Optimization design and test of large diameter eccentric Venturi fertilizer injector
In order to improve the fertilizer absorption performance of the existing large diameter Ven-turi fertilizer injectors,the structure optimization design was carried out.Based on the large diameter symmetrical Venturi fertilizer injector(M-type),it was modified and designed as an eccentric Venturi fertilizer injector(P-type).Orthogonal design method and numerical simulation technology were ap-plied,and the absorption efficiency was used as the evaluation index to determine the optimal combina-tion of structural parameters of the eccentric Venturi injector.Experimental testing and numerical simu-lation comparative analysis were conducted on two types of fertilizer applicators.The result shows that the optimal combination of structural parameters is a throat inlet diameter d1(17 mm),a diffusion angle β(3°),a throat outlet diameter d2(20 mm),a straight section length L2(16.6 mm),a throat groove diameter d(27 mm),a throat groove width L1(4 mm)and a contraction angle α(23.5°).Through experimental tests and comparative analysis,it is found that the optimized P-type injector in-creases the maximum fertilizer absorption flow rate by 21.4%compared to the maximum suction flow of the M-type injector.When the inlet pressure is 0.25 MPa,the maximum fertilizer absorption concentra-tion is increased by about 30.7%,and its maximum fertilizer absorption efficiency is increased by about 13.9%.Flow field analysis shows that compared with the M-type fertilizer injector,the P-type in-jector is less prone to cavitation under the same pressure difference,and the flow pattern of the P-type Venturi injector is more stable and its energy loss is smaller.The preceding research demonstrates that the optimized eccentric Venturi fertilizer injector can improve the fertilizer absorption performance.