Vertical Lift Gates Research Articles

Influence of Gate Lip Angle on Downpull Forces for Vertical Lift Gates

Underestimation of hydrodynamic downpull force is one of the most dangerous risks when operating a vertical lift gate. The downpull force acting on the gate is affected by gate geometry. The purpose of this study is to investigate the influence of gate lip angle on the downpull force of vertical lift gates using Flow-3D®, a commercial CFD software. Simultaneously, the performance of Flow-3D® in estimating downpull force is evaluated. The influence of gate lip angle on the downpull force is investigated by simulating flow under different gate lip angles at different gate openings. The setup of the numerical model is similar to the experiment setup used by Naudascher in 1964. Results show that the higher the gate lip angle, the higher the bottom downpull coefficient. Majority of the numerical results show good agreement with the experimental results. Case 2 at 30% gate opening and case 3 at 50% and 60% gate opening showed obvious deviation from the experimental results due to flow separation occurred at the gate lip. This could be due to the limitations of the Fractional Area-Volume Obstacle Representation (FAVOR) method employed by Flow-3D® in which gate lip part that is smaller than mesh cell could not be exactly reproduced.

Effects of Dam Gate Geometry on Pressure Variation Aided by Map Presentation

The dam vertical lift gate is one of the most important operational parts that regulate the high head water flow to power plants as well as satisfying the water needs for projects and areas downstream of the dam. Due to the high water levels in the dam reservoir, the gates are subjected to many hydrostatic and dynamic pressures that affect their performance and stability. Hence, it became necessary to study all parameters that may cause excessive pressures which may lead to reduce the gate performance efficiency or even cause failure. In the current study, the pressure distribution along the bottom surface of various gate lip shapes has been measured and presented as contour maps using Surfer software. The pressure fluctuation was observed to indicate the intensity of flow separation and reattachment which, in turn, causes a vibration that may threaten the stability of the gate or impede its proper functioning. The pressures in this study are expressed as a dimensional coefficient through the integration of pressure measurements at 8 points distributed over the bottom gate surface. The high intensity of pressure attachment indicates the critical condition for hydraulic design.

Variation of Pressure Coefficient Along Bottom of Dam Vertical Lift Gates

The vertical lift gates are exposed to hydrodynamic forces that arise as a result of pressurized flow established by the large-scale effect of the water levels in the dam reservoirs. The most influential forces are those that are applied on the gate vertically upward due to the intensity of the flow under the gate and downward as a result of passage flow above the gate. The difference between these two forces generates a downpull force that is the most important gate stability indicator. In this research, an arbitrary hydraulic model was constructed to investigate the effects of many gate lip shapes with and without extensions on the magnitudes and distribution of bottom pressure coefficient when the values of flow and shaft gap width ratio (b2/bl) are constant. The results indicate that the bottom pressure coefficient appears to vary uniformly with gate openings and seem to be influenced effectively by the gate lip geometry. So, for the given value of (b2/bl), the top pressure coefficient regarding the downward force will mostly be with uniform changes and hence the downpull coefficient depends on the magnitudes and distribution of bottom pressure coefficient. An attempt by using the correlation coefficient of Statistical Package of Social Sciences was made to determine whether the pressure fluctuation is significantly shown at the bottom pressure distribution curve, which in turn is considered as appropriate indicator for the vibration occurrence. Full range of maximum bottom pressure coefficients in a matrix form is made to assist in design purposes. The results are analyzed and many conclusions are obtained.

Swing gate generated dam-break waves

ABSTRACTThe study presented herein examines the influence of a swing gate on the generation of dam-break waves. Recently, researchers have been using swing gate systems, as opposed to vertical lift gates, as swing gates can be more economical as well as simpler to design and construct. The experimental programme presented herein examines the influence of the swing gate opening time on the generation, propagation and evolution of the dam-break wave profile and hydrodynamics downstream of the gate. Wave profiles were measured at several locations downstream of the gate to determine the influence of the gate opening time on its characteristics. The gate opening time was demonstrated to have a linear dependence on the wave arrival time, likely due to the gate interference in the formation of the wave. The wave profile, however, was not found to be significantly influenced by the gate opening time.

An experimental study on the discharge characteristics of underflow type floating vertical lift gate at free-flow condition

An experimental study on the discharge characteristics of underflow type floating vertical lift gate at free-flow condition

100 Successful Years of Vertical Lift Gates of Bhatghar Dam—Design, Manufacturing, Erection, and Maintenance: A Case Study

The Bhatghar dam is having 81 vertical lift gates (fixed wheel type) on waste ways. The design of these gates is so beautiful and based on simple principles of science and engineering that these gates outlast for 100 years without failure, performing their intended purpose satisfactorily. It is achieved by meticulous design, manufacturing, erection, subsequent use and maintenance practices. It has become guiding and inspiration for further practices in design, manufacturing, erection, and maintenance for dam gates as well as all other disciplines of engineering today.

