偏心文丘里流量计的试验与数值模拟

[目的]克服传统的文丘里流量计用于低压管道输水灌溉系统测流时上游侧容易产生淤积的问题.[方法]以直管段管径DN100、缩径比为0.35的偏心文丘里管为例,分别进行了实际测流试验及基于FLOW-3D的数值模拟研究,并对偏心文丘里管压力差及流出系数进行了对比分析.[结果]数值模拟的流出系数与试验流出系数基本一致,利用FLO...     

沾益区炎方乡来远银杏苗圃滴灌工程设计

云南省沾益区炎方乡来远银杏苗圃采用滴灌方式灌溉,设计灌溉面积180hm2,支管、毛管铺设是滴灌设计的核心内容.以项目区基本资料和灌溉制度为基础,通过水力计算来确定支管、毛管铺设参数.项目区分10组轮灌,灌水周期5d,灌水延续时间6h,净灌水定额18mm,毛灌水定额20mm.滴头流量2L/h,工作压力水头15m.最终:支管铺设长60m,间距60m,50孔,选用0.8MPa DN63PE100级管;毛管铺设长100m,间距1.2m,100孔,选用0.6MPaDN25PE100级管;选用16(0.15MPa)压力补偿滴头.     

Subsurface drip irrigation and reclaimed water quality effects on phosphorus and salinity distribution and forage production

In the Canary Islands, water scarcity is one of the constraints for agricultural activity. Non-conventional water resources generally represent more water volume than conventional ones. The distribution of these resources frequently permits the possibility of a conjunctive use of desalinated (DW) water and reclaimed municipal wastewater (RW). Field testing with both water qualities and different irrigation systems is necessary for optimal site-specific management. The objective of this work was to evaluate soil salinity and phosphorus distribution, and alfalfa yield in a 20 month field experiment carried out in the island of Gran Canaria, using municipal RW and freshwater (FW) under subsurface drip irrigation (SDI). Phosphorus speciation was performed both in irrigation waters and in soils (Olsen's inorganic, organic, and microbial). RW had large EC values (2.4 dS m⁻¹) with a remarkable nutrient load contribution and an average total P around 3 mg L⁻¹, predominantly hydrolysable forms, while FW had very low salinity and negligible amounts of P. For the RW treatment a salt gradient was established, causing plant mortality between the irrigation lines. The study of P speciation allows describing P distribution and plant uptake in terms of P forms. Large values of microbial P were produced for the two irrigation waters around the emitters, especially for FW.A faster P-cycling could have contributed to the significantly larger inorganic P contents observed in FW irrigated soils, in spite no external sources were added by the irrigation water.     

滴灌毛管泥沙分布与灌水器堵塞试验研究

为探明滴灌毛管泥沙分布及灌水器堵塞规律,通过对8种粒径的泥沙进行短周期浑水试验和堵塞试验,研究了泥沙在不同毛管分布和灌水器堵塞规律。结果表明:泥沙在不同毛管中淤积量的不均匀程度可以通过毛管淤积分布系数来衡量;泥沙在支管中的运动状态对进入毛管中的泥沙量影响很大,通过计算支管泥沙悬浮指数,可确定泥沙在不同毛管中的淤积状况,悬浮指数越大,泥沙在各毛管淤积量越不均匀,突变发生在悬浮指数等于0.325处;大颗粒泥沙在毛管底部以推移质形式运动,是造成灌水器突然堵塞的直接原因,且主要出现在第1、2条毛管中,而细小颗粒的絮凝作用是造成灌水器逐渐堵塞的主要原因。     

基于混合蛙跳算法的自压微灌管网系统优化设计

[目的]解决自压微灌管网系统布置与管径优化设计的问题,节省工程投资造价.[方法]以新疆某灌区一微灌工程为研究对象,以微灌系统中各级管道的管段长度、管径为决策变量,支毛管允许水头差、工作压力、管径、流速等为约束条件,以管网总投资最小为目标,分别建立了双向毛管布置和单向毛管布置的自压微灌管网数学模型,并采用混合蛙跳算法进行...     

