关键词: 液肥, 计算流体力学, 矩形分配器, 均匀分配, 数值模拟

Abstract: In the operation of returning liquid fertilizer to the field, the uniformity of the flow rate of each pipeline outlet of the distributor is the key condition for quantitative application of fertilizer. However, although the imported horizontal distributor and vertical distributor can achieve high fertilizer delivery accuracy, they are costly and difficult to maintain. Although the existing rectangular distributor has low cost and simple structure, the uniformity of flow rate at the outlet of each fertilizer outlet pipe is poor, which affects the fertilizer application precision and controllability. In order to solve these problems, numerical simulation of fluid flow in the rectangular distributor was carried out based on FLUENT fluid simulation software, and the structure of the rectangular distributor was improved. The results show that when the position of the fertilizer inlet is located on one side of the rectangular distributor, the difference between the flow rate on the left side and the right side of the rectangular distributor reaches 10.27%, the difference between the mass flow rate of the maximum flow rate outlet and the minimum flow rate outlet is 0.26 kg/s, and the standard deviation of the mass flow rate of the outlets is 0.088 95, and the flow rate variability of the fertilizer outlet ports is large, which has a large negative impact on the uniform application of liquid fertilizer. By changing the layout of the fertilizer inlet pipeline, redesigning the distributor structure, and setting the fertilizer inlet port in the middle of the distributor, the uniformity of flow distribution can be effectively improved on the basis of not increasing the manufacturing difficulty and manufacturing cost. After the improvement of the rectangular distributor, the difference of mass flow rate between the outlet of the largest flow rate and the outlet of the lowest flow rate was reduced from 0.26 kg/s to 0.12 kg/s, the difference between the left and right flow rates was reduced from 10.27% to 0.18%, and the standard deviation of the mass flow rate of the outlets was reduced from 0.088 95 to 0.038 7. The improved rectangular distributor has achieved a great improvement of the homogeneity of the distribution of fluids.

Key words:  liquid fertilizer, computational fluid dynamics, rectangular distributor, uniform distribution, numerical simulation