Optical measurements of droplet size distributions: Special considerations in the parameter definition for fuel atomizers

Fuel nozzle performance, the droplet size distribution which is frequently characterized by the Sauter mean diameter one of the dominant parameters was evaluated. The importance of flow parameters and size distribution in applying nonintrusive optical techniques is emphasized. An optical diffraction type particle sizer was used for analysis of fuel sprays from airblast and pressure atomizers. It is shown that the Sauter mean diameter alone is generally not suited for describing the nozzle performance. The influence of the flow field on the apparent droplet size distribution is outlined.