In agricultural spray application of pesticides, the volumetric droplet size distribution (VDSD) critically influences the efficacy of the application as well as the risk of off-target spray deposition. It is critical to have accurate predictions of the VDSD for development of new agrochemicals and spray nozzles. VDSD parameterization and subsequent prediction is complicated in agrochemical sprays by the unique geometries of the nozzles employed, which typically do not have clearly evident hydraulic diameters and vary in size, as well as by the effects of active herbicides and adjuvants on the spray. Herein, scaling based on conservation of energy is utilized to develop a relationship predicting the VDSD for flat fan sprays used in agrochemical application with agrochemical products. To examine the proposed scaling relationship, we made measurements of VDSDs using laser diffraction interferometry for agriculturally relevant tank mixtures, including active pesticides and both emulsion-forming and rheology-modifying drift control adjuvants, sprayed with complex geometry, flat fan nozzles typical of field application. We show that for three distinct nozzle types and three tank mixtures (nine combinations), VDSDs can be normalized by the Sauter mean diameter (D₃₂), and normalized distributions collapse for given nozzle type-spray tank mix combination. Subsequently, we show for all test combinations that the Sauter mean diameter normalized by the nozzle hydraulic diameter (D_H) scales with the ratio of product of tank mix surface tension and hydraulic diameter divided by the nozzle pressure drop, with a scaling exponent of 1/3.

中文翻译：

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农用水箱混合物的扁平扇形喷雾的液滴尺寸分布参数化

在农药的农用喷雾应用中，体积液滴尺寸分布 (VDSD) 对应用的功效以及脱靶喷雾沉积的风险具有关键影响。准确预测 VDSD 对于开发新型农用化学品和喷嘴至关重要。由于所用喷嘴的独特几何形状（通常没有明显的水力直径和尺寸变化）以及活性除草剂和助剂对喷雾的影响，VDSD 参数化和随后的预测在农化喷雾中变得复杂。在此，利用基于能量守恒的缩放比例来建立预测用于农化产品的扇形喷雾的 VDSD 的关系。要检查建议的比例关系，我们使用激光衍射干涉仪对农业相关的罐混合物进行了 VDSD 测量，包括活性杀虫剂以及乳液形成和流变改性漂移控制助剂，喷洒了复杂的几何形状，典型的现场应用扁平扇形喷嘴。我们表明，对于三种不同的喷嘴类型和三种罐混合物（九种组合），VDSD 可以通过 Sauter 平均直径（D ₃₂ )，并且对于给定的喷嘴类型-喷雾罐混合组合，归一化分布崩溃。随后，我们表明，对于所有测试组合，由喷嘴水力直径 ( D _H ) 归一化的 Sauter 平均直径与罐混合表面张力和水力直径的乘积除以喷嘴压降之比成比例，比例指数为 1 /3。