Sökning: "developed for conventional large tubes"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden developed for conventional large tubes.

1. 1. Heat-transfer Enhancement for Slurries from Biogas Plants− Properties, processes, and thermal systems

   Författare :Jingjing Chen; Xiaoyan Ji; Bona Lu; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; heat-transfer enhancement; slurry; rheological properties; computational fluid dynamics; twisted tubes; biogas production; Energiteknik; Energy Engineering;

   Sammanfattning :  Biomethane production from renewable residues with anaerobic digestion gains increasing attention as a crucial alternative to petroleum fuels. It has been vigorously developed, but the large amounts of subsidy from the government indicate that the process efficiency needs to be further improved. LÄS MER

3. 2. HFC Mixtures as Replacement for HCFC-22 in Large-Scale Heat Pumps and Chillers

   Författare :Cecilia Gabrielii; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; R404A; R143a; R125; performance; R134a; R32; replacement; zeotropic HFC mixtures; simulations; design; measurements; chiller; R407C; condenser evaporator; screening; optimization; heat pump; R22;

   Sammanfattning : Replacement of the conventional refrigerant HCFC-22 (R22) is one of the urgent issues to be solved within the scheduled time-frame of the international regulation of the HCFCs. Since there exists no pure fluid that can replace R22 in the same general way as HFC-134a (R134a) is a replacement for CFC-12, HFC mixtures are suggested as possible substitutes. LÄS MER

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

   Författare :Wahib Owhaib; Björn Palm; Tassos Karayiannis; KTH; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

5. 4. Microstructure of Zirconium Alloys Oxidized in Steam

   Författare :Pia Tejland; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; EDX; ADF; TEM; Zircaloy-2; FIB-SEM; STEM; GD-OES; SPP; SEM; Zirconium; HAADF;

   Sammanfattning : Zirconium alloys are widely used in nuclear reactors as fuel cladding tubes because of their low thermal neutron capture cross-section, good corrosion properties and satisfactory mechanical properties. However, the main limiting factor of these materials is the oxidation behavior. LÄS MER

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

   Författare :Claudi Martin Callizo; Björn Palm; Predrag Hrnjak; KTH; []
   Nyckelord :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