In recent years, the development and application of multi-dimensional CFD models have advanced rapidly based on the usage of commercial (Star-CD, Fluent, FIRE, CONVERGE) or public and/or open source (KIVA3V/KIVA4V, OpenFOAM, AVBP) codes. The CFD models implemented in these codes
are based on the numerical solutions of the Navier-Stokes equations representing viscous, compressible, reaction flows. Additional sub-models are required to simulate new fuel properties, fuel injection, spray atomization, droplet
evaporation, ignition, combustion, turbulence and turbulence/chemistry interaction.
A trend in current engine research is to study blends of fuels with very different chemical behavior, typically a mix of low and high Octane number fuels – dual (liquid) fuel combustion. This set new requirement on the spray model since the volatility of the components in this kind of blends usually varies substantially. Care has to be taken implementing this differential evaporation process concerning thermo dynamical equilibrium while keeping the robustness of its solution.
Blended or dual fuel combustion requires a large chemical mechanism in order to correctly predict ignition and combustion and hence solving for a large number of species transport equations in CFD.