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Articles de revues sur le sujet "OGV (Outlet Guide Vanes)"
1
Wadia, A. R., P. N. Szucs et K. L. Gundy-Burlet. « Design and Testing of Swept and Leaned Outlet Guide Vanes to Reduce Stator–Strut–Splitter Aerodynamic Flow Interactions ». Journal of Turbomachinery 121, no 3 (1 juillet 1999) : 416–27. http://dx.doi.org/10.1115/1.2841334.
Texte intégralRésumé :
Large circumferentially varying pressure levels produced by aerodynamic flow interactions between downstream stators and struts present a potential noise and stability margin liability in a compression component. These interactions are presently controlled by tailoring the camber and/or stagger angles of vanes neighboring the fan frame struts. This paper reports on the design and testing of a unique set of swept and leaned fan outlet guide vanes (OGVs) that do not require this local tailoring even though the OGVs are closely coupled with the fan frame struts and splitter to reduce engine length. The swept and leaned OGVs not only reduce core-duct diffusion, but they also reduce the potential flow interaction between the stator and the strut relative to that produced by conventional radial OGVs. First, the design of the outlet guide vanes using a single blade row three-dimensional viscous flow analysis is outlined. Next, a two-dimensional potential flow analysis was used for the coupled OGV–frame system to obtain a circumferentially nonuniform stator stagger angle distribution to reduce the upstream static pressure disturbance further. Recognizing the limitations of the two-dimensional potential flow analysis for this highly three-dimensional set of leaned OGVs, as a final evaluation of the OGV–strut system design, a full three-dimensional viscous analysis of a periodic circumferential sector of the OGVs, including the fan frame struts and splitter, was performed. The computer model was derived from a NASA-developed code used in simulating the flow field for external aerodynamic applications with complex geometries. The three-dimensional coupled OGV–frame analysis included the uniformly staggered OGV configuration and the variably staggered OGV configuration determined by the two-dimensional potential flow analysis. Contrary to the two-dimensional calculations, the three-dimensional analysis revealed significant flow problems with the variably staggered OGV configuration and showed less upstream flow nonuniformity with the uniformly staggered OGV configuration. The flow redistribution in both the radial and tangential directions, captured fully only in the three-dimensional analysis, was identified as the prime contributor to the lower flow nonuniformity with the uniformly staggered OGV configuration. The coupled three-dimensional analysis was also used to validate the design at off-design conditions. Engine test performance and stability measurements with both uniformly and variably staggered OGV configurations with and without the presence of inlet distortion confirmed the conclusions from the three-dimensional analysis.
2
Jonsson, Isak, Valery Chernoray et Radheesh Dhanasegaran. « Infrared Thermography Investigation of Heat Transfer on Outlet Guide Vanes in a Turbine Rear Structure ». International Journal of Turbomachinery, Propulsion and Power 5, no 3 (1 septembre 2020) : 23. http://dx.doi.org/10.3390/ijtpp5030023.
Texte intégralRésumé :
Aerothermal heat transfer measurements in fluid dynamics have a relatively high acceptance of uncertainty due to the intricate nature of the experiments. The large velocity and pressure gradients present in turbomachinery application add further complexity to the measurement procedure. Recent method and manufacturing development has addressed some of the primary sources of uncertainty in these heat transfer measurements. However, new methods have so far not been applied in a holistic approach for heat transfer studies. This gap is bridged in the present study where a cost-effective and highly accurate method for heat transfer measurements is implemented, utilising infrared thermography technique (IRT) for surface temperature measurement. Novel heat transfer results are obtained for the turbine rear sturcture (TRS), at engine representative conditions for three different outlet guide vane (OGV) blade loading and at Reynolds Number of 235000. In addition to that, an extensive description of the implementation and error mitigation is presented.
3
Mårtensson, Hans. « Harmonic Forcing from Distortion in a Boundary Layer Ingesting Fan ». Aerospace 8, no 3 (24 février 2021) : 58. http://dx.doi.org/10.3390/aerospace8030058.
