Biofuels are playing more and more important roles
worldwide. While it will reduce the overall emission of
greenhouse gases, it may damage the combustion system
through corrosion and poor lubrication, and generates more
local air pollution than fossil fuels if the biofuel burning
properties are not well understood and controlled. This work
investigates the effect of blending diesel fuel by biodiesel on
the combustion of a single fuel droplet. Biodiesel blends
substituting diesel oil in different concentrations on volumetric
basis, in addition to pure diesel and purer biodiesel were
studied. Schlieren and bbacklighting imaging techniques have
been used to track the droplet combustion throughout its
complete lifetime using a high speed camera. The results
showed that partial substitution of diesel oil by biodiesel at the
test conditions led to increasing secondary atomization from the
droplet, compared to pure diesel or biodiesel fuel droplets. This
in turn enhances evaporation, mixing, and then combustion.
Additionally, the results showed a slight decrease in droplet
burning rate of the blend compared to the pure fuel droplets.
Nucleation has also been traced to take place inside the droplets
of the blends. Moreover, flame size (height and width) has been
reduced by increasing biodiesel concentration in the blend.
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.