Impact of Orifice Angle Configurations on the Droplet Atomization Enhancement of Diesel Fuel in a Group-Hole Nozzle

This paper presents the effect of orifice configuration on the droplet atomization characteristics of diesel fuel injected through different types of group-hole nozzle angles, which are converged $(θ=−3deg)$⁠, parallel $(θ=0deg)$⁠, and diverged $(θ=+3deg)$ orifices in atmospheric pressure and room temperature condition (0.1 MPa, 293 K). It was revealed that the parallel hole nozzle has the largest Sauter mean diameter (SMD) value and both sprays from diverged and converged hole nozzles show better atomization. A comparison of spray tip penetration illustrates that as the orifice angle is converged, spray tip penetration becomes longer, and it must be the reason for the fast spray velocity. These results can confirm the relationship among time, distance, and velocity. Therefore, it can be concluded that the droplet atomization enhancement can be expected in the converged nozzle spray rather than in the parallel and diverged nozzle sprays based on the results of smaller SMD, faster velocity, better air utilization, and higher percentage of small size of droplets in the measuring area.