Demonstration of Center Pivot Uniformity Evaluation and Retrofit to Improve Water Use Efficiency

Agricultural irrigation is a primary user for freshwater withdrawal. Irrigation plays an important role in crop production, as it provides the benefit of reducing the effects of prolonged dryness and erratic precipitation. Center pivot irrigation system is the most common irrigation system in agriculture. As the center pivot irrigation system ages, the system could develop a leaking joint, clogged sprinklers, and physical damage. This can cause areas of non-uniformity that can lead to under- or over-irrigated in some areas of the land, resulting in excess energy use and cost, wasting resources, and environmental impacts. Thus, it is important to evaluate the performance of a center pivot irrigation system regularly to maximize return on investments and minimize wasting resources. This study focuses on evaluating the impacts and benefits of improved center pivot irrigation distribution uniformity by performing distribution uniformity evaluations pre- and post-retrofit. This study also focused on demonstrating an unmanned aerial vehicle (UAV) to assess the performance of the center pivot irrigation system in two irrigated farmlands. The Coefficient of Uniformity (CU), Distribution Uniformity (DU), and Scheduling Coefficient (SC) were calculated based on the catch can test data. The values were utilized to evaluate water and energy savings from the improved coefficients. The team has found that replacing sprinkler packages increased the CU from 78 to 89 and the DU from 77 to 82, and reduced the SC from 1.3 to 1.2 in Field A. In Field B, replacing sprinkler packages increased the CU from 73 to 91 and the DU from 62 to 84 and reduced the SC from 1.6 to 1.2. The estimated water savings in Field A due to the reduced scheduling coefficient was approximately 151,000 liters/hectare/year, with consideration of the corn and soybean rotation field in Michigan. The estimated water savings in Field B was 608,000 liters/hectare/year. The data from this demonstration study showed the value of distribution uniformity evaluation and retrofit of irrigation systems. This information will encourage farmers and agricultural industries to consider performing more distribution uniformity evaluations, ultimately improving irrigation water use efficiency and supporting sustainable water management in agriculture.

养殖肥水喷灌条件下摇臂式喷头水力性能研究

【目的】研究不同喷灌介质对喷头水力性能的影响。【方法】以20PY2H摇臂式喷头为研究对象,在不同工作压力下测定了清水和养殖肥水2种喷灌介质对喷头压力-流量、喷头水量分布的影响。通过模拟计算和田间喷灌试验分析相结合的方法,探查喷灌介质、工作压力、组合间距、田间气象条件与喷灌均匀性之间的关系。【结果】(1)与清水灌溉相比,养殖肥水运行下喷头流量降低了2.06%~5.38%,射程前中段径向水量分布差异较大;(2)工作压力为200~300k Pa、组合间距为1.0R~1.4R条件下,MATLAB拟合出的CU模拟值为0.74~0.88,CU试验值为0.66~0.79。复杂的大田气象条件导致喷灌均匀系数下降了6.28%~12.78%。工作压力、喷头组合间距对清水运行喷灌均匀性的影响大于养殖肥水运行。【结论】养殖肥水喷灌更利于喷灌系统降低工作压力和增加喷头布置间距以降低设计成本。

农田灌溉节水技术滴灌、喷灌与微喷灌的效果对比分析

农田灌溉节水技术是提高水资源利用效率、保障全球粮食安全的有效手段。该文对滴灌、喷灌和微喷灌技术进行综合分析,评价其节水效果、生产效益、经济效益和环境效益。研究结果表明,滴灌技术在节水方面具有显著优势,喷灌技术在生产效益方面表现突出,而微喷灌技术则具有一定的经济效益和环境效益。因此,在实际应用中,需要根据当地水资源状况、作物类型及生产需求等因素,合理选择和搭配灌溉技术,以实现可持续发展。

