Computational fluid dynamic simulation of a pulse-width modulated spray nozzle

Computational fluid dynamics (CFD) is a useful tool used by engineers in many industries to study fluid flow. A relatively new industry to adopt the use of CFD is the agricultural industry. A spray nozzle commonly used in agricultural spraying, the Teejet 110-degree nozzle (TeeJet Technologies, 2020), was simulated. A method was developed to pulse the spray. A user-defined function was used to define the velocity at the inlet of the nozzle to pulse the spray. The domain was then extended to allow the examination of a slice 20 inches below the nozzle. The simulation results were compared to experimental results collected from a sprayer testbed. The effect of frequency was then investigated by changing the frequency of the pulses. Results from these studies show that a userdefined function can be used to pulse the spray. CFD can be used to model spray nozzles, but the validity of the results are strongly related to the computational resources available, and increasing the frequency of the pulses results in a higher concentrated spray toward the center of the spray plume. The simulations were carried out using a commercial code (CD-Adapco, 2019).