Evaporation characteristics of dual component droplet of benzyl azides-hexadecane mixtures at elevated temperatures

The evaporation characteristics of different dual component droplets are experimentally studied through a suspended droplet device and a high-speed video camera. The droplets of hexadecane, dodecane-hexadecane mixture and benzyl azides-hexadecane mixture are studied. The initial diameter of droplet is about 1.21-1.23 mm, and the elevated temperature environment in the range of 473 and 773 K is provided by an electric furnace. The results indicate that the evaporation trend of the dodecane-hexadecane blend droplet is the same as hexadecane at the different ambient temperatures, while the evaporation characteristics of the benzyl azides-hexadecane blend droplet are completely different from that of the dodecane-hexadecane at the high temperature of 673 K. The evaporation process of the benzyl azides-hexadecane blend droplet consists of three stages: transient heating, fluctuation evaporation and steady evaporation at the high ambient temperatures. The bubble formation and expansion, droplet distortion, puffing and incomplete micro-explosion are observed for benzyl azides-hexadecane droplet due to the reactivity of benzyl azides at liquid phase. Moreover, the reduction of the benzyl azides-hexadecane blend droplet lifetime is larger than that of the dodecane-hexadecane blend droplet with increasing ambient temperature. The increase of the liquid-phase reaction rate of benzyl azides is the main reason for improving the evaporation of the binary fuel droplet. In addition, with increasing benzyl azides mass fraction, the benzyl azides-hexadecane binary droplet lifetime decreases.