Single droplet combustion of aluminum nanoparticles added to a biofuel: effect of particle concentration and ambient temperature

Abstract

The fast expansion and growth of the aviation sector, coupled with the greenhouse gas and pollutant emissions, requires urgent solutions. A starting point to change this sector paradigm could be a new energy source for aviation gas turbines, focused on potential carbon neutral fuels, e.g., biofuels. A possible solution is nanoparticles addition to improve the biofuel properties and mitigate the problems inherent to their use. The present work experimentally evaluates the combustion characteristics of single droplets of HVO (NExBTL) with aluminum nanoparticles. The ambient temperature was varied from 600°C to 1000°C. Three particle concentrations (0.2, 0.5, and 1.0 wt.%) were investigated with a fixed particle size of 40 nm. This study examined the combustion of droplets with an initial diameter of 250 µm using a falling droplet method. The results reveal that for nanofuels, the droplet size evolution curve is not in agreement with D 2 -law and display a unique disruptive burning phenomenon at the end of the droplet lifetime. It was noticed that the burning rate of biofuel is considerably enhanced with the addition of nanoparticles, being the highest value for the nanofuel with a particle concentration of 1.0 wt.%.