Spray Characteristics and Droplet Micro-Explosion of Water in Diesel Emulsion

This paper highlights the potential usefulness of water-in-diesel emulsions when exposed to high-temperature, thereby improving the air–fuel mixing process utilising micro-explosion resulting from multi-component fuel combustion.Although the high injection pressure significantly affects the spray characteristics and fuel mixing process, observation of micro-explosion in the spray is rarely addressed.In this study, an emulsion made with 5%, 10%, and 15% of water by volume is investigated at different injection pressure (500, 750 and 1000 bar).The experiments are conducted in a constant volume chamber under evaporative conditions.A high-speed camera coupled with a long-distance microscope was used to magnify and visualise the spray droplets micro-explosion in the spray.The raw images of spray were then analysed using a purpose-built image processing algorithm to identify both spray penetration length and dispersion angle.Our measurements indicated that the differences in water content (10 and 15%w) suggest an increase in both spray penetration length and cone angle due to fuel evaporation and micro-explosion.Furthermore, the spray breakup enhances with the increase in water content.