This study represents an evaluation of the extent to which conventional and recently introduced modern diagnostics can assess the symmetry of sprays formed by three atomizers of identical design. The conventional diagnostics include sheet-lit photography, which provides a measure of the gross flowfield asymmetries; patternation, which identifies nonuniforaiities in the gross mass flux distribution; and laser diffraction, which reveals variations in line-of-sight measurement of Sauter mean diameter (SMD). The modern diagnostic is laser interfere me try (phase Doppler), which measures local values of droplet size, two-components of droplet velocity, and droplet volume flux. Symmetry is assessed in ambient conditions for four atomizer orientations (0, 60,120, and 180 deg), and comparisons are made between the diagnostic techniques. The results demonstrate that 1) conventionaland modern diagnostics are consistent in the assessment of symmetry, 2) patternation and phase Dopplerare most effective in establishing symmetry of mass flux, and 3) phase Doppler, although more tedious to employ, provides the additional information n cessary to establish the sources of detected asymmetries in terms of non-uniformities in droplet velocites, size distributions, volume flux, and concentration. © 1990, American Institute of Aeronautics and Astronautics, Inc., All rights reserved.

Phase Doppler interferometry is providing detailed information about the structure of sprays. Such information is attractive to those developing numerical models that predict spray behavior. However, the inherent complexity of sprays and advanced diagnostics warrants the development of a reference point for measurements. Hence, a "standard" spray is evaluated in the current study which can be used to evaluate instrument and operator performance and, once sufficient data sets are generated, can provide a benchmark data set for modeling challenges. A comprehensive set of mean and variation in five sets of measurements is provided. In general, the results reveal reasonable reproducibility, especially in quantities which are dependent solely upon the number of drops (e.g., mean velocities). It is also shown that statistics derived from individual drop sizes reveal less variability than those derived from the entire spray population. Finally, it is observed that quantities whichdepend upon drop volume and/or sample volume area (e.g., Sauter mean diameter, volume flux) are subject to the greatest variability. © 1994, American Institute of Aeronautics and Astronautics, Inc., All rights reserved.