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You searched for subject:(Rotor stator cavity). Showing records 1 – 3 of 3 total matches.

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UCLA

1. Amouyal, Solal. Numerical simulation of a closed rotor-stator system using Large Eddy Simulation.

Degree: Aerospace Engineering, 2014, UCLA

A large eddy simulation of an enclosed annular rotor stator cavity is presented. Thegeometry is characterized by a large aspect ratio G = (b-a)/h = 18.32 and a small radiusratio a/b = 0.152, where a and b are the inner and outer radii of the rotating disk and h isthe interdisk spacing. The rotation rate ω under consideration is equivalent to the rotationalReynolds number Re = ω b<super>2<super> /ν= 9.5x10<super>4<super> , where ν is the kinematic viscosity.The main objective of this study is to correctly simulate the rotor stator cavity using a loworder numerical scheme on unstructured grids. The numerical simulations were run on thesoftware AVBP developed by the Centre Européen de Recherche et de Formation Avancée en Calcul Scientific. The results were compared to the experimental results obtained by Sebastien Poncet of Universit é Aix-Marseille. Two large eddy simulations techniques were used: the Smagorinsky and Wall-adapting local eddy-viscosity models. The simulations were run on three set of grids, each with a different cell resolution-14, 35 and 50- along the thickness of the system. Results from each mesh show a good qualitative agreement of the mean velocity field with Poncet's experimental results. It was found that the Samgorinsky model to be more appropriate for this configuration.

Subjects/Keywords: Aerospace engineering; Large Eddy Simulation; Rotor-stator cavity

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Amouyal, S. (2014). Numerical simulation of a closed rotor-stator system using Large Eddy Simulation. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/975761j8

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Amouyal, Solal. “Numerical simulation of a closed rotor-stator system using Large Eddy Simulation.” 2014. Thesis, UCLA. Accessed October 14, 2019. http://www.escholarship.org/uc/item/975761j8.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Amouyal, Solal. “Numerical simulation of a closed rotor-stator system using Large Eddy Simulation.” 2014. Web. 14 Oct 2019.

Vancouver:

Amouyal S. Numerical simulation of a closed rotor-stator system using Large Eddy Simulation. [Internet] [Thesis]. UCLA; 2014. [cited 2019 Oct 14]. Available from: http://www.escholarship.org/uc/item/975761j8.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Amouyal S. Numerical simulation of a closed rotor-stator system using Large Eddy Simulation. [Thesis]. UCLA; 2014. Available from: http://www.escholarship.org/uc/item/975761j8

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Peres, Noele. A 3D pseudospectral method for cylindrical coordinates. Application to the simulations of rotating cavity flows : Professional sanction in business criminal law : a contribution to a general theory of sanction.

Degree: Docteur es, Mécanique et physique des fluides, 2012, Aix Marseille Université

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.

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…

Advisors/Committee Members: Serre, Eric (thesis director), Poncet, Sébastien (thesis director).

Subjects/Keywords: Méthodes spectrales; Singularité en coordonnées cylindriques; Éclatement tourbillonnaire; Écoulement rotor-stator; Spectral methods; Cylindrical coordinate singularity; Rotating cavity flows

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Peres, N. (2012). A 3D pseudospectral method for cylindrical coordinates. Application to the simulations of rotating cavity flows : Professional sanction in business criminal law : a contribution to a general theory of sanction. (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2012AIXM4309

Chicago Manual of Style (16th Edition):

Peres, Noele. “A 3D pseudospectral method for cylindrical coordinates. Application to the simulations of rotating cavity flows : Professional sanction in business criminal law : a contribution to a general theory of sanction.” 2012. Doctoral Dissertation, Aix Marseille Université. Accessed October 14, 2019. http://www.theses.fr/2012AIXM4309.

MLA Handbook (7th Edition):

Peres, Noele. “A 3D pseudospectral method for cylindrical coordinates. Application to the simulations of rotating cavity flows : Professional sanction in business criminal law : a contribution to a general theory of sanction.” 2012. Web. 14 Oct 2019.

Vancouver:

Peres N. A 3D pseudospectral method for cylindrical coordinates. Application to the simulations of rotating cavity flows : Professional sanction in business criminal law : a contribution to a general theory of sanction. [Internet] [Doctoral dissertation]. Aix Marseille Université 2012. [cited 2019 Oct 14]. Available from: http://www.theses.fr/2012AIXM4309.

