Improvement of Atomization Characteristics of Spray by Multi-Hole Nozzle(Thermal Engineering)

Abstract

The purpose of this study is to improve of spray characteristics of direct injection Diesel nozzle, which the spray with large spray angle, short liquid core length and small droplet diameter is obtained. In the previous study, the single hole atomization enhancement nozzle, which excellent spray characteristics are obtained at relatively low injection pressure, was developed. In this study, it was investigated about atomization of the spray of the multi-hole atomization enhancement nozzle, and aimed to improve atomization characteristics and to obtain excellent spray characteristics. The effects of dimensions of the atomization enhancement nozzle such as hole number, hole diameter, position of nozzle hole on atomization of the spray and atomization characteristics were investigated. As a result, it was cleared that in case of the multi-hole nozzle with hole number of N=4, breakup length becomes short about 70% and spray angle becomes large about three times, droplet diameter of the spray becomes considerably small compared with the single hole nozzle. Atomization characteristics were improved considerably by using the multi-hole nozzle with hole number of N=4.