The puffing and micro-explosion phenomena have been observed and photographed in water and hydrocarbon blended fuels. Hexane, Decane, Tridecane. Hexadecane gasoline and diesel were tested as parent fuels at various percent by volume of water. The intensity of puffing and micro-explosion increases with the volume fraction of water, the droplet size and the carbon-chain length of the emulsion fuels. Time needed for droplet disappearance is observed to be linearly proportional to the size of fuel droplets. Temperature of the blended fuel droplet as a function of time were recorded experimentally. A mathematical model for temperature-time relationship of droplet is constructed to correlate the occurence of puff phenomena as a function of environmental temperature, droplet size and parent fuel properties. Application of the mathematical model to the compression stroke of an engine process and its effect later on mass burning rate is presented.