The effect of ethanol on the particle size distributions in ethylene premixed flames

In the present study a laminar premixed ethylene flame was doped with different amounts of ethanol in order to understand the influence on biofuels in the total amount of particulate matter and the size distribution functions of the formed carbonaceous particles. Four different flames were investigated: one of pure ethylene as reference and three with an increased amount of ethanol, i.e. 10%, 20% and 30%. The equivalence ratio of the four flames was kept constant at 2.01. The particle size distribution functions were obtained using a nano-Differential Mobility Analyzer (nano-DMA). The results showed a general reduction of the total volume fraction of particulate when ethanol was added. The reduction of the formed particles increased as a function of the amount of ethanol added. The particle size distribution for pure ethylene flame and ethanol doped flames at different heights with the same amount of particles are quite similar. This indicates that in premixed flames, ethanol mostly affects gas phase chemistry and consequently the formation of incipient particles.