Experimental evaluation of the effect of emulsion stability on micro-explosion phenomena for water-in-oil emulsions

•Combustion of water/diesel fuel emulsion droplets was studied in a cell at 0.1MPa.•The combustion features were inferred by means of high speed backlight shadowgraphy.•Emulsions of different stability were prepared by varying their internal parameters.•A correlation between micro-explosion tendency and stability of an emulsion is found.•Micro-explosions proceed by either coalescence or cooperative mechanisms. The combustion features of water-in-diesel fuel emulsions were studied in a single drop combustion chamber by means of high speed shadowgraphs, suspending emulsion drops to a thermocouple in order to follow their thermal history. Several emulsions were prepared by varying the internal parameters that affect their stability, such as water volume fraction, water particle size distribution and the amount of surfactant. It was found that the emulsion internal parameter which have influence on emulsion stability (water volume fraction and size distribution, quantity of surfactant) also influence the tendency towards micro-explosion.