Blowoff Characteristics of Laminar Partially Premixed Flames of Palm Methyl Ester/Jet A Blends

The blowoff characteristics of laminar partially premixed flames of prevaporized palm methyl ester (PME) and Jet A blends were studied over a range of equivalence ratios of 0.53–0.83 with and without heated coflow. The injector was designed to produce a uniform inner flow and had an inner diameter of 12.7 mm. The coflow velocity ranged up to 3.5 m/s. The flames were laminar and blue in color (dominated by homogeneous gas-phase reactions). The temperature profiles in all the flames were similar with a peak temperature of 1740 K. The blowoff velocity increased with equivalence ratio for all the flames; the difference in blowoff velocity of pure PME flames and pure Jet A flames was within experimental uncertainty. A Damköhler number (based on the velocity gradient at the jet boundary and chemical reaction timescale estimated from laminar flame velocity) of 2–8 characterized the blowoff velocity. As the coflow velocity was increased, the blowoff velocity was increased, and the differences between the values for the various flames became smaller.