首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 265 毫秒
1.
滴灌系统灌水器堵塞一直是制约滴灌技术应用推广的关键问题,为探索预防、解决该问题的方法,首先,从灌溉水源、灌水器流道结构、滴灌系统运行方式等方面总结了灌水器堵塞类型,论述了该领域的研究成果;其次,通过控制水源处理、配置合适过滤设备、改进灌水器流道、选用较优系统运行方案等方式提高灌水器抗堵塞性能,提出进一步研究发展灌水器堵塞防治新技术;最后,讨论了目前研究中存在的问题及下一步研究建议,为更好地防治灌水器堵塞问题提供新思路。   相似文献   

2.
滴灌灌水器流道设计理论研究若干问题的综述   总被引:7,自引:1,他引:6  
灌水器是滴灌系统最关键的部件之一,其结构与水力性能的优劣对滴灌系统的灌水均匀性、抗堵塞能力以及寿命影响很大。在简要论述国内外滴灌灌水器流道发展现状的基础上,从灌水器流量压力关系、流道内流体流动机理、流道堵塞与防治三个方面详细阐述了灌水器流道设计理论的研究进展,最后提出了滴灌灌水器流道的发展趋势以及国内在灌水器流道设计理论研究中急需解决的问题。  相似文献   

3.
单翼迷宫灌水器进口流场数值模拟与结构优化   总被引:1,自引:0,他引:1  
针对单翼迷宫式滴灌灌水器工程应用中,大多数堵塞都发生在灌水器进口及其邻近区域的问题,对单翼迷宫式滴灌灌水器进口结构特性和水力性能进行分析,并对内部流场的计算流体进行动力学(CFD)数值模拟研究,发现目前广泛使用的单翼迷宫式滴灌灌水器的进口在实现灌水器多进口安全保障、过滤、抗堵塞等功能方面的设计存在不足之处.应用CAD-CFD技术改进单翼迷宫式滴灌灌水器进口的结构,优化其水力性能.改进后的灌水器5个进口流量基本相同,流速分布也较为均匀.不存在超低流速区,能有效减少灌水器进口的沉积和堵塞,提高灌水器的抗堵塞能力,实现了多进口的安全保障功能.  相似文献   

4.
王栋 《节水灌溉》2007,(2):54-57
从制约地下滴灌技术发展的地下灌水器(滴头)灌水均匀度差、滴头容易堵塞等问题出发,立足于地下滴灌急需解决的理论和技术问题,以减小滴头堵塞率为目标,以满足灌水均匀度为前提,以确定滴头设计工作压力为突破口,以滴头优化设计为手段,从地下灌水器灌水均匀度设计指标、滴头设计工作压力取值和结构优化设计3个方面进行了深入细致的研究试验,最终达到完善地下滴灌灌水器设计理论、实现结构设计优化、提高地下滴灌适用性的目标.  相似文献   

5.
再生水滴灌条件下灌水器抗堵塞试验研究   总被引:1,自引:0,他引:1  
随着新农村的建设,农村污水处理系统建设逐渐完善,同时节水灌溉技术的推广,农村再生水的利用成为农业灌溉节水的一种新方法。本试验针对农村污水处理系统,进行再生水滴灌试验。结果表明:市场常见的灌水器产品对农村的再生水有一定的适用性,具有抗堵塞的功能,可在农村推广再生水滴灌技术。宽齿形灌水器具有自清洗功能,抗堵塞性能优于其他3中灌水器,且大流量的灌水器的抗堵塞性能优于低流量的灌水器。由微生物与固体颗粒团体等组成的生物膜易沉积于灌水器的格栅和出水口缓冲区,引起灌水器堵塞,其是直接诱发灌水器堵塞的原因。灌水器流道内沉积物质的随机生长与脱落,造成灌水器的堵塞是一种随机的过程。滴灌系统运行大概350h,应对其进行清洗,以提高灌水器的抗堵塞性能。  相似文献   

6.
目前国内外内镶式灌水器设计和生产中普遍采用的在灌水器上直接设置单一紊流态细小流道的生产工艺,在实际应用中存在着滴头易堵塞、对水质要求高等问题,为此,研制内镶式反滤防堵塞灌水器及滴灌管,既能防物理性堵塞,还能防生物性和化学性堵塞,解决滴灌系统灌水器的易堵塞难题,不仅可用于常规的地表滴灌,还可用于地下滴灌和灌溉施肥。  相似文献   

