Determination of the optimum operating parameters of an axial fan used on the conventional air blast orchard sprayer

Abstract

The pesticide droplets are carried to the tree canopy with the assist of the air flow which is generated by an axial fan of orchard sprayer. The designers manufacture the fan of orchard sprayer with ability of 6 different working conditions under constant PTO speed. Previous studies were related to evaluating the effectiveness of sprayers. In this study, 6 different options that presented to farmers was evaluated with view of energy consumption and air flow. A Conventional orchard sprayer having an axial fan with 36" diameter was operated at two fan revolutions (1890 and 2430 rpm) and at three blade angles (15º, 30º, 45º), and measured air capacity, the fuel consumption, variations of air velocities in air jet profile of the fan and calculated power consumption for each operating parameters potentially to be chosen by farmers. As a result, for each blade angle, if the fan speed increase, the air jet of the fan become more uniform than before. The maximum fan efficiency and system efficiency were %73,25 and %59,98 respectively which were obtained 30 o blade angle and 2430 rpm fan rotation speed condition. The minimum fuel consumption and torque need was obtained under conditions of 15 o blade angle and 1890 rpm fan rotation speed. However, considering maximum air capacity and the best air velocity uniformity in the profile of fan jet was established at, 45 o blade angle and 2430 rpm fan rotation speed operating parameters.