潮州三百门电厂冷却水排放的数值模拟研究     

倪培桐  江洧 《中国农村水利水电》2004,(5):25-27

海湾及潮汐河口的冷却水工程研究近年来受到人们的重视，由于受到潮汐的影响，其冷却水布置及热污染特性比河道及水库型更为复杂。采用数值模拟的方法，首先对电厂附近的潮流特性及冷却水输移扩散进行模拟计算，研究了电厂近海水域的水动力结构及其对冷却水排放的影响，给出电厂取水温升及热污染范围，为电厂取水设计工作提供依据。  相似文献   

N480Q曲轴滚压机床滚压系统设计计算     

董丽涛  刘荣昌  薛隆泉  马淑英  王庆祝 《拖拉机与农用运输车》2007,34(6):27-28

本文对滚压刀具的结构形式和配置进行了讨论,设计了用于曲轴滚压加工的专用滚压头,对滚压加工过程中的功率消耗、滚压加工时曲轴的轴向变形量进行了计算,可为研制国产化的曲轴滚压专用设备提供帮助。  相似文献   

Managing the water balance of The Fayoum Depression,Egypt     

W. Wolters  Nadi Selim Ghobrial  H. M. Van Leeuwen  M. G. Bos 《Irrigation and Drainage Systems》1989,3(2):103-123

A study of the water balances of The Fayoum irrigated lands and Lake Qarun was made to investigate the management of the irrigation system and the efficiency of irrigation water use. The two water balances are strongly interrelated. The drainage flow to Lake Qarun and the water level of the Lake are in delicate balance. A rise in Lake level causes the inundation of adjacent land. Management of The Fayoum water balance assumes control over irrigation water flows, but this control has technical and organizational limitations. Also discussed is the influence of irrigation practices in The Fayoum on the water balance (e.g., the autumn flushing of fields and farmers' preference for not irrigating at night in winter). Notwithstanding a high overall efficiency, irrigation efficiency during the winter is low. The reasons for this are given, together with the constraints against improving system management. Improved uniformity of the division and application of irrigation water will enable a better technical control of flows and will result in better water management in The Fayoum. Abbreviations: FID — Fayoum Irrigation Department, 1 feddan (fe) — 0.4 ha, 1 mcm — 1 million cubic metres: an average annual flow of 3.17 m³/s gives 100 mcm, m³/fe.year — supplied volume (m³) per surface area (fe) per year: 1000 m³/fe.year equals 240 mm/year, MSL — Mean Sea Level  相似文献   

Division of irrigation water in The Fayoum,Egypt     

W. Wolters  Nadi Selim Ghobrial  M. G. Bos 《Irrigation and Drainage Systems》1987,1(2):159-172

The division of irrigation water in The Fayoum, Egypt, has been measured. Factors influencing this division are discussed: the hydraulic conditions at structures and canals, the operation regime of gates, lack of reliable gauge data for system operation, shortage of labour, and the water level in Lake Qarun. A deviation from uniform supply has been found for the entire Fayoum, but also along a lateral and sub-lateral. The reasons for this are discussed and suggestions for possible technical improvements of The Fayoum system are given.Abbreviations FWSBM Fayoum Water and Salt Balance Model Project - MSL Mean Sea Level at Alexandria - FID Fayoum Irrigation Department - mcm million cubic metres  相似文献   

Effects of arrangement of surge-rootirrigation emitters on growth,yield andwater use efficiency of apple trees     

LI Zhongjie  FEI Liangjun  HAO Kun  LIU Teng  CHEN Nanshu  ZHANG Quanju  HUANG Deliang 《排灌机械工程学报》2020,38(7):713-719