Texte intégralRésumé :
Integrating a fan with a boundary layer ingestion (BLI) configuration into an aircraft fuselage can improve propulsion efficiency by utilizing the lower momentum airflow in the boundary layer developed due to the surface drag of the fuselage. As a consequence, velocity and total pressure variations distort the flow field entering the fan in both the circumferential and radial directions. Such variations can negatively affect fan aerodynamics and give rise to vibration issues. A fan configuration to benefit from BLI needs to allow for distortion without large penalties. Full annulus unsteady computational fluid dynamics (CFD) with all blades and vanes is used to evaluate the effects on aerodynamic loading and forcing on a fan designed to be mounted on an adapted rear fuselage of a Fokker 100 aircraft, i.e., a tail cone thruster. The distortion pattern used as a boundary condition on the fan is taken from a CFD analysis of the whole aircraft with a simplified model of the installed fan. Detailed simulations of the fan are conducted to better understand the relation between ingested distortion and the harmonic forcing. The results suggest that the normalized harmonic forcing spectrum is primarily correlated to the circumferential variation of inlet total pressure. In this study, the evaluated harmonic forces correlate with the total pressure variation at the inlet for the first 12 engine orders, with some exceptions where the response is very low. At higher harmonics, the distortion content as well as the response become very low, with amplitudes in the order of magnitude lower than the principal disturbances. The change in harmonic forcing resulting from raising the working line, thus, increasing the incidence on the fan rotor, increases the forcing moderately. The distortion transfers through the fan resulting in a non-axisymmetric aerodynamic loading of the outlet guide vane (OGV) that has a clear effect on the aerodynamics. The time average aerodynamic load and also the harmonic forcing of the OGV vary strongly around the circumference. In particular, this is the case for some of the vanes at higher back pressure, most likely due to an interaction with separations starting to occur on vanes operating in unfavorable conditions.
4
Barker, A. G., et J. F. Carrotte. « Compressor Exit Conditions and Their Impact on Flame Tube Injector Flows ». Journal of Engineering for Gas Turbines and Power 124, no 1 (1 mars 1999) : 10–19. http://dx.doi.org/10.1115/1.1383773.
Texte intégralRésumé :
Within a gas turbine engine the flow field issuing from the compression system is nonuniform containing, for example, circumferential and radial variations in the flow field due to wakes from the upstream compressor outlet guide vanes (OGVs). In addition, variations can arise due to the presence of radial load bearing struts within the pre-diffuser. This paper is concerned with the characterization of this nonuniform flow field, prior to the combustion system, and the subsequent effect on the flame tube fuel injector flows and hence combustion processes. A mainly experimental investigation has been undertaken using a fully annular test facility which incorporates a single stage axial flow compressor, diffuser, and flame tube. Measurements have been made of the flow field, and its frequency content, within the dump cavity. Furthermore, the stagnation pressure presented to the core, outer and dome swirler passages of a fuel injector has been obtained for different circumferential positions of the upstream OGV/pre-diffuser assembly. These pressure variations, amounting to as much as 20 percent of the pressure drop across the fuel injector, also affect the flow field immediately downstream of the injector. In addition, general variations in pressure around the fuel injector have also been observed due to, for example, the fuel injector position relative to pre-diffuser exit and the flame tube cowl.
5
Luo, Lei, Chenglong Wang, Lei Wang, Bengt Sundén et Songtao Wang. « Endwall heat transfer and aerodynamic performance of bowed outlet guide vanes (OGVs) with on- and off-design conditions ». Numerical Heat Transfer, Part A : Applications 69, no 4 (30 novembre 2015) : 352–68. http://dx.doi.org/10.1080/10407782.2015.1081021.
Texte intégral
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Chikere, Aja O., Hussain H. Al-Kayiem et Zainal Ambri A. Karim. « Thermal Diffusion Performance of a Diffuser by various Guide Vanes configurations ». MATEC Web of Conferences 225 (2018) : 03018. http://dx.doi.org/10.1051/matecconf/201822503018.
