Experimental study on the dynamics of binary fuel droplet impacts on a heated surface

The dynamics of a binary fuel droplet impinging on a heated surface was studied experimentally. The fuel droplets consisted of a mixture of n-hexane and n-decane fuels which have significantly different boiling temperatures. We show that the impact regimes obtained with binary fuel droplets are significantly different from those obtained with single component droplets, especially when surface temperatures exceeded the boiling point of n-hexane, the more volatile component in the mixture. Six distinctive impact regimes were identified and classified for binary and single component droplets' cases. Some of them were applicable for both cases, while others proved to be unique for only one of them. In addition, the effect of the droplet's impact velocity on the subsequent impact regime was examined. It was found that an increased droplet's impact velocity actually lowered the surface temperatures characterizing the specific impact regime. Furthermore, a droplet breakup phenomenon which takes place when a droplet impacts a hot surface was also examined. Minimal critical surface temperature needed for a droplet breakup was found. This temperature appears to be independent of impact velocity above a certain value (within the examined range).