风幕式喷杆喷雾气液两相流动形态与流动特性研究

Because of the serious pesticide spray droplet drift at present, the gas-liquid two phase flow patterns and features for air assisted sleeve boom spray are studied in this project by theoretical analysis, numerical simulation and experimental tests. Phase Doppler Particle Analyzer (PDPA) and Rheometer system are applied to measure the physical parameters of the spay droplets, in order to build the stress-strain constitutive equation of gas-liquid two phase flow. The two phase flow field is also been recorded and analyzed to detect the physical forms and structural features by means of numerical simulation and high speed digital photography technology. Mass and momentum transfers between two phases will be established. Gas-liquid two phase flow patterns and modes will be investigated under no crosswind condition. The two phase flow field characteristics are about to be analyzed, including spray droplet group spatial movement and settlement process, to determine mathematic description for the two phase flow. Spray droplets drift, settlement, and target penetrate rule will be studied under outside crosswind and air flow conditions, to find out the physical and mathematic models for spray droplet group drift. Finally, mathematic models for gas-liquid two phase flow patterns and features will be established with and without crosswind conditions. Suitable calculation and parameter optimization methods will be proposed as well. It is of theoretical help to improve the air assisted sleeve boom sprayer performance, structure and operating parameter optimization, environmental protection and high efficiency pesticide machines.

针对药液雾滴飘移严重的现状，项目采用理论分析、数值计算和实验测试相结合的方法研究风幕式喷杆喷雾气液两相流动形态与特性。运用相位多普勒粒子分析仪、流变测试系统等测试工具，对药液雾滴的物性参数进行测定，从而建立气液两相流动的应力应变本构方程；采用数值计算方法和运用高速数码拍摄技术对气液两相流场进行记录和分析，探明其物理形态和结构特性，建立气液两相间传质、传动耦合模型；研究无侧风条件下气液两相流动形态和模式，分析包括雾滴群空间运动结构和沉降过程在内的气液两相喷雾流场的特性，确定两相流动的数学描述；研究在外界侧风和相应的气流场条件下雾滴的飘移、沉降及对靶穿透规律，建立雾滴群飘移的物理数学模型；在上述基础之上，建立有无侧风两种条件下反映气液两相流动形态和特性的数学模型，并提出相应的计算方法和喷雾参数优化方法。从而为提高风幕式喷杆喷雾机性能，优化其结构及运行参数，设计环保、高效的施药机具提供理论依据。

针对药液雾滴飘移严重的现状，为提高农药有效利用率，开展了风幕式喷杆喷雾场中雾滴群运动形态与结构特性的研究。本项目创新性地将两相流动理论、雾化理论及雾滴飘移沉积理论相结合，进行学科交叉研究，以探明风幕式气液两相流动的物理本质，深化对雾滴飘移机理的认识。采用理论分析、数值计算和实验测试相结合的方法，运用相位多普勒粒子分析仪、流变测试系统等测试工具，在对雾滴的物性参数进行测定的基础上建立气液两相流动的应力应变本构方程；采用数值计算方法和运用高速数码拍摄技术对气液两相流场进行记录和分析，探明其物理形态和结构特性，建立气液两相间传质、传动耦合模型；研究无侧风条件下气液两相流动形态和模式，分析包括雾滴群空间运动结构和沉降过程在内的气液两相喷雾流场的特性，确定两相流动的数学描述；研究在外界侧风和相应的气流场条件下雾滴的飘移、沉降及对靶穿透规律，建立雾滴群飘移的物理数学模型；在上述基础之上，建立有无侧风两种条件下反映气液两相流动形态和特性的数学模型，并提出了相应的计算方法和喷雾参数优化方法。通过这些研究，掌握了雾滴飘移机理，为进一步提高农药有效利用率奠定理论基础，同时提出的喷雾参数优化方法，为设计环保、高效的施药机具提供了理论依据。