Gaseous Reactive Flows Around Catalytically Combusting Micro-Wires

136 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2008.The reactive flow around catalytically coated cylinders was investigated experimentally in the regime of Reynolds and Peclet numbers that are relevant to small-scale power generation. Methane and propane combustion was established on the surface of the catalyst by placing a small-diameter wire in the outlet of a pre-heater that controlled temperature, composition and velocity of the reactant-air pre-mixture. The results highlight the combined importance of both surface chemistry and transport phenomena for the determination of the structure of these flow fields. Specifically, the temperature of the catalytic wire was measured with a thermocouple welded to the support metal of the wire and the results indicated that because of the strongly non-adiabatic nature of the combustion, temperature maxima are affected by Re and occur for equivalence ratios different than the ones predicted from thermochemistry. Particle image velocimetry (PIV) measurements were performed and the resulting velocity fields show that both the Reynolds number and the equivalence ratio of the flow influence the structure of the flow field. Moreover, the catalytically coated wires were shown to affect a much larger region of the flow than what they physically block, which points to the fact that micro-wires are appropriate elements for the construction of compact reactors that will convert reactants efficiently with minimal blockage of frontal area. Line Raman imaging of major combustion species was performed downstream the catalytic wire and in combination with the PIV results showed that both species distribution and velocity fields differ significantly between lean and rich conditions.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD