Structure optimization and fertilizer injection performance analysis of a non-axisymmetric Venturi injector

To improve the fertilizer injection performance of a non-axisymmetric Venturi injector (NAVI), the effects of the contraction angle, diffusion angle, throat diameter and tilt angle of the injection pipe on the fertilizer injection performance of NAVI were examined. Based on the test, the original NAVI was optimized, and the fertilizer injection performance of NAVI before (F1) and after (F2) optimization was compared. Then, a non-axisymmetric Venturi injector with arc diffusion (F3) was proposed. The results showed that when the water inlet diameter of the non-axisymmetric Venturi injector was 25 mm, the optimal structural parameters were as follows: the contraction angle was 40°, the diffusion angle 6°, the throat diameter 7 mm and the tilt angle of the injection pipe was 120°. Compared with F1, the injection rate and fertilizer injection efficiency of F2 increased by 21–66 and 27–79%, respectively. Changing the diffusion section of NAVI into an arc structure was conducive to reducing the vortex area size by 11% and improving the injection rate by 20–62%. The results can provide an important reference for the structural design of Venturi injectors.