Texte intégralRésumé :
The use of vane-less diffuser with large diffusion angle has shown a setback in the diffusion process of high temperature working fluids. The hot gas flow was characterized as a jet-like flow. This paper presents problem, encountered practically, using a vane-less diffuser with large diffusion angle and how the problem is solved by CFD simulation. The investigated thermal diffuser has a length of 0.3 m, an inlet to outlet crosssectional area ratio of 1:25 and diffusion angle of 115.44o. To resolve the jet-like flow problem and poor distribution of the flow temperature at the diffuser outlet, the study suggested the use of guide-vanes into the diffuser. The study employed CFD simulation by ANSYS-FLUENT software to analyze the flow and thermal process in the diffuser. Three different shapes of guide vanes; block-shaped, oval-shaped and airfoil-shaped were considered in this study and at different vanes diffusion angles, as well as vane-less case, which was adopted as the bench mark case. The simulation results of the velocity, temperature and pressure at the diffuser outlet were compared for all cases. It was found that the guide vanes with symmetrical airfoil profile provided the best performance with most uniform distribution at the outlet of the diffuser. Also, the airfoil-shaped guide vanes resulted in lower pressure losses compared to the block-shaped and oval-shaped guide vanes. According to the analysis results, the diffuser was redesigned to improve the diffusion and temperature distribution across the diffuser outlet.
7
Carrotte, J. F., K. F. Young et S. J. Stevens. « Measurements of the Flow Field Within a Compressor Outlet Guide Vane Passage ». Journal of Turbomachinery 117, no 1 (1 janvier 1995) : 29–37. http://dx.doi.org/10.1115/1.2835641.
Texte intégralRésumé :
A series of tests have been carried out to investigate the flow in a Compressor Outlet Guide Vane (OGV) blade row downstream of a single-stage rotor. The subsequent flow field that developed within an OGV passage was measured, at intervals of 10 percent axial chord, using a novel design of miniature five-hole pressure probe. In addition to indicating overall pressure levels and the growth of regions containing low-energy fluid, secondary flow features were identified from calculated axial vorticity contours and flow vectors. Close to each casing the development of classical secondary flow was observed, but toward the center of the annulus large well-defined regions of opposite rotation were measured. These latter flows were due to the streamwise vorticity at inlet to the blade row associated with the skewed inlet profile. Surface static pressures were also measured and used to obtain the blade pressure force at three spanwise locations. These values were compared with the local changes in flow momentum calculated from the measured velocity distributions. With the exception of the flow close to the outer casing, which is affected by rotor tip leakage, good agreement was found between these quantities indicating relatively weak radial mixing.
8
Zhu, Honggeng, et Rentian Zhang. « Numerical Simulation of Internal Flow and Performance Prediction of Tubular Pump with Adjustable Guide Vanes ». Advances in Mechanical Engineering 6 (1 janvier 2014) : 171504. http://dx.doi.org/10.1155/2014/171504.
Texte intégralRésumé :
Aiming at the performance defect of tubular pump with fixed guide vanes, a design scheme of tubular pump with adjustable guide vanes is proposed, so that the inlet setting angle of guide vanes can be flexibly adjusted to coordinate with the operation conditions of pump, to ensure the inlet setting angle of guide vanes changing with the outlet flow angle of the impeller. The three-dimensional time-averaged incompressible Navier-Stokes equations are adopted to numerically simulate the internal flow field of a tubular pump with fixed and adjustable guide vanes, respectively. Computed results indicate that with the design of adjustable guide vanes and at off-design flow rates the flow conditions inside the diffuser of tubular pump can be improved effectively, and its hydraulic losses can be reduced. When the impeller blade angles are fixed the best efficiency points are within 0.51% while adjusting setting angles of guide vanes within a certain range. Under off-design conditions the hydraulic efficiency of tubular pump with adjustable guide vanes can be obviously improved by 1.70% at 0.75 Q0 and 2.19% at 1.20 Q0, when the blade angle is 0 degrees and the angle of guide vanes is adjusted to be 2 degrees smaller and larger, respectively.
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Han, Fenghui, Zhe Wang, Yijun Mao, Jiajian Tan et Wenhua Li. « Experimental and numerical studies on the influence of inlet guide vanes of centrifugal compressor on the flow field characteristics of inlet chamber ». Advances in Mechanical Engineering 12, no 11 (novembre 2020) : 168781402097490. http://dx.doi.org/10.1177/1687814020974909.
