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冬小麦田植保无人飞机喷施除草剂雾滴粒径及沉积飘移分布特性评估 被引量:5
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作者 王国宾 韩鑫 +3 位作者 宋灿灿 伊丽丽 鲁文霞 兰玉彬 《智慧农业(中英文)》 2021年第3期38-51,共14页
随着植保无人飞机作业面积的增加,雾滴飘移风险也日益凸显,尤其以除草剂飘移风险危害最高。为明确除草剂溶液对雾滴粒径的影响及植保无人飞机喷施除草剂雾滴沉积飘移分布特性,本研究通过室内雾化室测定了植保无人飞机安装的离心转盘雾... 随着植保无人飞机作业面积的增加,雾滴飘移风险也日益凸显,尤其以除草剂飘移风险危害最高。为明确除草剂溶液对雾滴粒径的影响及植保无人飞机喷施除草剂雾滴沉积飘移分布特性,本研究通过室内雾化室测定了植保无人飞机安装的离心转盘雾化喷头喷洒清水及常用的15种麦田除草剂溶液的雾滴粒径分布,并通过田间试验在药箱中添加荧光示踪剂(60 g/hm^(2))测定喷施作业区和飘移区的雾滴沉积量分布。室内测定结果表明,与清水相比,除草剂溶液对雾滴粒径影响显著。除唑草酮水分散粒剂外,其余溶液经离心转盘雾化喷头喷洒后,雾滴体积中径较清水均有所降低,且最大降低22.0%;小雾滴(V<150μm)比例均有所增加,最大增加50.8%。田间飘移试验表明,植保无人飞机喷洒150μm雾滴,在环境侧风风速为3.76 m/s时,作业区的雾滴沉积覆盖度和雾滴沉积密度仅为风速0.74 m/s时的41.3%和42.2%,且均匀性显著降低。在飘移区下风向12 m位置,雾滴沉积量为作业区的10%以下;下风向50 m处,雾滴沉积量低于检测限(0.0002μL/cm^(2))。飘移比率随风速的增加而增加,当风速达到3.76 m/s时,雾滴飘移比率达到46.4%。不同侧风风速下,90%的累积飘移位置在4.8~22.4 m。对飘移区沉积量与飘移距离、侧风风速拟合,结果表明下风向沉积量与风速呈正比。本研究为植保无人飞机冬麦田不同风速作业下的雾滴飘移距离提供数据支持,为喷雾飘移缓冲带、飘移风险评估提供依据。 展开更多
关键词 植保无人飞机 小麦 除草剂剂型 雾滴粒径 侧风风速 雾滴沉积飘移量
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Dynamic behaviors and mitigation measures of a train passing through windbreak transitions from ground to cutting 被引量:2
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作者 CHEN Zheng-wei LIU Tang-hong +3 位作者 GUO Zi-jian HUO Xiao-shuai LIWen-hui XIAYu-tao 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第8期2675-2689,共15页
In this paper,the effects of a right-angle windbreak transition(RWT)from the flat ground to cutting on train aerodynamic and dynamic responses were investigated,then a mitigation measure,an oblique structure transitio... In this paper,the effects of a right-angle windbreak transition(RWT)from the flat ground to cutting on train aerodynamic and dynamic responses were investigated,then a mitigation measure,an oblique structure transition(OST)was proposed to reduce the impact of RWT on the train aerodynamic and dynamic performance.The results showed that in the RWT region,the airflow was divided into two parts.One part of the airflow induced a strong backflow in the flat ground position,and the other part of the airflow induced a strong backflow in the cutting position.Therefore,there were two lateral impacts on the train.For the head car with the OST,the drop ratios of the peak-to-peak values compared with RWT were 47%,40%,and 52%for the side force coefficient C_(Fy),lift force coefficient C_(Fz) and overturning moment coefficient C_(Mx),respectively.For the peak-to-peak value of the dynamic parameters,the drop ratios of OST compared with RWT were all larger than 50%.The maximum dynamic overturning coefficients for RWT and OST were 0.75 and 0.3,respectively. 展开更多
关键词 high-speed train windbreak wall CROSSWIND CFD train aerodynamics vehicle system dynamics
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