PRACTICAL STUDY ON HIGH-DISPERSION AND HIGH-PENETRATION DIESEL INJECTION NOZZLE (SECOND REPORT: ATOMIZATION OF INTERMITTENT SPRAY OF HIGH-DISPERSION ATOMIZATION ENHANCEMENT NOZZLE AT HIGH-AMBIENT PRESSURE)

It is important to obtain excellent spray characteristics and combustion characteristics in order to reduce fuel consumption ratio and carbon dioxide for control of global warming. In the previous studies, it was clarified that disturbance of the liquid flow in the nozzle hole due to occurrence of cavitation has a dominant effect on atomization of the liquid jet [1]-[13]. It has developed the atomization enhancement nozzle, which excellent spray characteristics correspond to super-high injection pressure of 200 MPa are obtained at relatively low injection pressure of 10 MPa [14]. Cavitation has a dominant effect on atomization of the liquid jet. The purpose of this study is to develop the atomization enhancement nozzle which is obtained the spray with high-dispersion and high-penetration, and it is to improve the spray characteristics of a D. I. Diesel nozzle. At previous results, it has been developed that although the spray tip penetration of the atomization enhancement nozzle [14] invented in this study is short, spread of the spray becomes large considerably compared with a previous single hole nozzle for a D. I. Diesel injector at the intermittent spray [15]. In this paper, the effect of the atomization enhancement nozzle [14], which was invented in the previous study on atomization of the intermittent spray at high-ambient pressure condition and application to the actual Diesel injector, were investigated. The test nozzles were used a single hole nozzle and the atomization enhancement nozzle [14]. The effects of geometric shape and dimensions of the atomization enhancement nozzle such as the hole diameter, the hole length, the gap diameter made at the nozzle hole, the bypass number which was connected between the upstream chamber and the gap on atomization of the intermittent spray and atomization characteristics were investigated. As a result, it was cleared that although the spray tip penetration of the atomization enhancement nozzle is short, spread of the spray becomes large considerably compared with the previous single hole nozzle at high-ambient pressure of 1.6 MPa at ambient temperature of 300 K. 2. EXPERIMENTAL APPARATUS AND METHORD