Advanced search

Showing result 1 - 5 of 18 swedish dissertations matching the above criteria.

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

   Author : Jelle Kranenbarg; Michel Cervantes; Lisa Prahl Wittberg; Luleå tekniska universitet; []
   Keywords : 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;

   Abstract : 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. READ MORE

4. 2. Experimental study of turbulent flows through pipe bends

   Author : Athanasia Kalpakli; P. Henrik Alfredsson; Ramis Örlü; Christoph Brücker; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent flow; swirl; pulsation; pipe bend; hot-wire anemometry; cold-wire anemometry; laser Doppler velocimetry; stereoscopic particle image velocimetry.;

   Abstract : This thesis deals with turbulent flows in 90 degree curved pipes of circular cross-section. The flow cases investigated experimentally are turbulent flow with and without an additional motion, swirling or pulsating, superposed on the primary flow. READ MORE

5. 3. Vortices in turbulent curved pipe flow-rocking, rolling and pulsating motions

   Author : Athanasia Kalpakli Vester; P. Henrik Alfredsson; Ramis Örlü; Nils Tillmark; Knud Meyer; KTH; []
   Keywords : Turbulence; curved pipes; swirling flow; pulsatile flow; time-resolved stereoscopic particle image velocimetry; hot-wire anemometry; proper orthogonal decomposition; turbocharger;

   Abstract : This thesis is motivated by the necessity to understand the flow structure of turbulent flows in bends encountered in many technical applications such as heat exchangers, nuclear reactors and internal combustion engines. Flows in bends are characterised by strong secondary motions in terms of counter-rotating vortices (Dean cells) set up by a centrifugal instability. READ MORE

6. 4. Experimental design and vortex analyses in turbulent wake flows

   Author : Bengt E. G. Fallenius; Jens H. M. Fransson; Henrik Alfredsson; Marianna Braza; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bluff bodies; wake flow; experimental design; vortex detection; flow control; asymptotic suction boundary layer;

   Abstract : A new experimental setup for studies on wake flow instability and its control that successfully has been designed and manufactured, is introduced and de- scribed. The main body is a dual-sided flat plate with an elliptic leading edge and a blunt trailing edge. READ MORE

7. 5. Computational modelling of blood flow in medical assist devices

   Author : Francesco Fiusco; Lisa Prahl Wittberg; Lars Mikael Broman; Anders Dahlkild; David Ku; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; computational fluid dynamics; haemodynamics; platelet activation; thrombogenicity; haemolysis; extracorporeal membrane oxygenation; sensitivity; Teknisk mekanik; Engineering Mechanics;

   Abstract : Extracorporeal membrane oxygenation (ECMO) is a life-saving support treat-ment in case of pulmonary and/or cardiac failure. An artificial extracorporealcircuit is used to offload the function of lungs and/or heart. READ MORE