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Visar resultat 1 - 5 av 55 avhandlingar som matchar ovanstående sökkriterier.

1. 1. SOFC Modeling Considering Mass and Heat Transfer, Fluid Flow with Internal Reforming Reactions

   Författare :Martin Andersson; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; COMSOL Multiphysics; Modeling; Catalyst; CFD; Transport phenomena; Internal reforming reaction; IT-SOFC; LTNE;

   Sammanfattning : Fuel cells are promising for future energy systems, since they are energy efficient and, when hydrogen is used as fuel, there are no emissions of greenhouse gases. Fuel cells have during recent years various improvements, however the technology is still in the early phases of development. LÄS MER

3. 2. Zero and Multi-Dimensional Modeling of Internal Combustion Engines with respect to Ion Current and Soot Formation

   Författare :Abdelhadi Ahmedi; Institutioner vid LTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; engine knock; pollutant emissions; detailed chemical kinetics; thermal ionization.; ion current sensor; method of moments; ionization; soot formation oxidation; modeling; auto-ignition; Spark ignition engine; diesel engine;

   Sammanfattning : The work presented in this thesis can be divided into the three following fields of investigation: First of all the ionization model developed in this thesis is meant to simulate the thermal ionization process or the so-called second peak. Equilibrium assumptions have been adopted for the modeling of the thermal ionization, in which Saha’s equation was derived for singly ionized molecules. LÄS MER

4. 3. Modeling of Gas Flows in Steelmaking Decarburization Processes

   Författare :Zhili Jack Song; Pär Jönsson; Seppo Louhenkilpi; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; VOD; nozzle; jet; vacuum; BOF; LD; AOD; post combustion; flue; CFD;

   Sammanfattning : The purpose of the current study is to increase the understanding of different steelmaking processes at the decarburization stages by use of mathematical modeling. More specifically, two De-Laval nozzles from a VOD (Vaccum Oxygen Decarburization) process, which is used for producing stainless steels with ultra-low carbon grades, was investigated for different vessel pressures. LÄS MER

5. 4. Solid Oxide Fuel Cell Modeling at the Cell Scale - Focusing on Species, Heat, Charge and Momentum Transport as well as the Reaction Kinetics and Effects

   Författare :Martin Andersson; Värmeöverföring; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; SOFC; anode-supported; modeling; CFD; charge species heat momentum transport; electrochemical internal reforming reactions; TPB; area-to-volume ratio; COMSOL Multiphysics;

   Sammanfattning : Fuel cells are electrochemical devices that directly transform chemical energy into electricity. They are promising for future energy systems, since they are energy efficient, able to use renewable fuels and, when hydrogen is used as fuel, there are no direct emissions of greenhouse gases. LÄS MER

7. 5. Fuel dispersion and bubble flow distribution in fluidized beds

   Författare :Johanna Olsson; Högskolan i Borås; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fluidised bed; fuel mixing; bubble distribution; digital image analysis; particle tracking; Energi och material; Resource Recovery; Resursåtervinning;

   Sammanfattning : Fluidized bed technology is used for thermal conversion of solid fuels (combustion and gasification) and is especially suitable for conversion of low-rank fuels such as biomass and waste. The performance of fluidized bed units depends on the fuel mixing and fuel-gas contact. LÄS MER