Avancerad sökning

Hittade 5 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. On efficient and adaptive modelling of friction damping in bladed disks

    Författare :Mohammad Afzal; Leif Kari; Ines Lopez Arteaga; Muzio M Gola; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High cycle fatigue; Friction contact; Jacobian matrix; Shroud contact; Strip damper; Multiharmonic balance method; Contact stiffness; Cyclic symmetry; Nodal diameter; Magnetostrictive actuator; Magnetic field; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : This work focuses on efficient modelling and adaptive control of friction damping in bladed disks. To efficiently simulate the friction contact, a full-3D time-discrete contact model is reformulated and an analytical expression for the Jacobian matrix is derived that reduces the computation time drastically with respect to the classical finite difference method. LÄS MER

  3. 2. Numerical modelling and analysis of friction contact for turbine blades

    Författare :Mohammad Afzal; Leif Kari; Viktor Berbyuk; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vehicle and Maritime Engineering; Farkostteknik;

    Sammanfattning : High cycle fatigue failure of turbine and compressor blades due to resonance in the operating frequency range is one of the main problems in the design of gas turbine engines. To suppress excessive vibrations in the blades and prevent high cycle fatigue, dry friction dampers are used by the engine manufacturers. LÄS MER

  4. 3. Formation of non-metallic inclusions and the possibility of their removal during ingot casting

    Författare :Lars Ragnarsson; Sichen Du; Carlo Mapelli; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ingot casting; tool steel; inclusion; runner; refractory; erosion; casting powder; cold model; argon shroud; reoxidation; oxygen measurement; CFD; PIV; Metallurgical process engineering; Metallurgisk processteknik;

    Sammanfattning : The present study was carried out to investigate the formation and evolution of non-metallic inclusions during ingot casting. Emphasize have been on understanding the types of inclusions formed and developed through the casting process and on the development of already existing inclusions carried over from the ladle during casting. LÄS MER

  5. 4. 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

  7. 5. An experimental and numerical study of an automotive cooling module

    Författare :Anders Rynell; Gunilla Efraimsson; Michael Shur; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fan installation effects; spectral decomposition; aeroacoustics; Vehicle and Maritime Engineering; Farkostteknik;

    Sammanfattning : Heavy vehicles are major emitters of noise. Especially at idle or low vehicle speeds a large portion of the noise emanates from the fan that forces the flow through the cooling module. The aim of this work is to investigate and reveal aerodynamic and acoustic installation effects linked to the cooling package. LÄS MER