EFFECTS OF HYDRAULIC AND GEOMETRIC PARAMETERS ON DOWNSTREAM CAVITY LENGTH OF DISCHARGE TUNNEL SERVICE GATE

Aerators on discharge tunnel outlets may be regarded as an effective protection against cavitation erosion. The air entrainment of aerators is governed by a number of independent parameters, including the bottom slope of releasing free-surface flow tunnel downstream of service gate, the end top slope of pressure tunnel, the height of step, and the Froude number at take-off. During eight phases of experiments, the effects of above-mentioned parameters were observed on the cavity length downstream of the fully open operating service gate of a discharge tunnel. The results show that, the bottom slope of releasing free-surface flow tunnel has obvious effect on the cavity length as well as the Froude number at gate take-off. The effect of the step height variations on the cavity length could be considered for higher discharges and steeper tunnel top slope, particularly in higher discharges, resulting in shorter cavity length downstream of service gate.     

THEORETICAL AND EXPERIMENTAL STUDIES OF HYDRAULIC CHARACTERISTICS OF DISCHARGE TUNNEL WITH VORTEX DROP

The velocities at given points in the volute chamber,the contracted section and the vertical dropshaft of a discharge tunnel with vortex drop were measured by a small specially designed L-shaped tube,as Laser Doppler Velocimetry(LDV) or Particle Image Velocimetry(PIV) would not work there due to the special structure of the discharge tunnel with vortex drop.Hydraulic empirical formulas were proposed to predict the velocities and the angles of the velocities made with the vertical direction θ.The theoretical analysis results were in good agreement with experimental data.Therefore,the method proposed in this paper can be used to analyze related characteristics of discharge tunnels with vortex drop.Additionally,different model scales were considered to predict the cavitation characteristics on the wall of a dropshaft in practical engineering.     

EXPERIMENTAL INVESTIGATION OF EMERGENCY GATE SHUTTING FOR ORIFICE TUNNEL

In the process of the emergence gate shutting of one orifice tunnel, a big noise and great vibration may be observed in the mid gate chamber. In order to guarantee the working safety of orifice tunnels, an experimental investiga-tion is carried out in Sichuan University. In the investigation,the fluctuation pressure along the tunnel and the wind velocity in the entry of emergency gate are measured. In the mean time, the fluid state in orifice tunnel is carefully observed and analyzed. The reasons of the noise and vibration in the mid gate chamber are found out and some countermeasures are presented in this paper. The conclusions are useful to the ori-fice tunnels with high water head and huge discharge.     

HYDRAULIC CHARACTERISTICS OF PLUG ENERGY DISSIPATER IN FLOOD DISCHARGE TUNNEL

The hydraulic characteristics of three types of plugs, namely, the single plug, the stepped plug and the gradually contracted plug were studied by means of experimental and numerical simulations. Main research findings are as follows. For the single plug, the pressure recovery lengths inside and after the plug range from 0.63–1.05 times and 2.02–2.84 times of the tunnel diameter, respectively. For the stepped plug, the lengths are 0.24–0.32 times and 1.62–2.84 times of the tunnel diameter, respectively. The best ratio of the inlet diameter to the outlet diameter of the gradually contracted plug can be expressed by a linear function. The relationship between the head loss coefficient and the area contraction ratio is obtained. The incipient cavitation numbers of different plugs are experimentally and numerically determined, and the incipient cavitation numbers are expressed by a formula. Model experiment with scale of 1:50 was carried out on a pressure tunnel with three-stage gradually contracted plugs. The results show that this type of energy dissipater is suitable for spill tunnels of high head (nearly 200 m) and large flow rate (nearly 2500 m³/s).     