7.
滴灌用灌水器的发展及研究   总被引:14,自引:1,他引:13  
本文对滴灌技术的发展历史进行了回顾,对灌水器的发展历史以分类和工作原理进行了总结,对新型的重力滴灌做了介绍,对滴灌系统的堵塞原因及防治措施进行分析,还对灌水器的水力特性分析研究现状作了简单介绍,对今后的研究方向提出了建议,这些对于子解滴灌的历史以及研究现状都有一定意义。  相似文献   

8.
灌水器是滴灌系统中的核心部件。滴灌技术在农业节水灌溉系统中发挥着举足轻重的作用。针对传统滴灌灌水器流道易堵塞,结构较复杂,流量不稳定等缺点,提出一种新型蠕动式滴灌灌水器。该灌水器以转轮为核心部件,水流推动转轮间歇挤压具有较好弹性的软管,达到定时定量输水的目的。基于CFD三维数值模拟技术,对该滴灌器内部流道结构进行模拟,得到流量-压力关系式。蠕动滴灌器提高了滴头流道的抗堵性能,具有"自清洗"功能;装置结构简单,便于使用和安装。  相似文献   

9.
通过控制不同环境条件,采用不同型号的滴灌带进行灌水器堵塞室内模拟试验,探索了室内引黄滴灌系统灌水器堵塞的过程和堵塞物的微生物组分。结果表明,在试验可控的环境条件变化范围内,浊度越高,温度越高,滴灌带的额定流量越小,则灌水器出流量下降越快,越容易堵塞,而堵塞导致灌水均匀性变差,灌水均匀度变小,灌水质量变差。堵塞物中均含有细菌总数和叶绿素a,随着水体浊度的增加和温度的升高,堵塞物中细菌总数逐渐增多。黄河水泥沙颗粒物和微生物的共同作用是引起灌水器堵塞的主要原因。  相似文献   

10.
地下滴灌应用试验研究   总被引:8,自引:3,他引:5  
将孔口式、发丝管式和内镶式滴灌带等三种常用的灌水器应用于地下滴灌系统,并进行田间试验,分析其流量变化规律、灌水均匀度及对堵塞的敏感性,探讨地下滴灌技术的适用性。结果表明,地下滴灌技术在实践中是可以运用的,但仍需对灌水器选择及系统布置等方面开展研究  相似文献   

11.
The hydraulic design of micro-irrigation systems to achieve high system uniformity has led design engineers to over-design irrigation systems arbitrarily. Commonly used emitter flow variations of 10–20% are equivalent to a uniformity coefficient of about 98-95%, or a coefficient of variation of emitter flow of only 3–7%. The uniformity of a micro-irrigation system is affected by not only hydraulic design but also manufacturer's variation, grouping of emitters, plugging, soil hydraulic characteristics and emitter spacings. Among all the factors affecting the uniformity, the hydraulic design, with an emitter flow variation of 10–20%, produces only a few percent change in uniformity. The manufacturer's variation of micro-irrigation emitters ranges from 2% to 20%. The hydraulic variation will be less significant when an emitter with 10% or more manufacturer's variation is selected. The grouping effect will reduce the coefficient of variation to half or more if four or more emitters can be grouped together. The effect of hydraulic design is also less significant with plugging situations. When there is no plugging, the emitter flow variation from 10% to 20% in hydraulic design will reduce spatial uniformity only about 8% from 93% to 85% when the emitter spacing is designed as half of the wetting diameter in the field. The hydraulic design criterion can be relaxed to 30%v of emitter flow variation, qvar(H), which can still achieve less than 20%v in coefficient of variation, or over 80% of uniformity coefficient in spatial uniformity of a micro-irrigation system  相似文献   

12.
Water quality in drip/trickle irrigation: A review   总被引:8,自引:2,他引:8  
Summary The intensive treatment of irrigation water required for the proper operation of drip irrigation systems is presently an accepted practice. To control emitter clogging, we need to know the basic causes of clogging. The major clogging factors have been identified and control measures developed to prevent emitter malfunction. All emitter clogging problems, however, have not been solved primarily because of cost. The main approach to control clogging is proper water treatment. The type of treatment is based on the quality of the irrigation water, which can be classified in terms of its physical, chemical and biological composition. The causes of emitter clogging and possible water treatment and preventive measures to maintain reliable operation are reviewed.  相似文献   

