Experimental study of combustion of ethanol and primary reference fuels in laminar nonuniform flows

Abstract

Experimental studies are carried out on extinction and autoignition of ethanol, n-heptane and iso-octane flames using stagnation flow configuration. n-Heptane and iso-octane constitute primary reference fuels (PRF), considered as components of surrogates of gasoline because of the similarity in terms of the ignition and combustion characteristics. In this work, a comparative study has been conducted to investigate the extinction and autoignition characteristics of these fuels on nonpremixed and premixed flames. The counterflow burner used in this study has two ducts. Studies in the nonpremixed configuration are carried out by injecting a stream made up of fuel vapors and nitrogen from one duct, and a stream made up of oxygen and nitrogen from the other duct. The liquid fuel is introduced thorough a liquid fuel feeder with a high precision metering pump to control the liquid flow rates. In the premixed configuration, the strain rate at extinction is measured over a wide range of equivalence ratio by injecting the premixed-reactant stream from one duct and nitrogen from the other duct. Numerical calculations are also performed using detailed chemistry at conditions corresponding to those used in the experiments for ethanol nonpremixed flames to validate chemical kinetics.