Academic literature on the topic 'Simulations rotor/stator'
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Journal articles on the topic "Simulations rotor/stator"
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Tang, Jing, Jie Chen, Kan Dong, Yongheng Yang, Haichen Lv, and Zhigang Liu. "Modeling and Evaluation of Stator and Rotor Faults for Induction Motors." Energies 13, no. 1 (2019): 133. http://dx.doi.org/10.3390/en13010133.
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The modeling of stator and rotor faults is the basis of the development of online monitoring techniques. To obtain reliable stator and rotor fault models, this paper focuses on dynamic modeling of the stator and rotor faults in real-time, which adopts a multiple-coupled-circuit method by using a winding function approach for inductance calculation. Firstly, the model of the induction machine with a healthy cage is introduced, where a rotor mesh that consists of a few rotor loops and an end ring loop is considered. Then, the stator inter-turn fault model is presented by adding an extra branch with short circuit resistance on the fault part of a stator phase winding. The broken rotor bar fault is then detailed by merging and removing the broken-bar-related loops. Finally, the discrete models under healthy and faulty conditions are developed by using the Tustin transformation for digital implementation. Moreover, the stator and rotor mutual inductances are derived as a function of the rotor position according to the turn and winding functions distribution. Simulations and experiments are performed on a 2.2-kW/380-V/50-Hz three-phase and four-pole induction motor to show the performance of the stator and rotor faults, where the saturation effect is considered in simulations by exploiting the measurements of a no load test. The simulation results are in close agreement with the experimental results. Furthermore, magnitudes of the characteristic frequencies of 2f1 in torque and (1 ± 2s)f1 in current are analyzed to evaluate the stator and rotor fault severity. Both indicate that the stator fault severity is related to the short circuit resistance. Further, the number of shorted turns and the number of continuous broken bars determines the rotor fault severity.
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Reinmo¨ller, U., B. Stephan, S. Schmidt, and R. Niehuis. "Clocking Effects in a 1.5 Stage Axial Turbine—Steady and Unsteady Experimental Investigations Supported by Numerical Simulations." Journal of Turbomachinery 124, no. 1 (2001): 52–60. http://dx.doi.org/10.1115/1.1425811.
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The interaction between rotor and stator airfoils in a multistage turbomachine causes an inherently unsteady flow field. In addition, different relative circumferential positions of several stator rows and rotor rows, respectively, have an influence on the flow behavior in terms of loss generation, energy transport and secondary flow. The objective of the presented study is to investigate the effects of stator airfoil clocking on the performance of a 1-1/2 stage axial cold air turbine. The investigated axial turbine consists of two identical stators. The low aspect ratio of the blades and their prismatic design leads to a three-dimensional outlet flow with a high degree of secondary flow phenomena. Nevertheless, the small axial gaps between the blade rows are responsible for strong potential flow interaction with the radial wake regions in the measurement planes. Consequently, parts of the wakes of the first stator are clearly detected in the rotor outlet flow. To give an overview of the time-averaged flow field, measurements with pneumatic probes are conducted behind each blade row at ten different clocking-positions of the second stator. Further, an optimized clocking position was found due to a minimum in pressure loss behind the second stator. The unsteady measurements are carried out with hot-wire probes for three selected stator-stator positions. Animations of selected flow properties show the influence of different circumferential positions of the second stator on the unsteady flow behavior and secondary flow field. In addition and compared with experimental results three-dimensional unsteady viscous flow computations are performed.
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Karanayil, Baburaj, Muhammed Fazlur Rahman, and Colin Grantham. "Identification of Induction Motor Parameters in Industrial Drives with Artificial Neural Networks." Advances in Fuzzy Systems 2009 (2009): 1–10. http://dx.doi.org/10.1155/2009/241809.
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This paper presents a new method of online estimation of the stator and rotor resistance of the induction motor in the indirect vector-controlled drive, with artificial neural networks. The back propagation algorithm is used for training of the neural networks. The error between the rotor flux linkages based on a neural network model and a voltage model is back propagated to adjust the weights of the neural network model for the rotor resistance estimation. For the stator resistance estimation, the error between the measured stator current and the estimated stator current using neural network is back propagated to adjust the weights of the neural network. The performance of the stator and rotor resistance estimators and torque and flux responses of the drive, together with these estimators, is investigated with the help of simulations for variations in the stator and rotor resistance from their nominal values. Both types of resistance are estimated experimentally, using the proposed neural network in a vector-controlled induction motor drive. Data on tracking performances of these estimators are presented. With this approach, the rotor resistance estimation was found to be insensitive to the stator resistance variations both in simulation and experiment.
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Xu, Jieqiong, Qunhong Li, and Shimin Wang. "Impulsive Control of the Rotor-Stator Rub Based on Phase Characteristic." Abstract and Applied Analysis 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/495747.
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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 inx-direction andy-direction several times to avoid the rotor-stator rubbing. The practical feasibility of this approach is investigated by numerical simulations.
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Wang, Ziwei, Xiong Jiang, Ti Chen, Yan Hao, and Min Qiu. "Numerical simulation of transonic compressor under circumferential inlet distortion and rotor/stator interference using harmonic balance method." Modern Physics Letters B 32, no. 12n13 (2018): 1840021. http://dx.doi.org/10.1142/s0217984918400213.
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Simulating the unsteady flow of compressor under circumferential inlet distortion and rotor/stator interference would need full-annulus grid with a dual time method. This process is time consuming and needs a large amount of computational resources. Harmonic balance method simulates the unsteady flow in compressor on single passage grid with a series of steady simulations. This will largely increase the computational efficiency in comparison with the dual time method. However, most simulations with harmonic balance method are conducted on the flow under either circumferential inlet distortion or rotor/stator interference. Based on an in-house CFD code, the harmonic balance method is applied in the simulation of flow in the NASA Stage 35 under both circumferential inlet distortion and rotor/stator interference. As the unsteady flow is influenced by two different unsteady disturbances, it leads to the computational instability. The instability can be avoided by coupling the harmonic balance method with an optimizing algorithm. The computational result of harmonic balance method is compared with the result of full-annulus simulation. It denotes that, the harmonic balance method simulates the flow under circumferential inlet distortion and rotor/stator interference as precise as the full-annulus simulation with a speed-up of about 8 times.
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Akwa, J. V., and A. P. Petry. "STATORS USE INFLUENCE ON THE PERFORMANCE OF A SAVONIUS WIND ROTOR USING COMPUTATIONAL FLUID DYNAMICS." Revista de Engenharia Térmica 10, no. 1-2 (2011): 63. http://dx.doi.org/10.5380/reterm.v10i1-2.61965.
