南阳渠工程南阳山陡坡消能水工模型试验研究

南阳山陡坡由于陡坡落差大,且处于不良的地质条件下,为消力池的选择形式带来了困难.尾栅式消力池是由放置在池中的一定位置的弧形消力墩、池尾的栅式尾坎和池后的二级消力墩组成.弧形消力墩可基本解决渠道初始放水过程中消力池的水流垂直跃起的问题,在较小级流量时,可起到稳定水跃跃首位置的作用,而在较大级流量时增加了消能的效果.池末尾栅的几何尺寸及角度经过优化后可保证在各级流量下池内均呈理想的小淹没水跃状态,在跃首位置几乎一样的情况下,尾栅设计可最大限度地降低池末尾水高度,均化池后水流流速,同时还有消能及保证冬季消力池内水流排空的作用.池后的二级消能墩的主要作用是保证在各级流量下,池后水流均能以缓流形式光滑与墩后水流相接.     

辅助消能工联合运用试验研究及数值模拟

通过新疆迪那河五一水库溢洪洞梯形墩消力池物理模型试验,对其梯形墩消力池消能结构形式进行了优化,提出采用悬栅—梯形墩联合运用的综合式消力池,解决了在校核流量下,消力池内单独设置梯形墩水流溢出池外,不能形成淹没水跃的问题.在不同流量下,对悬栅高度进行合理性验证.利用流体力学计算软件FLUENT,得到了悬栅—梯形墩消力池内详细的流场,对悬栅的体型及布置提出具体修改意见,为辅助消能工的结构设计和其他同类工程优化消力池提供参考.     

新集水电站泄洪消能防冲刷优化研究

在低水头、大单宽流量泄洪建筑物下游普遍存在河床冲刷等问题,结合新集水利枢纽工程、利用水工物理模型试验,通过对比分析原消力池(由连接闸室底板的斜坡段和带尾坎的水平护坦组成)和T型墩+尾坎联合消能工两种方案消力池段及海漫段的流速分布、消力池消能率、流场分布及下游河床冲刷情况,得到以下结论:T型墩+尾坎联合消能工通过扩散和挑起水流,增大池内消能比重,削弱波状水跃~([1]),降低了出池流速,并在海漫段形成二次水跃,大幅提高了整个消能段消能率,下游河床冲刷明显降低。该消能工优化设计方案为工程的消能优化研究提供了强有力的依据。     

铜信溪水电站综合消能工设计

根据工程实际情况，设计采用宽尾墩结合消力池综合消能工布置设计，并对比设计进行了水工模型试验。试验结果表明，消力池内各级流量下均能形成稳定淹没水跃，消能率达到63%-83%，消能充分，投资节省。     

水利工程溢洪道底流消能水力特性分析

合理地选择溢洪道建筑物消能型式,是关系到整个水利工程安全与经济的重要问题.通过溢洪道设计规范进行消能方式水力学计算,结合物理模型试验对传统底流消能与跌坎型底流消能水力特性进行了对比分析,结果表明：传统底流消能在校核洪水下泄流量时,底流消能方水流进入消力池后产生一定程度的远驱式水跃,消力池消能主要位于消力池后部,消力池后部及出口水面壅高较大,且波动剧烈,没有形成相对稳定的消能水体,消力池消能效果不佳,需要增加消力池长度;跌坎型底流消能消力池底板高程降低1 m时,临底流速较底流消能得到大幅度降低,池内水流扩散充分,剪切明显,消力池后段形成了稳定的水体,消能效果良好,出水渠内水流流态得到改善,难以对消力池产生冲刷破坏.跌坎型底流消能空化数增大降低了空蚀发生概率,可避免消力池产生空蚀破坏,最大水跃位置向前移动7 m,水流不会冲击底板和尾坎,水流垂直溅起,因此消力池内流态稳定,雾化影响较小,其具有适应性强,消能效率高、流态稳定等优点.     