茶树喷灌防霜中植株储水/冰量动态变化与影响因素研究

喷灌是园艺作物有效的防霜技术之一。为确定茶树喷灌防霜需水量和节约水资源,需研究喷灌过程中植株的储水/冰量动态变化及影响因素。本文设计了一种防滴落、茎杆水收集及称量组合装置,可直接精确获取整株茶树的储水/冰量;试验分析非冻结和冻结、微量和摇臂2类喷头条件下储水/冰量变化的异同;最后探究了冻结下微量喷头喷灌时长对储冰量和茎杆水量的影响。研究结果表明,非冻结条件下,茶树储水量变化经历积累、动平衡和干燥3个阶段;冻结条件下的储冰量随喷灌进行持续增加,并在停喷后较长时间内保持不变,即积累和保持阶段,随后依次经历融化流失和干燥阶段;相同喷灌压力和时长下,微量喷头的储水量和储冰量分别是摇臂喷头的1.2倍和2.0倍;微量喷头喷灌时长对最大储水量无明显影响,约为0.22 kg,最大储冰量则随喷灌时长的增加而显著增加,1.5 h的储冰量是0.5 h的2.9倍。微量喷头作用的茎杆水量,在非冻结和冻结条件下也较高,分别是摇臂喷头的3.0倍和2.7倍。本文研究了茶树植株表面储水/冰量变化及影响因素,改进了灌木类植物冠层截留量的测量方法,为提升防霜效果和实现精准喷灌奠定了基础。

某援外大剧院消防给水系统设计研究

某大剧院定性为乙等中型剧院,根据驻场固定剧目的表演内容,合理设置消防给水系统,简化系统形式和管网布置,在满足规范要求的前提下,以达到经济有效的设计目的。

某医药工业甲类厂房消防给排水设计及若干问题讨论

介绍了某医药工业甲类厂房的生产污废水系统、室内外消火栓系统、闭式泡沫-水喷淋系统及建筑灭火器的配置,对甲类车间生产污废水的收集、预作用闭式泡沫-水喷淋系统在甲类厂房设计中的使用问题进行分析探讨。

不同修复措施对温性草原植被特征的影响

试验以温性草原为研究对象,通过实施免耕补播、喷灌补水+免耕补播、保水剂+免耕补播和飞播等4种修复措施,比较天然草原植被特征和土壤理化特性的改良效果,为退化草原保护修复提供参考。结果显示:与项目区外相比,免耕补播、喷灌补水+免耕补播、保水剂+免耕补播和飞播区的植物种数增加,植被平均高度提高2~5 cm,喷灌补水+免耕补播显著提升了植被盖度、地上生物量和土壤含水量(P<0.05)。研究表明,喷灌补水+免耕补播对地上植被特征和土壤涵水能力的修复效果最佳,保水剂+免耕补播次之,水分仍是限制退化草原生态修复效果的主要因素。

地铁地下车站水消防系统设计的优化研究

在消防安全、节能减排、节约工程投资的基础上,对地铁地下车站常规室内外消火栓系统设置方案及自动喷水灭火系统的设置范围提出优化建议。分析并探讨利用市政管网进行稳压、地铁地下车站设置区域消防系统,以及区间采用常高压系统的可行性。同时,对地下车站室外水消防方案争议点进行归纳,提出地下车站室外水消防设置建议;对地铁地下车站设置自动喷水灭火系统优缺点进行分析,提出地下车站设置自动喷水灭火系统的设置条件和范围。

Irrigation Water Demand Model as a Comparative Tool for Assessing Effects of Land Use Changes for Agricultural Crops in Fraser Valley, Canada

