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.