气送式水稻施肥机输肥装置气固两相流仿真分析

通过计算流体动力学和离散元法耦合的方法对气送式水稻施肥机的气体肥料混合腔进行气固耦合数值研究。在数值模型中,使用EDEM软件模拟肥料颗粒,ANSYS Fluent软件描述气体相。通过研究混合腔喉部面积、喉部长度、气体入口压力和肥料排出速率的影响,分析气体和肥料的运动规律。模拟结果表明,2型喉管的气体肥料混合腔断面性能良好,喉部压力损失较小,气流速度最快。喉部面积和气流入口压力主要影响气流出口速度和混合腔轴向方向的肥料颗粒速度,肥料颗粒的移动受混合腔喉部长度和肥料进料速率的影响较小。喉部截面积的增加导致气流速度和压力损失在一定范围内下降。随着气流入口压力的增加,肥料所受合力和肥料颗粒速度均增加,适宜的气流入口压力为450~550Pa。结果表明,CFD-EDM耦合方法作为理解气流场中肥料颗粒运动规律的分析工具是可靠的,基于CFD-EDM耦合方法的肥料颗粒运动的数值模拟可为水稻侧深施肥装置的开发提供理论依据。该研究得到的优化后气体肥料混合腔结构参数及气动参数,对现有气送式水稻施肥机输肥装置的优化改进具有指导意义。

Simulation Analysis of Gas-Solid Two Phase Flow in Pneumatic Conveying Fertilizer Feeder of Rice Fertilizer Applicator

The computational method of fluid dynamics and discrete element method were used to study the air-solid flow of a fertilizer air mixing chamber in a synchronous deep fertilization unit. In this model, the fertilizer particles were simulated by EDEM software, and the gas phase was demonstrated by ANSYS Fluent software. The movement rule of gas and fertilizer was analyzed by studying the influence of throat area, throat length, gas inlet pressure and fertilizer removal rate. The simulation results showed that the cross-section performance of the gas-fertilizer mixing chamber with type 2 throat was good, the pressure loss in the throat was small, and the air velocity was the fastest. The throat area and the fertilizer particle flow entrance pressure mainly affected the airflow velocity and the axial speed of the mixing chamber. The movement of fertilizer particles was less affected by mixing throat length and feed rate of fertilizer. The increase of throat cross-sectional area led to the decrease of airflow velocity and pressure loss in a certain range. With the increase of air inlet pressure, the resultant force and velocity of fertilizer particles were increased, and the suitable inlet air pressure was from 450Pa to 550Pa. The results showed that the CFD-EDM coupling method was reliable as an analytical tool for understanding the movement of fertilizer particles in airflow field, and the numerical simulation of fertilizer particle movement based on CFD-EDM coupling method can provide a theoretical basis for the development of rice lateral deep fertilization device. It had guiding significance for the optimization and improvement of the existing pneumatic rice fertilizer applicator.