Characteristics of auto-ignition and micro-explosion behavior of a single droplet of water-in-fuel

The characteristics of auto-ignition and micro-explosion behaviors of a single fuel droplet have been investigated experimentally with varying droplet sizes, ambient temperature, and water content. The fuel used for this experiment was pure n-decane, which was emulsified with several water content varied from 10% to 30% to compare the effects of water content in the emulsified fuel. Imaging with a high-speed digital camera was adopted to measure the ignition delay and flame life-time, as well as to observe micro-explosion behavior. The increase of droplet size and furnace temperature causes a decrease of the ignition delay time. The flame life-time is augmented as the droplet size increases, however it doesn't seem to be affected by the ambient temperature relatively. As the water content increases, the ignition delay increases and the micro-explosion behavior is strengthened. The start timings of micro-explosion and fuel puffing are compared for different droplet sizes and the amount of water content.