Effect of double‐droplet interaction on ignition and combustion characteristics of heptane‐based nanofluid fuels in a high‐temperature environment

Abstract

AbstractThe ignition and combustion characteristics of a single droplet or double droplets of the Al/n‐heptane‐based nanofluid fuels with different arrangements were investigated by a droplet‐suspension method at high temperature. The addition of ricinoleic acid and nano‐sized Al particles to n‐heptane can improve the ignition performance of n‐heptane droplets, and the ignition delay times of n‐heptane droplets are decreased by the maximum of 19.0% and 31.0%, respectively. The mixing effect of combustible vapor of adjacent droplets and the heat transfer effect of adjacent flames are responsible for the different combustion processes of nanofluid fuel droplets with different arrangements. Compared with the single droplet, the ignition delay times of the horizontal and vertical double droplets are decreased by the maximum of 26.9% and 45.7%, respectively. The vertical double droplets have better ignition performance than the horizontal double droplets due to the disturbance and mixing of the vapor flow with different directions. In addition, the droplet arrangement has different promotion effects on different droplets.