ARS | Publication request: Air velocity distributions from air-assisted five-port sprayer

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: March 15, 2012
Publication Date: August 1, 2012
Citation: Gu, J., Zhu, H., Ding, W. 2012. Air velocity distributions from air-assisted five-port sprayer. ASABE Annual International Meeting. Paper No. 121337320.

Technical Abstract: Capability to control both liquid and air flow rates based on tree structures would be one of the advantages of future variable-rate orchard and nursery sprayers. Air jet velocity distributions from an air assisted, five-port sprayer which was under the development to achieve variable-rate functions were measured at various heights above the ground and various distances from nozzle outlets. The air jet velocity was controlled by changing the sprayer fan inlet diameter. Air jet initial region length, transition length and expansion angle from five-port nozzles were calculated with an air jet model. The interaction point between adjacent air jets from the five-port nozzles was also determined from the air jet expansion angle. Air velocities at the sprayer travel speed ranging from 0 to 8.0 km/h were measured with a constant temperature anemometer system coupled with hot-film sensors. Air jets expanded at 50° angle and interacted at 0.027 from the nozzle outlets. When the sprayer travel speed was 0 km/h, the axial air velocity increased as the fan inlet diameter increased while it decreased in the hyperbola function with the increase of distance from the nozzle outlets. When the sprayer was on the move, due to the air entrainment and air jet diversity, the peak air velocity decreased with the increase of distance from nozzle outlets. The peak air velocity also increased slightly as the fan inlet diameter increased but the increase scale was not as great as the increase scale of the fan inlet diameter. There were little variations in the peak air velocity with the travel speed and measurement height, confirming the sprayer was able to discharge uniform air profiles to achieve variable air flow rates by controlling the fan inlet diameter.