Optimization of Blade Geometry in Air Assisted Sprayer Fans Using Computational Fluid Dynamics

Abstract

The blower impeller is a vital component of an air-assisted sprayer, as it generates the necessary air velocity and discharge required to direct spray droplets from the nozzle onto the target surfaces, including both the upper and lower sides of plant leaf canopies. To better understand and optimize this process, a Computational Fluid Dynamics (CFD) model was developed to analyze the air velocity distribution produced by the impeller and blower system. Three impeller diameters—95 mm, 115 mm, and 127 mm—were selected for evaluation at three rotational speeds: 2000, 4000, and 6000 rpm. The CFD analysis revealed that the 127 mm impeller consumed the highest power at each speed: 35 W at 2000 rpm, 39 W at 4000 rpm, and 47 W at 6000 rpm. This trend is attributed to the increased air suction that occurs with higher impeller speeds, resulting in greater power demand. Furthermore, the 127 mm diameter impeller exhibited superior performance, producing a maximum discharge of 154 m³/h, a velocity of 27 m/s, and a pressure of 640 Pa. The minimum values observed for the same impeller were 92 m³/h, 14 m/s, and 340 Pa, respectively. Overall, the impeller with a 127 mm diameter at 6000 rpm demonstrated the best results in terms of air discharge, velocity, pressure, and overall efficiency, confirming its suitability for achieving optimal spray coverage in air-assisted sprayer applications.