Sökning: "critical heat flux"

Visar resultat 1 - 5 av 25 avhandlingar innehållade orden critical heat flux.

  1. 1. Pool Boiling on Structured Surfaces: Heat Transfer and Critical Heat Flux : Experiments and Mechanistic Modelling

    Författare :Zhen Cao; NanoLund; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; pool boiling; heat transfer; critical heat flux; bubble dynamics; surface modification;

    Sammanfattning : In this thesis, pool boiling heat transfer was experimentally studied on structured surfaces with dielectric liquids (HFE-7200, NOVEC-649, FC-72), organic liquids (Acetone, Pentane) and deionized water.In the first step, nanoparticle coatings on copper surfaces were prepared by an electrophoretic deposition method, with Cu-Zn nanoparticles (100 nm) and Cu nanoparticles (150 nm). LÄS MER

  2. 2. Flow Boiling Heat Transfer in Single Vertical Channels of Small Diameter

    Författare :Claudi Martin Callizo; Björn Palm; Predrag Hrnjak; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; microchannel; heat exchanger; heat transfer; flow boiling; flow patterns; onset of nucleate boiling; dryout; critical heat flux; Mechanical and thermal engineering; Mekanisk och termisk energiteknik;

    Sammanfattning : Microchannel heat exchangers present many advantages, such as reduced size, high thermal efficiency and low fluid inventory; and are increasingly being used for heat transfer in a wide variety of applications including heat pumps, automotive air conditioners and for cooling of electronics.However, the fundamentals of fluid flow and heat transfer in microscalegeometries are not yet fully understood. LÄS MER

  3. 3. Limiting conditions for a sustained flame over condensed fuels : Analysis by experiments and stagnant layer theory

    Författare :Frida Vermina Plathner; Avdelningen för Brandteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Critical mass flux; diffusion flame; extinction; sustained ignition; chemical heat of combustion; Convective heat transfer coefficient; external heat flux;

    Sammanfattning : Ignition and extinction characteristics of a material determine whether a fire will be initiated and grow. In fire safety engineering, where modellers deal with a multitude of materials, simplified thresholds are commonly used to determine when ignition and extinction occur. LÄS MER

  4. 4. An Experimental Study on Micro-Hydrodynamics of Evaporating/Boiling Liquid Film

    Författare :Shengjie Gong; Ma Weimin; Horst-Michael Prasser; KTH; []
    Nyckelord :liquid film; critical thickness; boiling; critical heat flux; rupture; dry spot; confocal optical sensor; SRA - Energy; SRA - Energi;

    Sammanfattning : Study of liquid film dynamics is of significant importance to the understanding and control of various industrial processes that involve spray cooling (condensation), heating (boiling), coating, cleaning and lubrication. For instance, the critical heat flux (CHF) of boiling heat transfer is one of the key parameters ensuring the efficiency and safety of nuclear power plants under both operational and accident conditions, which occurs as the liquid layers (microlayer and macrolayer) near the heater wall lose their integrity. LÄS MER

  5. 5. Assessment and improvements of thermal-hydraulic correlations and methods for the analysis of the Jules Horowitz Reactor

    Författare :Alberto Ghione; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Flow instability; Uncertainty; Narrow channels; Jules Horowitz Reactor; Safety analysis; Critical heat flux; Thermal-hydraulic correlations; Heat transfer; Best-Estimate; Material Testing Reactor;

    Sammanfattning : Nuclear research reactors are used to test materials for current and future nuclear technologies, and to produce radioisotopes for medical purposes. Most of the existing Material Testing Reactors in Europe have operated for more than 50 years and new ones are needed. LÄS MER