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 15w) 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. © 2023, Institute of Technology PETRONAS Sdn Bhd.