Available water for human needs and agriculture is a growing global concern. Agriculture uses approximately 70% of global freshwater, mainly for irrigation. The Lower Fraser Valley (LFV), British Columbia, is one of the most productive agricultural regions in Canada, supporting livestock production and a wide variety of crops. Water scarcity is a growing concern that threatens the long-term productivity, sustainability, and economic viability of the LFV’s agriculture. We used the BC Agriculture Water Demand Model as a tool to determine how crop choice, irrigation system, and land-use changes can affect predicted water requirements under these different conditions, which can aid stakeholders to formulate better management decisions. We conducted a comparative assessment of the irrigation water demand of seven major commercial crops, by distinct soil management groups, at nineteen representative sites, that use both sprinkler vs drip irrigation. Drip irrigation was consistently more water-efficient than sprinkler irrigation for all crops. Of the major commercial crops assessed, raspberries were the most efficient in irrigation water demand, while forage and pasture had the highest calculated irrigation water demand. Significant reductions in total irrigation water demand (up to 57%) can be made by switching irrigation systems and/or crops. This assessment can aid LFV growers in their land-use choices and could contribute to the selection of water management decisions and agricultural policies.

Experimental Investigation of Soil Evaporation and Evapotranspiration of Winter Wheat Under Sprinkler Irrigation

Sprinkler irrigation is one of the typical irrigation technologies used for the winter wheat-summer maize double cropping system in the North China Plain. To evaluate the evapotranspiration （ET） of winter wheat under sprinkler irrigation in Beijing area, field experiments were conducted in growing seasons through 2005-2008, in the experimental station located in Tongzhou County, Beijing, China, with different irrigation depths. Results indicated that a relatively large variation of soil water content occurred within 0-40 cm soil layer. The seasonal ET of winter wheat generally increased with increasing irrigation amount, while the seasonal usage of soil water had a negative relationship with irrigation amount. Soil evaporation （Es） was about 25% of winter wheat ET during the period from reviving to maturity. Es increased while Es/ET decreased with increasing irrigation amount. Sprinkler irrigation scheduling with relatively large irrigation quota and low irrigation frequency can reduce Es and promote the irrigation water use efficiency.

Root-Zone Soil Water Balance and Sunflower Yield under Deficit Irrigated in Zambia

The study was conducted at the University of Zambia, Research Field Station, Lusaka, Zambia to evaluate the root zone soil water balance under full, and deficit irrigated sunflower. The specific objectives were: 1) to assess the sunflower growth and yield under varying irrigation water regimes;2) to evaluate the root-zone water balance;and 3) to evaluate the water use efficiency of sunflower. Sunflower (Helianthus annuus, var Milika) was planted in a Randomized Complete Block Design (RCBD) with four irrigated water regimes in four replications. The treatments comprised: treatment (T1) = 30% ETc;treatment (T2) = 54% ETc;treatment (T3) = 65% ETc;and treatment (T4) = 100% ETc. The sunflower crop was irrigated on a weekly irrigation schedule using sprinklers. The measured parameters included: weather data, soil moisture profiles, growth stages (emergence, flowering, maturity), above-ground biomass, and grain yield. The results of the study showed that growth parameter (biomass and seed yield) decreased with a decrease in applied irrigation water. The sunflower seed yield varied from 0.22 to 1.40-ton·ha-1 with an average yield of 0.81-ton·ha-1. The highest grain yield was obtained under treatment (T4), and the least grain in yield harvest was at treatment (T1). The statistical analysis showed significant differences in seed yield among the treatments. The treatments (T1 and T2) were not significantly different (p > 0.05). These results showed that when water deficit was set at 65% and 100% ETc and uniformly distributed throughout the sunflower growth, there were no significant differences in biomass, stover and seed yield. In literature, the allowable soil moisture depletion factor for irrigation scheduling of sunflower is set at 45%. The yield components decreased as irrigation levels decreased for each irrigation interval. The 65% ETc treatment could be recommended for sunflower irrigated in semi-arid regions and be used as a good basis for improved irrigation strategy development under water stressed environment.

