Sökning: "Turbomachinery"

Visar resultat 6 - 10 av 60 avhandlingar innehållade ordet Turbomachinery.

  1. 6. Modeling Unsteady flow Effects in 3D Throughflow Calculations

    Författare :Magnus Stridh; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; throughflow; turbomachinery; mixing-plane; rotor-stator interaction; cascade; Deterministic stress terms; Linear harmonic; compressor; preconditioned GMRES; Unsteady; linear Navier-Stokes; turbine;

    Sammanfattning : The flow field in a transonic multistage compressor is compressible, three-dimensional and highly unsteady and can be predicted in principle by the exact time-accurate Navier-Stokes equations. The high Reynolds number encountered in multistage turbomachinery together with the wall-bounded nature of the flow environment however prevent the use of DNS to solve the exact N-S equations. LÄS MER

  3. 7. Development of Numerical Methods for Turbulent Flow in Complex Rotating Systems

    Författare :Peter Hedberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; fluid mechanics; computer code; rotating geometries; turbomachinery;

    Sammanfattning : A computer code has been developed to predict three-dimensional incompressible turbulent flow in complex rotating geometries. The application in mind is turbomachinery in general. However such a code is able to treat a large number of problems in fluid mechanics. LÄS MER

  4. 8. 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

  5. 9. Numerical Methods for Aeroacoustic Analysis of Turbomachines

    Författare :Daniel Lindblad; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stability Analysis; Acoustic Analogy; Tonal Noise; Nonreflecting Boundary Conditions; Duct Modes; Turbomachinery; Harmonic Balance; Ffowcs Williams - Hawkings; Time Sampling; Aliasing;

    Sammanfattning : Numerical simulations are important tools for developing new aircraft that can meet future needs. When numerical simulations are used to compute aircraft noise, a two-step procedure is often employed. In the first step, the noise sources are determined using, e.g. LÄS MER

  7. 10. 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