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This paper aims at verifying the influence of using five kinds of stators in the averaged moment and power coefficients of a Savonius wind rotor using computational fluid dynamics (CFD). The analyzed stators have cylindrical shape with two and three openings, one and four deflector blades and walls shaped like a wings. The equations of continuity, Reynolds Averaged Navier-Stokes – RANS and the Eddy Viscosity Model k-ω SST, in its Low-Reynolds approaches, with hybrid near wall treatment; are numerically solved using the commercial software Star-CCM+, based on Finite Volume Method, resulting in the fields of pressure and velocity of the flow and the forces acting on the rotor buckets. The moment and power coefficients are achieved through integration of forces coming from the effects of pressure and viscosity of the wind on the buckets device. The influence of the stators use in the moment and power coefficients is checked by changing the geometry of the device for each simulations series, keeping the Reynolds number based on rotor diameter equal to 433,500. The obtained values for averaged moment and power coefficients indicate that for each type of stator used, there was maximum performance for a given tip speed ratio of rotor. Improvement in performance over the operation without stator was obtained only to the operations using stator with four deflector blades and to the stator with cylindrical shape with three openings. The improvement percentage in performance obtained for the best condition (use of four deflector blades at tip speed ratio equal to 1) is 12% compared to the performance of the rotor operating without stator.
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Rai, M. M., and N. K. Madavan. "Multi-Airfoil Navier–Stokes Simulations of Turbine Rotor–Stator Interaction." Journal of Turbomachinery 112, no. 3 (1990): 377–84. http://dx.doi.org/10.1115/1.2927670.
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An accurate numerical analysis of the flows associated with rotor–stator configurations in turbomachinery can be extremely helpful in optimizing the performance of turbomachinery. In this study the unsteady, thin-layer, Navier–Stokes equations in two spatial dimensions are solved on a system of patched and overlaid grids for an axial-turbine rotor–stator configuration. The governing equations are solved using a finite-difference, upwind algorithm that is set in an iterative, implicit framework. Results are presented in the form of pressure contours, time-averaged pressures, unsteady pressures, amplitudes, and phase. The numerical results are compared with experimental data and the agreement is found to be good. The results are also compared with those of an earlier study, which used only one rotor and one stator airfoil. The current study uses multiple rotor and stator airfoils and a pitch ratio that is much closer to the experimental ratio. Consequently, the results of this study are found to be closer to the experimental data.
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Brandão, André, Aline Souza de Paula, Marcelo Amorim Savi, and Fabrice Thouverez. "Nonlinear Dynamics and Chaos of a Nonsmooth Rotor-Stator System." Mathematical Problems in Engineering 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/8478951.
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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.
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Gaetani, Paolo, and Giacomo Persico. "Influence of the Rotor-Driven Perturbation on the Stator-Exit Flow within a High-Pressure Gas Turbine Stage." International Journal of Turbomachinery, Propulsion and Power 6, no. 3 (2021): 28. http://dx.doi.org/10.3390/ijtpp6030028.
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In stator–rotor interaction studies on axial turbines, the attention is commonly focused on the unsteady rotor aerodynamics resulting from the periodic perturbations induced by the stator flow structures. Conversely, less interest has been historically attracted regarding the influence of the rotor on the flow released by the stator, correlated to propagation of the blade potential field upstream of the rotor leading edge. In this paper, experiments in the research high-pressure turbine of the Laboratory of Fluid-Machines of the Politecnico di Milano, performed by applying a fast-response aerodynamic pressure probe, alongside fully-3D time-accurate CFD simulations of the flow, are combined with the aim of discussing the rotor-to-stator interaction. While rotating, the rotor induces periodic perturbations on the pressure and velocity field in the stator–rotor gap, altering the evolution of the total quantities and the flow rate discharged by each stator channel and eventually triggering energy-separation effects which result in total pressure and total temperature oscillations in the stator-exit flow. Such oscillations were found to rise up to almost ±10% of the stage total temperature drop.
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Ahriche, Aimad. "An Approach of Position and Torque Estimation for Induction Motor based Sensor-less Drive." International Journal of Circuits, Systems and Signal Processing 17 (March 6, 2023): 44–49. http://dx.doi.org/10.46300/9106.2023.17.5.
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This paper presents a new approach with stability analysis, simulation and experimental investigation of a sliding mode based estimator for rotor-position and torque-load calculation in high performance speed-sensor-less AC motor drive. The proposed algorithm is built based on the induction motor (IM) fluxes equations for two rotationg referential frames. The First equation calculates the stator flux vector while the second gives the rotor flux vector. Moreover, the stator flux equation is linked to a stator-flux rotating referential frame and the rotor flux equation is linked to a rotor-flux rotating referential frame. Among merits of the proposed technique is no necessity to rotor-speed measurement and adaptation. Thus, it is well suitable to the fully speed-sensorless scheme. The whole observer stability is verified by using of Lyapunov’s principle. Simulations are done by using Matlab-Simulink and experimental implementation is performed in order to prove the feasibility of proposed algorithm. The illustrated results are shown by using a DS1104 controller board.
Dissertations / Theses on the topic "Simulations rotor/stator"
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JACQUES, REMI. "Simulations numeriques d'ecoulements transitionnels et turbulents dans des configurations de type rotor-stator." Paris 11, 1997. http://www.theses.fr/1997PA112386.
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Ce travail de these porte sur l'etude numerique des ecoulements transitionnels et turbulents dans une cavite confinee formee de deux disques coaxiaux dont l'un est en rotation uniforme autour de son axe de revolution (rotor), et l'autre stationnaire (stator). Les simulations numeriques sont effectuees sous l'hypothese d'axisymetrie de l'ecoulement instantane. On utilise alors un code de calcul parallelise integrant une decomposition de domaine. Plusieurs caracteristiques des ecoulements entre deux disques tournants sont reproduites : existence de couches limites sur les deux disques tournants, separees par un region centrale de l'ecoulement en rotation moyenne uniforme, caractere plus instable de la couche limite liee au disque fixe. L'existence d'un regime d'ondes inertielles a egalement ete mis en evidence dans le cur de la cavite lorsque l'ecoulement est turbulent dans la couche limite liee au disque fixe. L'etude des equations de transport des tensions de reynolds montre que la rotation modifie les distributions spatiales de certains termes intervenant dans les bilans associes a ces equations. Ils mettent egalement en evidence les limitations de l'hypothese d'axisymetrie qui modifie alors des caracteristiques intrinseques de la turbulence. Des simulations numeriques tridimensionnelles avec un code de calcul parallelise sont alors effectuees pour le regime d'ecoulement laminaire instationnaire. Ces premieres simulations ont montre que l'hypothese d'axisymetrie stabilisait l'ecoulement. Enfin, les resultats de simulation numerique sont confrontes a des resultats fournis par une modelisation de la turbulence de type k - et des resultats experimentaux. Les deux methodologies numeriques fournissent des resultats relativement proches concernant les distributions de vitesse moyenne.
