用于农药喷施的液力式喷头雾化与沉积分布特性分析

Analysis of hydraulic nozzles for pesticide applications on atomization and droplets distribution characteristics

在众多类型的喷头中,液力式雾化喷头因其雾化量大、能耗低、设备简单、经济性好而得到更广泛应用。研究液力式喷头的雾化与沉积特性对改善农药喷施效果具有重要的指导意义。为明确液力式喷头的类型和喷雾参数对其雾化和沉积特性的影响,本文对6种类型的液力式喷头(标准扇形雾XR 110-015、防飘扇形雾DG 110-015、射流扇形雾AIXR 110-015、射流扇形雾AI 110-015、空心圆锥雾TXA 80-015和射流空心圆锥雾AITXA 80-015)的雾滴粒径、雾滴沉降速度以及沉积分布进行了测试。结果表明:6种供试喷头的雾滴粒径均随喷雾压力的增大而减小,不同喷雾压力下细雾滴(XR 110-015)和中等雾滴喷头(DG 110-015)的体积中值直径(D_(v0.5))差异较小,而粗雾滴(AIXR 110-015)和超粗雾滴喷头(AI 110-015和AITXA 80-015)对喷雾压力的敏感性更强,其雾滴的D_(v0.5)值随着喷雾压力的增加而急剧下降。雾滴沉降速度与分布特征主要由喷头类型决定,喷雾压力对雾滴沉降速度的影响较小,同一喷头在不同喷雾压力下的雾滴沉降速度分布趋势相似。相同喷雾压力下,细雾滴喷头的平均沉降速度(Vavg)高于其体积中值沉降速度(V_(v0.5)),但随着喷头雾滴的增大,中雾滴喷头和粗雾滴喷头的V_(v0.5)超过其Vavg,且雾滴的粒径越大两者差值越明显。雾滴的沉积结果显示,不同喷雾压力下各喷头的喷雾液流失率均在7.82%~9.75%范围内,各喷头在不同喷雾压力下的流量相似,且略低于其名义流量。喷雾压力对DG 110-015、XR 110-015和AIXR 110-015喷头的雾滴沉积分布均匀性无显著影响,但较高的喷雾压力可提高AITXA 80-015和TXA 80-015喷头的雾滴沉积分布均匀性。本研究可为田间施药时液力式喷头的选择和作业参数的优化提供理论指导和技术参考。

Hydraulic nozzles are widely used among many kinds of spray nozzles due to their large atomization volume,energy saving,simple structure,economical practicality.It’s important to study the atomization and deposition characteristics of hydraulic nozzles for optimizing pesticide application performance.In order to determine the influence of hydraulic nozzles on its atomization and deposition characteristics,droplet size,velocity and deposition distribution of 6 kinds of hydraulic nozzles(standard flat fan XR 110-015,anti-drift flat fan DG 110-015,air-induction flat fan AIXR 110-015,airinduction flat fan AI 110-015,hollow cone TXA 80-015 and air-induction hollow cone AITXA 80-015)were tested.The results showed that droplet sizes of all nozzles decreased with increasing spray pressure with little difference in volume median diameter(D_(v0.5))between fine(XR 110-015)and medium droplet nozzles(DG 110-015)under different spray pressures.In contrast,coarse(AIXR 110-015)and extremely coarse droplet nozzles(AI 110-015 and AITXA 80-015)were more sensitive to spray pressure,and the D_(v0.5) of droplet decreased dramatically with increasing spray pressure.Droplets velocity was mainly determined by nozzles type and spray pressure has little effect on droplet velocity,in which case the same nozzle at different spray pressures has similar droplet velocity trends.Under the same spray pressure,the average velocity(Vavg)of fine droplet nozzle was greater than its volume median droplet velocity(V_(v0.5)),while with the increase of the droplet diameter,the V_(v0.5) of nozzles exceeded its Vavg.The flow rates of all nozzles were quite close but lower than its nominal flow rates,and the loss rates of nozzles ranged from 7.82%to 9.75%.Spray pressure has little effect on droplet distribution uniformity of DG 110-015,XR 110-015 and AIXR 110-015,but a higher pressure was beneficial for the uniformity distribution of AITXA 80-015 and TXA 80-015.This study can provide theoretical guidance and technical reference for the selection of hydraulic nozzles and the optimization of pesticide application parameters.