Experimental study on streamwise interaction of burning compound droplets

Abstract

Compound droplet interaction is an important aspect of spray combustion. In this work, the stream wise interaction of burning compound droplets has been conducted experimentally in detail. The constant value of di = 500 μm is considered for the compound droplet diameter and two values of β = 50% and 85% are used for the H2O content. The effects of primary distance of compound droplet (Si) in the range of 2.5–100 and environmental O2 concentration (ΩO2) in the range of 21%–30% on the flame width, micro-explosion, and evaporation rate are investigated. The experimental results on the compound droplets indicate that, in general the flame length increases as the primary droplet distance decreases. However, as an exception, for a droplet string with the primary distance of 2.5, the trend is reversed due to the collision-merging of the drops. The micro-explosion can be observed due to the nucleation bubble blast in the H2O core of the compound drop. The flame spread through micro-explosion is observed at Si = 10, and the effects of distance on the droplet evaporation are diminished beyond Si = 30.

Keywords

• Streamwise droplet interaction
• Compound droplet
• Burning droplets
• Micro-explosion
• Flame width
• Evaporation rate