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基于彈道理論有風條件下折射式噴頭噴灌均勻度研究
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“十二五”國家科技支撐計劃項目(2015BAD22B01-02)


Uniformity of Fixed Sprayplate Sprinkler under Windy Condition Based on Ballistic Simulation
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    摘要:

    為計算有風條件下折射式噴頭水量分布及噴灌均勻度,以彈道軌跡理論為基礎(chǔ),依據(jù)風速分布模型,建立有風條件下折射式單噴頭水量分布計算方法,采用該方法模擬出有風條件下Nelson D3000型噴頭倒掛安裝方式下水量分布特性,通過與實測資料進行對比,驗證了模擬具有較高的準確度,可應用于有風條件下折射式噴頭水量分布計算。在此基礎(chǔ)上,選用476mm(24號)噴嘴直徑,模擬出不工況下單噴頭水量分布,計算出組合情況下噴灌均勻度,分析了風速、風向、噴頭間距、工作壓力和安裝高度5種因素對噴灌均勻度的影響,并對蒸發(fā)漂移損失進行了分析。結(jié)果表明:95%的置信區(qū)間下,噴頭布置間距對噴灌均勻度的影響最顯著,其次是安裝高度和噴頭工作壓力,風速和風向?qū)姽嗑鶆蚨扔绊懖伙@著。風速、噴頭工作壓力和安裝高度都會對蒸發(fā)漂移損失產(chǎn)生影響,其中工作壓力影響最大。當選用Nelson D3000型噴頭在風速小于6m/s的環(huán)境下噴灌時,應將噴頭安裝間距固定在2.13~3.04m范圍內(nèi)。另外,該安裝間距范圍內(nèi),噴頭安裝高度和噴灌壓力增大后,噴灌均勻度增大的效果不明顯,因此應采用低壓噴灌以降低噴灌系統(tǒng)運行成本;考慮到較高的噴頭安裝高度會產(chǎn)生較大的蒸發(fā)漂移損失,噴灌時還應適當降低噴頭安裝高度,以提高噴灌水分利用率。

    Abstract:

    In order to simulate fixed spray-plate sprinkler water distribution and Christiansen uniformity (CU) under open field conditions, the method for calculating water distribution was proposed by applying droplet size distribution, simulation of droplet distribution utilize droplet trajectory computations and wind-distored model. The accuracy of water distributions of Nelson D3000 spray sprinkler was validated by comparing simulated with observed patterns, it was found that the software appeared to be an effective predictor of sprinkler performance in wind. Under this premise, the water distribution was simulated at different wind speeds with 4.76mm nozzle diameters (24#), the factors, including wind speed, wind direction, sprinkler spacing, working pressure and riser height, which may affect CU, the wind drift and evaporation losses (WDEL) under different working conditions were analyzed. The results showed that sprinkler spacing had the most important influence on CU at 95% confidence interval, and it was followed by riser height and working pressure, wind speed and wind direction did not significantly affect CU. Increasing wind speed, working pressure or riser height indicated an increase in the OWDEL, and working pressure can dramatically affect the OWDEL on account of smashing large water droplet to pieces. Using this sprinkler, the lateral moving irrigation system can attain a high uniformity coefficient at 2.13~3.14m sprinkler spacing along the lateral when the wind speed was lower than 6m/s, and with this range of mounting spacing, increasing sprinkler riser height or working pressure cannot promote a higher CU distinctly, low working pressure was recommended considering little cost in the design of the sprinkler irrigation system. In addition, decreasing the riser height can reduce WDEL effectively, in order to increase water use efficiency, low height cooperated with plant height was reasonable.

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張以升,朱德蘭,宋博,張林.基于彈道理論有風條件下折射式噴頭噴灌均勻度研究[J].農(nóng)業(yè)機械學報,2017,48(2):91-97,81. ZHANG Yisheng, ZHU Delan, SONG Bo, ZHANG Lin. Uniformity of Fixed Sprayplate Sprinkler under Windy Condition Based on Ballistic Simulation[J]. Transactions of the Chinese Society for Agricultural Machinery,2017,48(2):91-97,81.

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  • 收稿日期:2016-06-13
  • 最后修改日期:2017-02-10
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  • 在線發(fā)布日期: 2017-02-10
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