Search for dissertations about: "drop tube"

Showing result 1 - 5 of 30 swedish dissertations containing the words drop tube.

  2. 1. Measurements and Modelling of Convective Vaporization for Refrigerants in a Horizontal Tube

    Author : Peter Melin; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; n-butane; HFC134a; pressure drop; propane; HFC143a; horizontal flow boiling; in-tube vaporization; HFC125; HFC32; experimental study; HCFC142b; HCFC22; non-azeotropic mixtures; CFC12; modelling; mixture effects;

    Abstract : An evaporator facility has been constructed to measure local values of heat transfer and pressure drop. The evaporator resembles a normal working evaporator tube in a direct-expansion evaporator applicable to large heat pump/refrigeration cycles, typically over 500 kW. The evaporator is brine-heated and uses an expansion valve to control the inlet. READ MORE

  4. 2. Flow Boiling Heat Transfer and Pressure Drop. Experiments and Model Development for Complex Geometries

    Author : Sven Wellsandt; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; pressure drop; zeotropic mixtures; heat transfer; herringbone microfin; dimple plate; modelling; evaporation; flow boiling; experiments;

    Abstract : Two very different evaporator geometries, a dimple plate and a herringbone microfin tube, have been studied. Heat transfer and pressure drop for both pure refrigerants and refrigerant mixtures have been determined experimentally. READ MORE

  5. 3. Mixture Effects in Shell-and-Tube Condensers. Theory and Calculations

    Author : Tord Karlsson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; shell-and-tube; heat transfer; zeotropic; condensation; mass transfer; mixture;

    Abstract : Zeotropic mixtures have come into more frequent use as working fluids (refrigerants) in heat pumps and air conditioning equipment due to the phase-out of ozone-depleting substances. Substantial drop in performance for shell-side condensation in shell-and-tube condensers when replacing a pure fluid with a mixture has been reported in the literature. READ MORE

  6. 4. Experimental Heat Transfer, pressure drop, and Flow Visualization of R-134a in Vertical Mini/Micro Tubes

    Author : Wahib Owhaib; Björn Palm; Tassos Karayiannis; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Minichannel; microchannel; heat transfer; pressure drop; single-phase; two-phase; flow boiling; flow visualization; dry out; bubble behavior; flow pattern.; Mechanical energy engineering; Mekanisk energiteknik;

    Abstract : For the application of minichannel heat exchangers, it is necessary to have accurate design tools for predicting heat transfer and pressure drop. Until recently, this type of heat exchangers was not well studied, and in the scientific literature there were large discrepancies between results reported by different investigators. READ MORE

  7. 5. Flow boiling heat transfer, pressure drop and dryout characteristics of low GWP refrigerants in a vertical mini-channel

    Author : Zahid Anwar; Björn Palm; Rahmatollah Khodabandeh; Maria Fernandino; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mini micro-channels; R1234yf; R152a; R600a; R134a; Boiling heat transfer; Pressure drop; Dryout; Correlation;

    Abstract : Two-phase heat transfer in mini/micro-channels is capable of meeting the high cooling demands of modern high heat flux applications. The phase change process ensures better temperature uniformity and control for local hot spots. Furthermore, these compact channels could be helpful in reducing the required charge and material inventories. READ MORE