ID 386

Effect of Nozzle Hole Diameter on Spray Atomization and Pattern in gasoline direct injection injector

 

Abstract:

The spray angle, droplet size distribution, and spray pattern are important factors in analyzing spray charac-teristics. In this paper, spray atomization and pattern characteristics were experimentally investigated according to the nozzle hole diameter of a single-hole gasoline direct injection injector using phase Doppler anemometry (PDA) and Mie-scattering technique. The experimental setup includes a fuel supply/injection system, a PDA system, and an injector control system. The spray pattern was analyzed from cross-section images taken by Nd:YAG laser and a high-speed camera. The length of the injector hole orifice was kept constant and the diam-eters were varied from 140 μm to 200 μm. The atomization characteristics were analyzed through the droplet size, distribution, and droplet velocity. The spray pattern was analyzed through the centroid and its deviation from the cross-section area of spray. The tests for spray atomization and spray pattern were conducted at 40 mm, 60 mm, and 80 mm positions from the injector tip. Results of the experiments indicate that the larger the hole diameter, the larger the spray droplet size and the smaller the rate of the spray droplet. The Sauter mean diameter of the 200 μm hole-diameter was larger than that of the 140 μm hole-diameter by approximately 8.9 %. In addition, the droplet velocity decreased when the hole-diameter increased. In the spray pattern exper-iment, the area of the spray pattern increased as the hole-diameter increased. This results in an increase in the variation of the centroid and instability of spray.