Sökning: "gas convection"

Visar resultat 1 - 5 av 54 avhandlingar innehållade orden gas convection.

  1. 1. Estimating the Air-Water Gas Transfer Velocity during Low Wind Conditions

    Författare :Sam Fredriksson; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Air.sea gas exchange; Turbulence; Heat flux; Natural convection; Shear; Direct numerical simulations; Gas transfer velocity; IR; Flux-chambers;

    Sammanfattning : The abundances of atmospheric carbon dioxide, CO2, and methane, CH4, are increasing. These increases affect e.g., the global carbon cycle and the climate both regionally and globally. LÄS MER

  3. 2. Heat Transfer in Circulating Fluidized Bed Boilers

    Författare :Claes Breitholtz; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; similarity; char; heat transfer; tube wall; circulating fluidized bed; particle; radiation; scaling; particle convection; gas convection;

    Sammanfattning : Heat transfer to single particles in the transport zone of circulating fluidized beds and heat transfer to membrane tube walls have been investigated. The heat transfer coefficient to spheres in the transport zone of a circulating fluidized bed boiler has been measured with dark and light calorimeters. LÄS MER

  4. 3. Melt convection in welding and crystal growth

    Författare :Minh Do-Quang; Gustav Amberg; Andreas Ludwig; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering physics; thermocapillary convection; gas-tungsten arc welding; floating zone; parallel computing; finite element method; Teknisk fysik; Engineering physics; Teknisk fysik;

    Sammanfattning : A parallel finite element code with adaptive meshing was developed and used to study three dimensional, time-dependent fluid flows caused by thermocapillary convection as well as temperature and dopant distribution in fusion welding and floating zone crystal growth. A comprehensive numerical model of the three dimensional time-dependent fluid flows in a weld pool had been developed. LÄS MER

  5. 4. On mechanisms controlling air-sea gas exchange

    Författare :Lucía Gutiérrez-Loza; Anna Rutgersson; Erik Sahlée; Marcus B. Wallin; Tom Bell; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Air-sea gas exchange; eddy covariance; gas transfer velocity; Baltic Sea; Meteorologi; Meteorology;

    Sammanfattning : Carbon is essential to the Earth’s system functioning, playing a major role in physical and biogeochemical processes in the atmosphere, the terrestrial biosphere, and the oceans. The concentration of carbon-based greenhouse gases in the atmosphere, such as carbon dioxide (CO2) and methane (CH4), has been increasing since the industrial era. LÄS MER

  7. 5. Carbon trace gas dynamics in subarctic lakes

    Författare :Joachim Jansen; Patrick Crill; Andreas Lorke; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lakes; methane; carbon dioxide; fluxes; gas transfer; proxy; climate change; geokemi; Geochemistry;

    Sammanfattning : Northern lakes are important sources of greenhouse gases carbon dioxide and methane to the atmosphere. Emissions are expected to increase as the climate continues to warm. Even so, lake carbon budgets are currently poorly constrained. This is in part because of a limited understanding of the processes that govern the flux. LÄS MER