Sökning: "superheat"

Visar resultat 1 - 5 av 18 avhandlingar innehållade ordet superheat.

1. 1. Integrated Control of Heat Pumps

   Författare :Fredrik Karlsson; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; variable speed compressor; superheat; electronic expansion valve; optimisation; performance indication; control; heat pump; energy efficiency;

   Sammanfattning : The purpose of the work presented in this thesis is to investigate the potential and prerequisites for improved energy efficiency of heat pump systems using efficient components and proper methods for optimisation of operation. The background is that several investigations have reported on possibilities for increased energy efficiency of heat pumps if variable-speed capacity control is used instead of conventional on/off control. LÄS MER

3. 2. Experimental and theoretical study of post-dryout heat transfer in annuli with flow obstacle

   Författare :Ionut Anghel; Henryk Anglart; Dariusz Mikielewicz; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; annulus; flow obstacles; critical heat flux; post-dryout; thermal margins; boiling water reactor; Fysik; Physics;

   Sammanfattning : An experimental study on post dryout heat transfer regime in annuli with flow obstacles wasconducted in the High-pressure Water Test (HWAT) loop at the Royal Institute of Technologyin Stockholm, Sweden. An annulus with flow obstacles, consisting of two concentric heatedpipes (12.7x24. LÄS MER

4. 3. Elastohydrodynamic lubrication and lubricant rheology in refrigeration compressors

   Författare :Ulf Jonsson; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Maskinelement; Machine Elements;

   Sammanfattning : The introductory chapter gives a general description of the lubrication of rolling element bearings in refrigeration compressors and rheological properties of oil-refrigerant mixtures. The influence of refrigerants on the viscosity, pressure-viscosity coefficient and film forming ability in a EHD-contact is described. LÄS MER

5. 4. An Experimental Study on Melt Fragmentation, Oxidation and Steam Explosion during Fuel Coolant Interactions

   Författare :Louis Manickam; Weimin Ma; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; severe accident; fuel coolant interactions; melt jet breakup; debris properties; steam explosion; oxidation; high-speed visualization; Physics; Fysik;

   Sammanfattning : Nordic type boiling water reactors (BWRs) adopt reactor cavity flooding as a severe accident mitigation strategy (SAMS) to achieve core melt fragmentation and long-term cooling of decay heat generating core debris. The qualification of this SAMS needs to address two main severe accident issues: debris bed coolability and steam explosion. LÄS MER

7. 5. On the Residual Stresses and Microstructure Formation of Aluminum-Silicon Cast Alloys

   Författare :Mohsen Sadrossadat; Sten Johansson; Ru Lin Peng; Ingvar L Svensson; Linköpings universitet; []
   Nyckelord :Al-Si alloys; residual stresses; microstructure; microsegregation; nucleation behavior; modeling; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Cast aluminum-silicon alloys are being increasingly used in automotive and aerospace industries for critical structure applications because of their excellent castability, low density, acceptable mechanical properties and low cost. Different casting and heat treatment parameters largely affect the microstructure and residual stress of the components, which in turn, has a great impact on their mechanical properties. LÄS MER