旋动射流混药器螺旋弯曲收缩管螺距和分流器位置的模拟优化分析

螺旋弯曲收缩管、混合管和分流器是脂溶性农药旋动射流混药器的主要组成部分。而螺旋弯曲收缩管的螺距、分流器在混合管中的位置直接影响旋动射流混药器的结构。为了分析收缩管螺距和分流器在混合管中的位置对旋动射流混药器混合均匀性的影响程度,采用两因素三水平对比试验,通过有限元软件FLUENT模拟仿真,引入面积加权平均均匀性指数(γa)判断药水混合均匀性,其越接近1,混药器内药水混合越均匀。试验结果表明:螺旋弯曲收缩管能够提高旋动射流混药器的混合均匀性,但不显著;分流器分别位于混合管入口、中间和出口三处位置时,对脂溶性农药的混合影响不大,混合均匀性基本一致;螺距为3倍的螺旋弯曲收缩管长度、分流器在混合管中间位置的旋动射流混药器对脂溶性农药的混合均匀性较好。

Simulation Optimization Analysis of Shrinking Tube pitch and Splitter Position of Rotating Jet Mixer

The main components of swirling jet mixer are spiral curved shrinkage tube, mixing tube and shunt. The pitch of spirally curved shrinkage tube and the position of shunt in mixing tube directly affect the structure of swirling jet mixer. In order to analyze the influence of swirling jet mixer among the pitch of shrinkage tube and the position of shunt on mixing uniformity, the structure of the mixer were optimized by orthogonal experiments with two factors and three levels. A computational fluid dynamics program (FLUENT) was used to simulate the flow field inside the swirling jet mixer to optimize its design. The mixture uniformity was evaluated by the uniformity index (γa), for which, the two liquids were blended homogenously when γa was near to 1. Simulated results briefly showed as follows: Spiral curved shrinkage tube improved mixing uniformity of swirling jet mixer, but it was not significant. When the shunt was located at the inlet, middle and outlet of the mixing pipe respectively, it had little effect on the mixing uniformity of fat-soluble pesticides, and the mixing uniformity of the mixer was basically the same. The mixing uniformity of the swirling jet mixer was the best with three times the pitch of the helical bending shrinkage tube and the shunt in the middle of the mixing tube.