对迷宫堰的研究

迷宫堰是岸边无闸溢洪道进口采用的堰型之一。其堰顶轴线在平面上形成首尾相接的三角形、梯形或矩形,状似迷宫,故称为迷宫堰,也有人称为锯齿堰。迷宫堰最主要的特点是在不增加泄水建筑物所占河谷宽度的情况下,泄流能力数倍于直线堰,有利于工程布置。无论对于改建还是新建工程,在满足同一前提条件下,用迷宫堰比用其它堰型更为经济。本文详细的介绍了迷宫堰的分类、基本参数、过水流态、影响水力特性的因素及现有研究成果和存在的问题。     

闸管灌配水口的优化设计

闸管灌是一种可实现精确灌溉的田间配水技术,配水口是闸管灌系统的重要设备之一,因此配水口的研究对闸管灌的推广应用具有重要意义。优化设计了两种结构简单、运行可靠的配水口,并对其水力学特性进行了研究。配水口水力学特性试验以配水口开度和配水口前的压力水头为影响因子,通过试验得到了配水口的流量—压力—开度关系,在此基础上,探讨了开度对压力敏感系数的影响。研究表明,优化设计的配水口压力敏感系数较小,且比较稳定,有较好的应用前景。     

竖流式沉淀池结构特性研究

介绍了采用三维有限元方法对某地面竖流式沉淀池进行的结构计算,根据计算结果,完成了施工图设计。该沉淀池已建成近一年,运行情况良好。     

HYDRAULIC CHARACTERISTICS OF SLIT-TYPE ENERGY DISSIPA-TERS

Slit-Type Energy Dissipater(STED) has been a kind of important devices for energy dissipation.The flow through the STED is longitudinally extended and the velocity is decreased by means of the cross-section increase of the flow,which is closely related to geometric and hydraulic parameters of the STED.Therefore,it is necessary to investigate and control the hydraulic condi-tions through the STED,including the nappe section form,the conversion condition,and the effect of energy dissipation with the geometric and hydraulic parameters.In the present work,"I-type" and "T-type" nappe forms were experimentally classified,the con-version conditions of the nappe forms were empirically provided,and the effects of geometric parameters of the STED on energy dissipation were roughly analyzed.It is concluded that the contraction angle of the STED is a key factor influencing the hydraulic characteristics of the STED.     

MOTION OF TRACER PARTICLES IN A CENTRIFUGAL PUMP AND ITS TRACKING CHARACTERISTICS

The Basset-Boussinesq-Oseen (BBO) equation can be used for most flows to trace the motion of a particle, but in a centrifugal pump, among the forces that act on the particles, one should also include those due to the impeller rotation, as additional effects. This paper firstly reviews various approximations of the BBO equation for the motion of dispersion particles in a viscous fluid. Then based on the motion equation for particles in low Reynolds number centrifugal pumps, a formula for calculating the tracking characteristics of tracer particles is deduced through the Fourier integral transformation. After that the deviations of the particle motion from the fluid motion, as predicted by the various approximations, are discussed and compared. At last, with an emphasis on the Particle Image Velocimetry (PIV) results, the tracking characteristics of particles are estimated. Also, advantages and disadvantages of different tracer particles are discussed and suitable tracer particles for application in PIV studies for flow fields in centrifugal pumps are suggested.     

消防恒压泵的水力特性与设计选型要点

消防恒压泵又称部分流泵或切线泵,因其流量扬程特性曲线平坦、结构简单、通用化程度高、维修方便等优点,在消防给水中得到大量应用.但是,消防切线泵的结构与常用的消防离心泵不同,其水力特性存在较大的差异,切线泵具有断流特性、不具备并联工作条件、水泵效率相对较低、启泵工作点有一定要求等,设计时一定要针对其水力特性采取相应的技术措施.同时,根据消防给水系统具体情况比较切线泵与离心泵性能的优缺点,扬长避短合理选择泵型,使消防给水系统更加完善,满足工程使用要求.     

蜀河水电站机组过速保护技术特性

文章介绍了蜀河水电站机组过速保护系统的技术特性、结构、功能、运行维护中存在的问题及其设置的重要性等,着重对日常机组过速保护系统的运行维护作了探讨。     

三峡库区重点珍稀濒危植物物种

一、荷叶铁线蕨荷叶铁线蕨是铁线蕨科、铁线蕨属的多年生常绿草本植物,现仅知分布于三峡库区重庆市万州区和石柱县,它是三峡库区的地方特有植物,也是国家第一批公布的二级重点保护植物。     

云南松华坝水库径流变化特性分析

松华坝水库是滇池流域内唯一一座大型水库,是具有防洪、城市供水、灌溉、发电等综合利用功能的大(二)型水利枢纽工程。分析该水库的径流变化特性,对于合理利用其水资源具有重要的现实意义。以松华坝水库1952～2009年(水文年)的径流系列为依据,对系列的代表性、入库径流的变化趋势、年内及年际变化等进行了分析,结果表明,其入库径流年际变化较大,年内分配极不均匀,径流均值虽然随系列的增长呈逐年减小的趋势,但系列均值变化在一定范围内基本稳定。