Evaporation characteristics of a jet fuel component droplet under non-reacting, high-temperature convective conditions

In the current energy transition, the aviation industry is exploring alternative liquid jet fuels to achieve net-zero emissions targets. In liquid-fuel combustion, droplet evaporation plays a crucial role, occurring between atomization and combustion processes and directly influencing the heat-release zones. However, fuel droplet evaporation characteristics under conditions relevant to actual combustor scenarios are scarce. To this end, this study aims to numerically investigate the evaporation characteristics of fuel droplets in high-temperature, inert, and convective conditions. Inert ambient conditions are considered to decouple the droplet evaporation from the combustion process. Time-dependent numerical simulations were performed to gain insights into the droplet evaporation process. First, the numerical results were validated against experimental data from the literature, and the numerical predictions agreed with the experimental trends within 5% deviations. Numerical predictions captured all three stages of liquid droplet evaporation. The variation in ambient gas temperature indicated that even a relatively small change could significantly alter the slopes of the temporal variation of droplet diameter. The effects of fuel composition were investigated using pure n-decane and n-pentadecane, as well as their mixtures at varying proportions. The evaporation characteristics of mixture droplets exhibited a strong correlation with the preferential evaporation dynamics within the mixture droplet. Furthermore, the initial droplet characteristics exhibited an inverse correlation with the evaporation trends. The insights gained will help understand the influence of droplet evaporation in a convective environment on heat-release zones.