Texte intégralRésumé :
Inlet chambers (IC) are the typical upstream component of centrifugal compressors, and inlet guide vanes in the IC have a great impact on its internal flow and aerodynamic loss, which will significantly influence the performance of the downstream compressor stages. In this paper, an experimental study was carried out on the flow characteristics inside a radial IC of an industrial centrifugal compressor, including five testing sections and 968 measuring points for two schemes with and without guide vanes. Detailed distributions of flow parameters on each section were obtained as well as the overall performance of the radial IC, and the causes of the flow loss inside the IC and the non-uniformity of flow parameters at the outlet section were investigated. Besides, numerical simulations were performed to further analyze the flow characteristics inside the radial IC. The experimental and numerical results indicate that, in the scheme without guide vanes, sudden expansions in the spiral channel and flow separations in the annular convergence channel are the major sources of flow loss and distortions generated in the radial IC; while in the scheme with guide vanes, the flow impacts, separations and wakes caused by the inappropriate design of guide vanes are the main reasons for the flow loss of the IC itself and the uneven flow distributions at the IC outlet.
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Harris, Jonah, Bharat Lad et Sina Stapelfeldt. « Two-Dimensional Investigation of the Fundamentals of OGV Buffeting ». International Journal of Turbomachinery, Propulsion and Power 7, no 2 (2 avril 2022) : 13. http://dx.doi.org/10.3390/ijtpp7020013.
Texte intégralRésumé :
The increased demands of compact modern aero engine architectures have highlighted the problem of outlet guide vane (OGV) buffeting in off-design conditions. This structural response to aerodynamic excitations is characterised by increased vibration, risking structural fatigue. Investigations focused on understanding, mitigation and avoidance are therefore of high priority. OGV buffet is a type of transonic buffet caused by unsteady shock movement, but the exact parameters driving it are not fully understood. To try and understand them, this paper examines the buffet of a quasi-2D OGV geometry. Parametric studies of the incidence angle and inlet Mach number were performed. Forcing frequencies for both studies were found to be close to the experimentally detected frequency of vibration in the first bow mode, which demonstrates that buffet is driven by quasi-2D flow features. Increasing the inlet Mach number increased the dominant forcing frequency, whereas increasing the incidence yielded little change. Profiles of unsteady pressure amplitudes were shown to smoothly increase in magnitude with an increasing incidence and inlet Mach number.
Thèses sur le sujet "OGV (Outlet Guide Vanes)"
1
Young, Kim F. « The performance of compressor outlet guide vanes and downstream diffuser ». Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/13622.
Texte intégralRésumé :
A large-scale compressor/diffuser test rig has been designed and constructed which,. together with an automated data acquisition system, permits more detailed and more accurate measurements than were previously possible - especially in the region of the compressor OGV's. Results are presented based on experiments carried out using two different single-stage axial-flow compressors operating immediately upstream of a straight-core annular diffuser, each compressor being tested with a conventional stator row and a double-dihedral chevron type of stator row i.e. four main configurations were investigated. In addition to these main tests, the effects of operating the stator row at low Reynolds number, and of operating the stator row with a small hub clearance have been investigated. The chevron OGV shows a clear improvement, compared to the straight OGV, in t=s of diffuser performance and diffuser exit velocity profiles, at the expense of a general tendency for the OGV loss to increase. When hub clearance is used on a straight OGV, a hub corner stall arises, but this can be eliminated by incorporating blade dihedral at the hub. It seems likely that further improvements in diffuser exit conditions could be achieved by . careful design of the blade shape to encourage radial movement of flow. Traversing within the blade passage, for a straight type OGV, has revealed significant vortices rotating in the opposite sense to classical curved duct secondary flows.
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Ezzine, Mouhamed Mounibe. « Etude de dispositifs passifs et actifs de réduction du bruit d’interaction soufflante–redresseur ». Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2024. http://www.theses.fr/2024ECDL0022.
