Abstract:Aiming at the problems of short air delivery distance and chemical waste of traditional air-driven sprayers, an axial-flow air-delivery system suitable for traditional orchard sprayers was designed. By setting the installation angle, quantity, length of different air duct guide vanes, taper and outlet layout of the conical multi-outlet device, the airflow field of the air delivery system was further guided, and the corresponding airflow field distribution model was established. The best optimal design scheme of the air delivery system was selected by comparison, and a verification test was carried out. The research results showed that the influence of the parameters of the fan guide vanes on the outlet wind speed was significant from large to small as the length, installation angle, and quantity. When the angle was 10°, the number was 6, the length was 20cm, the taper of the conical multi-outlet device was 2.25, and the outlet layout was type A, the uniformity and size of the outlet wind speed of the air delivery system were the best. The relative errors was 4.66% and coefficients of variation of the experimental values was 3.63%, which verified the reliability of the numerical simulation results. On this basis, through the external flow field test of the sprayer, it could be seen that the boundary range of the jet was increased with the increase of outlet diameter and rotation speed, and the air delivery distance was also increased. At the wind delivery distance of 0~2m, the wind speed was above 5m/s and the attenuation range was obvious, when the air delivery distance was greater than 2m, the attenuation of the airflow was relatively gentle, and the wind speed at 4m reached about 1.5m/s. After optimization, the air delivery system of the axial-flow orchard sprayer had a reasonable structure, and it could meet the needs of orchard plant protection machinery in terms of wind speed uniformity, size, boundary and range.
