Spray Characterization of a NASA MOD-1 Nozzle

An aerometrics Phase Doppler Particle Analyzer with Frequency Shifting (PDPA/FS) and a Laser Imaging and Video Processing System (LI/VPS) were used to perform a detailed analysis of the spray characteristics of a NASA MOD-1 air assist nozzle. These results were compared to the results obtained using an earlier version of a Phase Doppler Particle Analyzer (P/DPA). The spray plume was analyzed under two sets of operating conditions. For Case I, a water pressure of 105 psia (723.95 kPa) and air pressure of 65 psia (448.16 kPa), and for Case II, a water pressure of 115 psia (792.90 kPa) and air pressure of 45 psia (310.27 kPa) were used. Results for Case I indicated a deviation in arithmetic mean diameter (AMD) ranging from 0.1 to 2.8 μm deviation in Sauter mean diameter (SMD). For Case II, the deviation in AMD ranged from 0.4 to 7.1 μm, and for SMD from 0.2 to 8.2 μm. Results of the particle size comparisons between the light scattering instrument and the laser imaging system compared quite closely.