13.
Flushing is an important maintenance task that removes accumulated particles in microirrigation laterals that can help to reduce clogging problems. The effect of three dripline flushing frequency treatments (no flushing, one flushing at the end of each irrigation period, and a monthly flushing during the irrigation period) was studied in surface and subsurface drip irrigation systems that operated using a wastewater treatment plant effluent for three irrigation periods of 540 h each. The irrigation systems had two different emitters, one pressure compensating and the other not, both molded and welded onto the interior dripline wall, placed in laterals 87 m long. Dripline flow of the pressure compensating emitter increased 8% over time, while in the nonpressure compensating emitter, dripline flow increased 25% in the surface driplines and decreased 3% in the subsurface driplines by the emitter clogging. Emitter clogging was affected primarily by the interactions between emitter location, emitter type, and flushing frequency treatment. The number of completely clogged emitters was affected by the interaction between irrigation system and emitter type. There was an average of 3.7% less totally clogged emitters in flushed surface driplines with the pressure compensating emitter as compared to flushed subsurface laterals with the nonpressure compensating emitter.  相似文献   

14.
地下滴灌灌水器负压吸泥影响因素试验研究   总被引:3,自引:2,他引:1  
为了探究引起地下滴灌系统灌水器负压吸泥的影响因素,通过对比试验,研究分析了土壤类型、单次灌水量、灌溉次数、灌水器类型、保水剂和灌水间隔等6个因素对灌水器负压吸泥的影响规律。结果表明,1流量可调式灌水器出水孔外部及内部存在负压吸泥并引起堵塞情况。外部出水孔有3个被堵塞的所占比例最多,为26.7%;泥沙分布主要集中在灌水器出水孔的内侧附近,有极少部分泥沙甚至可以越过内凸边缘,进入灌水器内圈。2压力补偿式灌水器抗负压吸泥的能力强于流量可调式灌水器,压力补偿式灌水器外部出水口及内部未发现有泥沙,而流量可调式灌水器外部出水口及内部有泥沙;灌水器在红壤土中比黄沙土中更容易出现负压吸泥情况,灌水器在红壤土中的内部泥沙量是黄沙土中的1.12~1.76倍。3灌溉方式(单次灌水量、灌溉次数、灌水间隔)对灌水器负压吸泥的影响显著。单次灌水量小的灌水器内部泥沙量较多,灌水器单次灌水量为170 m L内部泥沙量是250 m L的1.61~2.94倍;灌溉次数与负压吸泥量成正比,灌溉次数为16次的内部泥沙量是8次的3.48~5.41倍;在同一灌溉次数的条件下,灌水间隔长度与负压吸泥量成正比。4保水剂能够有效阻隔泥沙进入灌水器内部,在添加了保水剂的灌水器中,其内部未出现负压吸泥的现象。  相似文献   

15.
以塔里木河下游35团8连绿洲-荒漠交界处滴灌条件下的新生林地为研究对象,对滴灌结束24 h后不同滴头间距下的土壤盐分分布特征进行了分析,结果显示①水平方向上,在3 m滴头间距下出现盐峰是在75 cm点处的土壤剖面,这一剖面与60 cm点处的土壤剖面盐分在0.01水平上呈显著相关,随着距滴头距离的减小相关性递减;在1 m滴头间距下出现盐峰是在45 cm点处的土层,这一土层与各点处的土壤剖面盐分在0.01水平上呈显著相关;无论在3 m滴头间距下还是在1 m滴头间距下,45 cm点处的土壤剖面盐分分布较均匀,离滴头越近的土壤剖面盐分分布越不均匀。②垂直方向上,无论是在3 m滴头间距下还是在1 m滴头间距下,40~60 cm的土层是盐分聚集区。在3 m滴头间距下,40~60 cm的土层盐分与各土层间的相关系数均未达显著相关水平;在1 m滴头间距下,40~60 cm的土层盐分与其它各土层间均为负相关关系;无论是在3 m滴头间距下还是在1 m滴头间距下,中下层土壤盐分分布较均匀,而越接近表层的土壤盐分分布越不均匀,在2种滴头间距下,中下层土壤盐分变异系数都较小,表层土壤变异系数较大。③在研究区特殊的强蒸发力下,原本可到达底部土层的盐分在毛管作用下随着水分向上运动,最终导致了盐分聚集于50 cm深度处(3 m滴头间距)与65 cm深度处(1 m滴头间距)。  相似文献   

