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An experimental study was conducted to investigate methanol autoignition including surface effects. Autoignition temperatures were determined for methanol using spherical, glass, constant volume bombs of various size, in order to assess the effects of changing the vessel surface-to-volume ratio on the minimum autoignition temperature and on the autoignition limits and ignition delays. Autoignition limit diagrams were constructed by determining the autoignition temperature for various methanol/oxygen/nitrogen mixtures. The diagrams were characterized by a minimum autoignition temperature occurring at a particular equivalence ratio, which was typically not stoichiometric. An empirical Arrhenius type expression for ignition delay was also developed and analyzed with respect to surface effects. This model was then compared with models used at higher temperatures.

An experimental study was conducted to investigate the autoignition characteristics of methanol. Experimental conditions which were explored included temperatures in the range of 650-800 K, equivalence ratios of 0.2-17.0, 1 atm pressure, and reactor surface-to-volume ratios. S/V, of 0.6 cm−1″ and 0.48 cm−1. The ignition delay times were correlated with initial temperatures, methanol, and oxygen concentrations and fit to an Arrhenius type expression. The analysis resulted in a global activation energy of 55.2 kcal/mol and fuel and oxidizer concentration exponents of −0.98 and −0.13, respectively. Also, autoignition limit diagrams were developed which distinguish the regions of ignition and non-ignition, as well as show the effects of equivalence ratio and surface-to-volume ratio changes on minimum autoignition temperatures.