Sökning: "blade clearance"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden blade clearance.

1. 1. Numerical investigation of the flow and instabilities at part-load and speed-no-load in an axial turbine

   Författare :Jelle Kranenbarg; Michel Cervantes; Lisa Prahl Wittberg; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Speed-no-load; vortical flow structures; flow instabilities; rotating stall; mitigation; independent guide vanes; axial turbine; swirling flow; off design operation; URANS; parametric study; blade clearance; head losses; diffusor; GEKO model; flow separation; hydraulic turbine; Strömningslära; Fluid Mechanics;

   Sammanfattning : Global renewable energy requirements rapidly increase with the transition to a fossil-free society. As a result, intermittent energy resources, such as wind- and solar power, have become increasingly popular. However, their energy production varies over time, both in the short- and long term. LÄS MER

3. 2. Simulation and Optimization of an Axial Compressor Considering Tip Clearance Flow

   Författare :Marcus Lejon; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; design; compressor; optimization; validation; CFD; turbulence models; tip clearance;

   Sammanfattning : With ever-increasing demands for high efficiency in axial compressors, it has become important to consider more geometrical features of the manufactured component in the design phase. Many possibilities open if the level of fidelity of the computational model can be increased. LÄS MER

4. 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

5. 4. Numerical Simulation of Some Heat Transfer and Fluid Flow Phenomena for Gas Turbine Blades and a Transonic Turbine Stage

   Författare :Fadil Mumic; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fluiddynamik; plasma; Thermal engineering; applied thermodynamics; plasmas; Gaser; fluid dynamics; Gases; transonic; numerical; heat transfer coefficient; shroud surface; squealer blade tip; flat blade tip; leakage flow; Termisk teknik; termodynamik; turbulence modeling;

   Sammanfattning : With the attempts to achieve higher thermal efficiency, turbine blades are exposed to very high temperature gases and may undergo severe thermal stress and fatigue. Thus, in order to develop optimal cooling strategies and reduce the heat transfer it is important to obtain a good understanding of both the complex flow field and the heat transfer characteristics in turbine rotor/stator hot-gas passages. LÄS MER

7. 5. Aerodynamic design framework for low-pressure compression systems

   Författare :Marcus Lejon; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; manufacturing variations; optimization; stage matching; tip clearance; validation; Turbomachinery; CFD; surface roughness; compressor;

   Sammanfattning : Aircraft engine manufacturers strive to improve current state of the art designs through continuous development efforts. By improving existing designs and exploring new alternatives, the goal is to reduce the fuel consumption - a topic of high relevance due to the remarkable growth rate of air traffc. LÄS MER