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D'Haudt, Emmanuel. "Étude expérimentale de l'influence des conditions périphériques sur un écoulement turbulent de type rotor-stator : premières confrontations avec des résultats de simulations numériques." Lille 1, 2006. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2006/50376-2006-D_Haudt.pdf.
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Les recherches effectuées sur des écoulements turbulents dans des cavités interdisques ont permis de mettre en évidence l'importance des conditions aux limites. Ce présent travail a pour but de mieux comprendre les phénomènes qui régissent l'apparition de différents types d'écoulements observés dans une cavité rotor-stator non soumise à un flux radial forcé. Dans cette optique, un banc d'essais a été adapté pour étudier plus spécifiquement l'influence de deux paramètres géométriques, l'un lié à une faible différence entre le rayon des disques, l'autre relatif à la présence d'un carter permettant de supprimer l'écoulement produit par la paroi externe du rotor. La base de données constituée à partir de mesures effectuées principalement par anémométrie à fils chauds a été confrontée à des résultats de simulations numériques réalisés à l'aide du code de calcul FLUENT. L'analyse des résultats montre en particulier qu'à la périphérie du système, le fluide éjecté par l'effet centrifuge du rotor est nécessairement compensé par une injection provenant partiellement du fluide au repos situé à l'extérieur à la cavité, près du stator, et de la réintroduction du fluide éjecté par le rotor. La proportion entre ces deux sources, qui dépend étroitement des paramètres géométriques retenus, influe sur le niveau de pré-rotation du fluide en entrée de cavité et conditionne ainsi l'apparition des différents types d'écoulement observés, notamment l'écoulement en bloc de type Batchelor.
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D'Haudt, Emmanuel Bois Gérard Debuchy Roger. "Étude expérimentale de l'influence des conditions périphériques sur un écoulement turbulent de type rotor-stator premières confrontations avec des résultats de simulations numériques /." Villeneuve d'Ascq : Université des sciences et technologies de Lille, 2007. https://iris.univ-lille1.fr/dspace/handle/1908/988.
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Reproduction de : Thèse de doctorat : Mécanique : Lille 1 : 2006.<br>N° d'ordre (Lille 1) :3874. Résumé en français et en anglais. Titre provenant de la page de titre du document numérisé. Bibliogr. p. 171-173.
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Peres, Noele. "A 3D pseudospectral method for cylindrical coordinates. Application to the simulations of rotating cavity flows." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4309/document.
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La simulation d'écoulements dans des cavités cylindriques en rotation présente une difficulté particulière en raison de l'apparition de singularités sur l'axe. Le présent travail propose une méthode collocative pseudospectrale suffisamment efficace et précise pour surmonter cette difficulté et résoudre les équations 3D de Navier-Stokes écrites en coordonnées cylindriques. Cette méthode a été développée dans le cadre des différentes études menées au laboratoire M2P2, utilisant une méthode collocative de type Chebychev dans les directions radiale et axiale et Fourier-Galerkin dans la direction azimutale [thêta]. Pour éviter de prescrire des conditions sur l'axe, une nouvelle approche a été développée. Le domaine de calcul est défini par (r,[thêta],z)∈[-1,1]×[0,2π]×[-1,1] avec un nombre N pair de points de collocation dans la direction radiale. Ainsi, r=0 n'est pas un point de collocation. La distribution de points de type Gauss-Lobatto selon r et z densifie le maillage seulement près des parois ce qui rend l'algorithme bien adapté pour simuler les écoulements dans des cavités cylindriques en rotation. Dans la direction azimutale, le chevauchement des points dû à la discrétisation est évitée par l'introduction d'un décalage égal à π/2K à [thêta]>π dans la transformée de Fourier. La méthode conserve la convergence spectrale. Des comparaisons avec des résultats expérimentaux et numériques de la littérature montrent un très bon accord pour des écoulements induits par la rotation d'un disque dans des cavités cylindriques fermées<br>When simulating flows in cylindrical rotating cavities, a difficulty arises from the singularities appearing on the axis. In the same time, the flow field itself does not have any singularity on the axis and this singularity is only apparent. The present work proposes an efficient and accurate collocation pseudospectral method for solving the 3D Navier-Stokes equations using cylindrical coordinates. This method has been developed in the framework of different studies of rotor-stator flows, using Chebyshev collocation in the radial and axial directions and Fourier-Galerkin approximation in the azimuthal periodic direction [thêta]. To avoid the difficulty on the axis without prescribing any pole and parity conditions usually required, a new approach has been developed. The calculation domain is defined as (r,[thêta];,z)∈[-1,1]×[0,2π]×[-1,1] using an even number N of collocation points in the radial direction. Thus, r=0 is not a collocation point. The method keeps the spectral convergence. The grid-point distribution densifies the mesh only near the boundaries that makes the algorithm well-suited to simulate rotating cavity flows where thin layers develop along the walls. In the azimuthal direction, the overlap in the discretization is avoided by introducing a shift equal to π/2K for [thêta]>π in the Fourier transform. Comparisons with reliable experimental and numerical results of the literature show good quantitative agreements for flows driven by rotating discs in cylindrical cavities. Associated to a Spectral Vanishing Viscosity, the method provides very promising LES results of turbulent cavity flows with or without heat transfer
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Sauvage, Bastien. "Approximation et adaptation numériques pour les écoulements en machines tournantes." Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ5045.
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Ce travail s'inscrit dans un projet de recherche dont l'objectif est de proposer des simulations numériques en fluides (CFD) capables de capturer le bruit produit par les machines tournantes.Cette thèse, au sein de ce projet, à pour objectif d'étudier des méthodes d'adaptation de maillages (instationnaires) pour des écoulements turbulents instationnaires.On commence par décrire les outils nécessaires à nos études, à savoir les méthodes numériques, les modèles de turbulences et l'adaptation de maillages. Une première partie est consacrée à l'étude de l'algorithme d'adaptation de maillage instationnaire "Transient Fixed Point" appliqué à des écoulements turbulents autour de cylindres à différents nombre de Reynolds. Puis on étudie une méthode pour prendre en compte la rotation dans les simulations,que l'on couple avec les méthodes d'adaptation de maillage. Des exemples numériques sont proposés.Ces premiers travaux se heurtent à deux importants problèmes ouverts en CFD maillage-adaptative.Afin de choisir de manière optimale le pas d'avancement en temps implicite, on présente une nouvelle méthode d'adaptation de maillages espace-temps, qui permet d'adapter simultanément le maillage en espace et le maillage en temps. Afin d'adapter le maillage à la fois à l’écoulement moyen et aux grandes structures turbulentes, on propose une nouvelle approche d'adaptation de maillage pour la turbulence en calcul LES et hybride<br>This work is part of a research project aimed at proposing numerical fluid simulations (CFD) capable of capturing the noise produced by rotating machines.The aim of this thesis is to study mesh adaptation methods for unsteady turbulent flows. We begin by describing the tools required for our studies, namely numerical methods, turbulence models and mesh adaptation. The first part is devoted to the study of the "Transient" unsteady mesh adaptation algorithms applied to turbulent flows around cylinders at different Reynolds numbers. A method for taking rotation into account in simulations is then studied, and coupled with mesh the adaptation methods. Numerical examples are proposed.This initial work encounted two major unsolved problems in CFD mesh-adaptation. In order to optimally select the implicit time step, a new space-time mesh adaptation method is presented, which simultaneously adapts the space mesh and the time mesh. In order to adapt the mesh to both mean flow and large turbulent structures, a new mesh adaptation approach is proposed for turbulence in LES and hybrid computation
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Jung, Alexander. "Berechnung der Stator-Rotor-Wechselwirkung in Turbomaschinen." [S.l. : s.n.], 2000. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB8862171.