Texte intégralRésumé :
Deux approches de diminution du bruit d'origine aéroacoustique associé à l'OGV des moteurs d'avion ont été examinées dans cette thèse. La première repose sur des solutions passives, utilisant des matériaux comme de la mousse poreuse et du tissu métallique (wire mesh) pour atténuer le bruit. L'efficacité de ces matériaux a été testée dans diverses configurations, montrant une capacité de réduction du bruit jusqu'à 6 dB sous certaines conditions, bien que cette efficacité puisse être affectée par des facteurs comme la vitesse de l'écoulement. La seconde partie de l'étude s'est intéressée aux techniques actives, notamment à l'utilisation de cellules piézoélectriques pour le contrôle du bruit. Ces technologies ont montré une réduction notable du bruit, atteignant jusqu'à 15 dB dans certains cas, bien qu'une amplification du bruit ait été notée dans d'autres situations, soulignant l'importance de la précision du design dans l'application de ces technologies. Enfin, l'optimisation numérique de l'impédance acoustique sur les profils aérodynamiques a été explorée, avec pour objectif de réduire davantage le bruit généré par les écoulements turbulents. Cette démarche a permis d'identifier des valeurs d'impédance optimales, conduisant à des réductions significatives de bruit pour certaines fréquences. Les résultats suggèrent qu'un choix précis de l'impédance acoustique sur les surfaces des profils peut être une méthode efficace pour minimiser le bruit d'origine aéroacoustique, bien que la géométrie du profil puisse influencer les résultats. Dans l'ensemble, ces études mettent en évidence le potentiel de différentes stratégies pour la réduction du bruit aéroacoustique, tout en soulignant la nécessité d'une application soigneuse et adaptée aux conditions spécifiques pour maximiser leur efficacitéTwo approaches to reduce aeroacoustic noise associated with the OGV of aircraft engines have been examined in this thesis. The first relies on passive solutions, using materials such as porous foam and wire mesh to attenuate noise. The effectiveness of these materials has been tested in various configurations, demonstrating a noise reduction capacity of up to 6 dB under certain conditions, although this efficiency may be affected by factors such as flow velocity. The second part of the study focused on active techniques, particularly the use of piezoelectric cells for noise control. These technologies have shown a notable reduction in noise, reaching up to 15 dB in some cases, although noise amplification has been noted in other situations, emphasizing the importance of precise design in the application of these technologies. Finally, numerical optimization of acoustic impedance on aerodynamic profiles was explored, aiming to further reduce noise generated by turbulent flows. This approach identified optimal impedance values, leading to significant noise reductions for certain frequencies. The results suggest that precise selection of acoustic impedance on profile surfaces can be an effective method for minimizing aeroacoustic noise, although profile geometry may influence the results. Overall, these studies highlight the potential of different strategies for aeroacoustic noise reduction, while emphasizing the need for careful application tailored to specific conditions to maximize their effectiveness
Actes de conférences sur le sujet "OGV (Outlet Guide Vanes)"
1
Parry, A. B. « Optimisation of Bypass Fan Outlet Guide Vanes ». Dans ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-433.
Texte intégralRésumé :
In this paper we describe an approach for combined intake-fan-OGV-pylon interactions that can be used to optimise the OGV design. The mean flow through the fan and OGVs, which is taken to be locally two-dimensional, is prescribed for a datum configuration, and the intake distortion and pylon potential field are fed in, from upstream and downstream respectively, as small incident perturbations to a coupled fan-OGV actuator disk system. In order to optimise the OGVs we suppose that the vanes are recambered in blocks, using only a limited number of vane types. The extent of each block, and the degree of over or undercambering in each block, are used as variables within a standard multi-variable optimisation package. Following validation of the approach, results are presented for a number of cases which show, in particular, the importance of the back effect of the fan on the perturbation field at the OGV leading edge, and the relative benefits obtained by increasing the number of vane types.
2
Merson, Jacob, et Sina Stapelfeldt. « Aerodynamic Forcing Analysis of Aerodynamically Mistuned Outlet Guide Vane Assemblies ». Dans ASME Turbo Expo 2023 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/gt2023-101253.