谈大坳水利枢纽工程导流隧洞的施工

阐述了大坳水利枢纽工程导流隧洞的施工。重点介绍了砼钢模台车技术施工工艺及其运用情况，结合工程实践，谈几点施工体会。     

泄洪闸门自动监控集成容错技术

从水电站安全运行实际需要出发，将计算机技术，PLC技术，现场总线技术应用于水电站闸门监控系统中，以改善现有水电站闸门监测，控制中存在的各种问题，并成为今后水电站闸门监控系统发展的新方向，文中重点研究了闸门监控系统和组建网络中的容错问题，指出在闸门自动监控系统中需要考虑的容错因素，并提出了多种容错策略，以达到提高系统可靠性的目的。     

人字形水力自控钢闸门在高安市排涝涵闸中的应用

结合工程实例阐述了，人字形水力自控钢闸门在小型排涝涵闸中的应用．     

EXPERIMENTAL FEEDBACK ON THE INVESTIGATION OF HYDRAULIC CHARACTERISTICS FOR THE SHIP-LOCK FILLING AND EMPTYING SYSTEM OF TGP

Where hydraulic characteristics of ship lock filling and emptying system are concerned, there are much bigger differences between prototype and model experiments. Based on the results of the prototype experiments fur the Three Gorges Project （TGP）, experiments on the feedback model were conducted of the ship-lock filling and emptying system, by means of technologies of drag reduction, under similar conditions as the operation of the prototype project. The experimental results show that the difference of drag co efficient reached-44% hetween the prototype and the model for the filling and emptying system of the ship-lock No. 3 for TGP and the difference of discharge coefficient was ahout 33% between them. The technologies of drag reduction are more efficient in the simulation of a ship lock filling and emptying system in order to he consistent for discharge, water level, time average pressure and pulsating pressure between prototypes and models.     

改善水工钢闸门承载能力的探讨

利用焊接特性(如焊接变形，焊接内应力等)，改革生产工艺，使得闸门横向弯曲凸向上游，使上游面产生内拉应力，下游面产生内压应力，从而抵消一部分由水压力产生的外应力，改善钢闸门的承载能力。     

A STUDY OF WAVE CHARACTERISTICS AFTER HYDRAULIC JUMP

An experimental study of wave characteristics after jump in energy dissipation ofhydraulic jump is presentedinthis paper.It was completed in a trough with a horizontal bed,40cm in width.Various elements of wave were measured,the wave form,period,spectrumand its attenuation along course are analyzed,and the physical mechanism of wave is discussed.An expression of the maximum wave height after jump is given,based on the measured data.Some measures to diminish wave are discussed preliminarily also.     

弧形闸门后拉式在三门滩工程中的应用

弧形闸门是一种常用的门型，广泛地应用于水利水电工程中，但其启吊方式一直没有很好的妥善解决，惯常的前拉方式，因钢绳长期浸泡水底而产生锈蚀，给为担忧及更换钢绳造成困难，在三门滩水利枢纽溢洪道露顶弧门中，选用了ＱＰＱ型启闭机后拉式起吊弧门，克服了这一缺陷，获得了很好的运行效果。     

STUDY ON THE CHARACTERISTICS OF LONG TERM DISCHARGE OF A CATCHMENT

1.　INTRODUCTIONItiswellknownthatthecharacteristicsofthecatchmentdischargewillchangewithlanduse.Inthispaper,thefocusistodiscussthemodeloflong-termdischargeofcatchmentwhichincludestwokindsoflanduse:oneisforestattheupperpartofthecatchment,theotherispaddyfieldatthelowerpartofthecatchment.Therehavebeenmanytypesofmodelsproposedforrunoffanalysis.Foralongtime,tankmodelhasbeenwidelyusedfordischargeanalysis.Attheverybeginning,therewaslessphysicalmeaning.Withtheintroductionofphysicalanalysisofhydr…     

THEORETICAL AND EXPERIMENTAL STUDIES OF THE FLARING GATE PIER ON THE SURFACE SPILLWAY IN A HIGH-ARCH DAM

The experimental studies of the flaring gate pier applied on the surface spillway in a high-arch dam show that a shock-wave will appear when the pattern of the flow is kept as super-critical. Meanwhile, the water depth at the outlet increases significantly, the flow moves downward in different directions, and the plunging jet is in a narrow and long shape, with a full longitudinal diffusion. In addition, the variation of the flaring gate pier design parameters affects little the discharge capacity of the surface spillway, these parameters including the contraction ratio , the contraction angle and the spillway chute angle . The pressure on the bottom of the spillway increases along the way and reaches the maximum before the outlet, and then decreases rapidly. Due to the flow impacting, the pressure on both sidewalls increases abruptly at the turning line of the flaring gate pier. To see the characteristics of the flow in the flaring gate pier, a simple calculation method is suggested based on the conversation of energy and mass, and the calculation methods for the jet trajectory and the horizontal length in air are also proposed. The results are found in good agreement with experimental data.     