16.
Control of emitter clogging in drip irrigation with reclaimed wastewater   总被引:4,自引:3,他引:4  
Summary Experiments were carried out to evaluate the performance of various types of drip irrigation emitters, widely used in Israel, using waste water from a storage reservoir. Fine particulate matter agglomerated by microbial by-products and in-line developed biomass were the principal clogging agents. Clogging fluctuated, increased as water quality deteriorated and decreased when it improved. There were definable differences between emitters of various types as to their clogging susceptibility which were not directly correlated with differences in emitter flow-rate, although, for any particular type, the emitter with smaller discharge was always more sensitive to clogging. The clogging process generally started with emitters located at the far end of the lateral and partial emitter clogging was more common than complete plugging. Overflow was also found in most emitter types and was more common in regulated emitters. Reliable long term operation of most emitter types was achieved with filtration at 80 mesh (180 m opening) combined with daily chlorination and bimonthly lateral flushing. Regular lateral discharge monitoring was found to be a convenient way to detect the initiation of the clogging process. Chlorination was most efficient when applied before the emitters became massively clogged.  相似文献   

17.
温室水肥滴灌系统迷宫式灌水器堵塞试验   总被引:5,自引:0,他引:5  
为探明温室滴灌灌水器堵塞的影响因素及机理,研究了灌水量和施肥量对灌水器堵塞的影响,并利用场发射扫描电镜分析了灌水器内的堵塞物质。结果表明,灌水器平均流量随着灌水量和施肥量的增加呈下降趋势,下降幅度在1.51%~14.16%之间。方差分析表明施肥量对灌水器平均流量的影响达到极显著水平(P0.01)。解剖灌水器后发现堵塞物质多沉积在流道前部。堵塞物质主要由生料带残渣、微小沙粒和白色粉末状化学沉淀物组成,其中白色粉末主要由钙、镁、碳、氧、磷元素等组成。说明本试验中灌水器堵塞主要是由物理堵塞和化学堵塞共同作用引起的。  相似文献   

18.
Trickle irrigation experiments with Colorado River water on citrus trees in southwestern Arizona were conducted to develop water treatment methods for preventing emitter clogging and maintaining long-term operation of the system under actual field conditions. Eight trickle emitter systems in combination with six water treatments were evaluated during a comprehensive 4-year study. Emitter clogging was related to emitter design and to degree of filtration treatments of Colorado River water. If not positioned upright, emitters designed with moving parts were more susceptible to malfunctioning and clogging. Emitters with flexible membranes either failed after a few months of use with chemically conditioned water or showed serious deterioration and decomposition after 4 years. Five of the eight emitter systems required sand and screen (200 mesh) filtration plus chemically conditioned water to keep suspended materials from physically clogging the emitter. However, two emitter systems with the same design but different flow rates have continued to operate with only screen (50 mesh) filtration. For emitters unaffected by material deterioration, the water conditioned continuously with acid alone was just as effective as a combination of continuous or intermittent chlorine and acid treatments in reducing emitter clogging. The dominant causes of emitter clogging and flow reduction were physical particles; next, and minor in comparison, was the combined development of biological and chemical deposits.  相似文献   

19.
滴灌条件下沙地土壤水分分布与运移规律   总被引:7,自引:0,他引:7  
通过对不同流量的滴头,不同灌水历时条件下沙地土壤滴灌湿润体的大小与形状的观测观察,以及对滴灌停止后不同间隔时间的土壤湿润锋运移,湿润体的发展,土壤水分的分布与再分布测量分析,使之对滴灌条件下土壤湿润体的大小及发展、土壤水分的分布与再分布规律等有了比较清楚的认识。本文不进行理论上的土壤水分分布模拟,仅从众多的实测资料分析着手,揭示土壤水分分布与运移规律,旨在为砂壤地玉米滴灌的参数确定(滴头间距、流量、灌水历时等)提供基本依据。通过土壤水分与湿润体实测资料分析认为,滴灌玉米的滴头流量在2.0l/h左右,灌水历时2~3h,滴头间距为50cm左右为宜。过长的灌水历时(大于3h)即可能导致灌溉水的无为损失,造成先进的节水灌溉技术条件下新的水浪费问题。滴头间距过密,会加大不必要的工程投资。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号