Texte intégralRésumé :
Abstract The next generation of aero engines feature a more compact design with a shorter distance between the fan rotor and bypass outlet guide vane (OGV) assembly. As such, potential forced response due to rotor-stator interactions has become a more significant concern with regards to high cycle fatigue and component lifespan. It has been shown that deploying a non-axisymmetric OGV configuration is able to reduce the first engine order (1EO) forcing on the fan’s blades. This paper explores the effects that a non-axisymmetric OGV configuration has on the aerodynamic forcing on the vanes themselves. A low pressure system representative of a modern low-speed fan with different non-axisymmetric OGV patterns is simulated and forcing amplitudes on the OGV stator vanes recorded. Six different non-axisymmetric patterns are generated: three with sinusoidally distributed varied stagger angles of up to 1, 2, and 4 degrees with a one-lobed (circumferential wavenumber m = 1) pattern and an additional three with the same stagger angle distributions with a two-lobed (m = 2) pattern. The forcing in assembly modes and on individual blades are analyzed, and the forcing amplitudes compared to those of the tuned (i.e. identical) OGV configuration. It is shown that aerodynamically mistuning an OGV assembly typically results in a relative increase in forcing amplitudes on most of the individual OGVs, with a maximum forcing amplitude increase of 50% on specific OGVs when configured in the two-lobed, 4 degree re-staggered sinusoidal pattern.
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Vikhorev, Valentin, Valery Chernoray, Oskar Thulin, Srikanth Deshpande et Jonas Larsson. « Detailed Experimental Study of the Flow in a Turbine Rear Structure at Engine Realistic Flow Conditions ». Dans ASME Turbo Expo 2020 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-15734.
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Abstract A good aerodynamic design of the turbine rear structure (TRS) is crucial for improving efficiency and reducing emissions from aero-engines. This paper presents a detailed experimental evaluation of an engine realistic TRS which was studied in an engine-realistic rig at Chalmers University of Technology, Sweden. The TRS test section was equipped with three types of outlet guide vanes (OGVs) which are typical of modern state-of-the-art TRS: regular vanes, thickened vanes and vanes with an engine mount recess (a shroud bump). Each of the three vane geometries were studied under on-design and off-design conditions at a fixed flow Reynolds number of 235,000. The study shows that the off-design performance of the TRS strongly depends on the presence of the local flow separation on the OGV suction side near the hub, which is greatly affected by the vane pressure distribution and inlet conditions. Similarly, the OGVs with increased thickness and with a vane shroud bump are shown to affect the performance of the TRS by influencing the losses on the OGV suction side near the hub. Furthermore, the presence of the bump is shown to have noticeable upstream influence on the outlet flow from the low-pressure turbine and noticeable downstream influence on the outlet flow from the TRS.
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Kulkarni, Davendu Y., et Luca di Mare. « Development of Translucent Design Philosophy for the Cyclic Pattern Design of Fan Outlet Guide Vanes ». Dans ASME Turbo Expo 2022 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-82636.
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Abstract The fan systems of typical high bypass civil engines encounter strong flow distortions originating in the intake and in the bypass ducts and its bifurcations. These flow distortions cause the fan stage operation point to vary from its design intent, thus reducing the fan stage performance and increasing low engine-order fan blade forcing. A cyclic pattern design for the fan Outlet Guide Vanes (OGV) can be effectively used to recover the fan stage performance and to control its system-level aeromechanical behaviour. This paper presents the development of a OGV pattern design philosophy using numerical experimentation technique. Multiple fan-intake unsteady CFD computations are conducted by clocking the circumferential pressure profile at fan exit to understand its effect on fan rotor efficiency and 1EO fan forced response. The study revealed that a mild, low-harmonic fan back pressure field with a suitable clocking position is able to improve the fan efficiency and reduce the fan forcing simultaneously. Such a pattern can be generated by designing a cyclic OGV pattern that allows the bifurcation potential fields of controlled intensity and phase to pass through the OGV blade row. The notion of deliberately generating a clocked 1EO intra-stage static pressure field by means of cyclic OGV pattern design is termed as the translucent design philosophy. Further, a sensitivity study is performed to assess the effects of simultaneous distortions upstream and downstream of the fan in two flight conditions. The study showed that a correctly clocked intra-stage static pressure field can effectively counter the fan upstream flow distortions and at the same time improve the fan rotor performance and fan system aeromechanical behaviour. The implementation of the proposed translucent design philosophy in a new OGV pattern design tool is discussed.
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Wadia, A. R., P. N. Szucs et K. L. Gundy-Burlet. « Design and Testing of Swept and Leaned Outlet Guide Vanes to Reduce Stator-Strut-Splitter Aerodynamic Flow Interactions ». Dans ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-070.
