Search for dissertations about: "Flow pulsations"

Showing result 1 - 5 of 30 swedish dissertations containing the words Flow pulsations.

  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. Catalytic Converters for Automotive Exhaust Applications. Flow Dynamics, Mass Transfer and Optimization

    Author : Fredrik Ekström; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TWC; optimization; exhaust; laboratory reactors; catalytic converter; catalysis; pressure drop; entrance effects; CFD; mass transfer; pulsations; flow distribution;

    Abstract : In order to reduce emissions from vehicles powered by an internal combustion engine, an exhaust aftertreatment system is normally mounted on the engine. This aftertreatment system normally consists of one or several catalytic converters. 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. Exergy Evaluation of Engine Operations : Combustion Process to Exhaust Flow

    Author : Beichuan Hong; Andreas Cronhjort; Mihai Mihaescu; Sundar Rajan Krishnan; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Thermal efficiency; Exergy analysis; Marine engine; Lean-burn combustion; Pulsating flow measurement; Pitot tube; Sensitivity analysis; Energy and exergy losses; Termisk verkningsgrad; Exergianalys; Marinmotor; Magertbränningsförbränning; Pulserande flödesmätning; Pitotrör; Känslighetsanalys; Energiförluster och exergiförluster; Machine Design; Maskinkonstruktion; Energiteknik; Energy Technology;

    Abstract : Transitioning the transport sector to clean energy sources is crucial for mitigating greenhouse gas emissions and achieving carbon neutrality. A collaborative solution, combining both electric vehicles and combustion engines using renewable fuels, may prove more effective than competitive ones. READ MORE

  7. 5. Flow Maldistribution in Exhaust Aftertreatment Systems - Numerical Simulations

    Author : Pratheeba Chanda Nagarajan; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Catalyst; Flow maldistribution; Transient; CFD Simulations; Reactive flows; Uniformity Index; Exhaust AfterTreatment Systems;

    Abstract : To comply with the stringent emission norms under every driving condition, including the coldstart conditions and Real Driving Emissions (RDE) tests, accurate models that capture the spatial and temporal variation of flow distribution information in Exhaust AfterTreatment Systems (EATS) are required. This study is aimed at characterizing and quantifying flow distribution in EATS under transient conditions with realistic geometry that illustrates the complex nature of the flow conditions. READ MORE