低Froude数新型消能尾坎数值模拟研究

低佛氏数水流在下挖式消力池的消能不充分,一般采用在消力池尾坎处增设消力坎形成综合式消力池,从而增加消力池内的消能率。针对新集水利枢纽工程综合式消力池的消力坎体型设计对消力池消能率的影响,基于Flow3D对不同形式的消力坎进行了数值计算,给出了Fr2.0时的综合式消力池的体型设计形式,提出一种新型消能尾坎,这种齿形消力坎对增加消力池消能率具有重要作用。     

拦河闸下游消力池陡坡段阶梯布置和研究

拦河闸下游河道河床下切、水位降低之后,其下游消力池需改造或重建,或者在保留现状消力池条件下,在现状消力池下游修建二级消力池,以确保拦河闸泄流的消能及其上、下游水流衔接过渡。通常,可在一级消力池下游陡坡段设置不连续的外凸型阶梯,增大陡坡段泄流消能率,以减小下游二级消力池的规模,节省工程投资。本文结合现有的研究成果,对拦河闸下游两级消力池之间陡坡段的外凸型阶梯布置和水力计算方法进行分析,并给出相应的算例,供类似工程设计参考。     

可降低开挖造价的高水头消力池

为了降低开挖造价,同时保证在高水头的工作状况下无气蚀现象发生,提出了一种新型的掺气消力池。现将在两条开敞式溢洪道上进行的模型试验综述如下:本文所提出的消力池(见图1)有一个掺气阶梯,一个斜坡,二排消力块,尾端还联接一个分布式堰,按不同流量要求渲泄尾水。这样设置的目的,是为了保证泄洪水跃在斜坡末端与第一排消力块之间产生。斜坡和消力块增进了水流稳定状况。水流的掺气,避免了气蚀现象的发生。利用下游分布式堰保     

弯曲河道上底流消能工布置试验研究

传统的底流消能工常布置在顺直河段,针对受实际条件限制必须在弯曲河道上布置底流消能工的技术难题,基于某水库工程的物理模型进行了试验对比研究。试验结果表明,所提出的主、辅两级消力池与导流消力墩这一消导结合的消能工结构在弯道段水流流态、消力池回流强度、弯道段坡脚冲刷强度等水力指标方面均优于传统直线型消力池布置方案和曲线型跌坎消力池布置方案,解决了弯曲河道段布置底流消能工的技术难题。     

高水头单侧渐扩消力池水力特性数值模拟研究

为研究单侧渐扩消力池水力特性,采用RNG k-ε双方程紊流模型,结合VOF方法,对消力池内水流进行了数值模拟。将计算得出的水面线、压强、流速与模型试验结果进行对比。结果表明:数值模拟与模型试验得到的结果基本吻合;深入分析发现,水流在渐扩侧尾部产生立轴漩涡;跃首旋滚横轴在渐扩侧向上游移动,跃尾横轴在渐扩侧向下游移动;对比计算紊动能和试验脉动压力发现,紊动能在一定程度上反映脉动压力分布情况;反弧段及消力池底板前部脉动压力较大,设计上应对这些区域加强防护。     

WebGIS在南阳灌区水资源管理系统构建中的应用

研究灌区植被供需水平衡的定量计算方法,以南阳灌区为实例构建了降水预测及需水计算数学模型.为了实现灌区的信息化管理,在开源WebGIS平台MapServer框架的基础上,构建南阳灌区水资源管理系统,为灌区水资源配置提供决策支持.     

浅谈沼气、水煤气、液化石油气三种气源掺混联供在南阳市管道燃气中的应用

沼气、液化石油气、水煤气三种燃气均为优质燃料，都可以单独作为气源使用，但要把三种气源有机地结合起来掺混综合利用，难度很大，本文重点介绍了三种气源的合理掺混比例，使用效果，共同行参考。     

Overland water and salt flows in a set of rice paddies

Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m⁻¹) and an infiltration rate of 5.8 mm day⁻¹. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day⁻¹), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day⁻¹ was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration.     

瓦房店市水果生产标准化发展研究

瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。     

金谷子耐旱TG118引种试种及推广应用

对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。     

对《种子法》存在问题的探讨

《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。     

Review of the Egyptian experience in implementing land drainage projects

About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered.     

和谐社会理论建设的几点哲学思考

在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.