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Bridel-Bertomeu, Thibault. "Investigation of unsteady phenomena in rotor/stator cavities using Large Eddy Simulation." Thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/17867/1/BRIDEL_BERTOMEU.pdf.
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This thesis provides a numerical and theoretical investigation of transitional and turbulent enclosed rotating flows, with a focus on the formation of macroscopic coherent flow structures. The underlying processes are strongly threedimensional due to the presence of boundary layers on the discs and on the walls of the outer (resp. inner) cylindrical shroud (resp. shaft). The complexity of these flows poses a great challenge in fundamental research however the present work is also of importance for industrial rotating machinery, from hard-drives to space engines turbopumps - the design issues of the latter being behind the motivation for this thesis. The present work consists of two major investigations. First, industrial cavities are modeled by smooth rotor/stator cavities and therein the dominant flow dynamics is investigated. For the experimental campaigns on industrial machinery revealed dangerous unsteady phenomena within the cavities, the emphasis is put on the reproduction and monitoring of unsteady pressure fluctuations within the smooth cavities. Then, the LES of three configurations of real industrial turbines are conducted to study in situ the pressure fluctuations and apply the diagnostics already vetted on academic problems.
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Barbosa, Emerson. "Etude numérique des écoulements tridimensionnels dans des cuves cylindriques rotor-stator." Phd thesis, Université d'Evry-Val d'Essonne, 2002. http://tel.archives-ouvertes.fr/tel-00354646.
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L'écoulement d'un fluide visqueux incompressible dans une cuve cylindrique rotor-stator est étudié. Ces écoulements ont fait l'objet de récents travaux numériques tridimensionnels pour des rapports d'aspect h>1,75. On propose une étude numérique de la rupture de l'axisymétrie de l'écoulement dans une cavité de rapport d'aspect réduit (h=1 et 1,5) et des nombres de Reynolds Re<8500. Les équations de Navier-Stokes sont résolues par un code vitesse-pression en coordonnées cylindriques qui repose sur des méthodes aux différences finies du second ordre. Deux approches numériques sont mises en œuvre pour mener cette investigation. L'une consiste à linéariser les équations autour d'un écoulement de base axisymétrique stationnaire. Les conditions initiales résultent de la superposition de l'écoulement de base et d'une perturbation aléatoire. Cette analyse de stabilité linéaire permet de déterminer le premier seuil de criticalité et met en évidence le mode azimutal kc le plus instable. L'autre consiste à intégrer les équations du mouvement avec différentes conditions initiales: (i) soit un écoulement de base axisymétrique stationnaire perturbé aléatoirement, (ii) soit un état où le fluide est au repos, (iii) soit un régime établi trouvé pour une autre valeur de Re. L'analyse de stabilité non-linéaire (i) montre que le développement d'un mode kc est responsable d'une bifurcation de Hopf super-critique lorsque Re dépasse une première valeur critique. L'écoulement de base bascule alors vers des solutions instationnaires de période T, dont les caractéristiques spatiales dépendent de la valeur de kc. L'axisymétrie de l'écoulement n'est brisée que lorsque kc est non nul. Dans ce cas, les solutions super-critiques sont des ondes qui exhibent une invariance par rotation d'angle 2pi/kc autour de l'axe et qui tournent avec une période azimutale TRWkc=kc*T. L'écoulement subit ensuite d'autres bifurcations et les caractéristiques spatio-temporelles des ondes tournantes bifurquées sont présentées en détails. L'utilisation d'autres conditions initiales (ii)-(iii) met en évidence des branches de solutions multiples: il apparaît que la convergence vers l'une ou l'autre des solutions possibles dépend de la façon dont est répartie l'énergie cinétique de départ.
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Batailly, Alain. "Simulation de l'interaction rotor/stator pour des turbo-machines aéronautiques en configuration non-accidentelle." Phd thesis, Ecole centrale de nantes - ECN, 2008. http://tel.archives-ouvertes.fr/tel-00364945.
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Dans le cadre de la conception de turbo-machines aéronautiques, l'amélioration du rendement est assurée, entre autres, par la diminution du jeu fonctionnel entre les parties tournantes et statiques, telles que les roues aubagées et le carter qui les entoure. Cette stratégie a des conséquences sur le comportement vibratoire des turbo-machines en favorisant l'apparition de contacts structuraux entre les sommets d'aubes et le carter, par exemple. Lorsque plusieurs points de contact co-existent, des phénomènes d'interaction modale peuvent apparaître. La simulation de ces phénomènes, potentiellement dangereux, dans un cadre indutriel est au cœur de notre étude. Du fait de la dimension du problème à traiter, des méthodes de réduction modale sont utilisées : une méthode à interfaces fixes, la méthode de Craig-Bampton, et une méthode à interfaces libres, la méthode de Craig-Martinez. L'étude porte notamment sur la performance de ces méthodes de réduction lorsqu'elles sont associées à une non linéarité de type contact. Le phénomène d'interaction modale est tout d'abord étudié sur des modèles 2D simplifiés avec l'analyse de la sensibilité des régimes d'interaction à la taille des modèles réduits, puis sur les modèles 3D industriels pour lesquels la solution vraie n'est pas accessible. La gestion du contact dans le 3D fait appel aux B-splines bicubiques surfaciques afin d'assurer de meilleures propriétés à la surface de contact et de faciliter la résolution numérique. Les résultats obtenus à l'aide des deux méthodes de réduction modale sont comparés et permettent de déterminer la méthode la plus appropriée pour l'industrialisation du code présentée en annexe de ce mémoire.
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Queguineur, Matthieu. "Stability and control of unsteady phenomena in rotor/stator cavities using Large Eddy Simulation." Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0043.
