Search for dissertations about: "rotating stall"

Found 5 swedish dissertations containing the words rotating stall.

  2. 1. Flow instabilities in centrifugal compressors at low mass flow rate

    Author : Elias Sundström; Mihai Mihaescu; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Centrifugal compressor; flow instabilities; rotational flows; rotating stall; surge; compressible Large Eddy Simulation; Engineering Mechanics; Teknisk mekanik;

    Abstract : A centrifugal compressor is a mechanical machine with purpose to convert kineticenergy from a rotating impeller wheel into the fluid medium by compressingit. One application involves supplying boost air pressure to downsized internalcombustion engines (ICE). READ MORE

  4. 2. 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

  5. 3. Operating conditions impact on flow and acoustics in turbocharger compressors

    Author : Emelie Trigell; Mihai Mihaescu; Mats Åbom; Lisa Prahl Wittberg; Damian Vogt; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbocharger; compressor; LES; surge; rotating stall; flow instabilities; inlet recirculation; aeroacoustics; acoustics; Teknisk mekanik; Engineering Mechanics;

    Abstract : Fluid machines are an integral part in energy conversion with applications from pumps, fans, propellers, compressors and turbines. In the automotive industry, turbochargers are commonly employed to counteract the effect of engine downsizing. READ MORE

  6. 4. Centrifugal compressor flow instabilities at low mass flow rate

    Author : Elias Sundström; Mihai Mihaescu; Håkan Nilsson; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Centrifugal Compressor; Large Eddy Simulation; Internal Com- bustion Engine; Aeroacoustics; Modal Flow Decomposition;

    Abstract : Turbochargers play an important role in increasing the energetic efficiency andreducing emissions of modern power-train systems based on downsized recipro-cating internal combustion engines (ICE). The centrifugal compressor in tur-bochargers is limited at off-design operating conditions by the inception of flowinstabilities causing rotating stall and surge. READ MORE

  7. 5. Measuring with pressure sensitive paint in time-varying flows

    Author : Markus Pastuhoff; Henrik Henrk Alfredsson; Ulrich Henne; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Pressure sensitive paint; fluid mechanics; internal flow; pulsating flow;

    Abstract : Increasingly tougher legislation on internal combustion engine emissions drives the development towards smaller engines with higher efficiency where an important component is the gas-exchange system and especially the turbocharger. The flow in the gas-exchange system is inherently pulsating and unsteady and the present thesis aims at investigating if and how pressure sensitive paint (PSP) can be used for internal unsteady flows of relevance for engine applications. READ MORE