SPRAY PERFORMANCE MODELS OF A DESIGNED SWIRL NOZZLE

An experimental swirl nozzle was developed as a conceptional design of a variable flow nozzle characterized with an improved turn-down ratio with consistent spray performance (Koo and Kuhlman, 1993). The spray characteristics of the experimental nozzle were calibrated using the t heoretical performance of swirl-type nozzles. The models of the discha rge coefficient, the swath coefficient, and the volume median diameter were assessed by comparing predictions to experimental data. Predicte d spray performance from the models correlated rationally with experim ental results. Spray characteristics of the experimental nozzle were g overned by the theoretical extreme conditions as well as major variabl es. The lower extreme condition was characterized by unique spray perf ormance in the turbulent flow region. The upper extreme condition was characterized by an increase of spray flow velocity due to the critica l limit of air core area. The calibrated models can be applied to the design and development of a variable flow nozzle.