Effect of water content on premixed laminar flames of hydrous acetone–n-butanol–ethanol (ABE)–air mixtures: An experimental and numerical study

Abstract

The effect of water content on characteristics of premixed laminar flames of hydrous ABE was investigated at a temperature of 393 K, a pressure of 0.1 MPa, equivalence ratios of 0.8–1.5, and water contents of 0–30%. ABE is the mixture of acetone, n-butanol and ethanol with the volume ratio of 3:6:1 at 1 atm and 298 K. The outwardly propagating spherical flame method was employed to experimentally determine laminar flame speeds and Markstein lengths of hydrous ABE–air mixtures. The one-dimensional planar flames were simulated by the CHEMKIN-PRO software, and based on the modeled result, the premixed laminar flames of hydrous ABE including chemical and physical effects of water were analyzed from the point of the chemical kinetics. The result shows that the laminar flame speed gradually decreases with the increase of water content, and the Markstein length gradually increases with the increase of water content at the equivalence ratios of 0.8 and 1.1. The reaction pathways of acetone and ethanol in ABE–water–air flames have obvious changes compared with those in ABE–air flames. The physical and chemical effects of water show inhibition on the laminar flame speed, and the physical effect plays a major role. The chemical effect promotes the OH production and has a more significant influence on the occurrence of elementary reactions with negative sensitivity coefficients than those with positive coefficients. The physical effect always shows inhibition on production of radicals and occurrence of elementary reactions.