Trickle irrigation: Predominant bacteria in treated Colorado River water and biologically clogged emitters

Summary Bacterial numbers and predominant bacterial types were determined in trickle irrigation systems receiving treated Colorado River water. Fourteen bacterial genera were isolated and identified from 86 water and sediment samples collected from trickle emitter systems receiving six water treatments. The bacteria identified were common aquatic and soil microbes and the genera in order of prevalence were Pseudomonas, Flavobacterium, Vibrio, Brevibacterium, Micrococcus, and Bacillus. A greater diversity of bacterial types was found in water that was sand filtered and received no chemical treatment. Regardless of the water treatment, Pseudomonas stutzeri was the predominant bacterium followed by Flavobacterium lutescens. The data indicated that pigmented bacteria, F. lutescens and ytophaga hutchinsonii caused the yellow color of the slime deposits in biologically clogged emitters; and, their growth was presumably supported by P. stutzeri., a nonpigmented bacterium. The occurrence of Bacillus sp. was enhanced by sand and screen filtration and markedly reduced by chemical conditioning the water with either chlorine and acid or acid alone. No strictly anaerobic bacteria, such as Clostridium sp., were detected in water treated with chlorine and acid. Iron bacteria, Sphaerotilus spp., were not detected in any water or sediment samples from trickle irrigation systems.Contribution from the U.S. Department of Agriculture, Science and Education Administration, Agricultural Research     

滴灌灌水小区优化设计的浅论及算例

滴灌工程建设规范规定,一条支管所控制的灌溉面积称为一个灌水小区,它是滴灌系统最基本的设计单元,在支管管径选择及压力均衡的验算方面起到十分重要的规范作用.为了满足系统各灌水小区压力均衡,在各支管入口设置压力调节阀,消除其余管线要求水头与水源设计水头之差,达到系统压力均衡,使系统流量偏率不大于20%.     

膜下滴灌暗管排水规律及土壤脱盐效果试验研究

为了探索膜下滴灌盐碱地在灌溉过程中暗管排水规律及土壤脱盐效率,设计了一种暗管排水模型试验装置系统来探究灌溉过程中暗管排水规律和排盐效果.试验通过控制灌水时间、灌水量、观测并记录暗管出水时间、排水流量、排水矿化度、土壤盐分剖面等指标,分析灌溉排水过程中暗管排水流速和排水矿化度特征以及各土层土壤脱盐效率.结果表明:经过3次灌水淋洗试验后,暗管排水流速最终趋于1.5~3.5 L/h稳定范围,排水矿化度稳定在20~40 g/L内;0~40 cm土层脱盐率高达85%,0~80 cm土层土壤脱盐率为80.5%,两暗管中间位置处脱盐率最小分别为57.96%,56.73%,69.29%,暗管上方脱盐率最大分别为71.73%,73.34%,84.26%,暗管排盐量占0~80 cm土层总盐分含量的28.9%,其余盐分被淋洗到了80 cm土层以下.     

SPRINKMOD – pressure and discharge simulation model for pressurized irrigation systems. 1. Model development and description

A computer model was developed to simulate pressure and flow rate distribution along pipes and laterals of pressurized irrigation systems in operation. The software runs in a Windows environment and is capable of simulating irrigation systems having multiple pump stations combined in series and/or in parallel, booster pump stations, parallel pipes and looping pipes. Hand-move, wheel line and center pivot laterals with pressure regulators, one or two drop pipes per outlet and booster pump can be simulated. Leakage can be included in the main pipe network or along the laterals. Lateral inlet pressure can be set to an upper limit to simulate valve closure. Practically any type of nozzle and pump can be simulated since cubic spline functions are used to interpolate values from head-flow rate sets of data. To accomplish these capabilities, algorithms were developed and adapted to convert laterals into a set of head-flow rate data so that a simplified algorithm could be adapted to solve the entire pipe network. A user-friendly interface was designed to allow data for pumps, nozzle and pressure regulators to be interactively entered, edited and analyzed prior to the simulation run. The layout of the irrigation system can be drawn on screen using the mouse. Data can be independently entered and edited for each irrigation system component already drawn in the screen, at any time and in any order. Data for the entire irrigation system are verified at many levels before the simulation is run, to make the model less susceptible to crash. The model proved to be a practical tool for upgrading and designing pressurized irrigation systems. Received: 20 November 1997     

内光外波纹双壁聚氯乙烯管的应用研究

研究生产质优价廉,施工方便的管材,对低压管道输水灌溉的发展极为重要。本文所研制的内光外波纹双壁聚氯乙烯管结构合理,物理力学性能良好。经多项性能试验,结果表明,过水能力与普通光滑硬塑料管基本一致;爆破压力达1.3～1.5MPa;扁平刚度0.36MPa,与国标管相近,约为薄壁管的4倍,在填土的外荷载作用下,其径向变形率为1.2％。双壁波纹管较国标管每米节省原材料52％,单价降低35％左右;较薄壁管每米也可节约原材料7.4～16.7％,是一种较理想的低压管道输水灌溉新型管材。     