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Les phénomènes instationnaires dans les cavités rotor/stator sont connus pour être la source de dangereuses vibrations dans les turbopompes spatiales. Bien que plusieurs mesures palliatives aient été prises en comptes durant les phases de conception, des campagnes d’essais ont mis en évidence de fortes oscillations des écoulements internes pouvant menacer le moteur cryogénique des lanceurs. Aujourd’hui, l’origine de ce phénomène, appelé «bandes de pression », est peu compris et difficile à prédire numériquement. L’objectif de cette thèse est d’analyser les mécanismes physiques de ce phénomène afin d’apporter des solutions pour le contrôler. Pour répondre à cette problématique, deux types de configuration sont étudiés: une cavité rotor/stator annulaire et une cavité de turbopompe spatiale. Les couches limites tournantes dans ces cavités sont connues pour être 3D et réceptives à plusieurs types d’instabilités prenant entre autre la forme de spirales ou d’anneaux. Les simulations basées sur la moyenne de Reynolds (RANS) ont par le passé échoué à prédire ce type d’écoulement. Cependant, les Simulations aux Grandes Echelles (SGE) se sont avérées être une alternative à ce problème et sont donc été utilisées tout au long de cette thèse. Des Densités Spectrales de Puissance (DSP) ainsi que des Décompositions modales dynamiques (DMD) appliqués aux résultats SGE, ont permis de montrer que le phénomène de bandes de pression est visible également dans une cavité annulaire de type académique et composé de trois modes dictant toute la dynamique du système. Afin d’étudier les interactions de ces modes, une nouvelle méthode appelée Dynamic Mode Tracking/Control (DMT/DMTC) a été proposée durant cette these. La DMT est construite pour extraire des structures cohérentes dans une simulation SGE. De plus, en ajoutant un terme de relaxation dans les équations de Navier-Stokes couplées avec la DMT, sa variante appelée DMTC permet de contrôler et de suivre en temps réelle un ou plusieurs modes et donc de pouvoir analyser de possibles interactions. Appliqué à la cavité académique annulaire, cette méthode a permis de montrer que le mode basse fréquence est généré dans l’écoulement par le mode dominant du système. Pour aller plus loin, des analyses de stabilité linéaire de type global (GLSA), sont effectuées sur la cavité académique. Grâce à des méthodes adjointes, la GLSA a permis de mettre en avant l’origine spatiale de chacun des trois modes. Deplus, afin de mettre en place des stratégies de contrôle, la sensibilité à la modification de l’écoulement de base, obtenue par GLSA, a permis d’identifier la région à modifier pour stabiliser un mode donné ou décaler sa fréquence. Appliqué au cas académique, il est montré et que contrôler la couche limite du stator est le moyen le plus efficace de supprimer le phénomène de bandes de pression à travers des injections/aspirations. Pour finir, le phénomène de bandes de pression est analysé dans une cavité de turbopompe spatiale. En particulier, la sensibilité de ce phénomène aux changements géométriques est abordée à travers deux configurations: une première sans les aubes du stator de la turbopompe et une deuxième avec. Bien que les aubes génèrent un écoulement complexe, des fréquences similaires de fluctuation de pression sont retrouvées dans les deux configurations avec cependant des nombres azimutaux caractéristiques différents. En se basant sur les études faites sur la cavité académique, une version adaptée de GLSA pour la dynamique de la turbopompe permet de mettre en avant que malgré que le phénomène de bandes pression soit particulièrement présent dans la veine de la turbopompe, la source de ces modes se situe dans les cavités inférieures entre le rotor et le stator. De plus les résultats de GLSA mettent en avant que deux moyens de contrôle pourraient être appliqués pour supprimer le phénomène de bandes de pression dans ce cas industriel: modifier le joint d’étanchéité ou modifier la fuite du moyeu<br>Unsteady phenomena in rotor/stator cavity are well known to be the source of dangerous vibrations in space turbopump. Even though many palliative measures have been taken during their design, experimental campaigns often reveal high flow oscillations that can jeopardize turbomachinery components and even the rocket engine. Today, the origin of such flow instabilities usually called ’pressure band phenomenon’(PBP) is not well understood and difficult to predict numerically. The main goal of this thesis is to investigate such phenomenon mechanism to find technical solutions so as to control it. This problematic is addressed here trough two types of configuration: an academic rotor/stator cavity and a space turbopump cavity. When it comes to cavity flows, their rotating boundary layers are known to be three dimensional and receptive to several instabilities taking the form of spirals or annuli. Reynolds Averaged Navier-Stokes Simulations (RANS)failed to predict such unsteady systems. However, Large Eddy Simulation (LES) proved to be a relevant alternative in many similar applications and is therefore chosen for the present work. Using Power Spectral Analysis (PSD) and Dynamic Mode Decomposition (DMD) on LES predictions, one shows that the PBP is retrieved in an annular smooth rotor/stator cavity and it is composed of three modes driving all the system dynamics. To investigate these mode organization and their possible interactions, a new tool called Dynamic Mode Tracking /Control (DMT/DMTC) is introduced. DMT is constructed so as to extract "on-thefly" flow coherent structures with a given frequency on the basis of LES. Furthermore, augmenting the Navier-Stokes equations with a relaxation term coupled to DMT, DMTC allows to control and follow the evolution of a controlled mode as well as non controlled ones and thereby observe interactions. This strategy after validation is applied to the annular rotating cavity and shows that the low frequency mode is generated by the dominant mode of the system. To go further, Global Linear Stability Analysis (GLSA) augmented with adjoint methods is used to shed some light on all mode origins and points out that the low frequency and dominant modes are coming from the stationary boundary layer. In order to set up control strategies, the GLSA framework is further developed introducing the concept of the sensitivity to base flow modifications which gives the location where the flow should be modified if one wants to stabilize or at least shift a frequency mode. Applied to the academic cavity, one shows that contrary to most studies in the literature, controlling the stator boundary layer is the more efficient way to damp the PBP through suction/injection devices. Finally, gathering all the previous understanding of this flow, the LES framework enables to validate the control strategies proposed and to stabilize the PBP for very low suction amplitudes. To finish, the PBP is analyzed in real space turbompump cavities. In particular, the sensitivity of this specific phenomenon to geometry changes is investigated through two configurations: one without and one with the blades of the stator of the turbopump. Even though the introduction of the blades in the LES creates a more complex flow with the presence of shocks, similar pressure fluctuation spectra are retrieved in both configurations but with azimuthal wavenumber modes that are shifted. Following the studies on the academic cavity, an adapted GLSA to the non-linear dynamics of the turbopump enables to point out that even though the PBP modes are particularly marked in the mainstream of the system, the source of these modes is located in the subcavity in the rotor-stator wheel space. In particular, GLSA results indicate that two possible ways to control the phenomenon are possible: modifying the flow around the seal rim and or modifying the leak around the hub
Books on the topic "Simulations rotor/stator"
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Center, Ames Research, ed. Three-dimensional Navier-Stokes simulations of turbine rotor-stator interaction. National Aeronautics and Space Administration, Ames Research Center, 1988.
