A Method for the Rapid Characterization of Combustion Properties of Liquid Fuels Using a Tubular Burner Available to Purchase

Knowledge of the combustion and pollutant emission characteristics is important in the application of both existing and newly developed fuels. A technique for the rapid characterization of flame radiation properties and emission characteristics of liquid fuels was developed for this purpose. Liquid fuel was injected into a heated air stream at known rates with a syringe pump; the feed line was heated (temperature of 425°C) to pre-vaporize the fuel before burning, to avoid the effects of evaporation parameters on measurements. Temperatures of the fuel and air were monitored using K-type thermocouples embedded within the feed lines. A laminar methane-air flame was issued from a stainless steel tubular burner (9.5mm inner diameter) and used as the ignition source. The methane supply was shut off after the onset of the burning of the vaporized liquid fuel, in order to eliminate the effects of burning methane in the measurements. Several liquid fuels were tested, including commercially available petroleum-based No. 2 diesel fuel, canola methyl ester (CME B 100) biodiesel, kerosene, methanol, toluene, and selected alkanes. A steady burning flame was achieved for all fuels. Radiative heat flux measurements were made with a high-sensitivity pyrheliometer and the radiant fraction of heat release calculated. The radiant heat fraction served as an indication of sooting tendency of the fuels. NO, CO, and CO₂ emission measurements were also made. The measurements demonstrate the feasibility of the current technique for the rapid characterization of combustion properties of liquid fuels, utilizing small fuel quantities.