Effects of alumina nanoparticles on evaporation and combustion characteristics of diesel fuel droplets

Background: Effects of alumina nanoparticles (Al2O3 -NPs) on the evaporation and combustion characteristics of diesel fuel (C10H22) droplets in a model combustion chamber are numerically investigated. The nanofuel (n-fuel) is resulted from adding Al2O3 -NPs in volume fractions of 0.5 and 1 percent (0.5 and 1 vol%) to the base fuel (C10H22).Methods: To model the two-phase flow, consisting of fuel droplets and inlet air, the Eulerian-Lagrangian approach is applied. The discrete ordinates (DO) radiation heat transfer model and the diffusion flamelet combustion model are employed in order to investigate the characteristics of the reactive flow.Significant findings: With the addition of 0.5 and 1 vol% of Al2O3 -NPs, average increases of 0.48% and 0.95% in the heat capacity, as well as 20% and 46% in the latent heat of evaporation, of the base fuel occur, respectively. The maximum temperature of the chamber drops by 30K and 60K, consecutively. Further, the average mole fractions of oxides of nitrogen (NOx) at the outlet decrease by 17.6% and 34.3%, respectively. However, the oxides of carbon (CO and CO2) decrease too, as drops of 5.6% and 7.7% in CO2 average mole fraction at the outlet are observed. This can indicate the lower evaporation and burning rate of the n-fuels, as compared with the pure fuel.