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Showing result 1 - 5 of 156 swedish dissertations matching the above criteria.

  2. 1. Numerical study of flow boiling in micro/mini channels

    Author : Qingming Liu; Björn Palm; Satish Kandlikar; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; numerical; boiling; micro channel; phase change.; Energiteknik; Energy Technology;

    Abstract : Boiling phenomena in micro scale has emerged as an interesting topic due to its complexity and increasing usage in micro electronic and mechanical systems (MEMS). Experimental visualization has discovered five main flow regimes: nucleate boiling, isolated bubbles, confine bubbly flow, elongated bubbly (or slug) flow, and annular flow. READ MORE

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

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

    Abstract : 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. READ MORE

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

    Author : Claudi Martin Callizo; Björn Palm; Predrag Hrnjak; KTH; []
    Keywords : 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;

    Abstract : 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. READ MORE

  6. 4. Interaction mechanisms for a laser-induced metallic boiling front

    Author : Ramiz Saeed Matti Samarjy; Alexander F.H. Kaplan; Torbjörn Ilar; Michael Schmidt; Luleå tekniska universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Laser remote fusion cutting; Boiling front; High speed imaging; Additive manufacturing; Ejection; Absorption; Wavy surface; Deposition; Produktionsutveckling; Manufacturing Systems Engineering;

    Abstract : This thesis is about fundamental interaction mechanisms of laser remote fusion cutting, RFC, which is based on the formation of a quasi-stationary laser-induced boiling front that causes drop ejection, preferably downwards. Laser cutting of metals, invented in 1967, has developed from a niche to a well established high quality cutting technique in the manufacturing industry. READ MORE

  7. 5. Flow boiling of ammonia and propane in mini channels

    Author : Muhammad Hamayun Maqbool; Björn Palm; Rahmatollah Khodabandeh; Satish Kandlikar; KTH; []
    Keywords : Flow Boiling; Mini channels; Global Warming Potential; Ammonia; Propane; R134a; HFC; Two-phase; Heat Transfer; Pressure Drop; Dry out.;

    Abstract : The environmental concerns in recent times have grown especially after signing Montreal protocol. In the last ten years, researchers have focussed mainly on understanding the boiling and condensation phenomena of HFC refrigerants in minichannels. READ MORE