Sökning: "swirl numbers"

Visar resultat 6 - 10 av 17 avhandlingar innehållade orden swirl numbers.

  1. 6. Thermal and Hydraulic Performance of Enhanced Rectangular Tubes for Compact Heat Exchangers

    Författare :Carl-Olof Olsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; LDV; heat exchanger; enhanced heat transfer; radiator; smoke visualization; pressure drop; secondary flow;

    Sammanfattning : The thermal and hydraulic performance of rib-roughened, dimpled and offset strip fin tubes has been investigated experimentally. Results from measurements on commercially manufactured tubes have shown that rib-roughened tubes have best potential for heat transfer enhancement with moderate pressure drop increase. LÄS MER

  3. 7. Time-accurate Turbulence Modeling of Swirling Flow for Hydropower Application

    Författare :Ardalan Javadi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hybrid RANS-LES; Swirling Flow; DES; Vortex Breakdown; Turbulence Modeling; Hydropower; LES;

    Sammanfattning : Hydraulic turbomachines have played a prominent role in the procurement of renewableenergy for more than a century. Embedded in the context of general technological progress,their design for efficiency and reliability has reached an outstanding level of quality. LÄS MER

  4. 8. Shapes of pipes

    Författare :Valerio Lupi; Philipp Schlatter; Ramis Örlü; Jean-Christophe Robinet; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Global stability; curved pipes; secondary flow; wall-bounded turbulence; Global stabilitet; krökta rör; sekundärflöde; turbulens; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Curved pipes are ubiquitous in several industrial applications and biological systems. The study of flows through these configurations is therefore of significant practical interest.In the present thesis, the modal stability of flows in both toroidal and spatially developing bent pipes is investigated to understand the onset of transition. LÄS MER

  5. 9. Aerothermal Investigation of an Intermediate Turbine Duct

    Författare :Carlos Arroyo; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flowfield measurements; heat transfer measurements.; Intermediate turbine duct;

    Sammanfattning : Intermediate turbine ducts are used to guide the flow in turbofan engines from the short-radius high-pressure turbine to the large-radius low-pressure turbine. The demand for more efficient and silent jet engines and with a reduced environmental impact requires turbofans with increasingly higher by-pass ratios. LÄS MER

  7. 10. Turbulence-resolving Simulations of Swirling Flows

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

    Sammanfattning : 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. LÄS MER