Heat resistance and water protection effectiveness for large single-pane fireproof glass

The effects and heat transfer mode of water film and sprinkler system on the heat-resistant property associated with the insulation of a fireproof glass were investigated. In the experiments, fireproof glass with a size of 3 300 mm (height) × 2 200 mm (width) × 12 mm (thickness) was exposed to an oil pool fire with a power of approximately 1.4 MW. The experimental results show that the application of the water film or sprinkler system on the glass can effectively resist the intensive heat from the fire in the test due to the absorption of latent heat. The permitted period of integrity and insulation with a water film and a sprinkler system could be extended to 60 min. It should be noted that the temperature of the glass surface can be kept under 60 °C in a 60 min test. The experimental results suggest that it is feasible to substitute fireproof glass with water film for a fireproof door as long as the water film or sprinkler system can work stably and water can cover the whole surface of the fireproof glass.

中心支轴式喷灌系统在水利工程中的应用分析

文章以山东省邹城市农业水利工程为例,介绍了该工程的基本情况,结合多种灌溉技术方案的对比,最终确定了中心支轴式喷灌系统,并对该高效节水灌溉系统进行了设计,随后以此为基础,对该系统的应用效果进行验证。通过验证可知,相对传统灌溉技术,中心支轴式喷灌系统可节约用水量11%以上,可将其推广到现代农业水利工程领域,以供参考和借鉴。

Retrofitting Sprinkler Systems for Suppressing Dust Generated by Moving Vehicles Inside Farms

Fugitive dust is one of the well known problems in agriculture and it affects both humans and machine producing quality. Dust problems can seriously cause harmful diseases to workers and ruin expensive equipments. In this study, a dust formation generated in open environment by vehicles was analyzed on unpaved roads. Formed dust was measured by calculating total forces on the PM10 （airborne particles smaller than 10 mm） of dust particles, such as air velocity, gravity forces and air turbulence generated by the moving vehicle. The water fogger nozzle discharge was measured to determine the approximate droplets quantity in the air. The foggers were used to suppress the generated dust in an open environment via installing a proposed automatic suppression system which opens automatically when vehicles pass under the system. The relationship between water droplet speed and ability of collecting fugitive dust showed that high air temperature above 40oC and wind speed above 10 m s-1 have negative effects on the system’s ability of collecting dust due to evaporation of small radius droplets and/or drifting water droplets away from the effective area. The overall system efficiency was found to be 85% and the proposed dust suppression system was found to be a satisfying solution for reducing fugitive dust hazards.

动态水压间歇脉冲喷灌喷洒水力性能研究

动态水压喷洒和基于脉冲宽度调制的间歇喷洒对喷头喷洒水力特性均有显著调节作用,为充分发挥动态水压和间歇喷洒的技术优势,本研究通过压缩空气储能调节同步实现动态水压和间歇脉冲喷洒,基于此开发出新型动态水压间歇脉冲喷灌装置,并对动态水压间歇脉冲喷洒条件下的喷灌水力性能指标进行了实测和计算。结果表明,动态水压间歇脉冲喷洒模式下,喷头工作压力呈“急速上升—波动下降—急速下降”三阶段变化趋势,喷头流量较恒压连续喷洒降低70.23%~82.77%;径向喷灌强度呈双峰型分布,峰值喷灌强度为连续喷洒下的12.7%~33%;喷洒水量分布均匀度较连续喷洒有小幅降低5.8%~14.1%,且可通过运行参数优化进一步提升;水滴对表层土壤的打击强度显著降低,动能强度峰值降幅50.6%~70.9%。研究结果表明动态水压间歇脉冲喷洒可灵活实现喷洒水力性能指标的同步提升,具有较大应用潜力。

