Comparative High Temperature Shock Tube Ignition of C1−C4 Primary Alcohols

Abstract

The high temperature ignition of C1−C4 primary alcohols, methanol, ethanol, n-propanol, and n-butanol, is studied behind reflected shock waves. The experiments are carried out at pressures of 2, 10, and 12 atm with argon/oxygen ratios of 10, 15, and 20 under lean, ϕ = 0.5, stoichiometric, ϕ = 1, and rich, ϕ = 2, conditions between 1070 and 1760 K. It is observed that the ignition delay time data for ethanol, n-propanol, and n-butanol collapse under conditions of constant equivalence ratio, pressure, and dilution. The ignition delay times of methanol are comparable with the other alcohols but show a slightly lower activation energy than the other fuels. The observed collapse of the ignition delay times for the four alcohols under lean-to-stoichiometric conditions is comparable with recent observations by Veloo et al. (Veloo, P. S.; Wang, Y. L.; Egolfopoulos, F. N.; Westbrook, C. K. Combust. Flame 2010, 157, 1989−2004) that over a range of equivalence ratios less than one, methanol, ethanol, and n-butanol h...