A modified model for ignition behavior of nano‐blended fuel droplets

Abstract In this paper, evaporation and ignition process of metallic and non‐metallic nano‐ blended fuels are discussed based on the measurement of thermophysical properties and radiation effect. Two samples of nano‐ blended fuels were prepared by addition of cerium oxide and graphene nanoparticles to B20 fuel at dilute concentrations of 0.03% and 0.05% (by mass). The ignition probability tests were done by hot plate experiments between 400°C and 660°C. Experiments showed that the ignition probability of B20 fuel considerably increase in the presence of nanoparticle. For instance, at 520°C, the ignition probability increases from 36% for B20 to 76% and 80%, respectively, for cerium oxide and grapheme nanoparticles, at the mass fraction of 0.05%. Also, an increase in the mass fraction of the nanoparticles results in a higher ignition probability of the nano‐ blended fuel. At such relatively low concentrations, it can be seen that the effect of nanoparticles on the fuel thermo‐physical properties and consequently the ignition behavior of B20 fuels is not significant. Therefore, ignition probability enhancement is mainly attributed to strong radiation absorption of the nanoparticles suspended within the droplets, which provides more energy from the flame to the liquid phase for evaporation. By considering the radiation effect, a modified model is proposed for description of the ignition behavior of a nano‐ blended fuel droplet.