The Effects of Ethanol-Butanol Ratio on the Droplet Behavior during Impact onto a Heated Surface

Droplets impacting onto the heated surface is a typical phenomenon either in CI engines or in GDI SI engines, which is regarded significant for their air-fuel mixing. Meanwhile, alcohols including ethanol and butanol, has been widely studied as internal combustion engine alternative fuels due to their excellent properties. In this paper, under different component ratio conditions, the ethanol-butanol droplet impacting onto the heated aluminum surface has been studied experimentally. The falling height of the droplets were set at 5cm. A high-speed camera, set at 512×512pixels, 5000 fps and 20 μs of exposure time, was used to visualize the droplet behavior impinging onto the hot aluminum surface. The impact regimes of the binary droplet were identified. The result showed that the Leidenfrost temperature of droplets was affected by the ratio of ethanol to butanol. The higher the content of butanol in the droplet, the higher the Leidenfrost temperature. Meanwhile, it was found that the resident time of the droplet impacting onto the heated surface increased with the increasing of the butanol content in the droplet. In addition, the dry satellite rebounding impact pattern, one of the five droplet impact pattern, was studied. The results showed that the number of the smaller droplet separated from the conical part increased with the increasing of the butanol content in the droplet.