农业工程学报2019，Vol.35Issue(17)：28-34,7.DOI:10.11975/ j.issn.1002-6819.2019.17.004
薄壁微喷带喷洒宽度模型构建
Model establishment of spraying width of thin-walled micro-sprinkling hose
摘要
Abstract
China is the biggest agricultural production country in the world and the agriculture is related to its stability and development. With the development in water-saving irrigation technology, micro-sprinkling hose has been widely promoted and applied in China in recent years as an improved equipment duo to its efficiency in water-saving. To facilitate production and upgrading, as well as guide planning and design of the micro-sprinkling hose in irrigation, we experimentally studied the spray width in the hose at Tianjin Agricultural Water Saving Technology Engineering Center (39°N, 116°E). After literature review and market research, we selected six common micro-sprinkling hoses available in the market, and measured and calculated their folding width, nozzle diameter and nozzle elevation angle in the spray width test. The length of the sample in the test was 5 m and the working pressure varied from 0.03 to 0.06 MPa. The micro-sprinkling hose was laid at the upfront to ensure uniform spraying on both sides of the hose. The water collecting bucket was on one side of the hose and five rays spaced 50 cm were arranged in the vertical direction of the hose, with the collecting bucket on the ray spaced 50 cm. At the end of the experiment, the amount of water in the bucket was measured and the spraying width was determined. In the meantime, we also measured the diameter of the spraying droplets using filter paper method. The quality of the paper was measured by a precision balance, and the water droplets were connected to the paper at the head, middle and end of the spray stream along the hose. The quality of the paper was measured again quickly by the precision balance prior to counting the number of water marks on it, which, along with mass balance, was used to calculate the diameter of the water droplets. The average diameter of the water droplets at different locations was taken as the diameter of the water droplets in the hose. Considering the factors such as air resistance, gravity and buoyancy that act on the water droplets, a model for water droplet moving in the hose was proposed based on the Newtonian fluid mechanics. We also derived a formula for the spray width, determined the parameters in the formula, validated them against experimental data, and analyzed the factors that affect the accuracy of the formula. The results show that the derived formula for spray width in the hose agreed well with both analytical values and experiment data, and, compared with the experimental data, its relative error for the six selected hoses was less than 10%. Both the experimental data and theoretical analysis of the formula reveal that the spray width in the hose increases with the elevation angle of the nozzle before declining after it peaked when the nozzle elevation angle was approximately 40°. The spray width increases with both working pressure and nozzle diameter within certain ranges. It was also found that the derived formula was accurate and can be used to calculate the spray width, offering a theoretical tool for planning and designing micro-sprinkling hose irrigation system.关键词
灌溉/流量/模型/微喷带/喷洒宽度/工作压力/喷孔直径/喷孔仰角Key words
irrigation/flow/model/micro-sprinkling hose/spray width/working pressure/nozzle diameter/nozzle elevation angle分类
农业科技引用本文复制引用
邸志刚,杨路华,苟万里,王金毅..薄壁微喷带喷洒宽度模型构建[J].农业工程学报,2019,35(17):28-34,7.基金项目
水利部海河水利委员会资助项目(TNHP2018001) （TNHP2018001）