EXPERIMENTAL STUDY ON CAVITATION AND WATER-WING FOR MIDDLE-PIERS OF DISCHARGE TUNNELS

1. INTRODUCTION Discharge tunnel ,specially , deep-water one , is a sort of usual flood discharge structure with pressure flows in the inlet section,followed pres- sure flows or free flows ,and is used in flood dis- charge or emptying a reservoir , and/or washing sands .For deep-water tunnels ,the designs were u- sually adopted of the manners of the shaft ,of the inclined sectionin the inlet or in the outlet ,called visually as “Dragon up one’s head”or “Dragon down one’s tail”in Chi…     

A GENERALIZED EXPLICIT SOLUTION OF THE SEQUENT DEPTH RATIO FOR THE HYDRAULIC JUMP

1.INTRODUCTIONIn most cases the hydraulic jump occurs in thetransition regi me from supercritical flow to subcritical flow.Hydraulic jumps have been widelyused for energy dissipation in hydraulic constructions.So,a number of researchers have paid theiattention to it for a long ti me.The purpose of hydraulic jump analysis is todetermine the sequent depth ratio,relative energydissipation andthejumplength.The sequent depthratio and the relative energy dissipation can be determined by momentu…     

汤浦水库引水隧洞工程Ⅰ标段隧洞洞挖爆破设计与施工概述

简要介绍了浙江省汤浦水库输水隧洞工程洞挖爆破的设计、施工及实施效果.     

HYBRID SIMULATION OF THE HYDRAULIC CHARACTERISTICS AT RIVER AND LAKE CONFLUENCE

The hydraulic characteristics at the confluence reach of river and lake are influenced by multiple factors such as inflow,topography and vegetation resistance,and are very complicated.In this article,the confluence reach of Yangtze River and Dong-ting Lake is selected as a special example and a hybrid model is built to study the flow at this confluence,with the consideration of the interactions between aquatic vegetation and flow.Validation tests and calculations show that the model is effective and highly accurate.The simulations show that the separation levee at the confluence reach may change the discharge capacity in the flood plain,which would be enhanced in the upper reach of the levee,hardly changed in the middle reach and reduced at the lower place.Moreover,the separation levee also limits the water exchange between the Yangtze River and Dong-ting Lake.     

THE TRANSIENT AERODYNAMIC CHARACTERISTICS AROUND VANS RUNNING INTO A ROAD TUNNEL

In this article,the processes of vans running into a one-way two-lane road tunnel are simulated numerically using the dynamic mesh technique and RNG k ? ε turbulence model.The transient aerodynamic characteristics around vans are obtained in three cases:a single van,two vans side-by-side and two vans one after another running into the tunnel,respectively.Through a comparison with the results of the wind tunnel experiment,the transient simulation method is verified.The results show that,when a van runs into the tunnel,the aerodynamic drag coefficient increases near the tunnel entrance,and after entering the tunnel,the side force is generated,pointing to the tunnel wall nearer to the van.When two vans run into the tunnel side-by-side,their drag coefficients increase by 50%,and the side force varies sharply with directions changing twice near the tunnel entrance.When two vans run into tunnel one after another,the aerodynamic characteristics around the van in the front is similar to that of a single van,but the aerodynamic forces on the van behind do not have obvious change.Among the three cases,the aerodynamic forces have a sharp change when two vans run side-by-side,so driving side-by-side into a tunnel should be avoided for safety.     

SILCO5静止励磁系统灭磁回路的计算和分析

0 引言SILCO5微机静止自并励励磁系统是GE公司比较成熟、可靠性高的定型产品,GE公司将其作为巨型发电机的最理想的配套励磁系统.其主要功能有:最大励磁限制、最小励磁限制、电力系统稳定器、转子过电压保护、发电机转子I2T保护、电压互感器断线保护等.由于其运行可靠、性能优良、功能齐备,国内已有二滩、隔河岩、刘家峡等巨型水电站选用该系统.随着GE公司被三峡工程中标,SILCO5微机静止自并励励磁系统将可能和GE公司的巨型发电机配套,出现在世界上最大的水电站中.但我们通过计算和分析发现,其灭磁回路的设计有较大缺陷.本文以二滩设备为例对此加以分析.