泵吸式施肥系统水力性能数值模拟与分析

Numerical Simulation and Analysis on Hydraulic Performance of Pump Suction Fertilization System

泵吸式施肥是一种直接借助泵前真空吸肥的简易施肥模式,已被广泛应用于小规模微喷田间施肥作业中。由于整个吸肥过程及其影响因素尚未被研究,致使泵吸式施肥系统的科学应用受到限制。建立了泵吸式施肥系统的管路数学模型,分别选取3种规格管径的肥水管和井水管,设定多种组合,模拟液位、管径、水泵动态扬程等因素对施肥系统水力性能的影响,可得出以下结论:肥水管流量受液位影响较大,井水管次之,干管流量基本保持恒定;肥水管管径与井水管管径相差越大,系统的抗干扰能力越强;泵吸施肥管路的水力计算必须要考虑离心泵的水力特性曲线;肥水管管径变化将导致肥水管流量的大幅度变化。

As a simple fertilization injector relying on the vacuum effect at centrifugal pump inlet,pump suction fertilization system has been widely applied in small-scale micro jet field fertilization.Because the whole process of fertilizer absorption and its influencing factors have not been studied,the scientific application of pump fertilization system is limited.In this paper,a mathematical model for pipes of pump suction fertilization system was set up,and three types of fertilization pipes and well water pipes varying in diameter were selected separately.A variety of combinations were set to simulate the effects of liquid level,pipe diameter and dynamic head of water pump on hydraulic performance of fertilization system.The results showed that:the flow rate of fertilization pipe was greatly influenced by liquid level,followed by that of well water pipe,and the flow rate of main pipe was basically kept constant;the larger the difference between the diameter of fertilization pipe and that of well water pipe,the stronger the anti-interference ability of the system;the hydraulic characteristic curve of centrifugal pump must be considered in the hydraulic calculation of pump suction fertilization pipeline;the change of diameter of fertilization pipe would lead to the great change of its flow rate.