Sökning: "hydraulic turbine."

Visar resultat 1 - 5 av 35 avhandlingar innehållade orden hydraulic turbine..

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

   Författare :Jelle Kranenbarg; Michel Cervantes; Lisa Prahl Wittberg; Luleå tekniska universitet; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

3. 2. 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

4. 3. Parameterisation and flow design optimisation of hydraulic turbine draft tubes

   Författare :Daniel Marjavaara; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

   Sammanfattning : In the present energy market, the demands of rehabilitation and modernisation of old constructions are increasing. Among the renewable energy resources, hydropower offers one of the highest potential for further improvements due to the fact that a great number of hydropower plants are ageing and that they are run at off-design conditions. LÄS MER

5. 4. Numerical modeling of deforming bubble transport related to cavitating hydraulic turbines

   Författare :Daniel Lörstad; Institutionen för energivetenskaper; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Gases; fluid dynamics; plasmas; Gaser; fluiddynamik; plasma; Energy research; Energiforskning; Direction Averaged Curvature DAC ; Direction Averaged Normal DAN ; Volume of Solid VOS ; Volume of Fluid VOF ; Lagrangian Particle Tracking LPT ; Large Eddy Simulation LES ; bubble; multiphase; turbulent flows; CFD; hydro-turbine;

   Sammanfattning : Cavitation is a problem in many hydroelectric power plants since it can cause adverse effects on performance and damage to nearby solid surfaces. The concerns of this thesis are the numerical aspects of flow simulations in cavitating hydraulic turbines which contain several difficulties: turbulent and complex flows, steady and moving parts of the geometry, bubble transport and cavitation development. LÄS MER

7. 5. CFD driven optimization of hydraulic turbine draft tubes using surrogate models

   Författare :Daniel Marjavaara; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

   Sammanfattning : The efficiency of a hydraulic reaction turbine is significantly affected by the performance of its draft tube. The shape and velocity distribution at the inlet are, in next turn, two main factors that affects the performance of the draft tube. LÄS MER