Measurements of laminar flame speeds of liquid fuels: Jet-A1, diesel, palm methyl esters and blends using particle imaging velocimetry (PIV)

Abstract

Laminar flame speeds of practical fuels including Jet-A1, diesel, palm methyl esters (PME) and blends of PME with diesel and Jet-A1 fuels are determined using the jet-wall stagnation flame configuration and particle imaging velocimetry (PIV) technique. The PME/Jet-A1 and PME/diesel blends are prepared by mixing 10%, 20% and 50% of PME with Jet-A1 and diesel fuels by volume respectively. The experiments are performed over a range of stoichiometries at elevated temperature of 470 K and atmospheric pressure under premixed conditions. The reference flame speed and imposed strain rates are determined from the two dimensional velocity profiles. Subsequently, laminar flame speeds are derived by extrapolating the reference flame speed back to zero strain rates. Experimental results are compared to experimental and simulation data from the literature for large n-alkanes and practical fuels. The results show that laminar flame speeds of Jet-A1 fuel are similar to those of n-decane and n-dodecane, indicating their potential use as surrogate fuels. Peak laminar flame speeds for diesel/air and PME/air mixtures at 470 K are similar, around 86.7 and 86.5 cm/s at equivalence ratios around 1.10 and 1.14 respectively, and that both mixtures exhibit lower flame speeds compared to n-decane and n-dodecane at fuel-leaner and stoichiometric conditions. Blending PME with Jet-A1 and diesel leads to reduced laminar flame speeds on the lean side but increased on the rich side.