Six-year old apple trees were selected for field experiment. The objective of this study was to obtain the reasonable arrangement of surge-root irrigation emitters in apple orchards. There were three factors: the buried depth H( 25,40,55 cm),the horizontal distance L( 30,40,60 cm) between the emitters and the trunk of the experimental tree,and the number of the irrigation emitters N( 1,2,4). The effect of the arrangement of surge-root irrigation emitters on the growth,yield and irrigation water use efficiency( IWUE) of apple trees were studied in Northern Shaanxi where the irrigation quota takes 60%-75% of the field water capacity. The results showed that the arrangement of emitters for surge-root irrigation had a significant effect on apple tree yield and IWUE,especially,the yield and IWUE reached 28 388. 17 kg/hm2 and 16. 83 kg/m3 in treatment T3,respectively. At the same L and N levels( T1,T2,and T3),the yield and IWUE in treatment T3 were the highest,and the yields in treatments T1 and T2 were decreased by 26.22% and 31.48%,while IWUE is reduced by14.02% and 18.12% compared with T3,respectively. At the same H and N levels( T3,T4,and T5),the yield and IWUE of apple trees were decreased with increasing L level. Especially,when L was 30 cm( T3),the yield and IWUE were the highest. The same L and H levels( T3,T6,and T7) could promote the growth of apple trees when N was 2( T3). Compared with treatment T3,it was found that the increment of new shoots was decreased by 8.07%-18.71%,and the fruit diameter was decreased by 5.41%-9.11%. Therefore,two emitters should be arranged symmetrically on both sides of an apple tree,each was buried at a 40 cm depth and 30 cm away from the trunk of the tree to effectively improve the yield and IWUE of the apple tree in mountainous areas in Northern Shaanxi.  相似文献   

万亩农田节水灌溉综合开发区的规划与效果     

李锡录  徐征和  王玉太  张涛 《中国农村水利水电》1993,(12)

通过对开发区农田生态系统的综合论证,提出研究目标、技术决策和规划原则,采用水利、农业相结合的节水技术体系,运用汇水、输水、调水、配水相结合的方式,联合调用地表、地下水资源,提高水的利用率,为中低产贫水区大面积推广综合节水灌溉提供可行的技术模式。  相似文献   

高度重视小型农机具利用率减少资源浪费     

迟振福 《中国农机化》2004,(6):88-89

为解决随着大、中型联合作业机具和跨区作业的发展．农村中占机具总量大部分的小型机具出现闲置．造成了农机资源的浪费问题，提出了4条提高利用率的途径和农机主管部门应做好的5项工作。  相似文献   

关于传动轴节叉的机加工工艺分析     

雷发林  王贵伟  相茂平  高云江 《农业装备与车辆工程》2007,(10):52-53

数控机床在机械制造业中的大量使用,使产品质量和加工效率显著提高。一个产品,可用多种数控设备加工都能保证质量的情况下,加工效率的高低、设备投资及运行的日常费用就成为选择何种数控设备的关键因素。本文分析了用全功能数控车床及立式加工中心加工传动轴节叉的工艺方案,比较了两种方案的加工效率、设备投资及运行的日常费用,为设备采购提供技术支持。  相似文献   

开发高效农业 拓宽增收之路     

SUN Yuan-hong WANG Ji-gang 《农机具之友》2007,(7)

近年来,沛县在农业综合开发中,坚持以改善农业生产基本条件为重点,以示范区项目建设为突破,以农业产业化开发为主线,以农业增效、农民增收为目标,着力培育优势主导产业、开发特色高效农业,大大提高了农业综合开发社会经济效益。  相似文献   

离心泵节能技术工作的改进措施     

邱明杰 《排灌机械》2007,25(5):65-68

针对离心泵节能问题,从设计、制造、配套等技术角度进行了阐述分析,提出可通过CAD/CFD技术的应用、传统设计方法的提高和改进、CAM技术在泵制造过程中的应用、提高铸造技术水平、调节转速以及提高离心泵选型的设计水平等措施来实现高效节能的目标。并通过分析目前存在的制约节能工作开展的问题,提出改进离心泵节能工作的实施办法。  相似文献