Simultaneous evaluation of tip and drop velocities in unsteady sprays

Simultaneous measurements of tip and drop velocities in unsteady sprays were performed at different chamber and injection pressures. LDV provided droplet velocity data and a high speed Digitized Image Acquisition System (DIAS) gave tip penetration and velocity.Droplet and tip velocities were found to be identical at the lower chamber pressure either at 45 and 60 mm from the injector. Higher chamber density conditions made LDV measurements more difficult avter the tip arrival and lowered droplet velocity data with respect to the spray tip velocity. Tip and droplet arrival times at the probe volume location were always consistent, and the lower droplet velocities could be associated to a wider droplet size distribution and to the presence of droplets injected at different times and speeds