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Numerical studies of spray breakup in a gasoline direct injection (GDI) engine

Jafarmadar Samad (Department of Mechanical Engineering, Urmia University, Urmia, Iran)
Heidarpoor Vahied (Department of Mechanical Engineering, Urmia University, Urmia, Iran)

The objective of this study is to investigate Spray Breakup process of sprays injected from single and two-hole nozzles for gasoline direct Injection (GDI) engines by using three dimensional CFD code. Spray characteristics were examined for spray tip penetration and other characteristics including: the vapor phase concentration distribution and droplet spatial distribution, which were acquired using the computational fluid dynamics (CFD) simulation. Results showed that as the hole-axis-angle (γ) of the two-hole nozzle decreased, the droplet coalescence increased and vapor mass decreased. The spray with cone angle (θ0) 5 deg for single hole nozzle has the longest spray tip penetration and the spray with the γ of 30 deg and spray cone angle θ0=30 deg for two hole nozzles had the shortest one. Also, when the spray cone angle (θ0) and hole-axis-angle (γ) increased from 5 to 30 deg, the Sauter mean diameter (SMD) decreased for both single-hole and two-hole nozzles used in this study. For a single-hole nozzle, when spray cone angle increased from 5 to 30 deg, the vaporization rate very much because of low level of coalescence. The result of model for tip penetration is good agreement with the corresponding experimental data in the literatures.

Keywords: DGI, spray, numerical simulation, hole-type nozzle