Search for dissertations about: "URANS"

Showing result 1 - 5 of 20 swedish dissertations containing the word URANS.

2. 1. Turbulence-resolving Simulations of Swirling Flows

   Author : Ardalan Javadi; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Swirling Flow; URANS; Hydropower; Hybrid URANS-LES; SAS; Flow Control; Turbulence Modeling; Vortex Breakdown; DDES; LES;

   Abstract : A series of numerical investigations is undertaken using a wide range of turbulence mod-els including conventional and non-conventional URANS models, hybrid URANS-LESmethods and LES to capture a large variety of physical mechanisms that produce pres-sure pulsations in the swirling flows. The available knowledge about these pulsations,which are usual in hydropower, are still far from complete. READ MORE

4. 2. A Numerical Study of Reacting Flows Using Finite Rate Chemistry

   Author : Mohammad Irannezhad; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Combustion modeling; Lean blow off; Finite rate chemistry; Inlet boundary condition; Combustion; Lean premixed; Engine configuration; Pulse Detonation Engine; Emissions; URANS; Unsteady phenomena; Flame stabilization; Low Swirl Burner; Large Eddy Simulation; Dynamic flame; Working cycle;

   Abstract : Fossil fuels will remain the main source of energy for mankind in theforeseeable future. Heat released in combustion of fossil fuels is alwaysaccompanied by emission of undesired pollutants. Environmental concernshave led to stringent emission rules for combustion industry speciallyfor reducing the amount of NOx production. READ MORE

5. 3. 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

6. 4. Computation and Analysis of EGR Mixing in Internal Combustion Engine Manifolds

   Author : Alexander Sakowitz; Laszlo Fuchs; Angelo Onorati; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent Mixing; Large Eddy Simulation; URANS; Internal Combustion Engines; Intake Manifolds; T-junction; Exhaust Gas Recirculation;

   Abstract : This thesis deals with turbulent mixing processes occurring in internal combustion engines, when applying exhaust gas recirculation (EGR). EGR is a very efficient way to reduce emissions of nitrogen oxides (NOx) in internal combustion engines. READ MORE

7. 5. Heat transfer in ordered porous media with application to batteries

   Author : Amin Moosavi; Staffan Lundström; Anna-Lena Ljung; Tomas Muld; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; battery thermal management system; heat exchanger; cylindrical lithium-ion battery; cross-flow; analytical model; URANS model; thermal evaluation; wall effect; spacing effect; temperature distribution; Strömningslära; Fluid Mechanics;

   Abstract : Environmental concerns, resource depletion, energy security, technological advancements, and global policies are just a few of the variables influencing the global energy perspective. In the case of technological advancement, lithium batteries play a key role in the development of a more sustainable energy infrastructure. READ MORE