characteristics of microscale rotor-stator cavity flow and the drag reduction mechanism of the superhydrophobic surface with high shearing stress were investigated. A microscale rotating flow testing system was established based on micro particle image velocimetry (micro-PIV), and the flow distribution under different Reynolds numbers (7.02 × 103 ≤ Re ≤ 3.51 × 104) and cavity aspect ratios (0.013 ≤ G ≤ 0.04) was measured. Experiments show that, for circumferential velocity, the flow field distributes linearly in rotating Couette flow in the case of low Reynolds number along the z-axis, while the boundary layer separates and forms Batchelor flow as the Reynolds number increases. The separation of the boundary layer is accelerated with the increase of cavity aspect ratio. The radial velocities distribute in an S-shape along the z-axis. As the Reynolds number and cavity aspect ratio increase, the maximum value of radial velocity increases, but the extremum position at rotating boundary remains at Z* = 0.85 with no obvious change, while the extremum position at the stationary boundary changes along the z-axis. The model for the generation of flow disturbance and the transmission process from the stationary to the rotating boundary was given by perturbation analysis. Under the action of superhydrophobic surface, velocity slip occurs near the rotating boundary and the shearing stress reduces, which leads to a maximum drag reduction over 51.4%. The contours of vortex swirling strength suggest that the superhydrophobic surface can suppress the vortex swirling strength and repel the vortex structures, resulting in the decrease of shearing Reynolds stress and then drag reduction.

  8. LES Investigation of Wake Development in a Transonic Fan Stage for Aeroacoustic Analysis

    Science.gov (United States)

    Hah, Chunill; Romeo, Michael

    2017-01-01

    Detailed development of the rotor wake and its interaction with the stator are investigated with a large eddy simulation (LES). Typical steady and unsteady Navier-Stokes approaches (RANS and URANS) do not calculate wake development accurately and do not provide all the necessary information for an aeroacoustic analysis. It is generally believed that higher fidelity analysis tools are required for an aeroacoustic investigation of transonic fan stages.

  9. T2-weighted liver MRI using the multiVane technique at 3T: Comparison with conventional T2-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyung A [Dept. of Radiology, Myongji Hospital, Seonam University College of Medicine, Goyang (Korea, Republic of); Kim, Young Kon; Jeong, Woo Kyoung; Choi, Dong Il; Lee, Won Jae [Dept. of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Eun Ju [Philips Healthcare Korea, Philips, Seoul (Korea, Republic of); Jung, Sin Ho; Baek, Sun Young [Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul (Korea, Republic of)

    2015-10-15

    To assess the value of applying MultiVane to liver T2-weighted imaging (T2WI) compared with conventional T2WIs with emphasis on detection of focal liver lesions. Seventy-eight patients (43 men and 35 women) with 86 hepatic lesions and 20 pancreatico-biliary diseases underwent MRI including T2WIs acquired using breath-hold (BH), respiratory-triggered (RT), and MultiVane technique at 3T. Two reviewers evaluated each T2WI with respect to artefacts, organ sharpness, and conspicuity of intrahepatic vessels, hilar duct, and main lesion using five-point scales, and made pairwise comparisons between T2WI sequences for these categories. Diagnostic accuracy (Az) and sensitivity for hepatic lesion detection were evaluated using alternative free-response receiver operating characteristic analysis. MultiVane T2WI was significantly better than BH-T2WI or RT-T2WI for organ sharpness and conspicuity of intrahepatic vessels and main lesion in both separate reviews and pairwise comparisons (p < 0.001). With regard to motion artefacts, MultiVane T2WI or BH-T2WI was better than RT-T2WI (p < 0.001). Conspicuity of hilar duct was better with BH-T2WI than with MultiVane T2WI (p = 0.030) or RT-T2WI (p < 0.001). For detection of 86 hepatic lesions, sensitivity (mean, 97.7%) of MultiVane T2WI was significantly higher than that of BH-T2WI (mean, 89.5%) (p = 0.008) or RT-T2WI (mean, 84.9%) (p = 0.001). Applying the MultiVane technique to T2WI of the liver is a promising approach to improving image quality that results in increased detection of focal liver lesions compared with conventional T2WI.

  10. Magnetic characterization of the stator core of a high-speed motor made of an ultrathin electrical steel sheet using the magnetic property evaluation system

    Science.gov (United States)

    Oka, Mohachiro; Enokizono, Masato; Mori, Yuji; Yamazaki, Kazumasa

    2018-04-01

    Recently, the application areas for electric motors have been expanding. For instance, electric motors are used in new technologies such as rovers, drones, cars, and robots. The motor used in such machinery should be small, high-powered, highly-efficient, and high-speed. In such motors, loss at high-speed rotation must be especially minimal. Eddy-current loss in the stator core is known to increase greatly during loss at high-speed rotation of the motor. To produce an efficient high-speed motor, we are developing a stator core for a motor using an ultrathin electrical steel sheet with only a small amount of eddy-current loss. Furthermore, the magnetic property evaluation for efficient, high-speed motor stator cores that use conventional commercial frequency is insufficient. Thus, we made a new high-speed magnetic property evaluation system to evaluate the magnetic properties of the efficient high-speed motor stator core. This system was composed of high-speed A/D converters, D/A converters, and a high-speed power amplifier. In experiments, the ultrathin electrical steel sheet dramatically suppressed iron loss and, in particular, eddy-current loss. In addition, a new high-speed magnetic property evaluation system accurately evaluated the magnetic properties of the efficient high-speed motor stator core.

  11. Aerodynamic and Performance Behavior of a Three-Stage High Efficiency Turbine at Design and Off-Design Operating Points

    Directory of Open Access Journals (Sweden)

    M. T. Schobeiri

    2004-01-01

    Full Text Available This article deals with the aerodynamic and performance behavior of a three-stage high pressure research turbine with 3-D curved blades at its design and off-design operating points. The research turbine configuration incorporates six rows beginning with a stator row. Interstage aerodynamic measurements were performed at three stations, namely downstream of the first rotor row, the second stator row, and the second rotor row. Interstage radial and circumferential traversing presented a detailed flow picture of the middle stage. Performance measurements were carried out within a rotational speed range of 75% to 116% of the design speed. The experimental investigations have been carried out on the recently established multi-stage turbine research facility at the Turbomachinery Performance and Flow Research Laboratory, TPFL, of Texas A&M University.

  12. Large scale motions of multiple limit-cycle high Reynolds number annular and toroidal rotor/stator cavities

    Science.gov (United States)

    Bridel-Bertomeu, Thibault; Gicquel, L. Y. M.; Staffelbach, G.

    2017-06-01

    Rotating cavity flows are essential components of industrial applications but their dynamics are still not fully understood when it comes to the relation between the fluid organization and monitored pressure fluctuations. From computer hard-drives to turbo-pumps of space launchers, designed devices often produce flow oscillations that can either destroy the component prematurely or produce too much noise. In such a context, large scale dynamics of high Reynolds number rotor/stator cavities need better understanding especially at the flow limit-cycle or associated statistically stationary state. In particular, the influence of curvature as well as cavity aspect ratio on the large scale organization and flow stability at a fixed rotating disc Reynolds number is fundamental. To probe such flows, wall-resolved large eddy simulation is applied to two different rotor/stator cylindrical cavities and one annular cavity. Validation of the predictions proves the method to be suited and to capture the disc boundary layer patterns reported in the literature. It is then shown that in complement to these disc boundary layer analyses, at the limit-cycle the rotating flows exhibit characteristic patterns at mid-height in the homogeneous core pointing the importance of large scale features. Indeed, dynamic modal decomposition reveals that the entire flow dynamics are driven by only a handful of atomic modes whose combination links the oscillatory patterns observed in the boundary layers as well as in the core of the cavity. These fluctuations form macro-structures, born in the unstable stator boundary layer and extending through the homogeneous inviscid core to the rotating disc boundary layer, causing its instability under some conditions. More importantly, the macro-structures significantly differ depending on the configuration pointing the need for deeper understanding of the influence of geometrical parameters as well as operating conditions.

  13. Heat transfer and flow region characteristics study in a non-annular channel between rotor and stator

    Directory of Open Access Journals (Sweden)

    Nili-Ahmadabadi M.

    2012-01-01

    Full Text Available This paper will present the results of the experimental investigation of heat transfer in a non-annular channel between rotor and stator similar to a real generator. Numerous experiments and numerical studies have examined flow and heat transfer characteristics of a fluid in an annulus with a rotating inner cylinder. In the current study, turbulent flow region and heat transfer characteristics have been studied in the air gap between the rotor and stator of a generator. The test rig has been built in a way which shows a very good agreement with the geometry of a real generator. The boundary condition supplies a non-homogenous heat flux through the passing air channel. The experimental devices and data acquisition method are carefully described in the paper. Surface-mounted thermocouples are located on the both stator and rotor surfaces and one slip ring transfers the collected temperature from rotor to the instrument display. The rotational speed of rotor is fixed at three under: 300rpm, 900 rpm and 1500 rpm. Based on these speeds and hydraulic diameter of the air gap, the Reynolds number has been considered in the range: 4000

  14. A Method to Transit the Rotor-to-Stator Rubbing to Normal Motion Using the Phase Characteristic

    Directory of Open Access Journals (Sweden)

    Jieqiong Xu

    2014-01-01

    Full Text Available A method is proposed to transit the rotor-to-stator rubbing to no-rub motion through active auxiliary bearing. The key point of this technique is to express the attractive domain of no-rub motion based on the phase characteristic and to represent the desired status. The feedback actuation is applied by an active auxiliary bearing to drive the rotor approaching the desired status. After that, the control actuation is turned off. Although the desired status is still in rubbing, it is in the attractive domain of no-rub motion, and the response of the rotor is automatically attracted to no-rub motion.

  15. The physical phenomena associated with stator winding insulation condition as detected by the ramped direct high-voltage method

    Science.gov (United States)

    Rux, Lorelynn Mary

    Deregulation of the electric utility industry has increased the need to monitor the state of powerplant equipment, such as critical generators and motors, to improve availability and reduce life cycle costs via condition-based maintenance. To achieve these goals, nondestructive condition assessment and diagnostic tests are necessary to evaluate the quality and condition of a machine's stator winding insulation system. Periodic tests are generally conducted to monitor insulation aging, diagnose problems, or provide some assurance that the winding has a minimum level of electrical strength. The basic principles of insulation testing are presented herein, and the physical mechanisms that affect the current versus voltage response are described. A stator winding insulation model was developed based on this theoretical foundation for use in understanding and analyzing the macroscopic behavior of complex insulation phenomena. A comprehensive, controlled laboratory experiment was conducted on a set of stator coils that were deliberately manufactured with and without insulation defects. Specific defects were chosen to represent the types of insulation problems typically encountered during manufacture or as a result of in-service aging, and included lack of resin cure, loosely-applied insulating tapes, internal conductive contamination, reduced density of the groundwall insulation, and thermal cycling damage. Results are presented from a series of electrical tests conducted on the coil specimens to compare the effectiveness of various test methods in detecting the different insulation problems. The tests included insulation resistance, polarization index, ramped direct voltage, dissipation factor, dielectric spectroscopy, partial discharge, and recovery voltage measurements. Dielectric principles and testing experience obtained during this investigation were applied to a collection of test results obtained by the author from in-service machines during the past ten years

  16. Parameters required to maximize a thermoset hydro-generator stator winding life; Part 1: Design, manufacture, installation

    Energy Technology Data Exchange (ETDEWEB)

    Lyles, J.F.; Goodeve, T.E.; Sedding, H.

    1994-09-01

    This paper and companion paper, Part 2 describe the parameters required for a thermoset hydro-generator stator winding to achieve a service life of 50 years. Such parameters covering design, manufacture, installation, on-line monitoring and maintenance functions have been found to be relevant based on 36 years of design and operation experience. The database includes North American, European and Far Eastern hydro generators up to 20.5 kV-500 MVA. Parameters covered can be simply stated as Design, Manufacture and Installation: the DIM rule. A companion paper, Part 2 covers Monitoring and Maintenance: which leads to the DIM rule.

  17. A geometric approach for fault detection and isolation of stator short circuit failure in a single asynchronous machine

    KAUST Repository

    Khelouat, Samir

    2012-06-01

    This paper deals with the problem of detection and isolation of stator short-circuit failure in a single asynchronous machine using a geometric approach. After recalling the basis of the geometric approach for fault detection and isolation in nonlinear systems, we will study some structural properties which are fault detectability and isolation fault filter existence. We will then design filters for residual generation. We will consider two approaches: a two-filters structure and a single filter structure, both aiming at generating residuals which are sensitive to one fault and insensitive to the other faults. Some numerical tests will be presented to illustrate the efficiency of the method.

  18. Modeling and control of a novel dual-stator brushless doubly-fed wind power generation system

    DEFF Research Database (Denmark)

    Cheng, Ming; Wei, Xinchi; Han, Peng

    2014-01-01

    A novel dual-stator brushless doubly-fed induction generator-based wind power generation system (DSBDFIG-WPGS), with the merits of reduced converter scale, compact structure and high reliability, is proposed in this paper. System topology, operational principle and power flow of the DSBDFIG......-WPGS are analyzed. Based on the modelling of the system, a vector control scheme is proposed to realize decoupled control of the reactive power and the speed. Furthermore, a speed based maximum power point tracking method is adopted in the system. The simulation results demonstrate stable operation of the DSBDFIG...

  19. Two-Stage Fan I: Aerodynamic and Mechanical Design

    Science.gov (United States)

    Messenger, H. E.; Kennedy, E. E.

    1972-01-01

    A two-stage, highly-loaded fan was designed to deliver an overall pressure ratio of 2.8 with an adiabatic efficiency of 83.9 percent. At the first rotor inlet, design flow per unit annulus area is 42 lbm/sec/sq ft (205 kg/sec/sq m), hub/tip ratio is 0.4 with a tip diameter of 31 inches (0.787 m), and design tip speed is 1450 ft/sec (441.96 m/sec). Other features include use of multiple-circular-arc airfoils, resettable stators, and split casings over the rotor tip sections for casing treatment tests.

  20. Analysis of the macroscopic mechanisms produced by rotor/stator interactions in turbomachinery; Analyse des mecanismes macroscopiques produits par les interactions rotot/stator dans les turbomachines

    Energy Technology Data Exchange (ETDEWEB)

    Callot, St.

    2002-01-15

    Unsteady phenomena produced by the relative motion between fixed and moving rows in turbomachinery is characterized by different scales in space and time. From the numerical point of view, taking into account those effects requires new models. The purpose of this work is a better understanding of the unsteady mechanisms in a multistage turbomachinery. In order to cast of any restricting hypothesis over the spatial periodicities, numerical simulations are operated over the whole circumference of each row. In the single stage case, it is shown that the unsteady flow presents a phase-lagged periodic condition which may be described by the double Fourier decomposition proposed by Tyler and Sofrin. The spatial modes precise the interaction between rows and a comparison is made with the Adamczyk's decomposition. The numerical simulation of a one and a half stage brings an extension of the analysis of the interactions in a multistage machine. (author)

  1. The VanE operon in Enterococcus faecalis N00-410 is found on a putative integrative and conjugative element, Tn6202.

    Science.gov (United States)

    Boyd, D A; Mulvey, M R

    2013-02-01

    To date no complete genetic structure of acquired DNA harbouring a d-Ala-d-Ser operon in an Enterococcus is known. We wished to characterize the acquired DNA harbouring the vanE operon located in the Enterococcus faecalis N00-410 chromosome. Whole genome sequencing of E. faecalis N00-410 was conducted by massively parallel sequencing. Two sequence contigs harbouring the vanE region were linked by PCR and the acquired DNA harbouring the vanE operon was completely characterized. Excision/integration of the region was determined by PCR and transfer attempted by conjugation. The regions flanking the vanE operon were analysed and a total of 42 open reading frames were identified in a region flanked by inverted terminal and direct repeats (Tn6202). Tn6202 could be excised from the chromosome, circularized and the target site rejoined, but transfer could not be demonstrated. The vanE operon was found on the putative integrative and conjugative element Tn6202 in the E. faecalis N00-410 chromosome. This represents the first characterization of acquired DNA harbouring a D-Ala-D-Ser operon.

  2. Influence of the rotor-stator interaction on the dynamic stresses of Francis runners

    International Nuclear Information System (INIS)

    Guillaume, R; Scolaro, D; Deniau, J L; Colombet, C

    2012-01-01

    Thanks to advances in computing capabilities and Computational Fluid Dynamics (CFD) techniques, it is now possible to calculate realistic unsteady pressure fields in Francis turbines. This paper will explain methods to calculate the structural loads and the dynamic behaviour in order to optimize the turbine design and maximize its reliability and lifetime. Depending on the operating conditions of a Francis turbine, different hydraulic phenomena may impact the mechanical behaviour of the structure. According to their nature, these highly variable phenomena should be treated differently and specifically in order to estimate the potential risks arising on submerged structures, in particular the runner. The operating condition studied thereafter is the point at maximum power with the maximum head. Under this condition, the runner is excited by only one dynamic phenomenon named the Rotor-Stator Interaction (RSI). The origin of the phenomenon is located on the radial gap of the turbine and is the source of pressure fluctuations. A fluid-structure analysis is performed to observe the influence of that dynamic pressure field on the runner behaviour. The first part of the paper deals with the unsteady fluid computation. The RSI phenomenon is totally unsteady so the fluid simulation must take into account the entire machine and its rotation movement, in order to obtain a dynamic pressure field. In the second part of the paper, a method suitable for the RSI study is developed. It is known that the fluctuating pressure in this gap can be described as a sum of spatial components. By evaluating these components in the CFD results and on the scale model, it is possible to assess the relevance of the numerical results on the whole runner. After this step, the numerical pressure field can be used as the dynamic load of the structure. The final part of the paper presentsthe mechanical finite element calculations. A modal analysis of the runner in water and a harmonic analysis of its

  3. The impact of different stator and rotor slot number combinations on iron losses of a three-phase induction motor at no-load

    International Nuclear Information System (INIS)

    Marcic, T.; Stumberger, B.; Stumberger, G.; Hadziselimovic, M.; Zagradisnik, I.

    2008-01-01

    The electromechanical characteristics of induction motors depend on the used stator and rotor slot combination. The correlation between the usage of different stator and rotor slot number combinations, magnetic flux density distributions, no-load iron losses and rated load winding over-temperatures for a specific induction motor is presented. The motor's magnetic field was analyzed by traces of the magnetic flux density vector, obtained by FEM. Post-processing of FE magnetic field solution was used for posterior iron loss calculation of the motor iron loss at no-load. The examined motor stator lamination had 36 semi-closed slots and the rotor laminations had 28, 33, 34, 44 and 46 semi-closed slots

  4. Simulative and experimental investigation on stator winding turn and unbalanced supply voltage fault diagnosis in induction motors using Artificial Neural Networks.

    Science.gov (United States)

    Lashkari, Negin; Poshtan, Javad; Azgomi, Hamid Fekri

    2015-11-01

    The three-phase shift between line current and phase voltage of induction motors can be used as an efficient fault indicator to detect and locate inter-turn stator short-circuit (ITSC) fault. However, unbalanced supply voltage is one of the contributing factors that inevitably affect stator currents and therefore the three-phase shift. Thus, it is necessary to propose a method that is able to identify whether the unbalance of three currents is caused by ITSC or supply voltage fault. This paper presents a feedforward multilayer-perceptron Neural Network (NN) trained by back propagation, based on monitoring negative sequence voltage and the three-phase shift. The data which are required for training and test NN are generated using simulated model of stator. The experimental results are presented to verify the superior accuracy of the proposed method. Copyright © 2015. Published by Elsevier Ltd.

  5. Analysis of Three-dimension Viscous Flow in the Model Axial Compressor Stage K1002L

    Science.gov (United States)

    Tribunskaia, K.; Kozhukhov, Y. V.

    2017-08-01

    The main investigation subject considered in this paper is axial compressor model stage K1002L. Three simulation models were designed: Scheme 1 - inlet stage model consisting of IGV (Inlet Guide Vane), rotor and diffuser; Scheme 2 - two-stage model: IGV, first-stage rotor, first-stage diffuser, second-stage rotor, EGV (Exit Guide Vane); Scheme 3 - full-round model: IGV, rotor, diffuser. Numerical investigation of the model stage was held for four circumferential velocities at the outer diameter (Uout=125,160,180,210 m/s) within the range of flow coefficient: ϕ = 0.4 - 0.6. The computational domain was created with ANSYS CFX Workbench. According to simulation results, there were constructed aerodynamic characteristic curves of adiabatic efficiency and the adiabatic head coefficient calculated for total parameters were compared with data from the full-scale test received at the Central Boiler and Turbine Institution (CBTI), thus, verification of the calculated data was carried out. Moreover, there were conducted the following studies: comparison of aerodynamic characteristics of the schemes 1, 2; comparison of the sector and full-round models. The analysis and conclusions are supplemented by gas-dynamic method calculation for axial compressor stages.

