Objective In order to explore clean energy sources for engines, the evaporation characteristics of fuels need to be investigated.

Method Nanofluidic fuels were prepared by adding CeO₂ nanoparticles with different concentrations to methyl palmitate (MP) and methyl oleate (MO), and the effects of CeO₂ doping (mass fraction of 0～500×10⁻⁶) on the evaporation characteristics of the MP and MO blended droplets were investigated by single-droplet evaporation experiments at 773 and 973 K. The results were summarized as follows.

Result The results show that at 773 K, the evaporation of MP20MO80 and MP20MO80+50CeO₂ droplets is dominated by fluctuating evaporation stage, but with the further increase of CeO₂ concentration, the evaporation stage of mixed droplets gradually changes to steady evaporation stage, and the evaporation process of droplets is dominated by fluctuating evaporation stage at 973 K; At 773 K, the proportion of transient evaporation phase time of biodiesel droplets with CeO₂ nanoparticles is less than that of droplets without nanoparticles, and the proportion of fluctuating evaporation phase time of droplets at 973 K is greatly improved compared with that at 773 K; At 773 K and 973 K, the evaporation rate of droplets increases first and then decreases with the increase of CeO₂ concentration. When the mass fraction of CeO₂ is 50×10⁻⁶, the evaporation rate of droplets reaches the maximum, which is 0.125 mm²/s and 0.373 mm²/s respectively. The evaporation rate of droplets at 973 K is higher than that at 773 K, because the temperature increase promotes the evaporation of droplets and the occurrence of micro-explosion.

Conclusion The results of the study can provide valuable references for the practical application of CeO₂ nanoparticles in engine fuels.