Experimental study on the evaporation and combustion characteristics of double Al/n-heptane based nanofluid fuel droplets in high temperature environment

Abstract

Nanofluid fuels can be used in scramjet. However, the interactions among fuel droplets in spray and combustion process are still a gray area. The study on the evaporation and combustion of the double droplets can better demonstrate the role of nanofluid droplets. In this paper, the evaporation and combustion characteristics of the double droplets of aluminum/n-heptane based nanofluid fuels were investigated by a droplet-suspension method, whose results were compared to those of the single droplet at 973 K and 0.1 MPa. The effect of the distance of the double droplets on their evaporation behavior, ignition delay time, combustion phenomena, and micro-explosion time were studied. The influence of thermocouple wire was also analyzed. The double droplets have a synergistic effect on the evaporation behavior, ignition delay time, and micro-explosion. The ignition delay time of double droplets of the aluminum/n-heptane based nanofluid fuel droplet has debased 25.3% compared with that of the single droplet, while the maximum micro-explosion duration has increased 7.2%. With the increase of the distance of both droplets, the synergistic effect is first strengthened and then weakened.