  6. Prospects for the domestic production of large-sized cast blades and vanes for industrial gas turbines

    Science.gov (United States)

    Kazanskiy, D. A.; Grin, E. A.; Klimov, A. N.; Berestevich, A. I.

    2017-10-01

    Russian experience in the production of large-sized cast blades and vanes for industrial gas turbines is analyzed for the past decades. It is noted that the production of small- and medium-sized blades and vanes made of Russian alloys using technologies for aviation, marine, and gas-pumping turbines cannot be scaled for industrial gas turbines. It is shown that, in order to provide manufacturability under large-scale casting from domestic nickel alloys, it is necessary to solve complex problems in changing their chemical composition, to develop new casting technologies and to optimize the heat treatment modes. An experience of PAO NPO Saturn in manufacturing the blades and vanes made of ChS88U-VI and IN738-LC foundry nickel alloys for the turbines of the GTE-110 gas turbine unit is considered in detail. Potentialities for achieving adopted target parameters for the mechanical properties of working blades cast from ChS88UM-VI modified alloy are established. For the blades made of IN738-LC alloy manufactured using the existing foundry technology, a complete compliance with the requirements of normative and technical documentation has been established. Currently, in Russia, the basis of the fleet of gas turbine plants is composed by foreign turbines, and, for the implementation of the import substitution program, one can use the positive experience of PAO NPO Saturn in casting blades from IN738-LC alloy based on a reverse engineering technique. A preliminary complex of studies of the original manufacturer's blades should be carried out, involving, first of all, the determination of geometric size using modern measurement methods as well as the studies on the chemical compositions of the used materials (base metal and protective coatings). Further, verifying the constructed calculation models based on the obtained data, one could choose available domestic materials that would meet the operating conditions of the blades according to their heat resistance and corrosion

  7. Extended residence time centrifugal contactor design modification and centrifugal contactor vane plate valving apparatus for extending mixing zone residence time

    Science.gov (United States)

    Wardle, Kent E.

    2017-06-06

    The present invention provides an annular centrifugal contactor, having a housing adapted to receive a plurality of flowing liquids; a rotor on the interior of the housing; an annular mixing zone, wherein the annular mixing zone has a plurality of fluid retention reservoirs with ingress apertures near the bottom of the annular mixing zone and egress apertures located above the ingress apertures of the annular mixing zone; and an adjustable vane plate stem, wherein the stem can be raised to restrict the flow of a liquid into the rotor or lowered to increase the flow of the liquid into the rotor.

  8. Simulink(Trademark) Controller for a Reluctance Motor With a Four-Pole Rotor and 36-Tooth Stator

    Science.gov (United States)

    Morrison, Carlos R.; Provenza, Andrew J.

    2017-01-01

    NASA Glenn Research Center has developed a Simulink(Trademark) controller logic for driving a room temperature, 36-teeth stator, four-pole rotor reluctance motor. The Simulink logic was extracted from an existing C++ motor controller that was previously employed to achieve a rotor speed of 3000 rpm. The Simulink controller has additional logic refinements that were not available in past C++ controller, such as the per rev logic component and its frequency filter. The filter provides a more accurate reading of the rotor input signals. The controller is versatile, and with slight modifications, can be used to drive other reluctance motor types incorporating dissimilar stator rotor pole combinations. The original C++ controller was designed with the goal (after appropriate modification) of controlling a future superconducting motor. This superconducting motor will be employed as a test bed for developing other superconducting aviation propulsion motors envisioned for future turbo-electric aircrafts. The Simulink results presented in this paper were generated from simulated rotor inputs. However, in an actual application, these simulated inputs are to be replaced by actual proximity probe signals emanating from D-Space hardware inputs.

  9. Vibrational spectra of C60C8H8 and C70C8H8 in the rotor-stator and polymer phases

    OpenAIRE

    Klupp, G.; Borondics, F.; Kováts, É.; Pekker, Á.; Bényei, G.; Jalsovszky, I.; Hackl, R.; Pekker, S.; Kamarás, K.

    2007-01-01

    C60-C8H8 and C70-C8H8 are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C60C8H8) and poly(C70C8H8) resulting from a solid state reaction occurring on heating. Based on the spectra we propose a connection pattern for the fullerene in poly(C60C8H8), where the symmetry of the C60 is D2h. On illuminating...

  10. The effect of unsteadiness on the time-mean thermal loads in a turbine stage

    Science.gov (United States)

    Kirtley, K. R.; Celestina, M. L.; Adamczyk, J. J.

    1993-01-01

    Two steady numerical analysis methods and one unsteady method are used to study the viscous three-dimensional flow in the middle stage of the Pratt & Whitney alternate design Space Shuttle Main Engine fuel turbine. The principal characteristic of this flow is that the secondary flows generated in the rotor blade reconfigure a radial inlet total temperature distortion into one with a pitchwise exit hot streak distortion. Secondary flows in the following vane redistribute the radial variation while unsteadiness causes a segregation of hot and cold flow from the hot streak within the vane. Such redistribution and segregation can lead to unexpected thermal loads and reduced durability. The physical phenomena and the ability of a steady analysis to capture them are investigated by performing a numerical experiment whereby the results of the two steady analysis methods are compared to the time-mean of the unsteady simulation. The flow physics related to the segregation and mixing of total temperature are discussed.

  11. Time-averaged aerodynamic loads on the vane sets of the 40- by 80-foot and 80- by 120-foot wind tunnel complex

    Science.gov (United States)

    Aoyagi, Kiyoshi; Olson, Lawrence E.; Peterson, Randall L.; Yamauchi, Gloria K.; Ross, James C.; Norman, Thomas R.

    1987-01-01

    Time-averaged aerodynamic loads are estimated for each of the vane sets in the National Full-Scale Aerodynamic Complex (NFAC). The methods used to compute global and local loads are presented. Experimental inputs used to calculate these loads are based primarily on data obtained from tests conducted in the NFAC 1/10-Scale Vane-Set Test Facility and from tests conducted in the NFAC 1/50-Scale Facility. For those vane sets located directly downstream of either the 40- by 80-ft test section or the 80- by 120-ft test section, aerodynamic loads caused by the impingement of model-generated wake vortices and model-generated jet and propeller wakes are also estimated.

  12. Aerodynamic Performance of a Compact, High Work-Factor Centrifugal Compressor at the Stage and Subcomponent Level

    Science.gov (United States)

    Braunscheidel, Edward P.; Welch, Gerard E.; Skoch, Gary J.; Medic, Gorazd; Sharma, Om P.

    2015-01-01

    The measured aerodynamic performance of a compact, high work-factor, single-stage centrifugal compressor, comprising an impeller, diffuser, 90deg-bend, and exit guide vane is reported. Performance levels are based on steady-state total-pressure and total-temperature rake and angularity-probe data acquired at key machine rating planes during recent testing at NASA Glenn Research Center. Aerodynamic performance at the stage level is reported for operation between 70 to 105 percent of design corrected speed, with subcomponent (impeller, diffuser, and exit-guide-vane) flow field measurements presented and discussed at the 100 percent design-speed condition. Individual component losses from measurements are compared with pre-test CFD predictions on a limited basis.

  13. Stage design

    International Nuclear Information System (INIS)

    Shacter, J.

    1975-01-01

    A method is described of cycling gases through a plurality of diffusion stages comprising the steps of admitting the diffused gases from a first diffusion stage into an axial compressor, simultaneously admitting the undiffused gases from a second diffusion stage into an intermediate pressure zone of said compressor corresponding in pressure to the pressure of said undiffused gases, and then admitting the resulting compressed mixture of diffused and undiffused gases into a third diffusion stage

  14. Influence of guide vane opening on the flow phenomena in a pump turbine during a fast transition from pump mode to generating mode

    Science.gov (United States)

    Stens, C.; Riedelbauch, S.

    2017-04-01

    Due to a more fluctuating energy production caused by renewable energies such as wind and solar power, the number of changes between operating points in pumped storage power plants has increased over the last years. To further increase available regulating power, it is desirable to speed up these changes of operation conditions in Hydro units. Previous studies showed that CFD is well capable of predicting the flow phenomena in the machine under unsteady conditions for a large guide vane opening angle. The present paper investigates the benefits of nearly closed guide vanes during the transition. Results are compared between the two different angles as well as between simulation and measurement.

  15. Effects of Mie tip-vane on pressure distribution of rotor blade and power augmentation of horizontal axis wind turbine; Yokutan shoyoku Mie ben ni yoru suiheijiku fusha yokumenjo no atsuryoku bunpu no kaizen to seino kojo tono kankei

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Y.; Maeda, T.; Kamada, Y. [Mie Univ., Mie (Japan); Seto, H. [Mitsubishi Motors Corp., Tokyo (Japan)

    2000-04-01

    By recent developments of exclusive rotor blade, the efficiency of wind turbine is improved substantially. By measuring pressure on rotor blades of horizontal axis wind turbines rotating in wind tunnels, this report clarified relation between improvement of pressure distribution on main rotor blades by Mie vane and upgrade of wind turbine performance. The results under mentioned have been got by measuring pressure distribution on rotor blades, visualization by tuft, and measuring resistance of Mie vane. (1) The difference of pressure between suction surface and pressure surface on the end of rotor blade increase, and output power of wind turbine improves. (2) Vortex of blade end is inhibited by Mie vane. (3) The reason of reduction on wind turbine performance with Mie vane in aria of high rotating speed ratio is the increase of Mie vane flow resistance.(NEDO)

  16. Influence of omni-directional guide vane on the performance of cross-flow rotor for urban wind energy

    Science.gov (United States)

    Wicaksono, Yoga Arob; Tjahjana, Dominicus Danardono Dwi Prija; Hadi, Syamsul

    2018-02-01

    Vertical axis wind turbine like cross-flow rotor have some advantage there are, high self-starting torque, low noise, and high stability; so, it can be installed in the urban area to produce electricity. But, the urban area has poor wind condition, so the cross-flow rotor needs a guide vane to increase its performance. The aim of this study is to determine experimentally the effect of Omni-Directional Guide Vane (ODGV) on the performance of a cross-flow wind turbine. Wind tunnel experiment has been carried out for various configurations. The ODGV was placed around the cross-flow rotor in order to increase ambient wind environment of the wind turbine. The maximum power coefficient is obtained as Cpmax = 0.125 at 60° wind direction. It was 21.46% higher compared to cross-flow wind turbine without ODGV. This result showed that the ODGV able to increase the performance of the cross-flow wind turbine.

  17. Computational Fluid Dynamics (CFD) Analyses in Support of Space Shuttle Main Engine (SSME) Heat Exchanger (HX) Vane Cracking Investigation

    Science.gov (United States)

    Garcia, Roberto; Benjamin, Theodore G.; Cornelison, J.; Fredmonski, A. J.

    1993-01-01

    Integration issues involved with installing the alternate turbopump (ATP) High Pressure Oxygen Turbopump (HPOTP) into the SSME have raised questions regarding the flow in the HPOTP turnaround duct (TAD). Steady-state Navier-Stokes CFD analyses have been performed by NASA and Pratt & Whitney (P&W) to address these questions. The analyses have consisted of two-dimensional axisymmetric calculations done at Marshall Space Flight Center and three-dimensional calculations performed at P&W. These analyses have identified flowfield differences between the baseline ATP and the Rocketdyne configurations. The results show that the baseline ATP configuration represents a more severe environment to the inner HX guide vane. This vane has limited life when tested in conjunction with the ATP but infinite life when tested with the current SSME HPOTP. The CFD results have helped interpret test results and have been used to assess proposed redesigns. This paper includes details of the axisymmetric model, its results, and its contribution towards resolving the problem.

  18. Numerical Study of the Effects of Thermal Barrier Coating and Turbulence Intensity on Cooling Performances of a Nozzle Guide Vane

    Directory of Open Access Journals (Sweden)

    Prasert Prapamonthon

    2017-03-01

    Full Text Available This work presents a numerical investigation of the combined effects of thermal barrier coating (TBC with mainstream turbulence intensity (Tu on a modified vane of the real film-cooled nozzle guide vane (NGV reported by Timko (NASA CR-168289. Using a 3D conjugate heat transfer (CHT analysis, the NGVs with and without TBC are simulated at three Tus (Tu = 3.3%, 10% and 20%. The overall cooling effectiveness, TBC effectiveness and heat transfer coefficient are analyzed and discussed. The results indicate the following three interesting phenomena: (1 TBC on the pressure side (PS is more effective than that on the suction side (SS due to a fewer number of film holes on the SS; (2 for all three Tus, the variation trends of the overall cooling effectiveness are similar, and TBC plays the positive and negative roles in heat flux at the same time, and significantly increases the overall cooling effectiveness in regions cooled ineffectively by cooling air; (3 when Tu increases, the TBC effect is more significant, for example, at the highest Tu (Tu = 20% the overall cooling effectiveness can increase as much as 24% in the film cooling ineffective regions, but near the trailing edge (TE and the exits and downstream of film holes on the SS, this phenomenon is slight.

  19. Studi Eksperimen Aliran Melalui Square Duct dan Square Elbow 90º dengan Double Guide Vane pada Variasi Sudut Bukaan Damper

    Directory of Open Access Journals (Sweden)

    Andrew Jaya Nazar

    2017-01-01

    Full Text Available Instalasi saluran udara tidak hanya berupa pipa lurus, tetapi juga terdapat fitting/aksesoris perpipaan misalnya elbow 90o dan damper. Aksesoris perpipaan ini berfungsi agar saluran udara dapat terpasang sesuai dengan kebutuhan. Namun, penggunaan aksesoris perpipaan ini menyebabkan bertambahnya pressure drop akibat adanya friction loss dan separation loss. Pemasangan guide vane pada elbow 90o diharapkan dapat mengurangi pressure drop karena dapat mengurangi terjadinya secondary flow, namun hal ini dapat menambah kerugian akibat gaya gesek. Saat ini penghematan energi menjadi sorotan terutama dalam dunia industri. Penurunan pressure drop pada belokan perpipaan sangat diharapkan, agar dapat menghemat energi lebih. Untuk itu perlu dilakukan usaha agar dapat menurunkan pressure drop yang terjadi. Penelitian ini dilakukan secara eksperimen dengan benda uji saluran udara yang terdiri dari: upstream duct (straight duct, square elbow 90o dengan r/Dh=1,5 dan dilengkapi double guide vane, damper, downstream duct (straight duct, dan induced fan. Pengukuran parameter yang dibutuhkan dilakukan dengan menggunakan: pitot tube, inclined manometer, pressure tranducer. Dari eksperimen ini diperoleh bahwa profil kecepatan pada masing-masing variasi sudut bukaan damper sudah mendekati keadaan recovery aliran pada akhir section baik dari bidang vertikal maupun horizontal. Pressure drop yang terjadi semakin naik seiring dengan bertambahnya nilai bilangan Reynolds dan sudut bukaan damper. Nilai konstanta damper semakin naik dari bukaan sudut 0o hingga 30o.

  20. Experimental comparison of the optical measurements of a cross-flow in a rod bundle with mixing vanes

    International Nuclear Information System (INIS)

    Chang, Seok Kyu; Choo, Yeon Jun; Kim, Bok Deuk; Song, Chul Hwa

    2008-01-01

    The lateral crossflow on subchannels in a rod bundle array was investigated to understand the flow characteristics related to the mixing vane types on a spacer grid by using the PIV technique. For more measurement resolutions, a 5x5 rod bundle was fabricated a 2.6 times larger than the real rod bundle size in a pressurized water reactor. A rod-embedded optic array was specially designed and used for the illumination of the inner subchannels. The crossflow field in a subchannel was characterized by the type and the arrangement of the mixing vanes. At a near downstream location from the spacer grid (z/D h =1) in the case of the split type, a couple of small vortices were generated diagonally in a subchannel. On the other hand, in the case of the swirl type, there was a large elliptic vortex generated in the center of a subchannel. The measurement results were compared with the experimental results which had been performed with the LDV technique at the same test facility. The magnitudes of the flow velocity and the vorticity in PIV results were less than those in LDV measurement results. It was shown that the instantaneous flow fields in a subchannel frequently have quite different shapes from the averaged one

  1. Experimental and Finite Element Analysis to Investigate the Vibration of Oblique-Stud Stator Frame in a Large Hydropower Generator Unit

    Directory of Open Access Journals (Sweden)

    Jianzhong Zhou

    2017-12-01

    Full Text Available This paper presents an investigation on the undesirable vibration of an oblique-stud stator frame in a large hydropower generator by means of experimental and finite element (FE analysis. First, field experimental tests were performed, and the results indicate that the main vibration component comes from electromagnetic factors. Then, a 2D-magnetic and 3D-mechanical FE model was developed to investigate the vibration of the stator frame under the action of electromagnetic forces. A set of contrast models was established to study the effects of different kinds of eccentricity and different structures. Based on the comparative analysis between the results of simulations and experimental tests, it can be inferred that the abnormal vibration is generated because of the lack of stiffness in the upper part of structure and the existence of dynamic eccentricity in the rotor–stator system. In addition, the structural simulation analysis shows that the flexible designed oblique-stud stator frame is relatively vulnerable against the electromagnetic forces.

  2. Influence of Stator MMF Harmonics on the Utilization of Reluctance Torque in Six-Phase PMA-SynRM with FSCW

    Directory of Open Access Journals (Sweden)

    Luming Cheng

    2018-01-01

    Full Text Available Although fractional-slot concentrated winding (FSCW offers many significant advantages, such as short end-turn windings, high slot filling factor, and low cogging torque, it is frequently limited by excessive stator magnetomotive force (MMF harmonics which will induce high eddy losses in the permanent magnets (PMs. What is more, in the literature, it can be observed that the reluctance torque of the salient-pole machine with FSCW is usually much lower than that obtained with integral slot winding. To explore the underlying reason why the reluctance torque in a salient machine with FSCW significantly decreases, a new six-phase FSCW with 24 slots and 10 poles, which can significantly reduce the undesirable stator MMF harmonics, is obtained by using the concept of stator shifting. Then, two permanent-magnet-assisted synchronous reluctance machines (PMA-SynRMs with the proposed winding layout and conventional asymmetric 12-slot/10-pole six-phase winding layout are designed and simulated by the finite-element method (FEM. The reluctance torque, total torque, and d/q-axis inductances with different current phase angles are also compared under different loaded conditions. The results show that a reduction in stator MMF harmonics can indeed lead to a significant enhancement in reluctance torque under heavy loaded conditions, while the dominance will diminish under light loaded conditions.

  3. A New Robust Decoupled Control of the Stator Active and Reactive Currents for Grid-Connected Doubly-Fed Induction Generators

    Directory of Open Access Journals (Sweden)

    Ahmad Bashar Ataji

    2016-03-01

    Full Text Available This paper addresses the grid-connected variable speed doubly-fed induction generator, and proposes a new decoupled control to replace the conventional decoupled active and reactive powers (P-Q control. The proposed decoupled control is based on decoupling the stator active and reactive currents, in contrast with the conventional decoupled P-Q control, which is based on decoupling the stator active and reactive powers by forcing the stator d- or q-voltage to zero. The proposed decoupled control has all the advantages of the conventional decoupled P-Q control such as constant switching frequency and robustness against slip angle inaccuracy, and it has some additional advantages: The proposed control requires less machine parameters; for the controller design, it requires the stator-to-rotor turns ratio only; for the online calculation, it does not requires any machine parameter. The proposed decoupled control is more flexible and robust since the control is independent of the grid voltage orientation. It is robust against variation in the grid voltage amplitude. Several experiments are carried out using a 1.1 kW doubly-fed induction generator (DFIG, and the results support the proposed decoupled control and demonstrate some of its advantages.