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Center, Ames Research, ed. Three-dimensional Navier-Stokes simulations of turbine rotor-stator interaction. National Aeronautics and Space Administration, Ames Research Center, 1988.
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Boretti, A. A. Three-dimensional Euler time accurate simulations of fan rotor-stator interactions. National Aeronautics and Space Administration, Lewis Research Center, Institute for Computational Mechanics in Propulsion, 1990.
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Boretti, A. A. Three-dimensional Euler time accurate simulations of fan rotor-stator interactions. Lewis Research Centre, 1990.
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Lewis Research Center. Institute for Computational Mechanics in Propulsion., ed. Three-dimensional Euler time accurate simulations of fan rotor-stator interactions. National Aeronautics and Space Administration, Lewis Research Center, Institute for Computational Mechanics in Propulsion, 1990.
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Boretti, A. A. Three-dimensional Euler time accurate simulations of fan rotor-stator interactions. National Aeronautics and Space Administration, Lewis Research Center, Institute for Computational Mechanics in Propulsion, 1990.
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Three-dimensional Navier-Stokes simulations of turbine rotor-stator interaction. National Aeronautics and Space Administration, Ames Research Center, 1988.
Find full textBook chapters on the topic "Simulations rotor/stator"
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Neuhauser, Magdalena, Francis Leboeuf, Jean-Christophe Marongiu, Etienne Parkinson, and Daniel Robb. "Simulations of Rotor–Stator Interactions with SPH-ALE." In Advances in Hydroinformatics. Springer Singapore, 2013. http://dx.doi.org/10.1007/978-981-4451-42-0_29.
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Song, An, Xiang Luo, Zhongliang He, and Jian He. "Numerical Investigation on Flow and Heat Transfer of a Rotor–Stator Cavity with Labyrinth Seal." In Computational and Experimental Simulations in Engineering. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-42515-8_56.
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Giangaspero, G., M. Almquist, K. Mattsson, and E. van der Weide. "Unsteady Simulations of Rotor Stator Interactions Using SBP-SAT Schemes: Status and Challenges." In Lecture Notes in Computational Science and Engineering. Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-19800-2_21.
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Serre, Eric, Patrick Bontoux, and Brian Launder. "Studies of Transitional and Turbulent Flows in Rotor-Stator Cavity Using High-Performance Computations." In Direct and Large-Eddy Simulation V. Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-1-4020-2313-2_22.
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Shahangian, Navid, Leila Sharifian, Rüdiger Beykirch, Albert Jeckel, Silja Klier, and Lothar Grupe. "Simulation of Oil Flow Behavior in the Air Gap between Rotor and Stator." In Proceedings. Springer Fachmedien Wiesbaden, 2023. http://dx.doi.org/10.1007/978-3-658-42940-9_6.
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Wang, Zhiqiang, Huang Yao, Weijun Bao, and Dianrong Gao. "Motion Simulation and Statics Analysis of the Stator and Rotor of Low Speed High Torque Water Hydraulic Motor." In Intelligent Robotics and Applications. Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-22879-2_16.
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Pustovetov, Mikhail, Konstantin Shukhmin, Sergey Goolak, Jonas Matijošius, and Kateryna Kravchenko. "The Shaft Load Simulations and Calculations of the IM Efficiency Using OrCAD PSpice Designer Software: Obtaining Static Characteristics Data Based on Dynamic Model Modifications of Electrical Machines." In Induction Motor Computer Models in Three-Phase Stator Reference Frames: A Technical Handbook. BENTHAM SCIENCE PUBLISHERS, 2023. http://dx.doi.org/10.2174/9789815124309123010006.
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In this chapter, authors suggest an approach to the shaft load simulations and calculations of the electrical machine efficiency with the use of OrCAD PSpice Designer Software, and in particular, visual programming of analogue component blocks. Also, a method for modifying the EM dynamic model is put forward. This method enables researchers and designers to acquire data for plotting static mechanical, electromechanical and performance curves vs the angular speed of the rotor. These data are obtained by modifications to the block-diagram of the motion equation of the drive where the instantaneous values of the electromagnetic torque of the motor and the load torque are equal by absolute values and opposite to each direction.
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Ardaneh, Fatemeh, Marta Zocca, Antti Uusitalo, and Teemu Turunen-Saaresti. "Numerical Analysis of Aerodynamics and Performance of a Radial-Inflow Micro-ORC Turbine." In Proceedings of the 7th International Seminar on ORC Power System (ORC 2023), 2024th ed. Editorial Universidad de Sevilla, 2024. http://dx.doi.org/10.12795/9788447227457_59.
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Organic Rankine Cycle (ORC) has proven to be an effective way to recover waste heat. The performance of ORC systems is profoundly affected by turbine selection, which is one of the most critical components. In this study, a numerical aerodynamic analysis of a micro-ORC turbine is carried out as an effort towards the formulation of a reduced order model (ROM) of the turbine for the dynamic simulation of the complete ORC system. The studied turbine is the radial-inflow turbine of the waste heat recovery micro-ORC test rig at the Laboratory of Fluid Dynamics, LUT University. The performance of the turbine, which features a highly supersonic flow at the stator outlet, is evaluated through steady-state CFD simulations of the complete turbine geometry using linear siloxane MDM (Octamethyltrisiloxane C8H24O2Si3) as working fluid. Results are discussed and compared with experimental data. Turbine efficiency is studied numerically at varying rotational speeds (25000-31000 rpm). A significant fluctuation in the flow angle at the stator is observed at low rotational speeds, while it decreases at higher speeds. At increasing rotational speed, the analysis shows a corresponding increase in the discharged flow rate, and the turbine efficiency up to 0.2061 kg/s and 79.3, respectively. Moreover, the flow features through the turbine nozzle ring and rotor blades are examined and discussed for selected operating conditions
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Vas, Peter. "Artificial-intelligence-based steady-state and transient analysis of d.c. machines, estimators, control." In Artificial-Intelligence-Based Electrical Machines and Drives. Oxford University PressOxford, 1999. http://dx.doi.org/10.1093/oso/9780198593973.003.0009.
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Abstract In the present chapter, first, the Al-based steady-state and transient analysis of d.c. machines is discussed. For this purpose ANNs and fuzzy-neural networks are used. This is followed by describing AI-based drives, e.g. d.c. drives with ANN speed estimators, d.c. drives with fuzzy controllers, d.c. drives with fuzzy-neural estimators, d.c. drives with neuro controllers (including combined controllers, e.g. where instead of using a separate speed and current controller, a single, ANN-based combined controller is used).Traditionally mathematical model-based analysis techniques have always been used for the steady-state and transient analysis of electrical machines and drives. There are many techniques, but they mainly differ in their complexity and the many assumptions used. In general, when generalized machine theory is used for transient analysis of a d.c. machine, the stator and rotor differential equations, together with the equation of motion, are used for simulation purposes. In a d.c. drive these equations are complemented by the equations governing the controllers and the converter. Thus, in general, a system of first-order non-linear differential equations is obtained, which can be solved by using a numerical technique (e.g. Runge-Kutta technique). However, it is also possible to perform the simulations by using neural networks, or fuzzy-neural networks, which do not require a mathematical model [Vas, 1998]. Such a system is not restricted by the many assumptions used in conventional electrical machine theories.