多孔渗灌管的防堵措施研究

对渗灌管堵塞的原因和机理进行了分析 ,从水质处理、PE管上冲孔及孔口防护等方面采取了综合防堵措施 ,在大田试验的基础上结合模拟试验 ,推算渗灌工程正常运行的年限达 6～ 7年以上 ,基本上解决了多孔渗灌管的易堵塞问题     

膜下滴灌输配水管道系统设计

滴灌系统的输配水管道设计影响整个滴灌工程质量。详细介绍膜下滴灌系统确定控制面积的方法以及管网的布置原则,采用公式计算各级管道的设计流量,为膜下滴灌输配水管道的合理设计提供参考。     

基于粒子群算法的低压管灌系统水力计算方法

为了应对水资源危机,中国大力推广低压管灌技术用于粮食作物的灌溉.基于水量平衡和能量守恒原理,以系统的水量偏差最小为目标函数,支管的能量守恒和水量平衡作为约束条件,支管进口流量为决策变量,建立了低压管道输水灌溉系统的一维恒定流水力模拟模型,并相应地提出了试算-粒子群算法(TPSA)进行求解,可以获得系统实际运行时水泵的工况点以及各级管道和出水口的实际流量.将该方法应用于上海市一灌区的低压管灌系统,对比了TPSA与梯度法的求解结果,证明在同时工作的支管数较多的情况下TPSA可以获得更佳的求解结果,误差最多可减小12.3%,耗时最多可减少16.3%.应用该方法可以对管灌系统的初步设计成果进行校核和调整,对提高设计可靠性具有一定作用.     

陕西省杨凌区绿色食品产地环境质量监测与评价

通过对陕西省杨凌区绿色食品产地环境中的大气、灌溉水、土壤进行调查、采样,对土壤中有机质、全氮、有效磷、速效钾、重金属元素,以及灌溉水中总汞、总镉、总砷、总铅、六价铬、氟化物、粪大肠菌群、石油类等成分进行检测,根据调查和监测结果对环境现状进行了综合评价,得出杨凌区3 357 hm2的设施蔬菜、猕猴桃、葡萄、西瓜、甜瓜、草莓等生产基地的大气、土壤、灌溉水各项检测指标符合绿色食品产地土壤环境质量标准,适合发展绿色农产品生产。     

Comparison between the efficiencies of surface and pressurized irrigation systems in Jordan

A study was carried out to determine the efficiencies of water use in irrigation in the Jordan Valley Project. The study aimed to evaluate, the overall or project efficiency (E_p) which includes: the irrigation system efficiency, being the combined conveyance and distribution efficiency (E_s); and the field application efficiency (E_a). Evaluation of these efficiencies includes the comparison of open canals with surface irrigation versus pressurized pipes with sprinkler or drip irrigation systems. Data was collected from different sources to achieve the above mentioned purposes, beside the field experiments which were carried out specially for this study.It was found that the overall or project efficiency (E_p) for open surface canal with surface irrigation under citrus was 53%. While it was 42% under vegetables. Whereas E_p for pressurized pipe systems was 68%, and 70% for sprinkler and drip irrigation methods, respectively.The E_s for an open canal, (King Abdullah Canal, KAC) was 65%. While it was 77% for pressurized pipe projects during 1989–1991. Concerning the E_a, it was found to be equal to 82% and 64%, for surface irrigation on citrus and vegetables, respectively. Whereas it was 88% for citrus under sprinkler, and 91% for vegetables under drip irrigation. These values for the field application efficiency are acceptable according to Finkle (1982). The low E_s value for the canal is due, mainly, to high evaporation and seepage, unreported deliveries, and unavoidable measurement losses. Whereas, in pressurized pipe projects, it is due to the unreported deliveries, unavoidable measurement losses, and leakage.     

几种地下滴灌(渗灌)灌水器性能的室内外试验研究

选择有代表性的 3种国产多孔渗水管和一种地面滴灌管进行室内外试验检测 ,比较各类灌水器的防堵性能、出流均匀性和压力流量关系等工作性能。结果表明 ,多孔管的上述测试指标均不理想 ,而具有压力补偿性能的滴灌管经无纺布外包处理地埋后 ,既具备防止负压堵塞的能力又可在田间 1m管距布设条件下获得良好的灌水均匀性。为此 ,研制一种既能抗负压堵塞、又具备较好压力补偿性能的地下滴灌灌水器是十分必要的。     

Sensitivity analysis of optimal operation of irrigation supply systems with water quality considerations