  4. Investigation of unsteady flow in axial turbine stage

    Directory of Open Access Journals (Sweden)

    Němec Martin

    2012-04-01

    Full Text Available The never ending process to increase the efficiency of turbine stages introduced an idea to create an axial turbine stage test rig as part of closed loop transonic wind tunnel at Vyzkumny a zkusebni letecky ustav (VZLU. Studying of unsteady flow field behaviours in turbine stages is nowadays essential in the development process. Therefore, the test rig was designed with focusing on possibility of detailed studying of unsteady flow fields in turbine stages. New methodologies and new instrumentations were developed at VZLU and successfully integrated to gain valuable information from experiments with turbine stages. Two different turbine stages were tested during the facility introduction process. The measurement of these two models demonstrated how flexible the test rig is. One of them was an enlarged model of small gas turbine stage. The other was scaled-down model of stage of intermediate-pressure steam turbine. The external characteristics of both models were acquired during experiments as well as the detailed unsteady flow field measurement. Turbine stages were tested in various regimes in order to check the capabilities of the facility, methodology and instrumentation together. The paper presents results of unsteady flow field investigation in the enlarged turbine stage with unshrouded rotor. The interaction of structures developed in a stator with the rotor flow field is depicted and the influence of turbine load on evolution of secondary flows in rotor is analysed.

  5. Trading stages

    DEFF Research Database (Denmark)

    Steiner, Uli; Tuljapurkar, Shripad; Coulson, Tim

    2012-01-01

    because they are hard to use and interpret, and tools for age and stage structured populations are missing. We present easily interpretable expressions for the sensitivities and elasticities of life expectancy to vital rates in age-stage models, and illustrate their application with two biological......Interest in stage-and age structured models has recently increased because they can describe quantitative traits such as size that are left out of age-only demography. Available methods for the analysis of effects of vital rates on lifespan in stage-structured models have not been widely applied...... examples. Much of our approach relies on trading of time and mortality risk in one stage for time and risk in others. Our approach contributes to the new framework of the study of age- and stage-structured biodemography....

  6. Dual rotor single- stator axial air gap PMSM motor/generator drive for high torque vehicles applications

    Science.gov (United States)

    Tutelea, L. N.; Deaconu, S. I.; Boldea, I.; Popa, G. N.

    2014-03-01

    The actual e - continuously variable transmission (e-CVT) solution for the parallel Hybrid Electric Vehicle (HEV) requires two electric machines, two inverters, and a planetary gear. A distinct electric generator and a propulsion electric motor, both with full power converters, are typical for a series HEV. In an effort to simplify the planetary-geared e-CVT for the parallel HEV or the series HEV we hereby propose to replace the basically two electric machines and their two power converters by a single, axial-air-gap, electric machine central stator, fed from a single PWM converter with dual frequency voltage output and two independent PM rotors, destined for hybrid electric vehicles (HEV) and military vehicles applications. The proposed topologies and the magneto-motive force analysis are the core of the paper.

  7. Influence of the Applied Working Fluid and the Arrangement of the Steering Edges on Multi-Vane Expander Performance in Micro ORC System

    Directory of Open Access Journals (Sweden)

    Józef Rak

    2018-04-01

    Full Text Available Micro-power domestic organic Rankine cycle (ORC systems are nowadays of great interest. These systems are considered for combined heat and power (CHP generation in domestic and distributed applications. The main issues of ORC systems design is selection of the expander and the working fluid. Thanks to their positive features, multi-vane expanders are especially promising for application in micro-power ORC systems. These expanders are very simple in design, small in dimensions, inexpensive and feature low gas flow capacity and expansion ratio. The application of multi-vane expanders in ORC systems is innovative and currently limited to prototype applications. However, a literature review indicates the growing interest in these machines and the potential for practical implementation. For this reason, it is necessary to conduct detailed studies on the multi-vane expanders operation in ORC systems. In this paper the results of experimental and numerical investigations on the influence of the applied working fluid and the arrangement of the steering edges on multi-vane expander performance in micro ORC system are reported. The experiments were performed using the specially designed lab test-stand, i.e. the domestic ORC system. Numerical simulations were proceeded in ANSYS CFX software (ANSYS, Inc., Canonsburg, PA, USA and were focused on determining the expander performance under various flow conditions of different working fluids. Detailed numerical analysis of the arrangement of the machine steering edges showed existence of optimal mutual position of the inlet and outlet port for which the multi-vane expander achieves maximum internal work and internal efficiency.

  8. Theoretical study on performance characteristics of a variable displacement vane pump according to a variable amount occurrence

    International Nuclear Information System (INIS)

    Oh, J. K.; Moon, H. B.; Cho, H.

    2015-01-01

    Theoretical studies were performed to understand the variation of performance of a variable displacement vane pump with automatic transmission according to the operating conditions and variable parameters. Chamber volume, discharge flow, pressure ripples, and cavitation occurrence were analyzed with variable amounts. The analysis result indicated that the discharge flow rate and pressure ripples increased with a rise of rotational speed, but decreased with variable amount increases. Increase of the oil temperature caused a slight decrease of the discharge flow and the driving torque. Cavitation definitely appeared at low temperatures and high rotational speeds, but it dramatically decreased with variable amount increases. The driving torque increased proportionally with the rotational speed and decreased with oil temperature. The maximum total efficiency was 73.8% at an oil temperature of 80 .deg. C but it decreased by 3.5% at 120 .deg. C.

  9. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...

  10. An improved low-voltage ride-through performance of DFIG based wind plant using stator dynamic composite fault current limiter.

    Science.gov (United States)

    Gayen, P K; Chatterjee, D; Goswami, S K

    2016-05-01

    In this paper, an enhanced low-voltage ride-through (LVRT) performance of a grid connected doubly fed induction generator (DFIG) has been presented with the usage of stator dynamic composite fault current limiter (SDCFCL). This protection circuit comprises of a suitable series resistor-inductor combination and parallel bidirectional semiconductor switch. The SDCFCL facilitates double benefits such as reduction of rotor induced open circuit voltage due to increased value of stator total inductance and concurrent increase of rotor impedance. Both effects will limit rotor circuit over current and over voltage situation more secured way in comparison to the conventional scheme like the dynamic rotor current limiter (RCL) during any type of fault situation. The proposed concept is validated through the simulation study of the grid integrated 2.0MW DFIG. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  11. Vibrational spectra of C60.C8H8 and C70.C8H8 in the rotor-stator and polymer phases.

    Science.gov (United States)

    Klupp, G; Borondics, F; Kováts, E; Pekker, A; Bényei, G; Jalsovszky, I; Hackl, R; Pekker, S; Kamarás, K

    2007-11-01

    C(60).C(8)H(8) and C(70).C(8)H(8) are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C(60)C(8)H(8)) and poly(C(70)C(8)H(8)) resulting from a solid-state reaction occurring on heating. On the basis of the spectra, we propose a connection pattern for the fullerene in poly(C(60)C(8)H(8)), where the symmetry of the C(60) molecule is D(2h). On illuminating the C(60).C(8)H(8) cocrystal with green or blue light, a photochemical reaction was observed leading to a product similar to that of the thermal polymerization.

  12. Development and testing of a 2.5 kW synchronous generator with a high temperature superconducting stator and permanent magnet rotor

    Science.gov (United States)

    Qu, Timing; Song, Peng; Yu, Xiaoyu; Gu, Chen; Li, Longnian; Li, Xiaohang; Wang, Dewen; Hu, Boping; Chen, Duxing; Zeng, Pan; Han, Zhenghe

    2014-04-01

    High temperature superconducting (HTS) armature windings have the potential for increasing the electric loading of a synchronous generator due to their high current transport capacity, which could increase the power density of an HTS rotating machine. In this work, a novel synchronous generator prototype with an HTS stator and permanent magnet rotor has been developed. It has a basic structure of four poles and six slots. The armature winding was constructed from six double-pancake race-track coils with 44 turns each. It was designed to deliver 2.5 kW at 300 rpm. A concentrated winding configuration was proposed, to prevent interference at the ends of adjacent HTS coils. The HTS stator was pressure mounted into a hollow Dewar cooled with liquid nitrogen. The whole stator could be cooled down to around 82 K by conduction cooling. In the preliminary testing, the machine worked properly and could deliver 1.8 kW power when the armature current was 14.4 A. Ic for the HTS coils was found to be suppressed due to the influence of the temperature and the leakage field.

  13. Development and testing of a 2.5 kW synchronous generator with a high temperature superconducting stator and permanent magnet rotor

    International Nuclear Information System (INIS)

    Qu, Timing; Yu, Xiaoyu; Zeng, Pan; Han, Zhenghe; Song, Peng; Gu, Chen; Li, Longnian; Li, Xiaohang; Wang, Dewen; Hu, Boping; Chen, Duxing

    2014-01-01

    High temperature superconducting (HTS) armature windings have the potential for increasing the electric loading of a synchronous generator due to their high current transport capacity, which could increase the power density of an HTS rotating machine. In this work, a novel synchronous generator prototype with an HTS stator and permanent magnet rotor has been developed. It has a basic structure of four poles and six slots. The armature winding was constructed from six double-pancake race-track coils with 44 turns each. It was designed to deliver 2.5 kW at 300 rpm. A concentrated winding configuration was proposed, to prevent interference at the ends of adjacent HTS coils. The HTS stator was pressure mounted into a hollow Dewar cooled with liquid nitrogen. The whole stator could be cooled down to around 82 K by conduction cooling. In the preliminary testing, the machine worked properly and could deliver 1.8 kW power when the armature current was 14.4 A. I c for the HTS coils was found to be suppressed due to the influence of the temperature and the leakage field. (paper)

  14. MotI (DgrA) acts as a molecular clutch on the flagellar stator protein MotA inBacillus subtilis.

    Science.gov (United States)

    Subramanian, Sundharraman; Gao, Xiaohui; Dann, Charles E; Kearns, Daniel B

    2017-12-19

    Stator elements consisting of MotA 4 MotB 2 complexes are anchored to the cell wall, extend through the cell membrane, and interact with FliG in the cytoplasmic C ring rotor of the flagellum. The cytoplasmic loop of MotA undergoes proton-driven conformational changes that drive flagellar rotation. Functional regulators inhibit motility by either disengaging or jamming the stator-rotor interaction. Here we show that the YcgR homolog MotI (formerly DgrA) of Bacillus subtilis inhibits motility like a molecular clutch that disengages MotA. MotI-inhibited flagella rotated freely by Brownian motion, and suppressor mutations in MotA that were immune to MotI inhibition were located two residues downstream of the critical force generation site. The 3D structure of MotI bound to c-di-GMP was solved, and MotI-fluorescent fusions localized as transient MotA-dependent puncta at the membrane when induced at subinhibitory levels. Finally, subinhibitory levels of MotI expression resulted in incomplete inhibition and proportional decreases in swimming speed. We propose a model in which flagellar stators are disengaged and sequestered from the flagellar rotor when bound by MotI.

  15. Diagnosis of Electric Submersible Centrifugal Pump

    Science.gov (United States)

    Kovalchuk, M. S.; Poddubniy, D. A.

    2018-01-01

    The paper deals with the development of system operational diagnostics of electrical submersible pumps (ESP). At the initial stage of studies have explored current methods of the diagnosis of ESP, examined the existing problems of their diagnosis. Resulting identified a number of main standard ESP faults, mechanical faults such as bearing wear, protective sleeves of the shaft and the hubs of guide vanes, misalignment and imbalance of the shafts, which causes the breakdown of the stator bottom or top bases. All this leads to electromagnetic faults: rotor eccentricity, weakening the pressing of steel packs, wire breakage or a short circuit in the stator winding, etc., leading to changes in the consumption current.

  16. Performance Analysis and Comparison of Symmetrical and Asymmetrical Dual Stator Induction Generators for Wind Energy Conversion Systems

    Directory of Open Access Journals (Sweden)

    R. Singh

    2018-02-01

    Full Text Available The emergence of micro/nano level wind generation has opened the research on induction generator (IG topologies having easier and finer control available in multiphase generators. To establish the suitability of multiphase generators for wind generators the analysis of their performance based on the developed model for the same rating of six phase symmetrical (60˚ and asymmetrical (30˚ IGs is presented. A comparative performance evaluation of grid-excited six phase symmetrical and asymmetrical IGs also known as Dual Stator Induction Generators (DSIGs is presented through simulation results in MATLAB/SIMULINK environment amidst load perturbations, limited variation of wind speed and perturbations in voltage and frequency of the non stiff micro-grid to which they are connected. Based on the performance indices like flux of direct and quadrature axis, speed variations, terminal voltage drop/rise, range of operational speed variation etc., a comparative analysis with the help of the results is drawn to establish the suitability of asymmetrical multiphase IGs for grid connected wind generators.

  17. Analytical estimation on divergence and flutter vibrations of symmetrical three-phase induction stator via field-synchronous coordinates

    Science.gov (United States)

    Xia, Ying; Wang, Shiyu; Sun, Wenjia; Xiu, Jie

    2017-01-01

    The electromagnetically induced parametric vibration of the symmetrical three-phase induction stator is examined. While it can be analyzed by an approximate analytical or numerical method, more accurate and simple analytical method is desirable. This work proposes a new method based on the field-synchronous coordinates. A mechanical-electromagnetic coupling model is developed under this frame such that a time-invariant governing equation with gyroscopic term can be developed. With the general vibration theory, the eigenvalue is formulated; the transition curves between the stable and unstable regions, and response are all determined as closed-form expressions of basic mechanical-electromagnetic parameters. The dependence of these parameters on the instability behaviors is demonstrated. The results imply that the divergence and flutter instabilities can occur even for symmetrical motors with balanced, constant amplitude and sinusoidal voltage. To verify the analytical predictions, this work also builds up a time-variant model of the same system under the conventional inertial frame. The Floquét theory is employed to predict the parametric instability and the numerical integration is used to obtain the parametric response. The parametric instability and response are both well compared against those under the field-synchronous coordinates. The proposed field-synchronous coordinates allows a quick estimation on the electromagnetically induced vibration. The convenience offered by the body-fixed coordinates is discussed across various fields.

  18. Simulation of 3-D viscous flow within a multi-stage turbine

    Science.gov (United States)

    Adamczyk, John J.; Celestina, Mark L.; Beach, Tim A.; Barnett, Mark

    1989-01-01

    This work outlines a procedure for simulating the flow field within multistage turbomachinery which includes the effects of unsteadiness, compressibility, and viscosity. The associated modeling equations are the average passage equation system which governs the time-averaged flow field within a typical passage of a blade row embedded within a multistage configuration. The results from a simulation of a low aspect ratio stage and a one-half turbine will be presented and compared with experimental measurements. It will be shown that the secondary flow field generated by the rotor causes the aerodynamic performance of the downstream vane to be significantly different from that of an isolated blade row.

  19. Staging Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    In recent years, the social sciences have taken a “mobilities turn.” There has been a developing realisation that mobilities do not “just happen.” Mobilities are carefully and meticulously designed, planned and staged (from above). However, they are equally importantly acted out, performed and li......, the book asks: what are the physical, social, technical, and cultural conditions to the staging of contemporary urban mobilities?...... that mobility is more than movement between point A and B. It explores how the movement of people, goods, information, and signs influences human understandings of self, other and the built environment. Moving towards a new understanding of the relationship between movement, interaction and environments...

  20. Preparation, melting behavior and thermal stability of poly(lactic acid)/poly(propylene carbonate) blends processed by vane extruder

    International Nuclear Information System (INIS)

    Zou, Wei; Chen, Rongyuan; Zhang, Haichen; Qu, Jinping

    2016-01-01

    Poly (lactic acid) (PLA)/Poly (propylene carbonate) (PPC) blends were prepared by vane extruder which is a type of novel polymer processing extruder based on elongation force field. Scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric (TG) were used respectively to analyze the compatibility, the melting behavior and thermal stability properties of PLA/PPC blends affected by the different content of PPC. The results showed that with the increase of the PPC content, the glass transition temperature of PLA was reduced, and the glass transition temperature of PPC was increased, which indicated that PLA and PPC had partial compatibility. The cold crystallization temperature of PLA increased with the increase of the PPC content, which showed that PPC hindered the cold crystallization process of PLA. The addition of PPC had little impact on the melting process of PLA, and the melting temperature of PLA was almost kept the same value. Thermogravimetric analysis showed that the thermal stability of PPC was worse than that of PLA, the addition of PPC reduced the thermal stability of PLA.

  1. Effects of grid spacer with mixing vane on entrainments and depositions in two-phase annular flows

    Directory of Open Access Journals (Sweden)

    Akimaro Kawahara

    2015-06-01

    Full Text Available The effects of mixing vanes (MVs attached to a grid spacer on the characteristics of air–water annular flows were experimentally investigated. To know the effects, a grid spacer with or without MV was inserted in a vertical circular pipe of 16-mm internal diameter. For three cases (i.e., no spacer, spacer without MV, and spacer with MV, the liquid film thickness, liquid entrainment fraction, and deposition rate were measured by the constant current method, single liquid film extraction method, and double liquid film extraction method, respectively. The MVs significantly promote the re-deposition of liquid droplets in the gas core flow into the liquid film on the channel walls. The deposition mass transfer coefficient is three times higher for the spacer with MV than for the spacer without MV, even for cases 0.3-m downstream from the spacer. The liquid film thickness becomes thicker upstream and downstream for the spacer with MV, compared with the thickness for the spacer without MV and for the case with no spacer.

  2. Preparation, melting behavior and thermal stability of poly(lactic acid)/poly(propylene carbonate) blends processed by vane extruder

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Wei, E-mail: zw55624@163.com; Chen, Rongyuan; Zhang, Haichen; Qu, Jinping, E-mail: jpqu@scut.edu.cn [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou 510640 (China)

    2016-03-09

    Poly (lactic acid) (PLA)/Poly (propylene carbonate) (PPC) blends were prepared by vane extruder which is a type of novel polymer processing extruder based on elongation force field. Scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric (TG) were used respectively to analyze the compatibility, the melting behavior and thermal stability properties of PLA/PPC blends affected by the different content of PPC. The results showed that with the increase of the PPC content, the glass transition temperature of PLA was reduced, and the glass transition temperature of PPC was increased, which indicated that PLA and PPC had partial compatibility. The cold crystallization temperature of PLA increased with the increase of the PPC content, which showed that PPC hindered the cold crystallization process of PLA. The addition of PPC had little impact on the melting process of PLA, and the melting temperature of PLA was almost kept the same value. Thermogravimetric analysis showed that the thermal stability of PPC was worse than that of PLA, the addition of PPC reduced the thermal stability of PLA.

  3. Zero-gravity Mean Free Surface Curvature of a Confined Liquid in a Radially-Vaned Container

    Science.gov (United States)

    Chen, Yongkang; Callahan, Michael; Weislogel, Mark

    2013-01-01

    A variety of increasingly intricate container geometries are under consideration for the passive manipulation of liquids aboard spacecraft where the impact of gravity may be neglected. In this study we examine the mean curvature of a liquid volume confined within a radial array of disconnected vanes of infinite extent. This particular geometry possesses a number of desirable characteristics relevant to waste water treatment aboard spacecraft for life support. It is observed that under certain conditions the slender shape of the free surface approaches an asymptote, which can be predicted analytically using new hybrid boundary conditions proposed herein. This contribution represents possibly the final extension of what has been referred to as the method of de Lazzer et al. (1996). The method enables the integration of the Young-Laplace equation over a domain with its boundaries, including the wetted portion of the solid boundaries, symmetry planes, and circular arcs representing free surfaces at the center plane of the liquid body. Asymptotic solutions at several limits are obtained and the analysis is confirmed with numerical computations.

  4. A conserved residue, PomB-F22, in the transmembrane segment of the flagellar stator complex, has a critical role in conducting ions and generating torque.

    Science.gov (United States)

    Terauchi, Takashi; Terashima, Hiroyuki; Kojima, Seiji; Homma, Michio

    2011-08-01

    Bacterial flagellar motors exploit the electrochemical potential gradient of a coupling ion (H(+) or Na(+)) as their energy source, and are composed of stator and rotor proteins. Sodium-driven and proton-driven motors have the stator proteins PomA and PomB or MotA and MotB, respectively, which interact with each other in their transmembrane (TM) regions to form an ion channel. The single TM region of PomB or MotB, which forms the ion-conduction pathway together with TM3 and TM4 of PomA or MotA, respectively, has a highly conserved aspartate residue that is the ion binding site and is essential for rotation. To investigate the ion conductivity and selectivity of the Na(+)-driven PomA/PomB stator complex, we replaced conserved residues predicted to be near the conserved aspartate with H(+)-type residues, PomA-N194Y, PomB-F22Y and/or PomB-S27T. Motility analysis revealed that the ion specificity was not changed by either of the PomB mutations. PomB-F22Y required a higher concentration of Na(+) to exhibit swimming, but this effect was suppressed by additional mutations, PomA-N194Y or PomB-S27T. Moreover, the motility of the PomB-F22Y mutant was resistant to phenamil, a specific inhibitor for the Na(+) channel. When PomB-F22 was changed to other amino acids and the effects on swimming ability were investigated, replacement with a hydrophilic residue decreased the maximum swimming speed and conferred strong resistance to phenamil. From these results, we speculate that the Na(+) flux is reduced by the PomB-F22Y mutation, and that PomB-F22 is important for the effective release of Na(+) from PomB-D24.

