Sökning: "Värmeöverföring"

Visar resultat 21 - 25 av 82 avhandlingar innehållade ordet Värmeöverföring.

1. 21. On CFD-Analysis of Heat Transfer of a Heavy-Duty Diesel Engine

   Författare :Helgi Fridriksson; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; Heat Transfer; Diesel Engine;

   Sammanfattning : In this work, a heavy-duty diesel engine was studied by employing CFD simulations on a closed volume engine segment. These simulations were used to evaluate both the effects from certain parameters on the wall heat transfer, and to examine how reduction of heat transfer would effect the engine performance and emission levels. LÄS MER

3. 22. Modelling of Turbulent Flow and Heat Transfer Phenomena in Pipes of District Heating Systems Including Transient Temperature Propagation

   Författare :Irina Gabrielaitiene; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; district heating systems ; Energiforskning; Energy research; turbulence modelling .; modelling temperature dynamics ;

   Sammanfattning : Modern district heating systems, a carbon lean technology, involves dual usage of the energy due to the possibility to redistribute heat derived from numerous sources, such as industrial processes, refuse incineration, geothermal sources and combined heat and power plants. Such heat source flexibility facilitates the optimal usage of energy resources by varying the amount of purchased heat depending on demand, price and availability. LÄS MER

4. 23. Heat Transfer and Fluid Flow Investigations in Ribbed Ducts and Impinging Jets Using Liquid Crystal Thermography and PIV

   Författare :Xiufang Gao; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Thermal engineering; applied thermodynamics; Termisk teknik; termodynamik; Particle Image Velocimetry PIV .; Liquid Crystal Thermography LCT ; secondary flow; impinging jets; Enhanced heat transfer; ribbed ducts;

   Sammanfattning : This thesis presents experimental investigations of local heat transfer and detailed flow measurements in ribbed rectangular ducts and impinging jets. The advanced measurement methods, Liquid Crystal Thermography (LCT) and Particle Image Velocimetry (PIV) are adopted to provide full field characteristics. LÄS MER

5. 24. Experimental Investigations of Heat Transfer in a Channel with Ribs and Obstacle

   Författare :Zahra Ghorbani-Tari; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Liquid crystal thermography; ribs; entrance region; control the heat transfer around an obstacle by rib;

   Sammanfattning : This thesis presents experimental investigations of local heat transfer in a rectangular channel (aspect ratio AR = 4) with continuous transverse ribs as well as an obstacle. Liquid crystal thermography (LCT) is employed to obtain the temperature fields in the heat transfer experiments. LÄS MER

7. 25. Full Cycle Engine Simulations with Detailed Chemistry

   Författare :Adina Gogan; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; plasmas; Gaser; Gases; fluid dynamics; aktuariematematik; programmering; operationsanalys; Statistik; actuarial mathematics; programming; operations research; Statistics; detailed kinetics; emissions; engine knock; autoignition; modeling; spark ignition engine; diesel engine; fluiddynamik; plasma; Technological sciences; Teknik; Thermal engineering; applied thermodynamics; Termisk teknik; termodynamik; Motors and propulsion systems; Motorer; framdrivningssystem; stochastic reactor model;

   Sammanfattning : The modeling work developed in this thesis can be divided in two main areas of investigations: autoignition related to spark ignition engine and combustion and emissions formation in relation to diesel engines. A first version of a detailed kinetics engine simulation program, extended to handle full cycle calculations, was employed in order to demonstrate the strong effect that nitric oxide from the residual gas has on the autoignition onset. LÄS MER