Texte intégralRésumé :
Large circumferential varying pressure levels produced by aerodynamic flow interactions between downstream stators and struts present a potential noise and stability margin liability in a compression component. These interactions are presently controlled by tailoring the camber and/or stagger angles of vanes neighboring the fan frame struts. This paper reports on the design and testing of a unique set of swept and leaned fan outlet guide vanes (OGVs) that do not require this local tailoring even though the OGVs are closely coupled with the fan frame struts and splitter to reduce engine length. The swept and leaned OGVs not only reduce core-duct diffusion, but they also reduce the potential flow interaction between the stator and the strut relative to that produced by conventional radial OGVs. First, the design of the outlet guide vanes using a single bladerow three-dimensional viscous flow analysis is outlined. Next, a two-dimensional potential flow analysis was used for the coupled OGV-frame system to obtain a circumferentially non-uniform stator stagger angle distribution to further reduce the upstream static pressure disturbance. Recognizing the limitations of the two-dimensional potential flow analysis for this highly three-dimensional set of leaned OGVs, as a final evaluation of the OGV-strut system design, a full three-dimensional viscous analysis of a periodic circumferential sector of the OGVs, including the fan frame struts and splitter, was performed. The computer model was derived from a NASA-developed code used in simulating the flow field for external aerodynamic applications with complex geometries. The three-dimensional coupled OGV-frame analysis included the uniformly-staggered OGVs configuration and the variably-staggered OGVs configuration determined by the two-dimensional potential flow analysis. Contrary to the two-dimensional calculations, the three-dimensional analysis revealed significant flow problems with the variably-staggered OGVs configuration and showed less upstream flow non-uniformity with the uniformly-staggered OGVs configuration. The flow redistribution in both the radial and tangential directions, captured fully only in the three-dimensional analysis, was identified as the prime contributor to the lower flow non-uniformity with the uniformly-staggered OGVs configuration. The coupled three-dimensional analysis was also used to validate the design at off-design conditions. Engine test performance and stability measurements with both uniformly- and variably-staggered OGVs configurations with and without the presence of inlet distortion confirmed the conclusions from the three-dimensional analysis.
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Harris, Jonah R., Bharat Lad et Sina Stapelfeldt. « Investigating the Causes of Outlet Guide Vane Buffeting ». Dans ASME Turbo Expo 2020 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-16063.
Texte intégralRésumé :
Abstract In the more aggressive architectures of future high-bypass aero engines, outlet guide vanes (OGVs) will be deployed even closer to the fan. Under certain circumstances this can lead to OGV buffeting. Buffeting is an aeroelastic instability, characterized as the structural response to aerodynamic excitations caused by self-sustaining flow instabilities. Buffeting of OGVs can cause structural fatigue within the low pressure system. This study aims to identify indications of buffet on an engine’s operating map, before assessing how the flow field interacts with the relevant vibrational mode. Steady simulations of the whole low pressure system were used to produce characteristics for three fan speeds and the operating points suspected of buffet were then subject to time-accurate simulations. The steady simulations were used to detect buffet symptoms and examine the change in shock formation, separation patterns and simulation residuals with changing conditions. The time-accurate CFD predicted the highest excitation of the first bow mode at the engine speed where high vibration levels were detected during static off-design engine tests. Time-averaged results of the time-accurate simulations were used to look for trends linking buffeting behaviour with aerodynamic parameters. The time-accurate data also gave indications of a transonic buffet phenomenon.
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Yang, Ping, Weiliang Xie, Feng Xu et Jinzhang Feng. « Influence of Non-Uniform OGV on High Pressure Compressor Performance ». Dans ASME Turbo Expo 2013 : Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95234.
