Hydrotreated vegetable oil (HVO) is a high-cetane number
alternative fuel with the potential of drastic emissions reductions
in high-pressure diesel engines. In this study the behavior of HVO
sprays is investigated computationally and compared with
conventional diesel fuel sprays. The simulations are performed with
a modified version of the C++ open source code OpenFOAM using
Reynolds-averaged conservation equations for mass, species,
momentum and energy. The turbulence has been modeled with a
modified version of the RNG k-ε model. In particular, the
turbulence interaction between the droplets and the gas has been
accounted for by introducing appropriate source terms in the
turbulence model equations.
The spray simulations reflect the setup of the constant-volume
combustion cell from which the experimental data were obtained.
Simulations of non-evaporating and evaporating sprays have been
performed for four different fuels, namely the diesel fuel DF2,
n-heptane, the European-normed EN 590 fuel and the HVO fuel. These
fuels have been compared with appropriate experimental data. The
evaluation criteria include the liquid and vapor penetrations, the
drop Sauter mean diameter (SMD) and the fuel vapor/air mixing.
The agreement between the simulations and the experiments is
generally acceptable in all cases, and it can be concluded that the
spray models are sufficiently universal to make correct predictions
for the alternative fuel HVO without any special adjustments.