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Morawiec, Marcin. "Robust Mechanism for Speed and Position Observers of Electrical Machines." In New Trends in Electric Machines - Technology and Applications [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.107898.
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In the sensorless control system, the rotor speed or position is not measured but reconstructed in the dedicated observer structure. The observer structure is based on the mathematical model of an electrical machine. This model is often determined in the space vector form by using the stator/rotor flux vector and stator/rotor current vector components. During the machine works, there exist working points in which the observer can be unstable or its accuracy is unsatisfactory. In order to increase the observer system stability, the Lyapunov theorem should be satisfied. Using this, the observer system’s proper stabilizing function can be determined. However, in many cases, this procedure is not sufficient and in close to an unstable region properties of the speed observer structure are very poor—the estimation errors have values exceeding 5%, which causes loss of synchronization in case of synchronous machines and errors in the values of electromagnetic torque or stator/rotor fluxes. In order to prevent this undesirable phenomenon, additional laws of estimation should be introduced to the speed or position estimation mechanism, which is proposed in this chapter. This mechanism is named in this chapter “robust” because during the machine works, it increases significantly the properties of the whole sensorless control system, minimizing the speed or position estimation errors almost to zero, close to the unstable region (small rotor speed with the regenerating machine mode or close to synchronous of rotor speed in case of the doubly fed generator). The proposed robust mechanism has been tested by using simulation and experimental investigations prepared for: the squirrel-cage induction machine, permanent magnet synchronous machine, and doubly fed induction generator.
Conference papers on the topic "Simulations rotor/stator"
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Sato, Masanori, Takashi Nagumo, Kazuyuki Toda, and Makoto Yamamoto. "Computation of Rotor/Stator Interaction With Hydrogen-Fuelled Combustion." In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45618.
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For the next-generation aircraft, a new propulsion system using hydrogen fuel has been proposed. In the present system, hydrogen fuel injected from a stator surface combusts in the turbine passages, accordingly, the conventional combustor can be cut out. The advantage of this system is that we can design a lighter and smaller engine with low emission. We have demonstrated the realizability of this system by using the cycle analysis and the numerical simulations. Through the previous studies, it was confirmed that the rotor/stator interaction has to be investigated, because the hydrogen combustion phenomena within the stator passage is so complex, and thus it would highly affect the rotor performance. In this paper, we focus on the rotor/stator interaction for the detailed investigation of realizability of this system. The 2- and 3-dimensional numerical simulations are performed for a single stage turbine with hydrogen-fuelled combustion. In the 2-dimensional study, the effects of the injection position and injection rate on the flow structure, the static temperature over the blades, and the blade performance are investigated. Furthermore, 3-dimensional numerical simulation is performed. The general aspect of 3-dimensional flow field is demonstrated, and the effect of hydrogen combustion on the components of turbine, for example hub, tip and blade, are investigated.
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RAI, MAN, and NATERI MADAVAN. "Multi-airfoil Navier-Stokes simulations of turbine rotor-stator interaction." In 26th Aerospace Sciences Meeting. American Institute of Aeronautics and Astronautics, 1988. http://dx.doi.org/10.2514/6.1988-361.
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Zhou, Haowei, Pengcheng Du, and Fangfei Ning. "Time step criteria for rotor-stator unsteady simulations of turbomachinery." In GPPS Chania24. GPPS, 2024. http://dx.doi.org/10.33737/gpps24-tc-065.
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With the rapid improvement of computing power, unsteady Reynolds-Averaged Navier-Stokes (U-RANS) solvers are increasingly used to get a deeper comprehension of the rotor-stator unsteady flows inside turbomachinery. The dual-time stepping method is adopted in most U-RANS solvers and the determination of the optimal size of physical time step is a crucial procedure for rotor-stator U-RANS simulations, and it is the primary purpose of this paper. The criteria for determining the size of physical time step for rotor-stator interactions with and without filtering mixing plane were proposed through theoretical analysis. For conventional no-filtering U-RANS simulations, the number of physical time steps is determined by the number of circumferential grid points and the characteristic propagation velocity of flow. While for U-RANS simulations adopting the filtering mixing plane method, the number of retained harmonics through the filtering mixing plane plays an important role. Then, three numerical cases including subsonic rotor-stator interactions, IGV-rotor interactions and rotor-stator interactions coupled with inlet distortion, were carried out to verify the effectiveness of proposed criteria. The results showed that the requirement of time step independence can be satisfied when the number of physical time steps exceeds the number estimated by the criteria, thus the effectiveness of the proposed criteria has been verified.
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Graf, Martin B., and Om P. Sharma. "Effects of Downstream Stator Pressure Field on Upstream Rotor Performance." In ASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-gt-507.
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Results of numerical simulations conducted for a high pressure compressor rotor with two different levels of tip clearance are presented. A three-dimensional, steady, Reynolds-Averaged Navier-Stokes code was utilized to perform the computations. The simulations were executed over a range of flow coefficients by specifying different axisymmetric radial profiles in static pressure downstream of the rotor. In this manner, the effect of the downstream stator row was approximated using a simple, circumferentially averaged, radial pressure profile as the boundary condition behind the rotor. The back pressure profiles utilized were those deduced from inviscid flow computations for two different stator designs: (1) a conventional radial stator, and (2) a three-dimensional “bowed” stator. Results of the rotor simulations with nominal tip clearance show that the boundary condition induced by the bowed stator causes a 2% decrease in rotor pressure rise capability, and a 9% increase in rotor loss as compared with the conventional stator. In addition, as the tip clearance is increased to twice the nominal value, the rotor loss grows at a rate 25% higher for the rotor subjected to the bowed stator pressure profile. Accompanying this is a dramatic reduction in rotor speedline slope and pressure rise capability. Analysis of the simulations shows these effects to be linked to the response of the rotor tip clearance vortex to the exit pressure profile set by the downstream stator. These results indicate the need to accurately model the effects of the radial variation in static pressure imposed by the downstream airfoil rows.
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Galpin, Paul, Thorsten Hansen, Georg Scheuerer, et al. "Validation of Transonic Axial Compressor Stage Unsteady-State Rotor-Stator Simulations." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-64786.