不同水氮组合对冬小麦产量及水氮利用效率的调控效应

【目的】探明喷灌条件下水氮调控对冬小麦产量、土壤养分及水氮吸收利用的影响,以期为关中地区小麦生产提供科学合理的水肥一体化施肥方案。【方法】采用喷灌施肥技术,在陕西扶风进行了小麦田间区域试验。试验采用裂区设计,主区为4个灌溉水平:30、60、90、120 mm,记为W1、W2、W3、W4;副区为4个施氮(N)水平:150.0、187.5、225.0、262.5 kg/hm^(2),记为N1、N2、N3、N4,共16个水肥组合。小麦收获期,采集0—20 cm土层土样测定土壤理化性质及微生物生物量碳、氮、磷含量,采集小麦植株样品测定干物质、氮素积累量,并调查产量及构成因素。【结果】小麦产量随灌溉、施氮水平的提高呈先上升后下降趋势,W3N2处理下产量最高,为9053 kg/hm^(2),较W1N1处理增产1973 kg/hm^(2);拟合曲面最高产量达8848 kg/hm^(2),此时灌溉量为98 mm,施氮量为212 kg/hm^(2)。提高灌溉量有利于小麦干物质与氮素积累,W3灌溉下平均干物质积累量和平均氮素积累量均最高,分别达20306 kg/hm^(2)和221 kg/hm^(2),干物质、氮素积累量均在W3N2处理达最高值,分别为21252、237 kg/hm^(2)。过量施氮不利于小麦氮素利用,N4处理下的氮肥偏生产力、氮素利用效率分别较N1处理降低34.5%~40.4%、2.5%~6.9%。各处理小麦水分利用效率处于15.1~21.6 kg/(hm^(2)·mm),施氮量控制在217~228 kg/hm^(2)时小麦的水分利用效率较高。W3灌溉条件下土壤理化性质最优,W4灌溉造成土壤硝态氮、微生物生物量碳、氮含量同步下降。路径分析表明,干物质及氮素积累量、水氮投入、土壤养分、产量构成因素对产量的总效应值分别为0.716、0.642、0.522、0.400,以干物质及氮素积累量的效应值最高;干物质及氮素积累量、产量构成要素以直接路径调控小麦产量,直接效应值分别为0.555、0.400;水氮投入、土壤养分主要以间接路径调控小麦产量,间接效应值分别为0.554、0.544。【结论】干物质及氮素积累量对小麦产量的直接影响最强,灌溉施氮水平对小麦产量的间接影响最强,二者是实现小麦增产的重要因素。过量灌溉、施氮反而降低产量、水氮利用效率和土壤理化指标。在关中地区采用喷灌方法条件下,冬小麦灌溉80~100 mm、施氮210~230 kg/hm^(2)时可以协同小麦高产与水氮高效。

旋转折射式喷头移动喷洒水量分布计算模型构建与应用

【目的】探讨旋转折射式喷头移动喷洒水力特性,优化喷灌机组运行参数和配置。【方法】采用喷灌强度等效拉伸法,构建了基于一次正交多项式拟合的移动喷洒水量分布计算模型,应用该模型对R3000、S3000、O3000喷头进行模拟计算,分析了工作压力(50~150 kPa)、移动速度(20~45 m/h)和组合间距(1.2~6 m)对3种喷头移动喷洒水量分布和均匀度的影响。【结果】①模型计算结果与实测值偏差在5%以内,模型精度较高。②R3000、S3000、O3000喷头移动降水深随距喷头距离的增加而减小,3种喷头移动喷洒均匀度较固定喷洒分别提高11.17%、10.72%和2.36%。③随着工作压力的增大,R3000、S3000、O3000喷头的有效喷灌半径逐渐增大,降水均匀度呈先增大后减小的趋势,最大降低幅度达35.66%,平均降水深和均匀度随移动速度的增大逐渐降低,但3种喷头喷洒均匀度的平均变化幅度仅为0.59%、1.38%、0.99%,说明移动速度对均匀度的影响较小。随着组合间距的不断增大,均匀度呈波动下降的趋势。④考虑工作压力和组合间距双因素影响,R3000、S3000、O3000喷头在低组合间距和高工作压力范围内取得较高的移动喷洒均匀度,在150 kPa/3.6 m、150 kPa/2.4 m、130 kPa/3.6 m的工作压力/组合间距配置组合条件下,喷洒均匀度最高。【结论】等效拉伸法降低了模型构建过程中的拟合次数,提高了计算精度;增大工作压力和降低组合间距有助于提高喷头移动喷洒均匀度。

