The flow behavior of liquid fuel through injectors greatly affects its atomization and combustion efficiency inside an engine. A computational fluid dynamics (CFD) model is developed using the open source CFD library OpenFOAM to predict the fuel flow in injectors that are used in the gasoline direct injection systems (GDI). Additionally, a method is formulated to couple this model with fluids that represent the physical properties of gasoline-ethanol blends like E85.