Computational Analysis of Gas Flow and Heat Transport Phenomena in Ducts Relevant for Fuel Cells

摘要: The thesis concerns modeling, simulation and numerical analysis of heat mass transport, fluid flow in ducts both solid oxide fuel cells (SOFCs) proton exchange membrane (PEMFCs). unique cell boundary conditions (thermal, mass) for the are identified applied. Various duct configurations have been studied, such as rectangular trapezoidal cross sections, composite geometries including porous layer, current inter-collector (-connector). Numerical simulations fully developed / developing laminar transfer presented with various Gr*, Re, Rem, aspect ratio (b/h) base angle at electrolyte supported SOFC conditions. It was verified that injection through one wall increases friction factor f decreases Nusselt number Nu; suction but Nu increases. Onset deviation from pure forced convection is caused by formation a vortex. vortices enhancement depends mainly on magnitude Ratio Gr*/Re2. For same design, combined effects buoyancy force simulated Grashof rate Rem Reynolds Re. found onset gas associated downward suction. can advance instability relative to all numbers. effect less significant than transfer. From velocity distribution PEMFC ducts, it diffusion layer only about few percent duct, secondary flows be clearly duct. also found, among parameters permeability thermal conductivity impact cathode anode fixed configuration. has revealed values fRe vary widely anode-supported where thickness large. low value due permeation entrance. By varying or more characteristic ratios this study, investigated terms Nu. A uniform main direction achieved appropriate adjustment Based concentration prediction, species transport from/to reaction site dominated entrance region after certain distance downstream inlet; position occurrence change several parameters, e.g., density. (Less)