Effects of platinum stagnation surface on the lean extinction limits of premixed methane/air flames at moderate surface temperatures

0010-2180/$ see front matter 2010 The Combust doi:10.1016/j.combustflame.2010.08.002 ⇑ Corresponding author. Fax: +1 734 647 3170. E-mail address: [email protected] (J.T. Wiswall A stagnation flow reactor was used to study the effects of platinum on the lean flammability limits of atmospheric pressure premixed methane/air flames at moderate stagnation surface temperatures. Experimental and computational methods were used to quantify the equivalence ratio at the lean extinction limit (/ext) and the corresponding stagnation surface temperature (Ts). A range of flow rates (57– 90 cm/s) and corresponding strain rates were considered. The results indicate that the gas-phase methane/air flames are sufficiently strong relative to the heterogeneous chemistry for Ts conditions less than 750 K that the platinum does not affect /ext. The computational results are in good agreement with the experimentally observed trends and further indicate that higher reactant flow rates (>139 cm/s) and levels of dilution (> 10% N2) are required to weaken the gas-phase flame sufficiently for surface reaction to play a positive role on extending the lean flammability limits. 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.