The Droplet Group Micro-Explosions in W/O Diesel Fuel Emulsion Sprays

The lump-fashioned droplet group micro-explosions in water-in-diesel fuel emulsion sprays during the atomization, evaporation and combustion processes in a high-pressure, high temperature bomb were observed with a multi-pulsed, off-axis, image-plane, ruby laser holocamera and a high-speed camera. The explosions expand the volume of spray, improve the fuel-air mixing process and speed up the flame propagation. A no-water layer formed by Hills vortex was also observed in emulsion droplets. The ambient temperature has the most important influence on the occurrence and violence of the micro-explosion.

The fuel consumption and exhaust emissions with emulsions of different water fractions were studied under various operating conditions by numerical simulation and engine tests.