地下车库场景下的全尺寸电动汽车火灾特征及抑制性能试验

本工作对地下车库场景下的电动汽车热失控火灾特性及水喷淋抑制效果进行了研究,通过对车内不同位置以及车外顶棚温度在水喷淋前后的变化,得出了电动汽车热失控发展过程的不同特点。搭建了全尺寸的地下车库电动汽车火灾试验平台,通过电加热的方式触发车内电池包中的锂离子电池热失控,测试了电动汽车热失控发展中电池包、车身、顶棚处的温度变化。结果表明电池包内的电池热失控过程是由近及远的,主要传热方式是热传导,其最高温度超过600℃。车舱内的温度变化相较于电池包的变化来说,存在一定的滞后性,会导致车内人员安全错觉。当现场已经充满了大量黑烟时,顶棚处的最高温度仅为46.1℃,相较于温度传感器,烟雾传感器可能是地下车库一个更好的选择。水喷淋灭火试验表明一般的水喷淋灭火方式灭火效果有限,主要由于水喷淋无法直接作用在电池,降温效果有限,只能起到一定的减缓作用,并不能使其降至安全温度。本工作研究结果有助于深入认识受限空间内的电动汽车热危险性,为地下车库的消防安全设计提供基础数据支持与参考。

喷灌水肥一体化技术在北疆苜蓿生产中的应用

苜蓿作为优质的高蛋白饲料,被称之为“牧草之王”。新疆作为中国五大牧区之一,人工饲草料地建设滞后,长期以来饲草生产中普遍存在灌溉管理水平差,水肥利用效率低,高投入低产出问题,成为制约新疆现代畜牧业发展的瓶颈。近年来,新疆的农牧业龙头企业大力发展以大型喷灌机为基础的节水牧草业,迫切需求喷灌苜蓿节水高产优质生产技术。把水肥一体化技术与喷灌苜蓿生产实践结合起来,从品种选择、地块的理化性状、平整土地、系统管理、种植模式及群体指标、苜蓿各生育期的水肥管理和配套栽培措施等方面,阐述了水肥一体化技术在苜蓿生产中的应用技术要点,形成了具有普遍指导性的水肥一体化技术规范。该技术要点体现了喷灌水肥一体化的技术优势,可为北疆的喷灌苜蓿生产、广大农技推广人员、农技推广服务和农业领域科研工作者提供技术指导和参考。

“槽型”驱动板对射流脉冲喷头水力性能的影响试验研究

为改善射流脉冲喷头的径向水量分布,基于射流脉冲喷头的“双驼峰”式水量分布以及挡水板结构的特点,创新了一种“槽型”驱动板结构,并进行了正交试验,得到一种新型结构的射流脉冲喷头.发现“槽型”驱动板的各结构因素对射流脉冲喷头喷灌均匀度影响的主次顺序及最优结构为内槽倾角13°、驱动板长度16 mm、槽宽3 mm、侧驱动板倾角17°、驱动板宽度11 mm.当进口压力为0.15,0.20,0.25,0.30 MPa时,开展了“槽型”射流脉冲喷头、原射流脉冲喷头与摇臂式喷头水力性能对比试验.试验结果表明:在0.15~0.30 MPa的进口压力下,新喷头进口流量相比原喷头进口流量减小0.12~0.17 m3/h,相比摇臂式喷头进口流量减小0.07~0.16 m3/h.“槽型”射流脉冲喷头喷灌均匀度比原射流脉冲喷头提高1.25%~7.43%,比摇臂式喷头高7.84%~14.42%.综合分析表明“槽型”驱动板结构设计合理,对射流脉冲喷头的喷灌均匀性改善显著.研究可为该型国产喷头后续研发和工程应用提供理论参考与数据支撑.