Direct Numerical Simulation of Fuel Droplet Collision in Diesel Engines 2005-24-056
Fuel droplet collision plays an important role in the mixture
formation mechanism in Internal Combustion Engines (ICE), since
this process significantly modifies the droplet sizes and
subsequent spray development and combustion. But one of the major
problems in the simulation of the droplet collision process is that
the criteria employed to determine outcomes of collisions have not
been assessed for accuracy under diesel spray conditions.
The numerical simulation of multiphase flows is a challenging
subject due to the difficulty in the tracking of interfaces, the
mass conservation of each fluid and the treatment of large density
ratio and surface tension.
In this paper a fully 3D two-phase Lattice-Boltzmann Method
(LBM) is used to perform Direct Numerical Simulation (DNS) of
droplet collision at diesel-like conditions. The LBM has great
advantages over conventional methods (e.g., VOF) since it does not
track interfaces, but can maintain sharp interfaces without any
artificial treatment, and is accurate for the mass conservation of
each component. The goal of the paper is to demonstrate that the
numerical tool developed can provide a detailed picture of the
mechanisms that govern the phenomenon, giving information where
experimental investigations are difficult. This approach can
therefore assist in the development of accurate collision models
for practical CFD applications.