Flow-field measurements of liquid and gaseous phases in the ultra-dense region of diesel sprays

The velocities of both the liquid and the gaseous phases in a diesel spray are determined for the first time simultaneously via laser flow tagging (LFT). The experimental setup and uncertainties introduced by seeding particles in the gas phase are greatly reduced by using phosphorescent tracer molecules, i.e. acetone and biacetyl, for the gaseous phase. In addition, simultaneous droplet velocimetry is achieved by doping the liquid fuel with a lanthanide–chelate complex.The relative velocity of gas and liquid phases can be determined from the data on the spray axis close to the nozzle for the first time. This is an important quantity for modeling droplet break-up and evaporation in ultra-dense sprays.