  5. Single Stator Dual PM Rotor Synchronous Machine with two-frequency single-inverter control, for the propulsion of hybrid electric vehicles

    Directory of Open Access Journals (Sweden)

    Topor Marcel

    2017-01-01

    Full Text Available This paper introduces a novel brushless, single winding and single stator, dual PM rotor axial-air-gap machine capable to deliver independently torque at the two rotors by adequate dual vector control. The proposed topologies, the circuit model, controlled dynamics simulation and preliminary 3D FEM torque production on a case study constitute the core of the paper. The proposed dual mechanical port system should be instrumental in parallel (with planetary gears or series hybrid electric vehicles (HEV aiming at a more compact and efficient electric propulsion system solution.

  6. An interactive physics-based unmanned ground vehicle simulator leveraging open source gaming technology: progress in the development and application of the virtual autonomous navigation environment (VANE) desktop

    Science.gov (United States)

    Rohde, Mitchell M.; Crawford, Justin; Toschlog, Matthew; Iagnemma, Karl D.; Kewlani, Guarav; Cummins, Christopher L.; Jones, Randolph A.; Horner, David A.

    2009-05-01

    It is widely recognized that simulation is pivotal to vehicle development, whether manned or unmanned. There are few dedicated choices, however, for those wishing to perform realistic, end-to-end simulations of unmanned ground vehicles (UGVs). The Virtual Autonomous Navigation Environment (VANE), under development by US Army Engineer Research and Development Center (ERDC), provides such capabilities but utilizes a High Performance Computing (HPC) Computational Testbed (CTB) and is not intended for on-line, real-time performance. A product of the VANE HPC research is a real-time desktop simulation application under development by the authors that provides a portal into the HPC environment as well as interaction with wider-scope semi-automated force simulations (e.g. OneSAF). This VANE desktop application, dubbed the Autonomous Navigation Virtual Environment Laboratory (ANVEL), enables analysis and testing of autonomous vehicle dynamics and terrain/obstacle interaction in real-time with the capability to interact within the HPC constructive geo-environmental CTB for high fidelity sensor evaluations. ANVEL leverages rigorous physics-based vehicle and vehicle-terrain interaction models in conjunction with high-quality, multimedia visualization techniques to form an intuitive, accurate engineering tool. The system provides an adaptable and customizable simulation platform that allows developers a controlled, repeatable testbed for advanced simulations. ANVEL leverages several key technologies not common to traditional engineering simulators, including techniques from the commercial video-game industry. These enable ANVEL to run on inexpensive commercial, off-the-shelf (COTS) hardware. In this paper, the authors describe key aspects of ANVEL and its development, as well as several initial applications of the system.

  7. Cold air study of the effect on turbine stator blade aerodynamic performance of coolant ejection from various trailing edge slot geometries. 2: Comparison of experimental and analytical results

    Science.gov (United States)

    Prust, H. W., Jr.

    1975-01-01

    Experimentally determined efficiencies of turbine stator blades having trailing-edge coolant ejection are compared with efficiencies predicted from two previously published approximate analytical methods. The experimental results were obtained from two-dimensional data with the temperature of the primary and coolant flows both being nearly ambient. Data from five stator blade configurations having different slotted trailing-edge geometries were included in the comparison. The two analytical methods gave results which agreed reasonably well with experimental results. An average of the absolute values of differences between experimental and predicted efficiencies for all five blade configurations showed that one method gave average efficiency differences which were about 1.3 percent different than experimental efficiencies, while the other method gave average efficiency differences that were about 0.7 percent different than experimental. However, in some instances, maximum differences of as much as 4 percent occurred. A comparison between experimental and analytical results indicated that the ratio of trailing-edge slot width to trailing-edge thickness influences the measured efficiencies to a greater extent than is accounted for by either analytical model.

  8. Investigation of the flow through an axial turbine stage

    Energy Technology Data Exchange (ETDEWEB)

    Svensdotter, S.; Wei Ning [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Energy Technology

    1995-12-31

    In this licentiate thesis the classical turbine theory and experimental results from the test turbine at KTH have been studied. The theory for the data evaluation program has also been studied and the loss models by Traupel and Denton have been investigated and applied to the measured results. The work has been performed to prepare for a theory concerning aerodynamic design of so called compound leaned blades and for future experiments on this non-conventional blade design with a new measurement system. A literature survey shows that the compound lean can be an effective three-dimensional technique in turbine designs, with significantly improved flow conditions, especially near the end-wall regions. A new measurement system, PSI, has been installed and the first preliminary tests shows good agreement with the existing system. The speed of the global measurements has been improved from about 10 minutes to about 12 seconds. The system reliability and documentation is also improved with the PSI system. The accuracy of the PSI-system is significantly better on the pressure measurement side, while the analogue side has somewhat less accuracy for the moment. From the analysis of the measurement results on the 25 mm stage, the tendencies of parameter variation versus pressure and velocity ratios were gained by the authors. The results show high secondary flow loss cores near the end-walls downstream the stator. The result is similar with those from the literature survey. The radial positions of the secondary flow cores change when simulating stator leakage flow. 140 refs, 54 figs, 14 tabs, 14 appendices

  9. Positioning and tail rotor of a small horizontal axis wind turbine of due to the influence of drag coefficient and lift affecting vane cola

    International Nuclear Information System (INIS)

    Farinnas Wong, E. Y.; Jauregui Rigo, S.; Betancourt Mena, J.

    2009-01-01

    In the present investigation was carried out an assessment on the state of technology on guidance systems and tail protection when used in small horizontal axis wind turbines, work was improved methodological approach for the development of guidance systems queue by time of these machines, to incorporate the use of coefficients of lift and drag behavior varies according to the aspect ratio, using the principles of continuum mechanics and CFD methods. Two versions are analyzed , original and updated, the wind turbine CEET-01, on which the author would have been granted a Certificate of Patent of Invention and one of Industrial Model, the updated version was derived from the procedure proposed by the author, this presents a holder for the longest vane and a larger area in the vane. In addition to analyzing the amount and cost of power generated and the capacity factor at three locations in the province of Villa Clara it was concluded that the updated variant of the turbine CEET-01 is superior to the original

  10. Understanding cancer staging

    Science.gov (United States)

    ... detailed information about the cancer stage. TNM Staging System The most common system for staging cancer in the form of solid tumor is the TNM system. Most providers and cancer centers use it to stage ...

  11. Effects of Hot Streak and Phantom Cooling on Heat Transfer in a Cooled Turbine Stage Including Particulate Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Bons, Jeffrey [The Ohio State Univ., Columbus, OH (United States); Ameri, Ali [The Ohio State Univ., Columbus, OH (United States)

    2016-01-08

    The objective of this research effort was to develop a validated computational modeling capability for the characterization of the effects of hot streaks and particulate deposition on the heat load of modern gas turbines. This was accomplished with a multi-faceted approach including analytical, experimental, and computational components. A 1-year no cost extension request was approved for this effort, so the total duration was 4 years. The research effort succeeded in its ultimate objective by leveraging extensive experimental deposition studies complemented by computational modeling. Experiments were conducted with hot streaks, vane cooling, and combinations of hot streaks with vane cooling. These studies contributed to a significant body of corporate knowledge of deposition, in combination with particle rebound and deposition studies funded by other agencies, to provide suitable conditions for the development of a new model. The model includes the following physical phenomena: elastic deformation, plastic deformation, adhesion, and shear removal. It also incorporates material property sensitivity to temperature and tangential-normal velocity rebound cross-dependencies observed in experiments. The model is well-suited for incorporation in CFD simulations of complex gas turbine flows due to its algebraic (explicit) formulation. This report contains model predictions compared to coefficient of restitution data available in the open literature as well as deposition results from two different high temperature turbine deposition facilities. While the model comparisons with experiments are in many cases promising, several key aspects of particle deposition remain elusive. The simple phenomenological nature of the model allows for parametric dependencies to be evaluated in a straightforward manner. This effort also included the first-ever full turbine stage deposition model published in the open literature. The simulations included hot streaks and simulated vane cooling

  12. Windage Power Loss in Gas Foil Bearings and the Rotor-Stator Clearance of High Speed Generators Operating in High Pressure Environments

    Science.gov (United States)

    Bruckner, Robert J.

    2009-01-01

    Closed Brayton Cycle (CBC) and Closed Supercritical Cycle (CSC) engines are prime candidates to convert heat from a reactor into electric power for robotic space exploration and habitation. These engine concepts incorporate a permanent magnet starter/generator mounted on the engine shaft along with the requisite turbomachinery. Successful completion of the long-duration missions currently anticipated for these engines will require designs that adequately address all losses within the machine. The preliminary thermal management concept for these engine types is to use the cycle working fluid to provide the required cooling. In addition to providing cooling, the working fluid will also serve as the bearing lubricant. Additional requirements, due to the unique application of these microturbines, are zero contamination of the working fluid and entirely maintenance-free operation for many years. Losses in the gas foil bearings and within the rotor-stator gap of the generator become increasingly important as both rotational speed and mean operating pressure are increased. This paper presents the results of an experimental study, which obtained direct torque measurements on gas foil bearings and generator rotor-stator gaps. Test conditions for these measurements included rotational speeds up to 42,000 revolutions per minute, pressures up to 45 atmospheres, and test gases of nitrogen, helium, and carbon dioxide. These conditions provided a maximum test Taylor number of nearly one million. The results show an exponential rise in power loss as mean operating density is increased for both the gas foil bearing and generator windage. These typical "secondary" losses can become larger than the total system output power if conventional design paradigms are followed. A nondimensional analysis is presented to extend the experimental results into the CSC range for the generator windage.

  13. Numerical simulation of the unsteady and turbulent flow in a high-pressure turbine stage; Simulation numerique de l'ecoulement instationnaire et turbulent dans un etage de turbine haute pression

    Energy Technology Data Exchange (ETDEWEB)

    Bastin, G.

    2004-09-15

    The aim of this study concerns the use of numerical methods for the resolution of the Reynolds Averaged Navier Stokes equations adapted to the simulation of the cooling of the trailing edge of a stator in a high pressure turbine. These methods, based on the elsA solver developed at ONERA, use a four steps Runge Kutta time discretization scheme and a Jameson centered space discretization scheme. The scheme is applied through a finite volume approach on control volume centered on the cells of a multi-block structured mesh. Turbulence is simulated either through the algebraic Michel model, or through the one-transport-equation Spalart-Allmaras model, or through the two-transport-equations k 1, k {omega} and k {epsilon} models, and through ASM model. A simulation of the flow in a bidimensional stator, without cooling, is carried out. The cooling, which is realized with trailing edge slots, is then simulated on a bidimensional stator. Because the slot is represented by meshes overlapping the mesh of the smooth blade, the Chimera method is chosen. This method makes it possible computations with overlapping meshes. The comparison with the experimental data, on these two first computations has validated this strategy to represent such slots. The tridimensional simulation of a single stator with taking account of the cooling is then realized. It showed the complex and tridimensional aspects of the main flow with focus on the influence of the cooling system. Finally two steady computations, without and with cooling, and an unsteady computation without cooling are carried out on a high pressure turbine stage. The comparison with the experimental data obtained in the frame of the European Brite-Euram program is made. These results make it possible to determine the effect of the cooling on the flow in a turbine stage. (authors)

  14. Prostate cancer staging

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000397.htm Prostate cancer staging To use the sharing features on this ... trials you may be able to join How Prostate Cancer Staging is Done Initial staging is based on ...

  15. Meat batter production in an extended vane pump-grinder injecting curing salt solutions to reduce energy requirements: variation of curing salt amount injected with the solution.

    Science.gov (United States)

    Irmscher, Stefan B; Terjung, Eva-Maria; Gibis, Monika; Herrmann, Kurt; Kohlus, Reinhard; Weiss, Jochen

    2017-01-01

    The integration of a nozzle in an extended vane pump-grinder system may enable the continuous injection of curing salt solutions during meat batter production. The purpose of this work was to examine the influence of the curing salt amount injected with the solution (0-100%) on protein solubilisation, water-binding, structure, colour and texture of emulsion-type sausages. The amount of myofibrillar protein solubilised during homogenisation varied slightly from 33 to 36 g kg -1 . Reddening was not noticeably impacted by the later addition of nitrite. L * ranged from 66.9 ± 0.3 to 67.8 ± 0.3, a * from 10.9 ± 0.1 to 11.2 ± 0.1 and b * from 7.7 ± 0.1 to 8.0 ± 0.1. Although softer sausages were produced when only water was injected, firmness increased with increasing curing salt amount injected and was similar to the control when the full amount of salt was used. The substitution of two-thirds of ice with a liquid brine may enable energy savings due to reduced power consumptions of the extended vane pump-grinder system by up to 23%. The injection of curing salt solutions is feasible without affecting structure and colour negatively. This constitutes a first step towards of an 'ice-free' meat batter production allowing for substantial energy savings due to lower comminution work. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  16. Combustion-driven oscillation in a furnace with multispud-type gas burners. 4th Report. Effects of position of secondary air guide sleeve and openness of secondary air guide vane on combustion oscillation condition; Multispud gata gas turner ni okeru nensho shindo. 4. Nijigen kuki sleeve ichi oyobi nijigen kuki vane kaido no shindo reiki ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Akiyama, I.; Okiura, K.; Baba, A.; Orimoto, M. [Babcock-Hitachi K.K., Tokyo (Japan)

    1994-07-25

    Effects of the position of a secondary air guide sleeve and the openness of a secondary air guide vane on combustion oscillation conditions were studied experimentally for multispud-type gas burners. Pressure fluctuation in furnaces was analyzed with the previously reported resonance factor which was proposed as an index to represent the degree of combustion oscillation. As a result, the combustion oscillation region was largely affected by both position of a guide sleeve and openness of a guide vane. As the openness having large effect on the ratio of primary and secondary air/tertiary air and the position hardly having effect on the ratio were adjusted skillfully, the burner with no combustion oscillation region was achieved in its normal operation range. In addition, as the effect of preheating combustion air was arranged with a standard flow rate or mass flow flux of air, it was suggested the combustion oscillation region due to preheating can be described with the same manner as that due to no preheating. 5 refs., 8 figs.

  17. Between Stage and Screen

    NARCIS (Netherlands)

    Tornqvist, Egil

    1996-01-01

    Ingmar Bergman is worldwide known as a film and stage director. Yet no-one has attempted to compare his stage and screen activities. In Between stage and screen Egil Tornqvist examines formal and thematical correspondences and differences between a number of Bergman's stage, screen, and radio

  18. Prediction of Stator Terminal Voltages in IPMSM based on Static and Transient FEM Solution: Trade-off between Accuracy and Speed of Computation

    Directory of Open Access Journals (Sweden)

    Hichem Bouras

    2017-12-01

    Full Text Available The present work deals with the calculation of the time varying induced emf in permanent magnet synchronous machines from the numerical finite element solution. A review of the existing methods is presented; their intrinsic merits, in terms of accuracy and speed of computation, are compared. The currently used method, which relies on a weighting averaging procedure of the magnetic vector potential (MVP over the slot area in order to derive the winding flux linkage and the stator induced, has been modified to enhance its accuracy. An alternative method, which relies on the magnetic vector potential distribution along the mid airgap line, is proposed to carry out the same task. This approach has turned out to be very efficient since it enables a straightforward data handling, signal reconstruction, filtering and spectrum analysis of the relevant waveforms to be easily implemented in a single post-processing function. Finally, the relevance and efficiency of each method, in terms of accuracy and speed of computation, has been confirmed by the experimental results.

  19. Breast cancer staging

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000911.htm Breast cancer staging To use the sharing features on this ... Once your health care team knows you have breast cancer , they will do more tests to stage it. ...

  20. Seven Stages of Alzheimer's

    Science.gov (United States)

    ... Dementias . Learn more: Daily Care and Behaviors Severe Alzheimer's disease (late-stage) Get support Late-stage care decisions can be some of the hardest families face. Connect with other caregivers who have been through the process on our ...

  1. Stages of Adolescence

    Science.gov (United States)

    ... Español Text Size Email Print Share Stages of Adolescence Page Content Article Body Adolescence, these years from puberty to adulthood, may be roughly divided into three stages: early adolescence, generally ages eleven to fourteen; middle adolescence, ages ...

  2. Beyond Erikson's Eight Stages.

    Science.gov (United States)

    Whitney, Ruth

    1979-01-01

    Erik Erikson has described eight stages of the healthy personality. This essay offers a revised version of the eight stages. Although most individuals develop through the eight stages, each is personally unique because patterns of fluctuation between safety and growth differ from one individual to another. (Author)

  3. Cervical Cancer Stage IIIA

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIA Add to My Pictures View /Download : ... 1275x1275 View Download Large: 2550x2550 View Download Title: Cervical Cancer Stage IIIA Description: Stage IIIA cervical cancer; drawing ...

  4. Cervical Cancer Stage IVA

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IVA Add to My Pictures View /Download : ... 1575x1200 View Download Large: 3150x2400 View Download Title: Cervical Cancer Stage IVA Description: Stage IVA cervical cancer; drawing ...

  5. Cervical Cancer Stage IVB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IVB Add to My Pictures View /Download : ... 1200x1305 View Download Large: 2400x2610 View Download Title: Cervical Cancer Stage IVB Description: Stage IVB cervical cancer; drawing ...

  6. Cervical Cancer Stage IIIB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIB Add to My Pictures View /Download : ... 1425x1326 View Download Large: 2850x2651 View Download Title: Cervical Cancer Stage IIIB Description: Stage IIIB cervical cancer; drawing ...

  7. Cervical Cancer Stage IB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IB Add to My Pictures View /Download : ... 1613x1200 View Download Large: 3225x2400 View Download Title: Cervical Cancer Stage IB Description: Stage IB1 and IB2 cervical ...

  8. Cervical Cancer Stage IA

    Science.gov (United States)

    ... historical Searches are case-insensitive Cervical Cancer Stage IA Add to My Pictures View /Download : Small: 720x576 ... Large: 3000x2400 View Download Title: Cervical Cancer Stage IA Description: Stage IA1 and IA2 cervical cancer; drawing ...

  9. Cetuximab, Cisplatin, and Radiation Therapy in Treating Patients With Stage IB, Stage II, Stage III, or Stage IVA Cervical Cancer

    Science.gov (United States)

    2014-12-29

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Small Cell Carcinoma; Cervical Squamous Cell Carcinoma; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer

  10. Prédiction des vibrations du stator d'une machine à réluctance variable en fonction du courant absorbé

    Science.gov (United States)

    Camus, F.; Gabsi, M.; Multon, B.

    1997-02-01

    In order to predict the radial vibration of the stator core of a Doubly Salient Switched Reluctance Motor (D.S.S.R.M.), different causes of vibrations are considered. In this kind of machine, electromagnetic stress is found to be the most significant cause of vibrations. The local magnetic stress distribution, depending on magnetic field and finally on the phase current, is calculated in the case of an unsatured operation. This magnetic stress acts in two ways: a tangential force (torque) and a radial attractive force. This radial force excites the vibration modes of the stator, this vibration behaviour is measured in the aligned position and is identified as a transfert function. Finally several experiments show the good accuracy of this simple model. This model will be later used to study the effect of phase current and of static converter on vibration and acoustic noise emitted by the D.S.S.R.M. L'étude du bruit et des vibrations dans le matériel électrique fait intervenir plusieurs systèmes physiques couplés. Le modèle complet est complexe et ne permet pas d'études paramétriques simples de la structure de la machine, de son alimentation et cela pour différents points de fonctionnement. Dans cet article est présenté un modèle simple permettant de prédire l'accélération radiale d'un Moteur à Réluctance Variable à Double Saillance (M.R.V.D.S.) en fonction du courant d'alimentation. Ce modèle permettra d'étudier ultérieurement l'influence de l'alimentation sur le comportement vibratoire de la machine. En premier lieu, les différentes sources de vibrations d'une machine tournante sont évoquées, pour finalement ne s'intéresser qu'aux efforts d'origine magnétique qui sont prépondérants dans les M.R.V.D.S. Le calcul de ces efforts en fonction du courant est présenté dans le cas d'une machine fonctionnant en régime linéaire (sans saturation magnétique). Ces efforts sont décomposés en une force tangentielle créant le couple de rotation

  11. Multiple stage railgun

    International Nuclear Information System (INIS)

    Aaland, K.; Hawke, R.S.; Scudder, J.K.