Texte intégralRésumé :
Generally, the outlet guide vanes (OGV) of a high pressure compressor (HPC) have a single vane profile and are placed uniformly circumferentially. However, in some situations, portions of the OGV are thickened to be accommodated to some special requirements which may result in negative influences on the HPC performance. This paper describes the design of a non-uniform OGV row of a multi-stage HPC. The OGV is periodically composed of one thick vane and two thin vanes. A series of vanes are selected by changing vane geometry parameters including vane stagger and camber, location of maximum thickness, thickness distribution, chord length and vane circumference position. Numerical simulations of these different non-uniform OGV rows along with the same rotor upstream are carried out to evaluate the impact of these parameters on the non-uniform OGV performance. Through this “manual-iteration” process, the best configuration is selected as the final “optimized” design. The results show that, firstly, it is beneficial to set the suction surface incidence angle of the thick airfoils the same with that of the thin airfoils for uniform incoming flow field; secondly, the divergence rate of passage should be carefully controlled to reduce the loss coefficient; thirdly, the vane circumference position should be adjusted to keep the mass flow of each passage being equal to ensure uniformity of the outlet flow field. Finally, it is demonstrated that after optimization, the adverse effects of the non-uniform OGV on the whole HPC performance can be nearly eliminated.
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Hja¨rne, Johan, Jonas Larsson et Lennart Lo¨fdahl. « Performance and Off-Design Characteristics for Low Pressure Turbine Outlet Guide Vanes : Measurements and Calculations ». Dans ASME Turbo Expo 2006 : Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90550.
Texte intégralRésumé :
This paper presents 2D and 3D-numerical simulations compared with experimental data from a linear Low Pressure Turbine/Outlet Guide Vane (LPT/OGV) cascade at Chalmers in Sweden. Various performance characteristics for both on and off design cases were investigated, including; pressure distributions, total pressure losses and turning. The numerical simulations were performed with the goal to validate simulation methods and create best-practice guidelines for how to accurately and reliably predict performance and off-design characteristics for an LPT/OGV. The numerical part of the paper presents results using different turbulence models and levels of mesh refinement in order to assess what is the most appropriate simulation approach. From these results it can be concluded that the k-ε Realizable model predicts both losses and turning most accurately for both on and off design conditions.
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Wang, Chenglong, Lei Wang, Bengt Sundén, Valery Chernoray et Hans Abrahamsson. « An Experimental Study of Heat Transfer on an Outlet Guide Vane ». Dans ASME Turbo Expo 2014 : Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25100.
Texte intégralRésumé :
In the present study, the heat transfer characteristics on the suction and pressure sides of an outlet guide vane (OGV) are investigated by using liquid crystal thermography (LCT) method in a linear cascade. Because the OGV has a complex curved surface, it is necessary to calibrate the LCT by taking into account the effect of viewing angles of the camera. Based on the calibration results, heat transfer measurements of the OGV were conducted. Both on- and off-design conditions were tested, where the incidence angles of the OGV were 25 degrees and −25 degrees, respectively. The Reynolds numbers, based on the axial flow velocity and the chord length, were 300,000 and 450,000. In addition, heat transfer on suction side of the OGV with +40 degrees incidence angle was measured. The results indicate that the Reynolds number and incidence angle have considerable influences upon the heat transfer on both pressure and suction surfaces. For on-design conditions, laminar-turbulent boundary layer transitions are on both sides, but no flow separation occurs; on the contrary, for off-design conditions, the position of laminar-turbulent boundary layer transition is significantly displaced downstream on the suction surface, and a separation occurs from the leading edge on the pressure surface. As expected, larger Reynolds number gives higher heat transfer coefficients on both sides of the OGV.
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Shrinivas, G. N., et M. B. Giles. « OGV Tailoring to Alleviate Pylon-OGV-Fan Interaction ». Dans ASME 1995 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/95-gt-198.
Texte intégralRésumé :
This paper studies the application of sensitivity analysis to the redesign of outlet guide vanes (OGV’s) in a commercial gas turbine engine. The redesign is necessitated by the interaction of the pylon induced static pressure field with the OGV’s and the fan, leading to reduced OGV efficiency and shortened fan life. The concept of cyclically varying camber is used to redesign the OGV row to achieve suppression of the downstream disturbance in the domain upstream of the OGV row. The harmonic nature of the disturbance and the tailoring permits the analysis for the redesign to be performed on only one blade passage. Sensitivity of the pressure field upstream of the OGV’s to changes in blade camber is computed, and used to modify the blade profile. The sensitivity is obtained from a linear perturbation CFD analysis; nonlinear CFD analysis and actuator disc theory (ADisc) provide validation at each step. The modifications reduce the pylon induced pressure variation at the fan by more than 70%. The presence of an interaction mechanism from the pylon to the OGV’s is investigated.