Abstract
In order to investigate the dggect of needle lift on the early tage of spray desintegration, simultaneous measurments of velocity and size of droplets were conducted by a mewly developed laser 2-focus velocimeter (L2F). The micro-scale prove is consisted of two foci tiwh a distance of 30u.m. The tested nozzle has single hole with a diameter D of 0.2 mm. The measurements of injection pressure, needle lift, and crank angle were synchronized with the L2Fmeasurements, It is clearly showm that droplets are desintegrated remarkably on the transient needle opening condition, Droplets with higher velocity and larger size than the breakup criteria are observed near the spray center on the full nedle lift condition. It is understood that large droplets penetrate along the spray axis and small droplets scatter radially near the nozzle exit.