Council of Science Editors:

Peres N. A 3D pseudospectral method for cylindrical coordinates. Application to the simulations of rotating cavity flows : Professional sanction in business criminal law : a contribution to a general theory of sanction. [Doctoral Dissertation]. Aix Marseille Université 2012. Available from: http://www.theses.fr/2012AIXM4309


ETH Zürich

3. Rebholz, Patrick S. Aeromechanical Challenges of Shrouded Low Pressure Turbines for Geared Turbofan Engines.

Degree: 2017, ETH Zürich

The primary scope of this thesis is to contribute to meeting the challenges associated to the integration of shrouded blades into high speed low pressure turbines of geared turbo-fan engines. Doubling the rotational speed of the low pressure shaft bears considerable advantages in terms of the fuel consumption, the noise emissions, the length as well as the part count compared to conventional multi-spool engine designs. However, the quadratic increase of the centrifugal blade stress with rotational speed has impeded the application of shrouded low pressure turbine blades, which are aerodynamically more favorable and have a higher robustness against flutter instabilities, in current designs due to high cycle fatigue concerns. As a consequence of the reduced error margin in the fatigue design of high speed blade rows, two immediately arising questions for the design of the next gener-ation of geared turbofan engines are addressed in this work: How accurately can current industrial methods predict the unsteady aerodynamic forces in a shrouded low pressure turbine? And: At what performance cost can the mass of a shroud be reduced by plat-form cutbacks to mitigate fatigue issues? The current work was carried out within the scope of a joint academic and industrial re-search effort to elucidate the aerodynamic forcing in a fully shrouded low pressure turbine experimentally and numerically as well as to determine the performance deterioration of different shroud platform geometries. The latest, optimized and tested design of a 1.5-stage fully shrouded low pressure turbine with non-axisymmetric enwalls operating with rim seal purge flow injection represents the baseline for both campaigns. A modular, high resolution and low noise, multi-purpose telemetry system has been developed and inte-grated into the axial research turbine facility “LISA” at ETH Zurich. A unique experi-mental data set comprised of fast response traverse and wall pressure measurements has been acquired. The unsteady surface pressure of both the rotor as well as the second sta-tor has been probed using a total of 60 flush-mounted, ultra-miniature size, piezo-resistive pressure transducers. The aerodynamic forcing functions and the turbine performance have been characterized using a combination of multi-hole pneumatic probe and fast re-sponse aerodynamic probe (FRAP) measurements on the inter-row planes. Leakage flows have been tracked using the unsteady entropy probe (FENT). The comparison of the ex-perimental data with time-accurate RANS simulations highlights the capabilities and lim-itations of commercial solvers and enables the quantification of the prediction error in the aerodynamically induced blade root stress. The unsteady rotor surface pressure in a shrouded, subsonic low pressure turbine is driv-en by convective perturbations and acoustic interaction. Five main forcing functions have been identified: Potential interaction with upstream and downstream rows, convective inflow perturbations and incidence variation in the main flow, secondary flow… Advisors/Committee Members: Abhari, Reza S., Vogt, Damian M., Kalfas, Anestis I..

Subjects/Keywords: Turbomachinery; Experimental Flow Physics; Computational Fluid Dynamics (CFD); Shrouded Low Pressure Turbine; Flush-mounted Fast Response Surface Pressure Instrumentation; Unsteady Turbine Blade and Stator Surface Pressure; Non-synchronous Pressure Perturbations and Cavity Modes; Unsteady Aerodynamic Forcing; Rim Seal Purge Flow Injection; Stator Clocking; Axial Blade Row Spacing; Partial Rotor Tip Shroud; Aeroengine Noise Generation

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Rebholz, P. S. (2017). Aeromechanical Challenges of Shrouded Low Pressure Turbines for Geared Turbofan Engines. (Doctoral Dissertation). ETH Zürich. Retrieved from http://hdl.handle.net/20.500.11850/183651

Chicago Manual of Style (16th Edition):

Rebholz, Patrick S. “Aeromechanical Challenges of Shrouded Low Pressure Turbines for Geared Turbofan Engines.” 2017. Doctoral Dissertation, ETH Zürich. Accessed October 14, 2019. http://hdl.handle.net/20.500.11850/183651.

MLA Handbook (7th Edition):

Rebholz, Patrick S. “Aeromechanical Challenges of Shrouded Low Pressure Turbines for Geared Turbofan Engines.” 2017. Web. 14 Oct 2019.

Vancouver:

Rebholz PS. Aeromechanical Challenges of Shrouded Low Pressure Turbines for Geared Turbofan Engines. [Internet] [Doctoral dissertation]. ETH Zürich; 2017. [cited 2019 Oct 14]. Available from: http://hdl.handle.net/20.500.11850/183651.

Council of Science Editors:

Rebholz PS. Aeromechanical Challenges of Shrouded Low Pressure Turbines for Geared Turbofan Engines. [Doctoral Dissertation]. ETH Zürich; 2017. Available from: http://hdl.handle.net/20.500.11850/183651

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