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Visar resultat 1 - 5 av 82 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Numerical predictions of heat-transfer applied to electrical machines

   Författare :Kristian Rönnberg; Christophe Duwig; Anders Dahlkild; Luca Peretti; Jens Honore Walther; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electric machines; energy efficiency; heat transfer; thermal management; high fidelity simulation; computational fluid dynamics CFD ; proper orthogonal decomposition POD ; lumped parameter thermal network LPTN ; Elektriska maskiner; energieffektivitet; verkningsgrad; värmeöverföring; värmehantering; simuleringar med hög upplösning; strömningsmekaniska beräkningar; proper orthogonal decomposition POD ; termiska nätverk; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : In order to meet the need for increased electrification, and at the same time reduce the total demand for electric energy, behavior change and technological innovation is needed. Over the decades power density of electric motors have increased, leading to increased demands on the cooling system design and performance. LÄS MER

3. 2. Exhaust Heat Utilisation and Losses in Internal Combustion Engines with Focus on the Gas Exchange System

   Författare :Habib Aghaali; Hans-Erik Ångström; Carlos Guardiola; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbocharger; heat transfer; heat loss; exhaust heat utilisation; waste heat recovery; turbocompound; divided exhaust period; internal combustion engine; gas exchange; pumping loss; variable valve timing; WHR; DEP; Turbo; värmeöverföring; värmeförluster; avgasvärme utnyttjande; förluster vid värmeåtervinning; turbocompound; delad avgasperiod; förbränningsmotor; gasväxling; pumpningsförlust; variabla ventiltider; WHR; DEP; Vehicle and Maritime Engineering; Farkostteknik; Energy Technology; Energiteknik;

   Sammanfattning : Exhaust gas energy recovery should be considered in improving fuel economy of internal combustion engines. A large portion of fuel energy is wasted through the exhaust of internal combustion engines. Turbocharger and turbocompound can, however, recover part of this wasted heat. LÄS MER

4. 3. Turbulent flows over permissive boundaries and porous walls

   Författare :Seyed Morteza Habibi Khorasani; Shervin Bagheri; Geert Brethouwer; Alfredo Soldati; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct numerical simulations; wall-bounded turbulence; flow control; porous walls; heat transfer; Direkta numeriska simuleringar; väggbunden turbulens; flödeskontroll; porösa väggar; värmeöverföring; Teknisk mekanik; Engineering Mechanics;

   Sammanfattning : This thesis investigates how in wall-bounded turbulent flows changes to the wall can induce changes in the flow. To this end, we investigate the use of wall boundary conditions meant to mimic the effect of textured surfaces. LÄS MER

5. 4. Advances in Ventilation Heat Recovery : An assessment of peak loads shaving using renewables

   Författare :Behrouz Nourozi; Sasan Sadrizadeh; Adnan Ploskic; Carey Simonson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Peak heat load shaving; renewable energy; ventilation heat recovery; frosting in heat exchangers; Heat transfer; förnybar energi; ventilation värmeåtervinning; frosting i värmeväxlare; värmeöverföring; Byggvetenskap; Civil and Architectural Engineering;

   Sammanfattning : The building sector accounts for approximately 40% of total global energy usage.In residential buildings located in cold climate countries, 30-60% of this energy isused for space heating, 20–30% is lost by discarded residential wastewater, and therest is devoted to ventilation heat loss. LÄS MER

7. 5. On-Engine Turbocharger Performance Considering Heat Transfer

   Författare :Habib Aghaali; Hans-Erik Ångström; Jose R. Serrrano; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbocharger; Internal combustion engine; heat transfer; turbocharged engine; on-engine turbocharger; turbocharger performance; توربو شارژر، موتور احتراق داخلی، انتقال حرارت، توربوچارجر; turbo; turboladdare; förbränningsmotor; värmeöverföring; turboladdad motor;

   Sammanfattning : Heat transfer plays an important role in affecting an on-engine turbocharger performance. However, it is normally not taken into account for turbocharged engine simulations. LÄS MER