背负式喷雾器雾滴分布特性的CFD模拟与试验

    CFD simulation and experiment of distribution characteristics for droplet of knapsack sprayer

    • 摘要: 为了解决不同喷雾条件对背负式喷雾器雾滴分布的影响问题,采用CFD离散相粒子跟踪模拟方法,研究了距喷嘴垂直高度分别为0.4、0.55和0.7 m,喷雾压力分别为0.15、0.2、0.3和0.35 MPa,风速分别为0、1、2、3 m/s情况下,雾滴沉积分布和粒径分布特性,并进行试验验证。结果表明:沉积率受风速影响显著,随风速增大而降低,但沉积率受喷雾压力影响不显著。模拟与试验结果回归决定系数R2和标准误差SE分别为0.9424、0.039,表明CFD离散相粒子跟踪模拟法可用于评估雾滴沉积分布。雾滴粒径分布模拟结果与试验结果相关性差,CFD模拟法不宜用于评估雾滴粒径分布情况。该研究为后续各类喷雾器数据测量提供参考。

       

      Abstract: In order to study the droplet distribution characteristics for the knapsack sprayer under different spray conditions, CFD technique (discrete phase particle tracking) was adopted to investigate the droplet distribution of deposition and particle size. In CFD simulations, vertical height from the spray nozzle were 0.4, 0.55 and 0.7 m, spray pressure were 0.15, 0.2, 0.3 and 0.35 MPa and wind speed were 0, 1, 2 and 3 m/s, and the same conditions had been set for knapsack sprayer. The results indicated that wind speed had significant effect on the deposition rate, and it decreased with the increasing of wind speed. The results also showed that wind speed had no significant effect on the pressure. The coefficients of determination and standard error for regression relationship between simulation and experimental results were 0.9424 and 0.039 respectively, which showed that the CFD technique (discrete phase particle tracking) can be used to evaluate deposition distribution, and it should not be used to evaluate particle size distribution because CFD simulation result had a bad correlation with experimental result. This research provides a theory reference for measuring data of sprayers.

       

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