Laminar combustion characteristics of ethyl acetate/hydrogen/air at elevated pressures

Abstract

Ethyl acetate/hydrogen/air (EA/H2/air) premixed flame combustion characteristics were investigated at the initial pressures of 1 bar, 2 bar, and 3 bar and a temperature of 358 K using H2 in air volumetric fractions of 0 %, 4 %, 8 %, and 12 %. Specifically, the laminar burning speed (LBS) and intrinsic flame instabilities of the EA/H2/air premixed flames were investigated. The laminar burning speed follows the order of 0 % < 4 % < 8 % < 12 %. The maximum laminar burning speeds of 0.85 m/s, 0.78 m/s, and 0.70 m/s were measured at the initial pressures of 1, 2, and 3 bar, respectively, when a 12 % concentration of hydrogen was added to EA. Reactions R98: H + O2 ⟺ O + OH and R136: CH3 + H (+M) ⟺ CH4 (+M) significantly promoted and inhibited EA/H2/air LBS, respectively. Furthermore, the decreased flame thickness or curvature effect mainly caused the instability and cellularity of the EA/H2/air premixed flames when the concentration of hydrogen and the initial pressure increased. Theoretically, EA/H2/air premixed flames were thermal-diffusively stable and hydrodynamically unstable. This study provides a profound understanding of the combustion characteristics of EA/H2/air relevant to its application in combustors.