    1982-01-01

    A multiple stage magnetic railgun accelerator for accelerating a projectile by movement of a plasma arc along the rails. The railgun is divided into a plurality of successive rail stages which are sequentially energized by separate energy sources as the projectile moves through the bore of the railgun. Propagation of energy from an energized rail stage back towards the breech end of the railgun can be prevented by connection of the energy sources to the rails through isolation diodes. Propagation of energy from an energized rail stage back towards the breech end of the railgun can also be prevented by dividing the rails into electrically isolated rail sections. In such case means are used to extinguish the arc at the end of each energized stage and a fuse or laser device is used to initiate a new plasma arc in the next energized rail stage

  12. Impact of cyclostationarity on fan broadband noise prediction

    Science.gov (United States)

    Wohlbrandt, A.; Kissner, C.; Guérin, S.

    2018-04-01

    One of the dominant noise sources of modern Ultra High Bypass Ratio (UHBR) engines is the interaction of the rotor wakes with the leading edges of the stator vanes in the fan stage. While the tonal components of this noise generation mechanism are fairly well understood by now, the broadband components are not. This calls to further the understanding of the broadband noise generation in the fan stage. This article introduces a new extension to the Random Particle Mesh (RPM) method, which accommodates in-depth studies of the impact of cyclostationary wake characteristics on the broadband noise in the fan stage. The RPM method is used to synthesize a turbulence field in the stator domain using a URANS simulation characterized by time-periodic turbulence and mean flow. The rotor-stator interaction noise is predicted by a two-dimensional CAA computation of the stator cascade. The impact of cyclostationarity is decomposed into various effects, which are separately investigated. This leads to the finding that the periodic turbulent kinetic energy (TKE) and periodic flow have only a negligible effect on the radiated sound power. The impact of the periodic integral length scale (TLS) is, however, substantial. The limits of a stationary representation of the TLS are demonstrated making this new extension to the RPM method indispensable when background and wake TKE are of comparable level. Good agreement of the predictions with measurements obtained from the 2015 AIAA Fan Broadband Noise Prediction Workshop are also shown.

  13. Analysis of Unsteady Tip and Endwall Heat Transfer in a Highly Loaded Transonic Turbine Stage

    Science.gov (United States)

    Shyam, Vikram; Ameri, Ali; Chen, Jen-Ping

    2010-01-01

    In a previous study, vane-rotor shock interactions and heat transfer on the rotor blade of a highly loaded transonic turbine stage were simulated. The geometry consists of a high pressure turbine vane and downstream rotor blade. This study focuses on the physics of flow and heat transfer in the rotor tip, casing and hub regions. The simulation was performed using the Unsteady Reynolds-Averaged Navier-Stokes (URANS) code MSU-TURBO. A low Reynolds number k-epsilon model was utilized to model turbulence. The rotor blade in question has a tip gap height of 2.1 percent of the blade height. The Reynolds number of the flow is approximately 3x10(exp 6) per meter. Unsteadiness was observed at the tip surface that results in intermittent "hot spots". It is demonstrated that unsteadiness in the tip gap is governed by inviscid effects due to high speed flow and is not strongly dependent on pressure ratio across the tip gap contrary to published observations that have primarily dealt with subsonic tip flows. The high relative Mach numbers in the tip gap lead to a choking of the leakage flow that translates to a relative attenuation of losses at higher loading. The efficacy of new tip geometry is discussed to minimize heat flux at the tip while maintaining choked conditions. In addition, an explanation is provided that shows the mechanism behind the rise in stagnation temperature on the casing to values above the absolute total temperature at the inlet. It is concluded that even in steady mode, work transfer to the near tip fluid occurs due to relative shearing by the casing. This is believed to be the first such explanation of the work transfer phenomenon in the open literature. The difference in pattern between steady and time-averaged heat flux at the hub is also explained.

  14. Turbine stage model

    International Nuclear Information System (INIS)

    Kazantsev, A.A.

    2009-01-01

    A model of turbine stage for calculations of NPP turbine department dynamics in real time was developed. The simulation results were compared with manufacturer calculations for NPP low-speed and fast turbines. The comparison results have shown that the model is valid for real time simulation of all modes of turbines operation. The model allows calculating turbine stage parameters with 1% accuracy. It was shown that the developed turbine stage model meets the accuracy requirements if the data of turbine blades setting angles for all turbine stages are available [ru

  15. Numerical three-dimensional turbulent flow analysis trough a pump-turbine in the turbine modes

    International Nuclear Information System (INIS)

    Cvetkovski, Zlatko; Popovski, Predrag; Markov, Zoran; Lipej, Andrej

    2004-01-01

    During the design of a new or rehabilitated hydraulic machines, prediction of the performances is one of the most important step in development procedure. However, for re-design of old machines, a fast and reliable flow analyses tool is necessary for allocation of the 'bed geometry' condition. This work describes new computational approaches for modern re-design of a radial type single stage pump-turbine. A pump-turbine with specific speed ns = 89 was calculated, as an example of the applicability of this methodology. The simulation of three-dimensional turbulent flow through a Pump-Turbine impeller at turbine mode, as a part of the complete pump-turbine calculation [3] during the re-design procedure is presented. Four operational regimes were calculated based on the Computational Fluid Dynamics - CFD Methodology (Navier-Stokes equations and the k-e turbulent model). The mesh discretization, boundary conditions and calculated results are presented and the)) shall be useful for development, optimisation, refurbishment or rehabilitation projects, because the impeller behaviour can be a major criterion for increasing the performances of the Pump-Turbines. The complete flow field consists of spiral case, a channel between stator vanes, a channel between guide vanes, a channel between rotor vanes and complete draft tube. Two step calculations are applied. In the first step, calculation was performed for the spiral case and the stator. Second step of the calculations was performed for cascade, rotor and draft tube. (Author)

  16. Staging of cutaneous melanoma

    NARCIS (Netherlands)

    P. Mohr (P.); A.M.M. Eggermont (Alexander); A. Hauschild (Axel); A. Buzaid (A.)

    2009-01-01

    textabstractThe American Joint Committee on Cancer (AJCC) staging of cutaneous melanoma is a continuously evolving system. The identification of increasingly more accurate prognostic factors has led to major changes in melanoma staging over the years, and the current system described in this review

  17. Synthesis of the turbulent mixing in a rod bundle with vaned spacer grids based on the OECD-KAERI CFD benchmark exercise

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Ryong; Kim, Jungwoo; Song, Chul-Hwa, E-mail: chsong@kaeri.re.kr

    2014-11-15

    Highlights: • OECD/KAERI international CFD benchmark exercise was operated by KAERI. • The purpose is to validate relevant CFD codes based on the MATiS-H experiments. • Blind calculation results were synthesized in terms of mean velocity and RMS. • Quality of control volume rather than the number of it was emphasized. • Major findings were followed OECD/NEA CSNI report. - Abstract: The second international CFD benchmark exercise on turbulent mixing in a rod bundle has been launched by OECD/NEA, to validate relevant CFD (Computational Fluid Dynamics) codes and develop problem-specific Best Practice Guidelines (BPG) based on the KAERI (Korea Atomic Energy Research Institute) MATiS-H experiments on the turbulent mixing in a 5 × 5 rod array having two different types of vaned spacer grids: split and swirl types. For this 2nd international benchmark exercise (IBE-2), the MATiS-H testing provided a unique set of experimental data such as axial and lateral velocity components, turbulent intensity, and vorticity information. Blind CFD calculation results were submitted by twenty-five (25) participants to KAERI, who is the host organization of the IBE-2, and then analyzed and synthesized by comparing them with the MATiS-H data. Based on the synthesis of the results from both the experiments and blind CFD calculations for the IBE-2, and also by comparing with the IBE-1 benchmark exercise on the mixing in a T-junction, useful information for simulating this kind of complicated physical problem in a rod bundle was obtained. And some additional Best Practice Guidelines (BPG) are newly proposed. A summary of the synthesis results obtained in the IBE-2 is presented in this paper.

  18. Synthesis of the turbulent mixing in a rod bundle with vaned spacer grids based on the OECD-KAERI CFD benchmark exercise

    International Nuclear Information System (INIS)

    Lee, Jae Ryong; Kim, Jungwoo; Song, Chul-Hwa

    2014-01-01

    Highlights: • OECD/KAERI international CFD benchmark exercise was operated by KAERI. • The purpose is to validate relevant CFD codes based on the MATiS-H experiments. • Blind calculation results were synthesized in terms of mean velocity and RMS. • Quality of control volume rather than the number of it was emphasized. • Major findings were followed OECD/NEA CSNI report. - Abstract: The second international CFD benchmark exercise on turbulent mixing in a rod bundle has been launched by OECD/NEA, to validate relevant CFD (Computational Fluid Dynamics) codes and develop problem-specific Best Practice Guidelines (BPG) based on the KAERI (Korea Atomic Energy Research Institute) MATiS-H experiments on the turbulent mixing in a 5 × 5 rod array having two different types of vaned spacer grids: split and swirl types. For this 2nd international benchmark exercise (IBE-2), the MATiS-H testing provided a unique set of experimental data such as axial and lateral velocity components, turbulent intensity, and vorticity information. Blind CFD calculation results were submitted by twenty-five (25) participants to KAERI, who is the host organization of the IBE-2, and then analyzed and synthesized by comparing them with the MATiS-H data. Based on the synthesis of the results from both the experiments and blind CFD calculations for the IBE-2, and also by comparing with the IBE-1 benchmark exercise on the mixing in a T-junction, useful information for simulating this kind of complicated physical problem in a rod bundle was obtained. And some additional Best Practice Guidelines (BPG) are newly proposed. A summary of the synthesis results obtained in the IBE-2 is presented in this paper

  19. Staging for vulvar cancer.

    Science.gov (United States)

    Hacker, Neville F; Barlow, Ellen L

    2015-08-01

    Vulvar cancer has been staged by the International Federation of Gynaecology and Obstetrics (FIGO) since 1969, and the original staging system was based on clinical findings only. This system provided a very good spread of prognostic groupings. Because vulvar cancer is virtually always treated surgically, the status of the lymph nodes is the most important prognostic factor and this can only be determined with certainty by histological examination of resected lymph nodes, FIGO introduced a surgical staging system in 1988. This was modified in 1994 to include a category of microinvasive vulvar cancer (stage IA), because such patients have virtually no risk of lymph node metastases. This system did not give a reasonably even spread of prognostic groupings. In addition, patients with stage III disease were shown to be a heterogeneous group prognostically, and the number of positive nodes and the morphology of those nodes were not taken into account. A new surgical staging system for vulvar cancer was introduced by FIGO in 2009. Initial retrospective analyses have suggested that this new staging system has overcome the major deficiencies in the 1994 system. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  20. Staging for vaginal cancer.

    Science.gov (United States)

    Rajaram, Shalini; Maheshwari, Amita; Srivastava, Astha

    2015-08-01

    Vaginal cancer is a rare cancer comprising about 3% of all gynecologic cancers. Primary vaginal cancer should be carefully assigned as spread from cervix, vulva, and other metastatic tumors to vagina can occur. Although vaginal cancer traditionally occurs in older postmenopausal women, the incidence of high-risk human papillomavirus (HPV)-induced cancers is increasing in younger women. Squamous cell carcinoma is still the most common histopathologic type followed by adenocarcinoma. With decreasing use of diethylstilbestrol in pregnancy, non-diethylstilbestrol-associated cancers are described. The Federation Internationale de Gynecologie et d'Obstetrique (FIGO) staging of vaginal cancer (2009) follows the same rules as cervical cancer; it is clinically staged and allows the use of routine investigative modalities for staging. Although FIGO encourages the use of advanced imaging modalities, such as computed tomography, magnetic resonance imaging (MRI), and positron emission tomography (PET), to guide therapy, the imaging findings may not be used to change or reassign the stage. TNM staging is the pathologic staging system proposed by the American Joint Committee on Cancer, and information available from examination of the resected specimen, including pelvic and inguinal lymph nodes, may be used for staging. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Design and test of a small two stage counter-rotating turbine for rocket engine application

    Science.gov (United States)

    Huber, F. W.; Branstrom, B. R.; Finke, A. K.; Johnson, P. D.; Rowey, R. J.; Veres, J. P.

    1993-01-01

    The aerodynamic design and rig test evaluation of a small counter-rotating turbine system is described. The technology represented by this turbine is being developed for application in an advanced upper stage rocket engine turbopump. This engine will employ an oxygen/hydrogen expander cycle and achieve high performance through efficient combustion, high combustion pressure, and high area ratio exhaust nozzle expansion. Engine performance goals require that the turbopump drive turbines achieve high efficiency at low gas flow rates. The low flow rates result in very small airfoil diameter, height and chord. The high efficiency and small size requirements present a challenging turbine design problem. The unconventional approach employed to meet this challenge is described, along with the detailed design process and resulting airfoil configurations. The method and results of full scale aerodynamic performance evaluation testing of both one and two stage configurations, as well as operation without the secondary stage stator are presented. The overall results of this effort illustrate that advanced aerodynamic design tools and hardware fabrication techniques have provided improved capability to produce small high performance turbines for advanced rocket engines.

  2. Staged bilateral carotid endarterectomy

    DEFF Research Database (Denmark)

    Schroeder, T; Sillesen, H; Engell, Hans Christian

    1986-01-01

    In a series of 56 staged bilateral carotid endarterectomies, new neurologic symptoms developed in 5% and 20% following the first and second procedure, respectively. All complications were transient or minor. The incidence of postendarterectomy hypertension was significantly higher following...... the second procedure, when operations were staged less than 3 weeks apart. A correlation between these hypertensive episodes and the occurrence of new neurologic symptoms could not be shown. However, as this correlation has been proved in several other reports, bilateral carotid endarterectomy is advised...... to be staged at least 3 weeks apart. In addition, a conservative attitude towards contralateral asymptomatic lesions is proposed....

  3. Staging of lung cancer.

    Science.gov (United States)

    de Groot, Patricia M; Carter, Brett W; Betancourt Cuellar, Sonia L; Erasmus, Jeremy J

    2015-06-01

    Primary lung cancer is the leading cause of cancer mortality in the world. Thorough clinical staging of patients with lung cancer is important, because therapeutic options and management are to a considerable degree dependent on stage at presentation. Radiologic imaging is an essential component of clinical staging, including chest radiography in some cases, computed tomography, MRI, and PET. Multiplanar imaging modalities allow assessment of features that are important for surgical, oncologic, and radiation therapy planning, including size of the primary tumor, location and relationship to normal anatomic structures in the thorax, and existence of nodal and/or metastatic disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Staging Mobilities / Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2015-01-01

    In recent years, urban research has taken a ‘mobilities turn’. There has been a developing realisation that mobilities do not ‘just happen.’ Mobilities are carefully and meticulously designed, planned and staged (from above). However, they are equally importantly acted out, performed and lived...... asks: what are the physical, social, technical, and cultural conditions to the staging of contemporary urban mobilities? The theoretical framing in the Staging mobilities book is applied to four in-depth cases in the accompanying volume Designing mobilities.This book explore how places, sites...

  5. Stages of Colon Cancer

    Science.gov (United States)

    ... types of surgery : Local excision or simple polypectomy . Resection and anastomosis . This is done when the tumor is too ... stage I colon cancer usually includes the following: Resection and anastomosis . Use our clinical trial search to find NCI- ...

  6. Stages of Labor

    Science.gov (United States)

    ... Moms Need Blog News & Media News Videos Mission stories Ambassadors Spotlights Tools & Resources Frequently asked media questions ... can be born. This stage can last as short as 20 minutes or as long as several ...

  7. Multiple Stages 2

    DEFF Research Database (Denmark)

    Andreasen, John

    Multiple stages 2: theatrical futures, set design, community plays, cultural capitals, democracy & drama, WWII dramas, performance on adoption, promenade about emigration, qualities in political theatre, performance analysis, dramaturgical education, Toulmin Variations...

  8. Stages of Esophageal Cancer

    Science.gov (United States)

    ... the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds , ... stage of the cancer being treated. External and internal radiation therapy are used to treat esophageal cancer. A plastic ...

  9. Stages of Anal Cancer

    Science.gov (United States)

    ... the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds , ... stage of the cancer being treated. External and internal radiation therapy are used to treat anal cancer. Chemotherapy Chemotherapy ...

  10. Stages of Penile Cancer

    Science.gov (United States)

    ... the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds , ... stage of the cancer being treated. External and internal radiation therapy are used to treat penile cancer. Chemotherapy Chemotherapy ...

  11. Staging interrail mobilities

    DEFF Research Database (Denmark)

    Jensen, Martin Trandberg; Gyimóthy, Szilvia; Jensen, Ole B.

    2016-01-01

    This article applies the multiscalar ‘staging mobilities’ framework from the emergent subfield of mobilities design to analyse an enduring European rail travel phenomenon, interrail. This discussion extends and contributes to tourism mobilities research. Second, the article enriches previous...

  12. Stages of ores formation

    International Nuclear Information System (INIS)

    Khasanov, A.Kh.

    1988-01-01

    Deposit formation (especially endogenous) is the complicated, multi-stage and long process. Establishment of deposit formation succession, age-specific correlations of minerals and aggregates have a high importance at solving genetic questions. Studying of minerals correlations and mineral aggregates, succession of their crystallization and other observations let restore the history of deposit formation, pick up in it different on duration and physical and chemical conditions stages

  13. Chemotherapy Toxicity On Quality of Life in Older Patients With Stage I, Stage II, Stage III, or Stage IV Ovarian Epithelial, Primary Peritoneal Cavity, or Fallopian Tube Cancer

    Science.gov (United States)

    2017-05-03

    Stage I Ovarian Cancer; Stage IA Fallopian Tube Cancer; Stage IB Fallopian Tube Cancer; Stage IC Fallopian Tube Cancer; Stage II Ovarian Cancer; Stage IIA Fallopian Tube Cancer; Stage IIB Fallopian Tube Cancer; Stage IIC Fallopian Tube Cancer; Stage III Ovarian Cancer; Stage III Primary Peritoneal Cancer; Stage IIIA Fallopian Tube Cancer; Stage IIIB Fallopian Tube Cancer; Stage IIIC Fallopian Tube Cancer; Stage IV Fallopian Tube Cancer; Stage IV Ovarian Cancer; Stage IV Primary Peritoneal Cancer

  14. Three-Dimensional Unsteady Simulation of a Modern High Pressure Turbine Stage Using Phase Lag Periodicity: Analysis of Flow and Heat Transfer

    Science.gov (United States)

    Shyam, Vikram; Ameri, Ali; Luk, Daniel F.; Chen, Jen-Ping

    2010-01-01

    Unsteady three-dimensional RANS simulations have been performed on a highly loaded transonic turbine stage and results are compared to steady calculations as well as experiment. A low Reynolds number k- turbulence model is employed to provide closure for the RANS system. A phase-lag boundary condition is used in the periodic direction. This allows the unsteady simulation to be performed by using only one blade from each of the two rows. The objective of this paper is to study the effect of unsteadiness on rotor heat transfer and to glean any insight into unsteady flow physics. The role of the stator wake passing on the pressure distribution at the leading edge is also studied. The simulated heat transfer and pressure results agreed favorably with experiment. The time-averaged heat transfer predicted by the unsteady simulation is higher than the heat transfer predicted by the steady simulation everywhere except at the leading edge. The shock structure formed due to stator-rotor interaction was analyzed. Heat transfer and pressure at the hub and casing were also studied. Thermal segregation was observed that leads to the heat transfer patterns predicted by steady and unsteady simulations to be different.

