Sökning: "Flutter"

Visar resultat 1 - 5 av 37 avhandlingar innehållade ordet Flutter.

  1. 1. Flutter in sectored turbine vanes

    Författare :Olga V. Chernysheva; KTH; []
    Nyckelord :turbomachinery; aerodynamics; unsteady CFD; design; flutter;

    Sammanfattning : In order to eliminate or reduce vibration problems inturbomachines without a high increase in the complexity of thevibratory behavior, the adjacent airfoils around the wheel areoften mechanically connected together with lacing wires, tip orpart-span shrouds in a number of identical sectors. Although anaerodynamic stabilizing effect of tying airfoils together ingroups on the whole cascade is indicated by numerical andexperimental studies, for some operating conditions suchsectored vane cascade can still remain unstable. LÄS MER

  2. 2. Contribution to Numerical and Experimental Studies of Flutter in Space Turbines. Aerodynamic Analysis of Subsonic or Supersonic Flows in Response to a Prescribed Vibratory Mode of the Structure

    Författare :Hakim Ferria; Pascal Ferrand; Torsten Fransson; François Moyroud; France Ecole Centrale de Lyon Laboratoire de Mécanique des Fluides et d'Acoustique; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flutter; space turbine; LRANS computation; flutter measurement; shock wave boundary layer interaction; blisk; cut-on cut-off condition; interblade phase angle; combined modes;

    Sammanfattning : Modern turbomachines are designed towards thinner, lighter and highly loaded blades. This gives rise to increased sensitivity to flow induced vibrations such as flutter, which leads to structure failure in a short period of time if not sufficiently damped. LÄS MER

  3. 3. Improved Flutter Prediction for Turbomachinery Blades with Tip Clearance Flows

    Författare :Tianrui Sun; Andrew R. Martin; Paul Petrie-Repar; Mihai Mihaescu; KTH; []
    Nyckelord :Steam turbine; Flutter; Aeroelastic stability; Tip clearance flow; Detached-Eddy Simulation; Energiteknik; Energy Technology;

    Sammanfattning : Recent design trends in steam turbines strive for high aerodynamic loading and high aspect ratio to meet the demand of higher efficiency. These design trends together with the low structural frequency in last stage steam turbines increase the susceptibility of the turbine blades to flutter. LÄS MER

  4. 4. Experimental Investigation of Three-Dimensional Mechanisms in Low-Pressure Turbine Flutter

    Författare :Damian Vogt; Torsten Fransson; Robert Kielb; KTH; []
    Nyckelord :Life sciences and physical sciences; turbomachinery; flutter; aeroelastic instability; aeroelastic testing; CFD; linearized unsteady numerical method; 3D aerodynamic effects; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : The continuous trend in gas turbine design towards lighter, more powerful and more reliable engines on one side and use of alternative fuels on the other side renders flutter problems as one of the paramount challenges in engine design. Flutter denotes a self-excited and self-sustained aeroelastic instability phenomenon that can lead to material fatigue and eventually damage of structure in a short period of time unless properly damped. LÄS MER

  5. 5. Numerical simulation of viscous compressible flows applied to turbomachinery blade flutter

    Författare :L. D. Gunnar Sidén; Chalmers University of Technology; []
    Nyckelord :unsteady; flutter; turbine; aeroengine; turbomachinery; numerical method; oscillating; Navier-Stokes; finite volume; viscious; finite element; turbulent; fan; aeroelastic; vibration; compressor; stall;

    Sammanfattning : .... LÄS MER