基于CFD的罩盖防飘移机理模拟及防飘移效果量化研究

探讨双圆弧罩盖的防飘移机理,对其防飘移效果进行量化研究。利用CFD技术对不同条件下双圆弧罩盖内部及周围的喷雾速度流场、雾滴运动轨迹进行模拟,研究喷嘴安装参数、喷嘴类型和型号,及风速对飘移率的影响。结果表明,双圆弧罩盖的防飘移机理是:内外圆弧形成的导风道使其下方产生了高速向下的气流(最大达7.42 m/s)和低速水平气流;双圆弧罩盖能有效减弱其后方的涡流强度,使其内外较大区域形成水平负向和垂直向下的速度流场。喷嘴的安装位置和安装角度与雾滴飘移率高度相关,相关系数为0.974;喷嘴类型、型号、风速、喷嘴类型和风速的交互作用,以及喷嘴型号和风速的交互作用与飘移率也高度相关,相关系数0.981。双圆弧罩盖能有效防止雾滴飘移,提高雾滴沉积率。

Simulation and quantification on drift-reduction of double-foil shield

The anti-drift principle and drift-reduction rate of double-foil shield spraying technology was studied in this paper.In order to analyze the effect of nozzle setting position(horizontal distance,vertical distance) and spray angle,the effect on drift rate of nozzle type,nozzle size and air velocity on drift rate,the velocity field and droplet trajectory in and around double-foil shield were simulated under different conditions by using the CFD software.The simulated result showed that the anti-drift principles of the shield are: 1) high-speed downward airflow and low-speed horizontal airflow was formed under double oil shield(the maximal speed is 7.42 m/s);and 2) air turbulence intensity behind the shield was obviously weakened and a big area of negative horizontal and negative vertical velocity fields was formed.Moreover,the regression result suggested that there was a high correlation relation among nozzle setting position, spray angle and drift rate and the correlation numbers were 0.974 and 0.981 among air velocity,nozzle size,nozzle type and drift rate.In a word,double-foil shield spraying technology could effectively reduce drift rate and increase deposition rate.