Sökning: "Wavy surface"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden Wavy surface.

1. 1. Interaction mechanisms for a laser-induced metallic boiling front

   Författare :Ramiz Saeed Matti Samarjy; Alexander F.H. Kaplan; Torbjörn Ilar; Michael Schmidt; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Laser remote fusion cutting; Boiling front; High speed imaging; Additive manufacturing; Ejection; Absorption; Wavy surface; Deposition; Produktionsutveckling; Manufacturing Systems Engineering;

   Sammanfattning : This thesis is about fundamental interaction mechanisms of laser remote fusion cutting, RFC, which is based on the formation of a quasi-stationary laser-induced boiling front that causes drop ejection, preferably downwards. Laser cutting of metals, invented in 1967, has developed from a niche to a well established high quality cutting technique in the manufacturing industry. LÄS MER

3. 2. Investigation of Surface Formation in As-Cast and Homogenized 6xxx Aluminium Billets

   Författare :Nazlin Bayat; Torbjörn Carlberg; Håkan Olin; Yanjun Li; Mittuniversitetet; []
   Nyckelord :DC casting; surface segregation; surface defects; intermetallic phase; phase transformation; homogenization;

   Sammanfattning : The direct chill (DC) casting technique to produce billets for extrusion and ingots for rollingwas developed in the 1930s. The principle, which is still valid, is a two-stage cooling with a primary cooling at a mould surface followed by water spraying directly on the surface. LÄS MER

4. 3. Potential Flow Panel Methods for the Calculation of Free-surface Flows with Lift

   Författare :Carl-Erik Janson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; desingularized; shape optimization; Rankine source; waves; OCTOPUS; dipole; MMA; Dawson operator; boundary layer; vortex; Method of Moving Asymptotes; nonlinear; sailing yacht; four point operator; surface piercing wing; Navier-Stokes; numerical method; lift force; raised panel method; discrete Fourier transform; collocation point shift; potential flow; CFD; free surface; induced drag; SHIPFLOW; dispersion; damping; analytical method; hydrofoil;

   Sammanfattning : Two non-linear Rankine-source panel methods are developed and implemented in the same computer code. The first method uses a four-point upwind operator on the free-surface to compute the velocity derivatives and to enforce the radiation condition while the second method uses an analytical expression for the velocity derivatives and a collocation point shift one panel upstream to prevent upstream waves. LÄS MER

5. 4. Chatter stability of turning and milling with process damping

   Författare :Mahdi Eynian; Yusuf Altintas; Canada The University of British Columbia The Faculty of Graduate Studies (Mechanical Engineering); []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : The prediction of chatter instability in machining steel and thermal-resistant alloys at low ‎cutting speeds has been difficult due to unknown process damping contributed by the ‎contact mechanism between tool flank and wavy surface finish. This thesis presents ‎modeling and measurement of process damping coefficients, and the prediction of chatter ‎stability limits for turning and milling operations at low cutting speeds. LÄS MER

7. 5. Investigation of Some Heat Transfer Surfaces for Gas Turbine Recuperators

   Författare :Esa Utriainen; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; trapezoidal; corrugated undulated; cross wavy; cross corrugated; chevron; pressure drop; heat transfer; microturbine; Recuperator; gas turbine; plate-fin; Technological sciences; Teknik; Thermal engineering; applied thermodynamics; Termisk teknik; termodynamik; Gases; fluid dynamics; plasmas; Gaser; fluiddynamik; plasma;

   Sammanfattning : A part of this thesis has been devoted to present general recuperator technology such as available gas turbine recuperator types, applications where recuperators are utilized, recuperator materials etc. An investigation of some compact and highly efficient heat transfer surfaces, for intended use in gas turbine recuperators, include the following surfaces: · Cross Wavy (CW) primary surface. LÄS MER