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The paper describes the validation of steady-state and unsteady CFD simulations against experimental data from a single-stage, transonic axial compressor stage. The experimental data include overall compressor performance, high-resolution traverses of total pressure and total temperature, and unsteady-state total pressure measurements downstream of the rotor. Various numerical rotor-stator interaction methods were applied across the operational speedline. These included a steady-state method mixing plane, and a transient time inclination method that accounts for the unsteady rotor to stator pitch change. Best practice procedures were employed to assess and quantify the sensitivity of the simulations to numerical error like mesh and timestep size, turbulence model error and systematic errors related to tip gap, and steady-state or unsteady-state flow assumptions. The effect of turbulence on the mean flow is modelled by a URANS approach based on the SST model and its extensions for laminar-turbulent transition and reattachment prediction. The complex unsteady flow interactions between the rotor and stator were validated against steady-state and unsteady experimental data. The compressor flow is explained in detail including transonic flow features like shock boundary layer interactions. Comparisons are made between the various rotor-stator interaction simulation methods and the experimental data.
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Dawes, W. N. "A Numerical Study of the Interaction of a Transonic Compressor Rotor Overtip Leakage Vortex With the Following Stator Blade Row." In ASME 1994 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/94-gt-156.
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This paper presents a numerical simulation of the unsteady flow in a transonic compressor stage. The simulations were performed using an unstructured mesh, 3D Navier-Stokes solver with a sliding interface between the mesh blocks containing the rotor and stator blades to permit a time-resolved calculation. The focus in the simulation is the endwall flow, its contrast with the mid-span flow and, in particular, the interaction of the rotor overtip leakage flow with the downstream stator. The endwall region of both the rotors and the stators was predicted to be proportionally responsible for much more loss production than the mid-span sections of the blading. Unsteady effects were predicted to be responsible for rather more of the total loss production in the rotors than in the stators but the unsteady loss production in the rotors did not seem to be associated with the endwall flow but rather occurred over the bulk of the blade span caused by unsteady shock motion. By contrast, the rotor overtip leakage flow was shown to cause a considerable degradation of the stator performance near the casing. In the stators nearly a third of the loss production near the endwall was predicted to be directly due to unsteady effects associated with the rotor vortex interaction and a number of individual physical loss generating mechanisms were identified.
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Goldman, Paul, and Agnes Muszynska. "Chaotic Behavior of Rotor/Stator Systems With Rubs." In ASME 1993 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/93-gt-387.
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This paper outlines the dynamic behavior of externally excited rotor/stator systems with occasional, partial rubbing conditions. The observed phenomenon have one major source of a strong nonlinearity: transition from no contact to contact state between mechanical elements, one of which is rotating. This results in variable stiffness and damping, impacting, and intermittent involvement of friction. A new model for such a transition (impact) is developed. In case of the contact between rotating and stationary elements, it correlates the local radial and tangential (“super ball”) effects with global behavior of the system. The results of numerical simulations of a simple rotor/stator system based on that model are presented in the form of bifurcation diagrams, rotor lateral vibration time–base waves, and orbits. The vibrational behavior of the considered system is characterized by orderly harmonic and subharmonic responses, as well as by chaotic vibrations. A new result (additional subharmonic regime of vibration) is obtained for the case of heavy rub of an anisotropically supported rotor. The correspondence between numerical simulation and previously obtained experimental data supports the adequacy of the new model of impact.
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Guérin, Nicolas, Anders Thorin, Fabrice Thouverez, Mathias Legrand, and Patricio Almeida. "Thermomechanical Model Reduction for Efficient Simulations of Rotor-Stator Contact Interaction." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75880.
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Turbomachinery rotor-stator unilateral contact induced interactions play a growing role in lifecycle analysis and thus motivate the use of accurate numerical prediction tools. Recent literature confirmed by ongoing in-house experiments have shown the importance of thermomechanical coupling effects in such interactions. However, most available (possibly reduced-order) models are restricted to the sole mechanical aspects. This work describes a reduction technique of thermomechanical models involving unilateral contact and frictional contact occurrences between rotor and stator components. The proposed methodology is grounded on Guyan and Craig–Bampton methods for the reduction of the structural dynamics in conjunction with Krylov subspace techniques, and specifically the Craig–Hale approach, for the reduction of the thermal equations. The method has the capability to drastically reduce the size of the model while preserving accuracy. It stands as a reliable strategy to perform simulations of thermomechanical models with localized mechanical and thermal loads.
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RAI, MAN. "Unsteady three-dimensional Navier-Stokes simulations of turbine rotor-stator interaction." In 23rd Joint Propulsion Conference. American Institute of Aeronautics and Astronautics, 1987. http://dx.doi.org/10.2514/6.1987-2058.
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Ramakrishna, P. V., and M. Govardhan. "Studies on Downstream Stator With Rotor Re-Staggering and Forward Sweeping in a Subsonic Axial Compressor Stage." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65101.
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The present numerical work studies the flow field in subsonic axial compressor stator passages for: (a) preceding rotor sweep (b) preceding rotor re-staggering (three stagger angle changes: 0°, +3° and +5°); and (c) stator sweeping (two 20° forward sweep schemes). The following are the motives for the study: at the off-design conditions, compressor rotors are re-staggered to alleviate the stage mismatching by adjusting the rows to the operating flow incidence. Fundamental to this is the understanding of the effects of rotor re-staggering on the downstream component. Secondly, sweeping the rotor stages alters the axial distance between the successive rotor-stator stages and necessitates that the stator vanes must also be swept. To the best of the author’s knowledge, stator sweeping to suit such scenarios has not been reported. The computational model for the study utilizes well resolved hexahedral grids. A commercial CFD package ANSYS® CFX 11.0 was used with standard k-ω turbulence model for the simulations. CFD results were well validated with experiments. The following observations were made: (1) When the rotor passage is closed by re-staggering, with the same mass flow rate and the same stator passage area, stators were subjected to negative incidences. (2) Effect of stator sweeping on the upstream rotor flow field is insignificant. Comparison of total pressure rise carried by the downstream stators suggests that an appropriate redesign of stator is essential to match with the swept rotors. (3) While sweeping the stator is not recommended, axial sweeping is preferable over true sweeping when it is necessary.
Reports on the topic "Simulations rotor/stator"
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Chatagny, Laurent. PR-471-16206-R02 Suction Piping Effect on Pump Performance CFD. Pipeline Research Council International, Inc. (PRCI), 2019. http://dx.doi.org/10.55274/r0011562.
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CFD simulations of pump suction piping coupled to a double suction volute pump were performed with oil at a viscosity of ~90 cSt. Two variants of the suction piping were modeled in order to investigate their effect on the pump performance. Measurement data obtained during PRCI project CPR-15A were used to validate the CFD setup. The CFD results were mostly in line with the measurements, in particular performance and pressure tap values in the suction piping. The pump rotor forces predicted by CFD however showed significant differences to the measured values. The CFD setup presented in this report provides a basis framework for further CFD investigations. This work will benefit the liquids pipeline station designers and operators and also CFD analysts by providing CFD comparisons to benchmark measurements.