  15. Kinetic Energy Losses and Efficiency of an Axial Turbine Stage in Numerical Modeling of Unsteady Flows

    Directory of Open Access Journals (Sweden)

    A. S. Laskin

    2015-01-01

    Full Text Available The article presents the results of numerical investigation of kinetic energy (KE loss and blading efficiency of the single-stage axial turbine under different operating conditions, characterized by the ratio u/C0. The calculations are performed by stationary (Stage method and nonstationary (Transient method methods using ANSYS CFX. The novelty of this work lies in the fact that the numerical simulation of steady and unsteady flows in a turbine stage is conducted, and the results are obtained to determine the loss of KE, both separately by the elements of the flow range and their total values, in the stage efficiency as well. The results obtained are compared with the calculated efficiency according to one-dimensional theory.To solve these problems was selected model of axial turbine stage with D/l = 13, blade profiles of rotor and stator of constant cross-section, similar to tested ones in inverted turbine when = 0.3. The degree of reactivity ρ = 0.27, the rotor speed was varied within the range 1000 ÷ 1800 rev/min.Results obtained allow us to draw the following conclusions:1. The level of averaged coefficients of total KE losses in the range of from 0.48 to 0.75 is from 18% to 21% when calculating by the Stage method and from 21% to 25% by the Transient one.2. The level of averaged coefficients of KE losses with the output speed of in the specified range is from 9% to 13%, and almost the same when in calculating by Stage and Transient methods.3. Levels of averaged coefficients of KE loss in blade tips (relative to the differential enthalpies per stage are changed in the range: from 4% to 3% (Stage and are stored to be equal to 5% (Transient; from 5% to 6% (Stage and from 6% to 8% (Transient.4. Coefficients of KE losses in blade tips GV and RB are higher in calculations of the model stage using the Transient method than the Stage one, respectively, by = 1.5 ÷ 2.5% and = 4 ÷ 5% of the absolute values. These are values to characterize the KE

  16. Staging of extrahepatic cholangiocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Eun; Choi, Jin-Young [Yonsei University College of Medicine, Department of Diagnostic Radiology, Research Institute of Radiological Science, Seoul (Korea); Kim, Myeong-Jin [Yonsei University College of Medicine, Department of Diagnostic Radiology, Research Institute of Radiological Science, Seoul (Korea); Yonsei University College of Medicine, Institute of Gastroenterology, Yonsei (Korea); Yonsei University Health System, Department of Diagnostic Radiology, Seoul (Korea); Park, Young Nyun [Yonsei University College of Medicine, Institute of Gastroenterology, Yonsei (Korea); Yonsei University College of Medicine, Department of Pathology, Yonsei (Korea); Lee, Yoon-Hee [Yonsei University College of Medicine, Department of Pathology, Yonsei (Korea)

    2008-10-15

    Preoperative staging of extrahepatic cholangiocarcinoma is important in determining the best treatment plan. Several classification systems have been suggested to determine the operability and extent of surgery. Longitudinal tumor extent is especially important in extrahepatic cholangiocarcinoma because operative methods differ depending on the tumor extent. The Bismuth-Corlette classification system provides useful information when planning for surgery. However, this classification system is not adequate for selecting surgical candidates. Anatomic variation of the bile duct and gross morphology of the tumor must be considered simultaneously. Lateral spread of the tumor can be evaluated based on the TNM staging provided by American Joint Committee on Cancer (AJCC). However, there is a potential for ambiguity in the distinction of T1 and T2 cancer from one another. In addition, T stage does not necessarily mean invasiveness. Blumgart T staging is helpful for the assessment of resectability with the consideration of nodal status and distant metastasis as suggested by the AJCC cancer staging system. Computed tomography (CT) and magnetic resonance imaging (MRI) are the primary tools used in the assessment of longitudinal and lateral spread of a tumor when determining respectability. Diagnostic laparoscopy and positron emission tomography (PET) may play additional roles in this regard. (orig.)

  17. Composers on stage

    DEFF Research Database (Denmark)

    Groth, Sanne Krogh

    A trend on the scene of contemporary music is composers going on stage, performing their pieces themselves. Within a discourse of popular music, this is more the rule than exception, but when it comes to the context of contemporary scored music, the historical and aesthetic context differs......, and something quite different is undergoing. This paper intends to discuss three examples of performances in which the composer’s appearance on stage was an important part of the piece, - both when it came to the role as a performer and as an individual person – as representer and presenter. The paper intends...... to rise the following questions: What happens to the status of the author, when he suddenly (re-)appears on stage? How is this appearance to be understood in both a contemporary and historical context: Is it the musical virtuous appearing again, are we witnessing musical works turning...

  18. Staging Collaborative Innovation Processes

    DEFF Research Database (Denmark)

    Pedersen, Signe; Clausen, Christian

    Organisations are currently challenged by demands for increased collaborative innovation internally as well as with external and new entities - e.g. across the value chain. The authors seek to develop new approaches to managing collaborative innovative processes in the context of open innovation...... and public private innovation partnerships. Based on a case study of a collaborative design process in a large electronics company the paper points to the key importance of staging and navigation of collaborative innovation process. Staging and navigation is presented as a combined activity: 1) to translate...

  19. Are stage IV vestibular schwannomas preoperatively different from other stages?

    Science.gov (United States)

    Tringali, Stéphane; Dubreuil, Christian; Zaouche, Sandra; Ferber-Viart, Chantal

    2008-01-01

    The aim of this study was to focus on the clinical and paraclinical symptoms of patients suffering from Stage IV vestibular schwannomas (VSs). In this prospective study, we included 734 patients who have VS and candidates for operation. Patients were classified as having Stage I, II, III, or IV tumors according to Tos criteria as evaluated by magnetic resonance imaging. PREOPERATIVE CLINICAL EVALUATION: We recorded the occurrence of complaints (%) and duration (yr) of hearing loss, tinnitus, and balance disorder. Preoperative paraclinical evaluation included pure-tone (PTA) and speech audiometry, auditory brainstem response (ABR) patterns, and vestibular deficit at videonystamography (VNG). Continuous variables were compared between Stage IV and other stages using analysis of variance. Qualitative variables expressed as a percentage of presence were compared between Stage IV and other stages using percentage comparison. Quantitative Parameters. Patients with Stage IV VS were significantly younger as compared with patients with other stages. Stage IV hearing loss was greater compared with other stages at 250 and 500 Hz but smaller at 2,000 and 8,000 Hz. We found no difference in the loss of PTA between Stage IV and the other stages. Speech discriminancy score was smaller in Stage IV. The durations of hearing loss, tinnitus, and balance disorders were similar whatever the tumor stage. Auditory brainstem response patterns showed no difference in Wave III latency between Stage IV VS and other stages, whereas Wave V latency and V-I interval were higher in Stage IV. Both ABR threshold and VNG caloric deficit were higher in Stage IV VS compared with other stages. Qualitative Parameters. The percentage of patients with Stage IV was lower than that with Stages II and III. The percentage of men and women was similar in all stages. The occurrence of hearing loss was similar in all stages, whereas that of tinnitus was lower in Stage IV compared with Stages I and II. In

  20. End-stage kidney disease

    Science.gov (United States)

    ... medlineplus.gov/ency/article/000500.htm End-stage kidney disease To use the sharing features on this page, please enable JavaScript. End-stage kidney disease (ESKD) is the last stage of long-term ( ...

  1. Stage theta pinch experiments

    International Nuclear Information System (INIS)

    Linford, R.K.; Downing, J.N.; Gribble, R.F.; Jacobson, A.R.; Platts, D.A.; Thomas, K.S.

    1975-01-01

    The Staged Theta Pinch program is designed to study the technological and physics problems associated with producing fat plasmas and separating the implosion heating from the adiabatic compression. Several methods of implosion heating are discussed. Circuit diagrams and theoretical magnetic field behavior are described for the STP and resonant heating experiments. (MOW)

  2. "Stage 40" Handbook.

    Science.gov (United States)

    Mill River Union High School, North Clarendon, VT.

    The policies, purposes, and guidelines of "Stage 40," an educational repertory company for students, are presented in this paper, which also explains how the company functions. The paper discusses the company's history, the relationship between the company and academics, and the responsibilities of a company member. Letters by the board…

  3. World Stage Design

    Index Scriptorium Estoniae

    2005-01-01

    12-19. III Torontos rahvusvaheline lavakujunduse, kostüümi ning valgus- ja helikujunduse näitus, mis toimub samaaegselt OISTATi (International Organization of Scenographers, Theatre Architects and Technicians) maailmakongressiga ja USITT (United States Institute for Theatre Technology) üritustega (konverents, Stage Expo). Eestit esindab lavakujunduse kategoorias Lilja Blumenfeld-Luhse

  4. Linac project - actual stage

    International Nuclear Information System (INIS)

    Carlin Filho, N.

    1990-01-01

    The actual development stage of Pelletron accelerator to study heavy ion reactions, nuclear structures and applied nuclear physics is presented. The construction of acceleration systems able to provide beams of several mass and energies up to 20 MeV/A, is discussed, describing acceleration structures and implemented systems. (M.C.K.)

  5. stage/page/play

    DEFF Research Database (Denmark)

    context. Contributors: Per Brask, Dario Fo, Jette Barnholdt Hansen, Pil Hansen, Sven Åke Heed, Ulla Kallenbach, Sofie Kluge, Annelis Kuhlmann, Kela Kvam, Anna Lawaetz, Bent Flemming Nielsen, Franco Perrelli, Magnus Tessing Schneider, Antonio Scuderi. stage/page/play is published as a festschrift...

  6. Staging Collaborative Innovation Processes

    DEFF Research Database (Denmark)

    Pedersen, Signe; Clausen, Christian

    Organisations are currently challenged by demands for increased collaborative innovation internally as well as with external and new entities - e.g. across the value chain. The authors seek to develop new approaches to managing collaborative innovative processes in the context of open innovation...... and public private innovation partnerships. Based on a case study of a collaborative design process in a large electronics company the paper points to the key importance of staging and navigation of collaborative innovation process. Staging and navigation is presented as a combined activity: 1) to translate...... the diverse matters of concern into a coherent product or service concept, and 2) in the same process move these diverse holders of the matters of concern into a translated actor network which carry or support the concept....

  7. Staging Sociotechnical Spaces

    DEFF Research Database (Denmark)

    Clausen, Christian; Yoshinaka, Yutaka

    2007-01-01

    The management of innovation and product development is increasingly facing complex challenges of staging design processes across heterogeneous organisational spaces, with multiple actor-concerns and sources of knowledge. This paper addresses how insights from the Actor-Network Theory and political...... process theory may contribute to a reflexive understanding of design as the staging of socio-technical relations and processes cutting across boundaries of diverse organisational, political and knowledge domains. This idea is pursued through the notion of ‘socio-technical spaces’. Socio-technical space...... of product development. The concept of socio-technical spaces is further illustrated through actual examples from industry dealing with early conceptualisation in product development and the role played by management concepts in the configuration of spaces....

  8. Calibration of Nanopositioning Stages

    Directory of Open Access Journals (Sweden)

    Ning Tan

    2015-12-01

    Full Text Available Accuracy is one of the most important criteria for the performance evaluation of micro- and nanorobots or systems. Nanopositioning stages are used to achieve the high positioning resolution and accuracy for a wide and growing scope of applications. However, their positioning accuracy and repeatability are not well known and difficult to guarantee, which induces many drawbacks for many applications. For example, in the mechanical characterisation of biological samples, it is difficult to perform several cycles in a repeatable way so as not to induce negative influences on the study. It also prevents one from controlling accurately a tool with respect to a sample without adding additional sensors for closed loop control. This paper aims at quantifying the positioning repeatability and accuracy based on the ISO 9283:1998 standard, and analyzing factors influencing positioning accuracy onto a case study of 1-DoF (Degree-of-Freedom nanopositioning stage. The influence of thermal drift is notably quantified. Performances improvement of the nanopositioning stage are then investigated through robot calibration (i.e., open-loop approach. Two models (static and adaptive models are proposed to compensate for both geometric errors and thermal drift. Validation experiments are conducted over a long period (several days showing that the accuracy of the stage is improved from typical micrometer range to 400 nm using the static model and even down to 100 nm using the adaptive model. In addition, we extend the 1-DoF calibration to multi-DoF with a case study of a 2-DoF nanopositioning robot. Results demonstrate that the model efficiently improved the 2D accuracy from 1400 nm to 200 nm.

  9. Nuclear Cryogenic Propulsion Stage

    Science.gov (United States)

    Houts, Michael G.; Borowski, S. K.; George, J. A.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Adams, R. B.

    2012-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced NEP.

  10. Fire on Stage

    Directory of Open Access Journals (Sweden)

    Nicholas Daly

    2017-12-01

    Full Text Available The nineteenth century theatre was fire-prone, to say the least. Across the century there were more than 1,100 major conflagrations in the world’s theatres, and countless smaller fires. In Great Britain almost every theatre seems to have burned down at some point. And yet, despite, or perhaps in part because of, this appalling record, fires were a staple feature of stage spectacle. Some plays placed them at the very centre of the entertainment, and as the century went on stage fires became more and more elaborate. Actual or simulated conflagrations were conjured up using a diverse array of technologies, some of them very simple, some depending on the most recent scientific discoveries. Here, I give a short tour of these technologies and their use in the plays of the period, and suggest some of the pleasures that they offered. While onstage flames could draw people in, offering an experience of immersive suspense, for instance, they also interrupted the dramatic flow, reminding audiences that they were seeing a performance, getting something for their money. To this extent, we are reminded that nineteenth-century drama provided something of a mixed and spectacular ‘theatre of attractions’, closer at times to the circus than to the novel.

  11. The principles of cancer staging.

    Science.gov (United States)

    Brierley, James; Gospodarowicz, Mary; O'Sullivan, Brian

    2016-01-01

    The anatomic disease extent or tumour stage of a cancer at diagnosis as a determinant of prognosis is discussed. The importance of cancer stage in individual patient prognosis and determination of treatment is reviewed as well as its value in research and cancer control activities. The conflict between the need for stability of cancer stage definitions over time and the need to evolve with advances in medicine are examined. The e cancer elearning modules on Cancer Stage are introduced.

  12. Science on stage

    Science.gov (United States)

    Ciceri, Piera

    2017-04-01

    Pictures and diaries of the legendary Antarctic Expedition of sir E. Shackleton and his crew aboard the Endurance (1914/16) have become the starting point to learn about Natural Science, Earth Science and Climate Change. Students, 12 years old, were involved in hands on activities, took part to a network project, used interactive virtual labs, talked to university researchers on Skype and became the writers of a play. The theater was the place to act the story of Shackleton's expedition, to "stage" some scientific experiments and to tell to the audience about ice cores, climate change, physical and geographical characteristic of polar regions, thermal phenomena related to adaptations of polar animals, solar radiation at different latitude, day/night duration. The project was carried out from teachers of science, letters, geography and English in collaboration with the "Piccolo Teatro di Milano", the association "Scienza Under 18", researchers of the "Byrd Polar and Climate Research Center of Ohio State University" and of "M. Zucchelli Station" based in Antarctica. In our opinion drama activities improve both verbal and non-verbal communication skills and soft skills such as teamwork, responsibility and commitment. To be able to write and to act, students need a deep understanding of contents. To have an audience different from their own teachers and classmates and to interact with university researchers offer real tasks. The project aims to develop a relevant skill for the students: to become awareness citizens in a changing word.

  13. Science on stage

    CERN Document Server

    2005-01-01

    During the opening ceremony, the audience was dazzled by a juggling show involving dramatic light effects. They also took away with them a teacher's sheet explaining some of the scientific concepts involved in juggling. Science teachers can sometimes be quite humorous when it comes to explaining serious matters, as those who took part in the 'Science on Stage' festival held at CERN from 21 to 25 November were able to see for themselves. The 500 or so participants from 27 different countries, mostly science teachers but also some university lecturers, science outreach specialists and students, had the opportunity to share their experience of the teaching of science. They also attended presentations and shows, took part in workshops and visited a fair with stands offering ideas on how to make school science lessons more appealing. The festival, organised by the EIROforum (a partnership between CERN, EFDA, ESA, ESO, EMBL, ESRF and ILL), marked the end of two years of projects for the promotion of science in vir...

  14. Matching mechanism analysis on an adaptive cycle engine

    Directory of Open Access Journals (Sweden)

    Junchao Zheng

    2017-04-01

    Full Text Available As a novel aero-engine concept, adaptive cycle aero-engines (ACEs are attracting wide attention in the international aviation industry due to their potential superior task adaptability along a wide flight regime. However, this superior task adaptability can only be demonstrated through proper combined engine control schedule design. It has resulted in an urgent need to investigate the effect of each variable geometry modulation on engine performance and stability. Thus, the aim of this paper is to predict and discuss the effect of each variable geometry modulation on the matching relationship between engine components as well as the overall engine performance at different operating modes, on the basis of a newly developed nonlinear component-based ACE performance model. Results show that at all four working modes, turning down the high pressure compressor variable stator vane, the low pressure turbine variable nozzle, the nozzle throat area, and turning up the core-driven fan stage variable stator vane, the high pressure turbine variable nozzle can increase the thrust at the expense of a higher high pressure turbine inlet total temperature. However, the influences of these adjustments on the trends of various engine components’ working points and working lines as well as the ratio of the rotation speed difference are different from each other. The above results provide valuable guidance and advice for engine combined control schedule design.

  15. Staged membrane oxidation reactor system

    Science.gov (United States)

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

    2012-09-11

    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  16. Staged Repository Development Programmes

    International Nuclear Information System (INIS)

    Isaacs, T

    2003-01-01

    Programs to manage and ultimately dispose of high-level radioactive wastes are unique from scientific and technological as well as socio-political aspects. From a scientific and technological perspective, high-level radioactive wastes remain potentially hazardous for geological time periods-many millennia-and scientific and technological programs must be put in place that result in a system that provides high confidence that the wastes will be isolated from the accessible environment for these many thousands of years. Of course, ''proof'' in the classical sense is not possible at the outset, since the performance of the system can only be known with assurance, if ever, after the waste has been emplaced for those geological time periods. Adding to this challenge, many uncertainties exist in both the natural and engineered systems that are intended to isolate the wastes, and some of the uncertainties will remain regardless of the time and expense in attempting to characterize the system and assess its performance. What was perhaps underappreciated in the early days of waste management and repository program development were the unique and intense reactions that the institutional, political, and public bodies would have to repository program development, particularly in programs attempting to identify and then select sites for characterization, design, licensing, and ultimate development. Reactions in most nations were strong, focused, unrelenting, and often successful in hindering, derailing, and even stopping national repository programs. The reasons for such reactions and the measures to successfully respond to them are still evolving and continue to be the focus of many national program and political leaders. Adaptive Staging suggests an approach to repository program development that reflects the unique challenges associated with the disposal of high-level radioactive waste. The step-wise, incremental, learn-as-you-go approach is intended to maximize the

  17. Second stage gasifier in staged gasification and integrated process

    Science.gov (United States)

    Liu, Guohai; Vimalchand, Pannalal; Peng, Wan Wang

    2015-10-06

    A second stage gasification unit in a staged gasification integrated process flow scheme and operating methods are disclosed to gasify a wide range of low reactivity fuels. The inclusion of second stage gasification unit operating at high temperatures closer to ash fusion temperatures in the bed provides sufficient flexibility in unit configurations, operating conditions and methods to achieve an overall carbon conversion of over 95% for low reactivity materials such as bituminous and anthracite coals, petroleum residues and coke. The second stage gasification unit includes a stationary fluidized bed gasifier operating with a sufficiently turbulent bed of predefined inert bed material with lean char carbon content. The second stage gasifier fluidized bed is operated at relatively high temperatures up to 1400.degree. C. Steam and oxidant mixture can be injected to further increase the freeboard region operating temperature in the range of approximately from 50 to 100.degree. C. above the bed temperature.

  18. Experimental investigation on ignition and lean blow-out performance of a multi-sector centrally staged combustor

    Science.gov (United States)

    Liu, Fuqiang; Zhang, Kaiyu; Mu, Yong; Liu, Cunxi; Yang, Jinhu; Xu, Gang; Zhu, Junqiang

    2014-10-01

    Improvement on extinction and pollution emission have become one of the most prominent research topics in gas turbine. It is widely recognized that the fuel/air mixture distribution in the recirculation zone is a critical factor in improving lean blow-out (LBO) and ignition. This paper proposed a new low emission scheme with fuel staged centrally and hybrid injector to improve flameout and emission. A relative small amount of fuel enters into central pilot airblast atomizer burner and then atomized by inner swirl air. The remaining majority of fuel is directly injected into vane channels of the primary swirler through a series of holes located on the sidewall of the main stage. Only pilot stage is fueled under ignition and lean flameout condition. The uniformity of fuel/air mixture distribution in the primary zone of the new design decreases NOX emission, meanwhile the fuel air mixture in pilot recirculation zone is locally rich to improve flameout and ignition. Experimental investigation was conducted to compare the new scheme with baseline design of dual-swirler in terms of LBO and ignition characteristics under the same condition in a multi-sector combustor. It is found that the fuel-air ratio of ignition limit and LBO decrease with the reference velocity increasing. The experimental results also show that the new scheme successfully improve lean blow-out and broaden the operation range of the combustor. The experimental results indicated that the centrally staged scheme can widen the operation boundary of the combustor and can provide guidance for design and optimization of combustion chamber.

