Effect of Methyl Butyrate blending on soot formation in Jet A laminar diffusion flame

Abstract

To investigate the effect of methyl butyrate (MB) blending on soot formation in a Jet A laminar diffusion flame, laser-induced incandescence (LII) and laser-induced fluorescence (LIF) techniques were employed to assess the distributions of soot-LII signal and polycyclic aromatic hydrocarbons (PAH) signal in Jet A with varying MB blending ratios from 0% to 80%. The experimental results revealed that an increase in the MB blending ratio resulted in decreased flame height, reduced radially integrated natural luminosity peak signal, and lower the total spatially integrated natural luminosity, while the flame base height increased. The starting position of soot-LII signal moved downstream gradually, and the peak signal magnitude on the axis decreased. The addition of MB effectively reduced the soot-LII signal in Jet A. Compared to pure Jet A, the average soot-LII signal for MB20, MB40, MB60, and MB80 decreased by 18.9%, 79.6%, 85.3%, and 94.2%, respectively. The maximum soot-LII signal decreased by 18.2%, 68.3%, 76.0%, and 93.5%, respectively. Furthermore, the PAH-LIF signal gradually decreased as the MB blending ratio increased. Moreover, the MB-Jet A-PAH mechanism was constructed, and the formation pathways of the soot precursor based on a diffusion flame model were calculated. The kinetic results indicate that an increase in the MB blending ratio reduces the rates of different reactions involved in the generation of A1, leading to a reduction in A1. The dilution of PBZ in Jet A by MB is identified as the primary factor for the reduction in soot.