A VARIABLE FLOW NOZZLE WITH CONSISTENT SPRAY PERFORMANCE

A variable flow nozzle, characterized by consistent spray performance over a wide flow range, was designed using a simulation technique with spray models of a prototype swirl nozzle (Koo and Kuhlman, 1993b). The models used in the simulation were developed and calibrated for the variable flow nozzle in previous studies. The use of a variable flow nozzle in the direct-injection-mixing, total-flow-control system is deemed necessary to pursue precise application and minimal exposure to chemicals. The consistent spray performance was maintained by the proper combination of nozzle pressure and inlet area with an improved turn-down ratio, defined as the ratio of maximum flow rate to minimum flow rate with acceptable spray performance. The coefficients of variance (CV) of the swath coefficient and volume median diameter were 3.4% and 3.5% for a 1. 19 mm orifice diameter (D3) with a turn-down ratio of 3.6. The simulated performance of the variable flow nozzle was consistent, and the flow range was wide enough for a total-flow-control system.