Effects of position angles in twin-jet spray applications on droplet penetration of hydraulic nozzles


Abstract: This study was conducted to determine the effects of different position angles in twin-jet spray applications on droplet penetration of different nozzle types. Seven different nozzle types (standard flat fan, ST; narrow flat fan, STN; multirange, LU; low-drift potential, AD; air-induction, IDK; twin-jet air-induction, IDKT) were used and nozzles were positioned +15° along the forward direction, perpendicular to ground surface 0? and reverse direction of forward -15°. Spray experiments at 100 L/ha constant application volume were conducted under controlled conditions of a closed facility. Water sensitive paper (WSP) was used as sampling surface. WSP samples were placed vertically and horizontally over both the metal frames and root collar of artificial plants. The present findings revealed that transport potential of spray droplets was quite lower on vertical planes than on horizontal planes. The greatest coverage was achieved with ST, STN, LU, and SC-type nozzles producing fine droplets. Compared to open targets, the coverage ratios around the root collars were quite low and insufficient. In all spray treatments, coverage ratio on the vertical planes was 86.1% lower than the coverage ratio on the horizontal plane. In other words, coverage ratio on the horizontal plane was 7.2 times greater than the coverage ratio on the vertical plane. Transfer efficiency of medium and coarse droplet-producing nozzles to root collars was greater than the transfer efficiency of fine droplet-producing nozzles. Such a ratio for AD, IDKT, and IDK-type nozzles was determined as 37.06, 37.85, and 41.02% respectively. According to the present findings, effects of nozzle position angle on droplet penetration were not found to be significant. However, nozzle position angle along the forward direction increased coverage ratios on the vertical planes.

Keywords: Flat fan nozzle, pesticide application, spray coverage, spray simulator, water sensitive paper

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