An experimental and numerical investigation of homogeneous ignition in catalytically stabilized combustion of hydrogen/air mixtures over platinum

• Published in: Combustion and flame 2002-03, Vol.128 (4), p.340-368
• Main Authors: APPEL, Christoph, MANTZARAS, John, SCHAEREN, Rolf, BOMBACH, Rolf, INAUEN, Andreas, KAEPPELI, Beat, HEMMERLING, Bernd, STAMPANONI, Anna
• Format: Article
• Language: English
• Subjects: Applied sciences; Combustion of gaseous fuels; Combustion. Flame; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Theoretical studies. Data and constants. Metering
• ISSN: 0010-2180; 1556-2921
• DOI: 10.1016/S0010-2180(01)00363-7

The gas-phase ignition of fuel-lean hydrogen/air mixtures over platinum was investigated experimentally and numerically in laminar channel-flow configurations. Experiments were performed at atmospheric pressure in an optically accessible catalytic channel combustor established by two Pt-coated parallel plates, 300 mm long (streamwise direction) and placed 7 mm apart (transverse direction). Planar laser induced fluorescence (PLIF) of the OH radical along the streamwise plane of symmetry was used to monitor the onset of homogeneous ignition, 1D Raman measurements (across the 7-mm transverse direction) provided the boundary layer profiles of the major species and temperature, and thermocouples embedded beneath the catalyst yielded the surface temperature distribution. Computations were carried out using a 2D elliptic fluid mechanical model that included multicomponent transport and elementary homogeneous (gas-phase) and heterogeneous (catalytic) chemical reaction schemes. Sensitivity analysis indicated that the discrepancies induced by the gas-phase schemes originated either from the presence of heterogeneously-produced water due to its effectiveness as a collision partner in the chain terminating reaction H + O2 + M = HO2 + M, or from an overall overprediction of the radical pool in the preignition zone. (Author)