Exploring Spray Nozzle Performance through Computational Fluid Dynamics with Pulse-Width Modulation

This study investigates the effect frequency has on the spray distribution characteristics by determining whether CFD can be used to study pulsed spray nozzles and simulate a spray nozzle that is pulsed at various frequencies. 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 [1], 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 user-defined function can be used to pulse the spray. Spray nozzles can be modeled using CFD, but the accuracy of the findings is highly dependent on the available computing power. Increasing the pulse frequency produces a more concentrated spray in the direction of the spray plume's center. The simulations were carried out using a commercial code (CD-Adapco, 2019). Further investigation is necessary to acquire that lower frequencies may provide better results. The lower frequencies provide a more uniform spray distribution which would provide more even coverage during the spraying process.