  19. Simulation of Indexing and Clocking with Harmonic Balance

    Directory of Open Access Journals (Sweden)

    Christian Frey

    2017-12-01

    Full Text Available The aim of this paper is to demonstrate how the harmonic balance method can be used to predict rotor–rotor and stator–stator interactions in turbomachinery. These interactions occur in the form of clocking and indexing. Whereas clocking refers to the dependency of the performance on the relative circumferential positioning of the rotors or stators, the term indexing is used when different blade (or vane counts lead to an aperiodic time-averaged flow. The approach developed here is closely related to the one presented by He, Chen, Wells, Li, and Ning, who generalised the Nonlinear Harmonic method to zero-frequency disturbances. In particular, configurations with only one passage per blade row are used for the simulations. We validate the methods by means of the simulation of a fan stage configuration with rotationally asymmetric inlet conditions. It is demonstrated that the harmonic balance solver is able to accurately predict the inhomogeneity of the time-averaged flow field in the stator row. Moreover, the results show that the approach offers a considerable gain in computational efficiency.

  20. Cooling circuit for steam and air-cooled turbine nozzle stage

    Science.gov (United States)

    Itzel, Gary Michael; Yu, Yufeng

    2002-01-01

    The turbine vane segment includes inner and outer walls with a vane extending therebetween. The vane includes leading and trailing edge cavities and intermediate cavities. An impingement plate is spaced from the outer wall to impingement-cool the outer wall. Post-impingement cooling air flows through holes in the outer wall to form a thin air-cooling film along the outer wall. Cooling air is supplied an insert sleeve with openings in the leading edge cavity for impingement-cooling the leading edge. Holes through the leading edge afford thin-film cooling about the leading edge. Cooling air is provided the trailing edge cavity and passes through holes in the side walls of the vane for thin-film cooling of the trailing edge. Steam flows through a pair of intermediate cavities for impingement-cooling of the side walls. Post-impingement steam flows to the inner wall for impingement-cooling of the inner wall and returns the post-impingement cooling steam through inserts in other intermediate cavities for impingement-cooling the side walls of the vane.

  1. Characterization of Aerodynamic Forcing Functions for Embedded Rotor Resonant Response in a Multistage Compressor

    Science.gov (United States)

    Kormanik, Nicholas J., III

    There are two main objectives associated with this research: The first portion examines the flow field within the embedded stage of the Purdue 3-Stage Axial Compressor and the aerodynamics responsible for exciting a forced response condition on an embedded rotor. The second portion focuses on the upgrades made to the facility to accommodate a new compressor design, as well as the basic performance characteristics that were acquired for the baseline model. With the first phase of this research endeavor, the first chord-wise bending vibratory mode was examined with a standard stator 1 (S1) blade-count configuration (44 vanes). Next, a reduced S1 blade-count configuration (38 vanes) was implemented to observe how a reduced vane count might impact the forced response at the first torsion vibratory mode. To capture these aerodynamic considerations, stagnation pressure and thermal anemometry probes were used throughout the embedded stage to provide a detailed picture of the influence associated with rotor and stator wakes. These data were also used to observe the potential field effects from the downstream blade-rows. The overall purpose of this campaign was to provide accurate and reliable dataset that could be used to further enhance and validate the computational aeromechanics tools used by the GUIde V consortium, the sponsors for this research. The second phase of this involves the redesign of the Purdue 3-Stage Axial Compressor Facility to accommodate a new compressor, designed by Rolls-Royce, that requires higher mass flow rates, pressure ratios, speeds, and temperatures. Along with many of the mechanical upgrades associated with an adaptation of the driveline and throttle system, health-monitoring upgrades were made to improve the safety and integrity of the compressor system, particularly with respect to temperature and vibrations. Instrumentation improvements include new pressure transducers to observe higher pressures and mass flow rates and the implementation

  2. Aerodynamic performance of 0.4066-scale model of JT8D refan stage with S-duct inlet

    Science.gov (United States)

    Moore, R. D.; Kovich, G.; Lewis, G. W., Jr.

    1977-01-01

    A scale model of the JT8D refan stage was tested with a scale model of the S-duct inlet design for the refanned Boeing 727 center engine. Detailed survey data of pressures, temperatures, and flow angles were obtained over a range of flows at speeds from 70 to 97 percent of design speed. Two S-duct configurations were tested; one with a bellmouth inlet and the other with a flight lip inlet. The results indicated that the overall performance was essentially unaffected by the distortion generated by the S-duct inlet. The stall weight flow increased by less than 0.5 kg/sec (approximately 1.5% of design flow) with the S-duct inlet compared with that obtained with uniform flow. The detailed measurements indicated that the inlet guide vane (IGV) significantly reduced circumferential variations. For example, the flow angles ahead of the IGV were positive in the right half of the inlet and negative in the left half. Behind the IGV, the flow angles tended to be more uniform circumferentially.

  3. Control of stage by stage changing linear dynamic systems

    Directory of Open Access Journals (Sweden)

    Barseghyan V.R.

    2012-01-01

    Full Text Available In this paper, the control problems of linear dynamic systems stage by stage changing and the optimal control with the criteria of quality set for the whole range of time intervals are considered. The necessary and sufficient conditions of total controllability are also stated. The constructive solving method of a control problem is offered, as well as the definitions of conditions for the existence of programmed control and motions. The explicit form of control action for a control problem is constructed. The method for solving optimal control problem is offered, and the solution of optimal control of a specific target is brought.

  4. Firebag stages 3 and 4

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Heather [Suncore Energy (Canada)

    2011-07-01

    In this presentation, Suncor Energy Inc. outlines the current and projected future status of their growth in the oil production industry. Under a new partnership with Total, Suncor has seen growth of 10% in its oil sands operations. Firebag stages 3 and 4 were fully sanctioned in 2008 for 125kbbl/day as a feed source for the Voyageur upgrader in 2010/2012. Although the projects were suspended in 2009, due to difficulties in the economy, safety strategies were put in place and the projects were subsequently restarted. Suncor's aim was to meet new expectations with respect to safety, timing, and costs. Currently, construction of Stage 3 is near completion, with most of the plant in turnover and start-up mode. Stage 4 construction is also making good progress with new safety plans, workforce planning, and repeat contractors. Future plans include the completion of stages 3 and 4, scheduling and strategy for stages 5 and 6, and program approaches for key elements of growth (engineering, construction, and labor shortages).

  5. Correlation for cross-flow resistance coefficient using STAR-CCM+ simulation data for flow of water through rod bundle supported by spacer grid with split-type mixing vane

    Energy Technology Data Exchange (ETDEWEB)

    Agbodemegbe, V.Y., E-mail: vincevalt@gmail.com [Karlsruhe Institute of Technology, Institute of Fusion and Reactor Technique, Kaiserstrasse 12, Karlsruhe (Germany); Cheng, Xu, E-mail: xu.cheng@kit.edu [Karlsruhe Institute of Technology, Institute of Fusion and Reactor Technique, Kaiserstrasse 12, Karlsruhe (Germany); Akaho, E.H.K, E-mail: akahoed@yahoo.com [School of Nuclear and Allied Sciences, University of Ghana, PO Box AE 1, Kwabenya, Accra (Ghana); Allotey, F.K.A, E-mail: fkallotey@gmail.com [Institute of Mathematical Sciences, PO Box LG 197, Legon, Accra (Ghana)

    2015-04-15

    Highlights: • Investigate spacer grid with split-type mixing vanes. • Extent of predictability of experimental data by STAR-CCM+. • Reliability of two equation turbulence models. • Resistance to cross-flow through gaps. - Abstract: Mass transfer by diversion cross-flow through gaps is an important inter-subchannel interaction in fuel bundle of power reactors. It is normally due to the lateral pressure difference between adjacent sub-channels. This phenomenon is augmented in the presence of flow deflectors and is referred to as, directed cross-flow. Diversion cross-flow carries the momentum and energy of flow and hence affects the velocity and temperature profile in the rod bundle. The resistance to cross-flow in the transverse momentum equations is specified by the cross-flow resistant coefficient which is the subject of concern in the present study. In order to obtain data to correlate cross-flow resistance coefficient, computational fluid dynamic simulation using STAR-CCM+ was performed for flow of water at the bundle Reynolds number of Re1 = 3.4×10{sup 4} through a 5 × 5 rod bundle geometry supported by spacer grid with split mixing vanes for which the rod to rod pitch to diameter ratio was 1.33 and the rod to wall pitch to diameter ratio was 0.74. The two layer k-epsilon turbulence model with an all y+ automatic wall treatment function in STAR-CCM+ were adopted for an isothermal single phase (water) flow through the geometry. The objectives were to primarily investigate the extent of predictability of the experimental data by the computational fluid dynamic (CFD) simulation as a measure of reliability on the CFD code employed and also apply the simulation data to develop correlations for determining resistance coefficient to cross-flow. Validation of simulation results with experimental data showed good correlation of mean flow parameters with experimental data whiles turbulent fluctuations deviated largely from experimental trends. Generally, the

  6. DIRECT COUPLED PROGRESSIVE STAGE PULSE COUNTER APPARATUS

    Science.gov (United States)

    Kaufman, W.M.

    1962-08-14

    A progressive electrical pulse counter circuit was designed for the counting of a chain of input pulses of random width and/or frequency. The circuit employs an odd and even pulse input line alternately connected to a series of directly connected bistable counting stages. Each bistable stage has two d-c operative states which stage, when in its rnrtial state, prevents the next succeeding stage from changing its condition when the latter stage is pulsed. Since only altennate stages are pulsed for each incoming pulse, only one stage will change its state for each input pulse thereby providing prog essive stage by stage counting. (AEC)

  7. PET in lung cancer staging

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, R. E. [Duke University Medical Center, Dept. of Radiology, Durham, NC (United States)

    2001-09-01

    The primary clinical application of FDG-PET is in the evaluation of patients with lung cancer and includes diagnosis, staging and restaging of non-small cell lung cancer. PET has a very high accuracy (sensitivity=97%, specificity=78%) for characterizing nodules that are indeterminate by chest radiograph and computed tomography. The major utility of PET in the evaluation of patients with lung cancer is the staging of the entire body. PET is more accurate than the conventional imaging modalities of CT and bone scans in the detection of metastatic disease. PET is accurate in the staging of the mediastinum, adrenal glands, and the skeletal system. PET is not as accurate in the detection of brain metastases because of their small size and the normal cortical accumulation.

  8. Acoustic Performance of Novel Fan Noise Reduction Technologies for a High Bypass Model Turbofan at Simulated Flights Conditions

    Science.gov (United States)

    Elliott, David M.; Woodward, Richard P.; Podboy, Gary G.

    2010-01-01

    Two novel fan noise reduction technologies, over the rotor acoustic treatment and soft stator vane technologies, were tested in an ultra-high bypass ratio turbofan model in the NASA Glenn Research Center s 9- by 15-Foot Low-Speed Wind Tunnel. The performance of these technologies was compared to that of the baseline fan configuration, which did not have these technologies. Sideline acoustic data and hot film flow data were acquired and are used to determine the effectiveness of the various treatments. The material used for the over the rotor treatment was foam metal and two different types were used. The soft stator vanes had several internal cavities tuned to target certain frequencies. In order to accommodate the cavities it was necessary to use a cut-on stator to demonstrate the soft vane concept.

  9. Early stage fuel cell funding

    International Nuclear Information System (INIS)

    Bergeron, C.

    2004-01-01

    'Full text:' Early stage venture funding requires an in depth understanding of both current and future markets as well as the key technical hurdles that need to be overcome for new technology to commercialize into successful products for mass markets. As the leading fuel cell and hydrogen investor, Chrysalix continuously reviews global trends and new technologies, evaluates them with industry leaders worldwide and tries to match them up with the best possible management teams when selecting its early stage investments. Chrysalix Energy Limited Partnership is an early-stage venture capital firm focusing on fuel cell and related fueling technology companies and is a private equity joint venture between Ballard Power Systems, BASF Venture Capital, The BOC Group, The Boeing Company, Duke Energy, Mitsubishi Corporation and Shell Hydrogen. Operating independently, Chrysalix offers a unique value proposition to its clients throughout the business planning, start-up and operations phases of development. Chrysalix provides early-stage funding to new companies as well as management assistance, technological knowledge, organized networking with industry players and experience in the management of intellectual property. (author)

  10. Stages of neuronal network formation

    Science.gov (United States)

    Woiterski, Lydia; Claudepierre, Thomas; Luxenhofer, Robert; Jordan, Rainer; Käs, Josef A.

    2013-02-01

    Graph theoretical approaches have become a powerful tool for investigating the architecture and dynamics of complex networks. The topology of network graphs revealed small-world properties for very different real systems among these neuronal networks. In this study, we observed the early development of mouse retinal ganglion cell (RGC) networks in vitro using time-lapse video microscopy. By means of a time-resolved graph theoretical analysis of the connectivity, shortest path length and the edge length, we were able to discover the different stages during the network formation. Starting from single cells, at the first stage neurons connected to each other ending up in a network with maximum complexity. In the further course, we observed a simplification of the network which manifested in a change of relevant network parameters such as the minimization of the path length. Moreover, we found that RGC networks self-organized as small-world networks at both stages; however, the optimization occurred only in the second stage.

  11. Metrics for Stage Lighting Technology.

    Science.gov (United States)

    Cooper, Gloria S., Ed; Magisos, Joel H., Ed.

    Designed to meet the job-related metric measurement needs of stage lighting technology students, this instructional package is one of five for the arts and humanities occupations cluster, part of a set of 55 packages for metric instruction in different occupations. The package is intended for students who already know the occupational terminology,…

  12. Stages of Merkel Cell Carcinoma

    Science.gov (United States)

    ... tissue. Merkel cells are in the layer of basal cells at the deepest part of the epidermis and are connected to nerves. Merkel cell carcinoma tends to grow quickly and to metastasize (spread) at an early stage . It usually spreads first to nearby lymph nodes and then may spread to lymph nodes or ...

  13. When science takes centre stage

    CERN Multimedia

    2005-01-01

    The teachers at 'Science on stage' are not emotionally attached to their chalk. Neither are they are weary old men who sport tweed jackets with elbow-patches and enter into conversation with their blackboards. Actually, 'Science on stage' teachers are far from the cliché of the boring physics teacher who can only inspire yawns from his pupils. Some present the basic principles of mechanics using a bicycle, others explain chemistry with examples from everyday life. The most audacious of them go so far as to explain the Doppler effect by means of a play in which Einstein dreams about jumping cows... These are but a few of the activities and plays that will be shown during the EIROforum1 Science on Stage Festival (organised by 7 European scientific organisations including CERN), to be held from 21 to 25 November at CERN, Geneva. This festival is dedicated to the teaching science in order to make it more attractive. After the first edition 'Physics on Stage' which was held in 2000 at CERN, the laboratory agai...

  14. Operation of staged membrane oxidation reactor systems

    Science.gov (United States)

    Repasky, John Michael

    2012-10-16

    A method of operating a multi-stage ion transport membrane oxidation system. The method comprises providing a multi-stage ion transport membrane oxidation system with at least a first membrane oxidation stage and a second membrane oxidation stage, operating the ion transport membrane oxidation system at operating conditions including a characteristic temperature of the first membrane oxidation stage and a characteristic temperature of the second membrane oxidation stage; and controlling the production capacity and/or the product quality by changing the characteristic temperature of the first membrane oxidation stage and/or changing the characteristic temperature of the second membrane oxidation stage.

  15. Survival Advantage Associated with Decrease in Stage at Detection from Stage IIIC to Stage IIIA Epithelial Ovarian Cancer

    Science.gov (United States)

    Lefringhouse, Jason; Pavlik, Edward; Miller, Rachel; DeSimone, Christopher; Ueland, Frederick; Kryscio, Richard; van Nagell, J. R.

    2014-01-01

    Objective. The aim of this study was to document the survival advantage of lowering stage at detection from Stage IIIC to Stage IIIA epithelial ovarian cancer. Methods. Treatment outcomes and survival were evaluated in patients with Stage IIIA and Stage IIIC epithelial ovarian cancer treated from 2000 to 2009 at the University of Kentucky Markey Cancer Center (UKMCC) and SEER institutions. Results. Cytoreduction to no visible disease (P < 0.0001) and complete response to platinum-based chemotherapy (P < 0.025) occurred more frequently in Stage IIIA than in Stage IIIC cases. Time to progression was shorter in patients with Stage IIIC ovarian cancer (17 ± 1 months) than in those with Stage II1A disease (36 ± 8 months). Five-year overall survival (OS) improved from 41% in Stage IIIC patients to 60% in Stage IIIA patients treated at UKMCC and from 37% to 56% in patients treated at SEER institutions for a survival advantage of 19% in both data sets. 53% of Stage IIIA and 14% of Stage IIIC patients had NED at last followup. Conclusions. Decreasing stage at detection from Stage IIIC to stage IIIA epithelial ovarian cancer is associated with a 5-year survival advantage of nearly 20% in patients treated by surgical tumor cytoreduction and platinum-based chemotherapy. PMID:25254047

  16. Staging N0 oral cancer

    DEFF Research Database (Denmark)

    Thomsen, Jørn Bo; Sørensen, Jens Ahm; Grupe, Peter

    2005-01-01

    PURPOSE: To compare sentinel lymph node biopsy, magnetic resonance imaging (MRI), Doppler ultrasonography, and palpation as staging tools in patients with T1/T2 N0 cancer of the oral cavity. MATERIAL AND METHODS: Forty consecutive patients were enrolled (17 F and 23 M, aged 32-90 years), 24 T1...... and 16 T2 cN0 squamous cell carcinoma of the oral cavity. Palpation was carried out by two observers prior to inclusion. MRI, gray-scale and Doppler ultrasonography were performed. Lymphoscintigraphies were done after peritumoral injections of 99mTc labelled rheniumsulphide nanocolloid, followed......%, but the sensitivity of MRI 36% was low. The specificities were 100%, 85%, and 93%, respectively. By combined sentinel lymph node biopsy and ultrasonography the overall sensitivity could have been 100%. CONCLUSION: Sentinel lymph node biopsy improved staging of patients with small N0 oral cancers. Combined sentinel...

  17. Sleep stages, memory and learning.

    Science.gov (United States)

    Dotto, L

    1996-04-15

    Learning and memory can be impaired by sleep loss during specific vulnerable "windows" for several days after new tasks have been learned. Different types of tasks are differentially vulnerable to the loss of different stages of sleep. Memory required to perform cognitive procedural tasks is affected by the loss of rapid-eye-movement (REM) sleep on the first night after learning occurs and again on the third night after learning. REM-sleep deprivation on the second night after learning does not produce memory deficits. Declarative memory, which is used for the recall of specific facts, is not similarly affected by REM-sleep loss. The learning of procedural motor tasks, including those required in many sports, is impaired by the loss of stage 2 sleep, which occurs primarily in the early hours of the morning. These findings have implications for the academic and athletic performance of students and for anyone whose work involves ongoing learning and demands high standards of performance.

  18. Acute pancreatitis: staging with CT

    International Nuclear Information System (INIS)

    Gialeli, E.; Petrocheilou, G.; Georgaki, S.; Tzemailas, I.; Adraktas, A.; Charilas, G.; Patsiogiannis, V.

