Sökning: "vortex generator"

Visar resultat 6 - 10 av 17 avhandlingar innehållade orden vortex generator.

1. 6. Flow Control and Shape Optimization of Intermediate Turbine Ducts for Turbofan Engines

   Författare :Fredrik Wallin; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; response surface methodology; intermediate turbine duct; vortex generators; turbine intermediate case; endwall contouring; turbine center frame; body-force model; shape optimization; mid-turbine frame; flow control;

   Sammanfattning : Demands on improved efficiency, reduced emissions and lowered noise levels cause a strive towards high by-pass ratios of commercial turbofan engines. This results in an increased radial offset between the high- and low-pressure turbines. Thus the design of the intermediate turbine duct connecting the two turbines becomes more challenging. LÄS MER

3. 7. Aerodynamic Design and Optimization of Intermediate Ducts for High By-pass Ratio Jet Engines

   Författare :Fredrik Wallin; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Intermediate transition ducts; vortex generators; S-shaped ducts; response surface methodology; source term model; optimization;

   Sammanfattning : Demands on improved efficiency and reduced noise levels cause a strive toward high by-pass ratio commercial aero engines. This results in multi-spool aero engines with small high-pressure ratio cores and large fans. The low-pressure system has a lower rotational speed and a larger radius than the high-pressure core system. LÄS MER

4. 8. FLOW FIELD IN A HIGH HEAD FRANCIS TURBINE DRAFT TUBE DURING TRANSIENT OPERATIONS

   Författare :Rahul Goyal; Michel J. Cervantes; Bhupendra K. Gandhi; Gabriel Ciocan; Lisa Prahl; Ramis Orlu; Gunilla Andree; Andrea Toffolo; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Francis turbine; Steady state; Transient; Particle Image Velocimetry; Vortex Rope; Strömningslära; Fluid Mechanics;

   Sammanfattning : Hydroelectricity plays an important role to balance the stability of grid network.  In order to improve the stability of presently high loaded grids, hydropower plants are being operated over a wide range of operations and experiencing frequent start-stop, load rejection, and load acceptance. LÄS MER

5. 9. Experimental study of the turbulent flow in a plane asymmetric diffuser

   Författare :Olle Törnblom; KTH; []
   Nyckelord :fluid mechanics; wind-tunnel. Burbulence; turbulence modelling; earsm; asymmetric diffuser; boundary layer;

   Sammanfattning : The separating turbulent flow in a plane asymmetric diffuseris investigated experimentally. The considered flow case issuitable for fundamental studies of separation, separationcontrol and turbulence modelling. The flow case has beenstudied in a specially designed wind-tunnel under wellcontrolled conditions. LÄS MER

7. 10. Multidisciplinary Design in Aeronautics, Enhanced by Simulation-Experiment Synergy

   Författare :Tomas Melin; Arthur Rizzi; Jesper Oppelstrup; Ray Whitford; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aeronautics; conceptual design; design; high lift systems; Vehicle engineering; Farkostteknik;

   Sammanfattning : This thesis covers some aspects of current aircraft design, and presents how experiment and simulation are used as tools. Together they give enhanced effects over employing either one separately. The work presented has been produced using both simulations and experiments. LÄS MER