Sökning: "self-excited"

Visar resultat 6 - 10 av 14 avhandlingar innehållade ordet self-excited.

1. 6. Experimental Investigation of the Influence of Local Flow Features on the Aerodynamic Damping of an Oscillating Blade Row

   Författare :Antonio Sanz Luengo; Torsten Fransson; Damian Vogt; Guillermo Paniagua; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbomachinery; Aeroelasticity; Flutter; Experimental Aerodynamics; CFD; Local Flow Features; Influence Coefficient; Linearity Assumption; Aerospace Engineering; Flyg- och rymdteknik;

   Sammanfattning : The general trend of efficiency increase, weight and noise reduction has derived in the design of more slender, loaded, and 3D shaped blades. This has a significant impact on the stability of fan, and low pressure turbine blades, which are more prone to aeroelastic phenomena such as flutter. LÄS MER

3. 7. 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

4. 8. Numerical Computations of Internal Combustion Engine related Transonic and Unsteady Flows

   Författare :Olle Bodin; Laszlo Fuchs; Daniel Lörstad; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LES; Transonic flow; Hysteresis; Shock boundary-layer interaction; Exhaust valve; Fluid mechanics; Strömningsmekanik;

   Sammanfattning : Vehicles with internal combustion (IC) engines fueled by hydrocarbon compounds have been used for more than 100 years for ground transportation. During the years and in particular in the last decade, the environmental aspects of IC engines have become a major political and research topic. LÄS MER

5. 9. Simulations of compressible flows associatedwith internal combustion engines

   Författare :Olle Bodin; Laszlo Fuchs; Mihai Mihaescu; Michael Leschziner; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LES; Gas exhange; exhaust port; exhaust manifold; POD; DMD; exhaust; LES; Gasväxling; avgasport; avgasgrenrör; POD; DMD;

   Sammanfattning : Vehicles with internal combustion (IC) engines fueled by hydrocarbon compoundshave been used for more than 100 years for ground transportation.During these years and in particular the last decade, the environmental aspectsof IC engines have become a major political and research topic. LÄS MER

7. 10. 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