A model for optimal operation of water supply/irrigation systems of various water quality sources, with treatment plants, multiple water quality conservative factors, and dilution junctions is presented. The objective function includes water cost at the sources, water conveyance costs which account for the hydraulics of the network indirectly, water treatment cost, and yield reduction costs of irrigated crops due to irrigation with poor quality water. The model can be used for systems with supply by canals as well as pipes, which serve both drinking water demands of urban/rural consumers and field irrigation requirements. The general nonlinear optimization problem has been simplified by decomposing it to a problem with linear constraints and nonlinear objective function. This problem is solved using the projected gradient method. The method is demonstrated for a regional water supply system in southern Israel that contains 39 pipes, 37 nodes, 11 sources, 10 agricultural consumers, and 4 domestic consumers. The optimal operation solution is described by discharge and salinity values for all pipes of the network. Sensitivity of the optimal solution to changes in the parameters is examined. The solution was found to be sensitive to the upper limit on drinking water quality, with total cost being reduced by 5% as the upper limit increases from 260 to 600 mg Cl l^–1. The effect of income from unit crop yield is more pronounced. An increase of income by a factor of 20 results in an increase of the total cost by a factor of 3, thus encouraging more use of fresh water as long as the marginal cost of water supply is smaller than the marginal decrease in yield loss. The effect of conveyance cost becomes more pronounced as its cost increases. An increase by a factor of 100 results in an increase of the total cost by about 14%. The network studied has a long pipe that connects two distinct parts of the network and permits the supply of fresh water from one part to the other. Increasing the maximum permitted discharge in this pipe from 0 to 200 m³ h^–1 reduces the total cost by 11%. Increasing the maximum discharge at one of the sources from 90 to 300 m³ h^–1 reduces the total cost by about 8%.     

灌溉管网调压池布置与管径同步优化研究

【目的】保证大规模自压式树状灌溉管网的安全运行,在管网系统中布置若干个调压池进行分区灌溉。【方法】采用基于整数编码的双重编码方法,将调压池和干管管网作为一个整体,以干管管道造价与调压池造价与干管管道造价之和最小为目标函数,以压力节点水头与管道流速为约束条件,建立相关数学模型,并运用遗传算法求解。【结果】该方法实现了调压池布置优化与管径优化的同步进行,最终在系统中共布置2座调压池,分别位于节点2与节点4,将管网系统分为3个区域。优化得到的配水干管总长度10 973.7 m,较人工经验法减少12.02%,系统总投资464.80万元,较人工经验法减少17.23%。优化后每个区域内各节点水头更为均衡,水头差最大区域为第Ⅰ区,仅有12.5m,较人工经验法的26.4m更为稳定均衡。【结论】基于整数编码的双重编码方法可获得较优的自压式树状灌溉管网调压池布置方案,为地形条件相似的管网布置提供了参考。     

外包滤料对暗管排水与土壤脱盐效果的影响

为了探究不同外包滤料条件下的暗管排水性能和土壤脱盐效果,基于室内试验研究成果,在田间设置4种暗管排水系统(各系统中暗管埋深均为80 cm,间距均为20 m),所用外包滤料分别为68 g/m²土工布(L)、砂滤料(S)、68 g/m²土工布+砂滤料(LS)和无外包滤料(W),以当地常规明沟排水(CK)作为对照,通过田间试验分析了春灌过程中各暗管系统的排水性能指标及土壤脱盐效率.结果表明:相比处理W,处理L,S和LS平均排水速率提升了7.44%,12.55%和15.75%,平均流量衰减度降低4.07%;处理S和LS累积排水量提高了5.11%和8.31%(P<0.05).各暗管处理春灌后平均土壤脱盐率均达47%以上,较CK提升显著,其中处理LS效果最优,为50.94%.综上,应优先选择处理LS作为河套灌区暗管排水系统外包滤料布设方案.该研究结果可为河套灌区暗管排盐技术的推广应用提供理论支撑和科学指导.     

奎河灌溉水体中微生物分布及与有机污染物的相关性研究

以奎河水体中微生物群落为研究对象,分析了其数量分布以及与有机污染物的相关性。结果表明：奎河徐州过境段水体中的微生物数量从上游地区（1号采样点）、中游地区（2号采样点）到下游地区（3号采样点）呈现先下降后升高的趋势;水体中的微生物数量与有机污染物含量关系密切,细菌总数、大肠菌群数与总氮显著正相关,且相关系数R分别为0.817、0.836;细菌总数、大肠菌群数、蛔虫卵数与COD显著正相关且R分别为0.821、0.838、0.949,大肠菌群数与悬浮固体（SS）显著正相关且R为0.737;细菌总数、大肠菌群数、蛔虫卵数与总磷、色度相关性不显著。