Reducing the environmentally harmful emissions from the highly efficient diesel engine is one of the challenges to be addressed to design ultra-low carbon diesel engines for the future. A blending of water with diesel is found to be effective in reducing NO_x emissions. However, when fuels with different volatilities are blended, it can result in puffing and/or micro explosion of a droplet, which can favor atomization and mixing. Creating simple models for micro explosion processes will help in simulating the spray evaporation process which requires understanding the dynamics of evaporation or micro explosion of droplets at different compositions and temperatures.

The present study focuses on a fundamental understanding of the heating and evaporation of a single droplet. Microemulsions of Dodecane and Water with different boiling points are prepared with water composition ranging from 10 to 30 % which will have water as a dispersed phase and dodecane as a continuous phase. The emulsified fuel droplet placed on a nichrome wire of diameter 100 µm is introduced rapidly into the heater with fused silica windows in conjunction with a temperature controller. The temporal evolution of the droplet is captured using a high-speed camera. Experimental results on evaporation and puffing/micro explosion of emulsion droplets along with the time taken for ignition under different ambient temperatures and droplet composition will be presented in the paper.