Search for dissertations about: "blades flutter"

Showing result 1 - 5 of 12 swedish dissertations containing the words blades flutter.

2. 1. Improved Flutter Prediction for Turbomachinery Blades with Tip Clearance Flows

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

   Abstract : 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. READ MORE

4. 2. Flutter in sectored turbine vanes

   Author : Olga V. Chernysheva; KTH; []
   Keywords : turbomachinery; aerodynamics; unsteady CFD; design; flutter;

   Abstract : 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. READ MORE

5. 3. 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

   Author : Hakim Ferria; Pascal Ferrand; Torsten Fransson; François Moyroud; France Ecole Centrale de Lyon Laboratoire de Mécanique des Fluides et d'Acoustique; []
   Keywords : 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;

   Abstract : 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. READ MORE

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

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

   Abstract : 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. READ MORE

7. 5. Sensitivity of Aeroelastic Properties of an Oscillating LPT Cascade

   Author : Nenad Glodic; Damian Vogt; Matthew Montgomery; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flutter; aeroelastic response; combined modes; bending-torsion flutter; mode superposition; aerodynamic asymmetries; ROM; probabilistic analysis;

   Abstract : Modern turbomachinery design is characterized by a tendency towards thinner, lighter and highly loaded blades, which in turn gives rise to increased sensitivity to flow induced vibration such as flutter. Flutter is a self-excited and self-sustained instability phenomenon that may lead to structural failure due to High Cycle Fatigue (HCF) or material overload. READ MORE