The balance between surface and kinetic energies within an optimal micro-explosion

•Micro-explosion of water-in-oil emulsion drops are investigated using IR Camera.•Kinetic and surface energies of secondary droplets are compared for two different water dispersion sizes.•Existence of an optimal water dispersion size regarding surface creation is confirmed.

Micro-explosion is caused by the sudden vaporization of water drops inside water-in-oil emulsion. Past studies have shown an optimal diameter for dispersed water. This optimal micro-explosion produces the largest number of secondary droplets, i.e. the largest interfacial area among the resulting spray. Such an increase in the interfacial area within the spray causes a better and less polluting combustion process. By using an infra-red camera, the present experiments can measure the size and planar velocity of secondary droplets issued from an optimal and also a non-optimal emulsion. The distributions of kinetic energy and surface energy among the spray are then calculated and discussed. Among the secondary droplets, it results that the optimal micro-explosion favors surface energy over kinetic energy.