Fundamental experiment on behaviors and characteristics of secondary breakup of a single droplet of water emulsified n-dodecane on a hot surface

Abstract

Fuel efficiency and emission have been the most important two issues in the field of combustion. Recently, eco-friendly alternative fuels have been of interest with the enhancement of global emission legislations. Water-emulsified-fuels have also been used in many practical combustion systems such as gas turbines with the main purposes of suppressing NOx emission and controlling flame characteristics. Atomization and combustion phenomena of emulsified fuel may differ from those of pure fuels. In a practical burner, sprayed droplets continuously impact on a high temperature surface such as the combustion chamber, and this phenomenon may be important in determination of the overall combustion characteristic. In this study, water emulsified n-dodecane was prepared, and their impinging behaviors were investigated with the experimental parameters of the impinging momentum and the surface temperature. A premixed burner was used as the hot plate, which consists of two transparent quartz plates and a methane-air flame inside. After impinging of a single droplet, detailed post-impinging behaviors were visualized simultaneously using two high-speed cameras, and the results were analyzed. The particle tracking velocimetry (PTV) method was used to quantify the velocities and number of secondary droplets. The pattern of secondary droplets after impinging was also presented.