Abstract
Keywords
common-rail injection system, spray tip penetration, spray cone angle, SMD, axial mean velocity
Abstract
The objective of this study is to analyze the macroscopic development and atomization characteristics of DME fuel spray injected through a common-rail injection system and the diesel spray characteristics at the same conditions. In order to investigate the macroscopic spray characteristics of DME, the spray development of DME were analyzed in terms of spray tip penetration, spray cone angle, spray area and centroid of spray by using spray visualization system which is composed of a Nd:YAG laser and an ICCD camera. The microscopic characteristics such as droplet size distributions and axial mean velocity were measured by using phase Doppler particle analyzer (PDPA) system. It was revealed that the DME spray has shorter spray tip penetrations, wider spray cone angles, larger spray area and more rapid evaporating processes than those of diesel fuel. The comparison of the axial direction centroid(Z) shows that the DME fuel has the large value. The comparison results of spray profiles in both fuels show the diesel fuel has larger SMD value than that of DME. On the other hand, the axial mean velocity of both fuels shows the similar trend with increase of axial distance.