    2012-01-01

    Full text: Introduction: Computed Tomography (CT) is the imaging modality of choice for the diagnosis and staging of acute pancreatitis and its complications. Objectives and tasks: The purpose of this presentation is to demonstrate the findings in CT images which are useful for staging acute pancreatitis according to Balthazar, their significance and restrictions. Materials and methods: CT images from patients who were referred to our Department for an abdominal CT scan for the diagnosis or/and staging of acute pancreatitis were retrospectively studied. Results: In acute pancreatitis, CT helps to stage the severity of inflammatory process, to detect pancreatic necrosis and to depict local complications. CT severity index (CTSI), which was proposed by Balthazar et al, combines the grade of pancreatitis with the extent of pancreatic necrosis assigning points to the patients in order to find the severity index which scales from 0-10. More points are given for a higher grade of pancreatitis and for more extensive necrosis. Types of pancreatitis according to CTSI are: interstitial (Balthazar grade A-C), exudative (Balthazar grade D or E), necrotising (Balthazar grade E, CTSI:10) and central gland necrotising. Patients with pancreatitis but no collections or necrosis have an interstitial (mild) pancreatitis. In exudative pancreatitis there is normal enhancement of the entire pancreas associated with extensive peripancreatic collections. Necrotizing (severe) pancreatitis is characterized by protacted clinical course, high incidence of local complications and high mortality rate. Central gland necrosis is a subtype of necrotizing pancreatitis. Conclusions: The combination of CT imaging and clinical and laboratory evaluation allows the early diagnosis of acute pancreatitis. Acute pancreatitis may vary from a mild uneventful disease to a severe life-threatening illness with multisystemic organ failure. Thus, it is crucial to identify patients who are at high risk of severe

  19. Patch stage of mycosis fungoides

    Directory of Open Access Journals (Sweden)

    Mavarkar Laxman

    2001-01-01

    Full Text Available Parapsoriasis is aeon troversial topic. There are many studies regarding the relationship of parapsoriasis to lymphoma but no correlation between histology and clinical appearance. Parapsoriasis satisfies histologic criteria for mycosis fungoides and therefore it should be considered as patch stage of mycosis fungoides. A 30-year-old man presented with scaly skin lesions over the trunk since 4 years. Routine blood and urine investigations were normal. Skin biopsy from the lesion revealed atypical lymphocytes within the epidermis without spongiosis.

  20. Images of gastric cancer stages

    International Nuclear Information System (INIS)

    Castro Aragon, I.M.

    1999-01-01

    The present work has the objective to review the importance of the images in the preoperating stage of the gastric cancer. It has been emphasized in the modalities of transabdominal ultrasound as much as endoscopic and TAC since they are most valuable in the stage. Certainly the importance of conventional radiology (gastroduodenal series) is also valuable in the stage of the tumor, specially in considering the depth of the same one. In order to make this overhaul, the recent bibliography was consulted but, specially the published one by Japaneses since they follow a classification and methodology different from the used one in most of the countries that belong to the World-wide Organization of the Health. They made an overhaul of approximately 200 cases of patients who have been diagnosed and treated in the Center of Detection of Gastric Cancer of Cartago. In each case review the file, radiological, sonographic and pathological studies, and the cases were chosen that better illustrated the exposed subjects. (Author) [es

  1. MR staging of endometrial carcinoma

    International Nuclear Information System (INIS)

    Innocenti, P.; Agostini, S.; Erroi, C.; Ambrogetti, D.; Cellerini, A.; Nori, J.

    1991-01-01

    Biopsy is the technique of choice for the definitive diagnosis of endometrial carcinoma. Since lymphatic tumor spread has been demonstrated to depend on the degree of myometrial involvement, the definition of the latter with imaging techniques may significantly affect both pfognosis and therapy. We investigated, by means of MR imaging at 0.5 T, 14 patients with endometrial carcinoma, to assess both tumor stage and myometrial involvement. FIGO staging system was employed, and M parameter evaluated (M0= no myometrial involvement; M1involvement confined to the inner third; M2= Involvement confined to the middle third; M3= involvement of the whole myometrium). Another parameter was the characteristic high signal of the tumor on PD and T2W images. The patients were then operated and MR information was correlated with surgical findings. Overall diagnostic accuracy of MR imaging was 85.7% in tumor staging, and 92.2% in defining M parameter. Tumor spread into adnexa and into cervical canal was poorly demonstrated by MR imaging

  2. Numerical and experimental investigation of the unsteady flow field over a simplified hydrofoil plate

    OpenAIRE

    Pislevikj, Jasmina

    2017-01-01

    In this thesis, the behavior of a simplified hydrofoil in an unsteady water flow field is tested. Due to frequent load variations in high head Francis turbines, the runner vanes happen to break. Rotor stator interaction causes vibrations on the runner vanes. To simulate those vibrations in laboratory conditions, the hydrofoil, mounted in a cascade test rig, is excited with piezo electric patches. The experiment in this thesis shows the behavior of the hydrofoil in different water flow velocit...

  3. Single conversion stage amplifier - SICAM

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.

    2005-12-15

    This Ph.D. thesis presents a thorough analysis of the so called SICAM - SIngle Converter stage AMplifier approach to building direct energy conversion audio power amplifiers. The mainstream approach for building isolated audio power amplifiers today consists of isolated DC power supply and Class D amplifier, which essentially represents a two stage solution, where each of the components can be viewed as separate and independent part. The proposed SICAM solution strives for direct energy conversion from the mains to the audio output, by dedicating the operation of the components one to another and integrating their functions, so that the final audio power amplifier represents a single-stage topology with higher efficiency, lower volume, less board space, lower component count and subsequently lower cost. The SICAM approach is both applicable to non-isolated and isolated audio power amplifiers, but the problems encountered in these two cases are different. Non-isolated SICAM solutions are intended for both AC mains-connected and battery-powered devices. In non-isolated mains-connected SICAMs the main idea is to simplify the power supply or even provide integrated power factor correction (PFC) functions, while still maintaining low component stress and good audio performance by generally decreasing the input voltage level to the Class D audio power amplifier. On the other hand, non-isolated battery-powered SICAMs have to cope with the ever changing battery voltage and provide output voltage levels which are both lower and higher than the battery voltage, while still being simple and single-stage energy conversion solutions. In isolated SICAMs the isolation transformer adjusts the voltage level on the secondary side to the desired level, so the main challenges here are decreasing the size of the magnetic core and reducing the number and size of bulky reactive components as much as possible. The main focus of this thesis is directed towards the isolated SICAMs and

  4. Preoperative staging of rectal cancer.

    Science.gov (United States)

    Smith, Neil; Brown, Gina

    2008-01-01

    Detailed preoperative staging using high resolution magnetic resonance imaging (MRI) enables the selection of patients that require preoperative therapy for tumour regression. This information can be used to instigate neoadjuvant therapy in those patients with poor prognostic features prior to disturbing the tumour bed and potentially disseminating disease. The design of trials incorporating MR assessment of prognostic factors prior to therapy has been found to be of value in assessing treatment modalities and outcomes that are targeted to these preoperative prognostic subgroups and in providing a quantifiable assessment of the efficacy of particular chemoradiation treatment protocols by comparing pre-treatment MR staging with post therapy histology assessment. At present, we are focused on achieving clear surgical margins of excision (CRM) to avoid local recurrence. We recommend that all patients with rectal cancer should undergo pre-operative MRI staging. Of these, about half will have good prognosis features (T1-T3b, N0, EMVI negative, CRM clear) and may safely undergo primary total mesorectal excision. Of the remainder, those with threatened or involved margins will certainly benefit from pre-operative chemoradiotherapy with the aim of downstaging to permit safe surgical excision. In the future, our ability to recognise features predicting distant failure, such as extramural vascular invasion (EMVI) may be used to stratify patients for neo-adjuvant systemic chemotherapy in an effort to prevent distant relapse. The optimal pre-operative treatment regimes for these patients (radiotherapy alone, systemic chemotherapy alone or combination chemo-radiotherapy) is the subject of current and future trials.

  5. [Initial stages of steel biocorrosion].

    Science.gov (United States)

    Zhigletsova, S K; Rodin, V B; Kobelev, V S; Aleksandrova, N V; Rasulova, G E; Kholodenko, V P

    2000-01-01

    Initial stages of corrosion of mild steel induced by Klebsiela rhinoscleromatis BO2 were studied in various media. The effect of the microorganism was detected 8-10 h after inoculation. The number of viable cells were virtually unchanged within one month in all media, but the corrosive activity of the strain decreased. The corrosive activity of microorganisms can be determined by spectrophotometry even only after incubation for 24 h. At a low level of organic substrate, even strong colonization with microorganisms does not inevitably result in a significant damage to metals.

  6. Staging Urban Experiences in Suburbia

    DEFF Research Database (Denmark)

    Jantzen, Christian; Vetner, Mikael

    2009-01-01

    Urban design provides props, requisites and decors for staging the users' performances in space. Design may facilitate or impede specific ways of moving around, interacting with objects and other people, feeling, learning and sense making.The actual design may very well contradict the explicit...... intentions of decision makers when commissioning, financing or planning new urban environments. Our case, the building of a new city centre for the Dutch city of Almere, illustrates this point. The project was supervised by Rem Koolhaas (OMA) and aimed at branding the city as a truly urban environment...

  7. Preadaptive Stage for Flight Origin

    Directory of Open Access Journals (Sweden)

    Bogdanovich I. A.

    2017-04-01

    Full Text Available Bipedalism as a preadaptive stage for bird’s flight is considered. We attribute the formation of full bipedalism in bird ancestors with pelvic limbs transition from segmental to parasagittal position. This transition was fast enough. We can assume that the pectoral limbs freed from the support remained while laterally spaced and gave set of transformations with different degrees of reduction. Thus morphologically “winglike” version of the thoracic limbs could appear. Parasagittal pelvic limbs allowed birds ancestors fast and maneuverable running, while the movements of free and highly movable thoracic limbs (feathered unrelated to flight provided dynamic stability of the animal. In addition, their fluttering movements facilitate hopping from one branch to another and the descent from the trees. On the bottom branches protobirds could jump with perching just by the pelvic anisodactyl limbs, not by thoracic as had supposed earlier. Active interaction of the primary simple feathers with air as well as its protective function could become an impetus for their transformation into differentiated structures. Unlike gliding (as preadaptive stage for active flight bipedalism with free feathered forelimbs provides per se parallel development of two autonomous enough locomotor systems of birds (flight and terrestrial locomotion and extensive adaptive radiation of representatives of the class.

  8. A simplified staging system based on the radiological findings in different stages of ochronotic spondyloarthropathy

    International Nuclear Information System (INIS)

    Jebaraj, Isaac; Chacko, Binita Riya; Chiramel, George Koshy; Matthai, Thomas; Parameswaran, Apurve

    2013-01-01

    This study describes a group of 26 patients with ochronotic spondyloarthropathy who were on regular treatment and follow-up at a tertiary level hospital and proposes a simplified staging system for ochronotic spondyloarthropathy based on radiographic findings seen in the thoracolumbar spine. This proposed classification makes it easy to identify the stage of the disease and start the appropriate management at an early stage. Four progressive stages are described: an inflammatory stage (stage 1), the stage of early discal calcification (stage 2), the stage of fibrous ankylosis (stage 3), and the stage of bony ankylosis (stage 4). To our knowledge, this is the largest reported series of radiological description of spinal ochronosis, and emphasizes the contribution of the spine radiograph in the diagnosis and staging of the disease

  9. Computational fluid dynamics analysis of the pump parameters in the helical flow pump.

    Science.gov (United States)

    Hosoda, Kyohei; Ishii, Kohei; Isoyama, Takashi; Saito, Itsuro; Inoue, Yusuke; Ariyoshi, Kouki; Ono, Toshiya; Nakagawa, Hidemoto; Imachi, Kou; Kumagai, Hiroshi; Abe, Yusuke

    2014-03-01

    The helical flow pump (HFP) was invented to develop a total artificial heart at the University of Tokyo in 2005. The HFP consists of the multi-vane impeller involving rotor magnets, a motor stator and pump housing having double-helical volutes. To investigate the characteristics of the HFP, computational fluid dynamics analysis was performed. Validation of the computational model was performed with the data of the actual pump. A control computational model in which the vane area corresponded approximately to that of the actual pump was designed for the parametric study. The parametric study was performed varying the vane height, vane width and helical volute pitch. When the vane height was varied from 0.5 to 1.5 times that of the control computational model, the H-Q (pressure head vs. flow) and efficiency curves were translated in parallel with the vane height. When the vane height was two and three times that of the control computational model, the profile of these curves changed. From the results, the best proportion for the vane was considered to be a vane height between 1.5 and 2 times the vane width. The effect of vane width was not very strong compared to that of the vane height. A similar tendency in vane height was observed by varying the helical volute pitch. The best helical volute-pitch size is considered to be between 1.5 and 2 times the vane width. Although further study is necessary to determine the best values for these parameters, the characteristics of the pump parameters in the HFP could be approximately clarified.

  10. Cooled Ceramic Turbine Vane, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — N&R Engineering will investigate the feasibility of cooled ceramics, such as ceramic matrix composite (CMC) turbine blade concepts that can decrease specific...

  11. Early stages of Ostwald ripening

    Science.gov (United States)

    Shneidman, Vitaly A.

    2013-07-01

    The Becker-Döring (BD) nucleation equation is known to predict a narrow double-exponential front (DEF) in the distribution of growing particles over sizes, which is due to early transient effects. When mass conservation is included, nucleation is eventually exhausted while independent growth is replaced by ripening. Despite the enormous difference in the associated time scales, and the resulting demand on numerics, within the generalized BD model the early DEF is shown to be crucial for the selection of the unique self-similar Lifshitz-Slyozov-Wagner asymptotic regime. Being preserved till the latest stages of growth, the DEF provides a universal part of the initial conditions for the ripening problem, regardless of the mass exchange mechanism between the nucleus and the matrix.

  12. The Nuclear Cryogenic Propulsion Stage

    Science.gov (United States)

    Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Doughty, Glen; Belvin, Anthony; Borowski, Stanley K.; Scott, John

    2014-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP). Nuclear propulsion can be affordable and viable compared to other propulsion systems and must overcome a biased public fear due to hyper-environmentalism and a false perception of radiation and explosion risk.

  13. Stage at diagnosis and ovarian cancer survival

    DEFF Research Database (Denmark)

    Maringe, Camille; Walters, Sarah; Butler, John

    2012-01-01

    We investigate what role stage at diagnosis bears in international differences in ovarian cancer survival.......We investigate what role stage at diagnosis bears in international differences in ovarian cancer survival....

  14. Interconnected Levels of Multi-Stage Marketing

    DEFF Research Database (Denmark)

    Vedel, Mette; Geersbro, Jens; Ritter, Thomas

    2012-01-01

    must not only decide in general on the merits of multi-stage marketing for their firm, but must also decide on which level they will engage in multi-stage marketing. The triadic perspective enables a rich and multi-dimensional understanding of how different business relationships influence each other......Multi-stage marketing gains increasing attention as knowledge of and influence on the customer's customer become more critical for the firm's success. Despite this increasing managerial relevance, systematic approaches for analyzing multi-stage marketing are still missing. This paper conceptualizes...... different levels of multi-stage marketing and illustrates these stages with a case study. In addition, a triadic perspective is introduced as an analytical tool for multi-stage marketing research. The results from the case study indicate that multi-stage marketing exists on different levels. Thus, managers...

  15. Stages of Ovarian Low Malignant Potential Tumors

    Science.gov (United States)

    ... tests or procedures are used for staging. Staging laparotomy (a surgical incision made in the wall of ... treatment. Two types of standard treatment are used: Surgery The type of surgery (removing the tumor in ...

  16. Research on the induction motor current signature for centrifugal pump at cavitation condition

    Directory of Open Access Journals (Sweden)

    Yin Luo

    2015-11-01

    Full Text Available Cavitation is a major undesirable phenomenon for centrifugal pump because it can cause hydraulic performance deterioration, pump damage by pitting and material erosion, and structural vibration and noise. Cavitation can appear within the entire range of the operating conditions; therefore, it must be prevented by all means. Sensorless monitoring technology based on motor current signature analysis is non-intrusive and economic for monitoring motor-driven equipment. Thus, this technology is suitable for centrifugal pump systems. The motor current signature for centrifugal pump load at the cavitation condition is the basis of this technology. However, systematic research is lacking on sensorless monitoring technology based on motor current signature. As a result, the tentative exploration for motor current signature at cavitation load was conducted in this study. The results show that the stator current is still a sinusoidal alternating current strictly to the law of sine. Moreover, the root mean square of the current fluctuates because of different flow regimes in the cavitation progress and decreases because vapor density is smaller than water density when cavitation is fully formed. For the stator current spectrum, the noise level, noise distribution, rotation speed, and vane pass frequency components show features in the cavitation process. These indicator indexes change according to the stage of cavitation development. Thus, the motor current signature analysis is found to be a feasible and cost-effective method for the stages of cavitation condition.

  17. Early-stage mantle cell lymphoma

    DEFF Research Database (Denmark)

    Dabaja, B S; Zelenetz, A D; Ng, A K

    2017-01-01

    Background: Mantle cell lymphoma (MCL) rarely presents as early-stage disease, but clinical observations suggest that patients who present with early-stage disease may have better outcomes than those with advanced-stage disease. Patients and methods: In this 13-institution study, we examined...

  18. Stages of tuberculous meningitis: a clinicoradiologic analysis

    International Nuclear Information System (INIS)

    Sher, K.; Firdaus, A.; Bullo, N.; Kumar, S.; Abbasi, A.

    2013-01-01

    Objective: To determine the frequencies and percentages of various clinicoradiologic variables of tuberculosis meningitis (TBM) with reference to British Medical Research Council (BMRC) staging of the disease. Study Design: A case series. Place and Duration of Study: Department of Neurology, Jinnah Postgraduate Medical Centre, Karachi, from October 2010 to September 2011. Methodology: The study included 93 adult patients with the diagnosis of tuberculous meningitis (TBM) at the study place. Patients were divided in three groups according to British Medical Research Council (BMRC) staging of TBM. Different clinical and radiological findings were analyzed at different stages of the disease. Data was analyzed using SPSS (Statistical Package of Social Sciences) version 11.0. Results: A majority of patients were found to be in stage-II disease at the time of admission. History of illness at the time of admission was more than 2 weeks in 50% of stage-I patients but around 80% in stage-II and stage-III patients. Neck stiffness was the most commonly reported finding in all stages. Cranial nerve palsies were higher in stage-III (75%) than in stage-II (43%) and in stage-I (24%) patients. Hydrocephalus and basal enhancement was the most frequently reported radiographic abnormalities. Conclusion: Duration of illness and cranial nerve palsies are important variables in the diagnosis of TBM stages and if TBM is suspected, empiric treatment should be started immediately without bacteriologic proof to prevent morbidity and mortality. (author)

  19. Two-Stage Series-Resonant Inverter

    Science.gov (United States)

    Stuart, Thomas A.

    1994-01-01

    Two-stage inverter includes variable-frequency, voltage-regulating first stage and fixed-frequency second stage. Lightweight circuit provides regulated power and is invulnerable to output short circuits. Does not require large capacitor across ac bus, like parallel resonant designs. Particularly suitable for use in ac-power-distribution system of aircraft.

  20. Stage control of tablets manufacturing

    Directory of Open Access Journals (Sweden)

    L. I. Kucherenko

    2014-08-01

    Full Text Available Today in Ukraine tuberculosis is the wide-spread infectious disease causing the death in most cases; about 700 thousand persons are suffering from it. In Ukraine epidemic of tuberculosis is progressing and spreading. In spite of all protective measures three inhabitants of our country contract tuberculosis per hour, every hour one patient dies and in common about 1.5% of the population is ill with tuberculosis. Isoniazid is antituberculous drug of the first line and it is the most effective one. Chemotherapy of tuberculosis requests long-lasting administration of antituberculous drugs that causes high risk of side effects. To prevent or lessen side effects of antituberculous medicines antioxidants use in complex therapy is perspective. Fulfilled investigations showed efficacy of combining two medical substances – isoniazid andthiotriazolin – in one dosage form. Objective.The aim of our investigation is working out the methods of standardization, in particularquantitative determination of isoniazid andthiotriazolin content in tablet mass by high-performance liquid chromatography (HPLC. Materials and Methods.During in-process investigations combined tableted remedy containing isoniazid andthiotriazolin and proper amount of adjuvants has been developed (it contains active substances isoniazid – 0.2 g,thiotriazolin – 0.05 g and adjuvants up to the 0.4 g of the tablet. During stage control of tablets manufacturingspecial attention is paid to the control of tablet mass quality. Especially it concerns quantitative determination of active substances in it. More and more attention is paid to modern physical-chemical methods of standardization in up-to-date analysis of drug products, such as ultraviolet spectrometry, high-performance liquid chromatography (HPLC etc. In previous scientific investigations we proved the possibility of standardization of active substances artificial compound by HPLC method and optimal conditions of analysis performing