Pressure Coefficients of Curved Lip of Vertical Lift Gate in Dam Tunnels

Pressure Coefficients of Curved Lip of Vertical Lift Gate in Dam Tunnels

Pressure Coefficients of Curved Lip of Vertical Lift Gate in Dam Tunnels

The vertical lift gate shaft is installed across the dam tunnel to regulate the flow rate passing toward the downstream side to satisfy the water demand in addition to the power generation requirements. The flow through the shaft is mostly divided into two parts, over and below the gate, and as a result, two forces will be created, vertically ,downward and upward on both top and bottom gate surfaces. The difference between these forces produces so-called hydrodynamic force or hydraulic downpull force which has a vital effect on gate operation, so that in the case of negative values, this force will prevent the closure of the gate. The downpull force influences by many parameters, however, the geometry of gate is considered as one of the most common effective factor that influence the values and behavior of downpull force. In present study, physical hydraulic model is used to assess the effects of different rounded gate lip shapes on downpull force with respect to different gate opening ratios. The variation of bottom pressure coefficient along the gate surface has also been studied and the results are discussed.

Experimental Study of Flow-Induced Vibration of Lens-Shaped Vertical Lift Gates

AbstractAn experimental study of two model-scale lens-shaped vertical gates consisting of a truss and plate is presented. Experimental results are applied to the design of the new Nakdong River gates in Busan, South Korea, for flood and irrigation control. Experimental models are developed using finite-element (FE) analysis. A 1:31 scale model is constructed for the short gate (47.5 m wide, 8.5 m high at full scale) using acrylic, and a 1:61 scale model is constructed for the long gate (95 m wide, 8.5 m high at full scale) using an acrylic truss and acrylonitrile butadiene styrene plate. Natural frequencies of the model gates are measured and calibrated with FE predictions. Dynamic characteristics of the flow-induced vibration are compared for two gate orientations. Vibrations of the model gates in Orientation 1 (plate convex in the upstream direction) and Orientation 2 (plate convex in the downstream direction) are measured for various flow conditions. A combination of bottom opening heights and upstream...

Minimising interference of hydraulic jump with hydraulic gates

Hydraulic gates are hydraulic control equipments to control the flow of water in any water resources project. The location of horizontal girders are influenced by type of hydraulic loading, fixity of it with gate and interference of hydraulic jump formed downstream of gate. When a high-head vertical lift gate is opened with a small opening, a hydraulic jump forms downstream, which interferes with the bottom-most horizontal girder. In the present paper, an attempt has been made using numerical experiments to highlight the effect of interference of hydraulic jump on horizontal girders of vertical lift hydraulic gate. For the numerical experiments, the design thickness of gate as 1.2 m with water head (H) as 13.7 m (without tail water) is considered. Hydraulic jump profiles for gate openings 0.05, 0.1, 0.2, 0.3, 0.4 and 0.5 m have been discussed. The methodology adopted leads to a bottom slope estimation which for a water pressure head of 13.7 m and a vertical lift gate of thickness 1.2 m leads to a bottom slope 30. Thus, this work provides a preliminary basis for minimising interference effects in fixing the bottom-most horizontal girder under high heads, dealing with an important field problem that has not yet been tackled to a satisfactory level.

Hydraulic studies of pressure distribution around vertical lift gates

Hydraulic studies of pressure distribution around vertical lift gates

Cavitation study in bottom outlet gate slots by pressure fluctuation

Around the high head gates as the velocity is too high, every non uniform object such as a slot makes the flow too disturbed. Vertical-lift gate required recessed slots in abutments for the movement of the gate slides. The flow of water across the slots causes flow separation at the upstream lip of the slot and reattachment on the downstream side. Eddies are set up within the slots and vortices are formed. Thus, under higher velocity flow conditions (due to high head), cavitations can occur within gate slots by fluctuations. In addition of cavitations the pressure fluctuation can make impacts on the structure too. This hydraulic phenomenon can be occurred with serious damages. In this research, experimental data is used based on measuring pressure fluctuation by pressure transducer under an experimental model which has built and taken place in Michelle Hydraulics Laboratory at civil engineering department of the University of Melbourne. Pressure fluctuations were measured under two group of seven piezometers along the two gate slots for gate positions of 10%-10%, 30%-10%, 50%-10%, 70%-10%, 30%-30%, 50%-30%, 70%-30%, 50%- 50%, 70%-50%, 70%-70%, head condition behind the gates were constant for all tests. The results were analyzed and presented as Cavitations Index in two slots. The cavitation indexes were calculated in based 0.1% probability levels of fluctuation pressures. Other probability levels contained 1%, 5% as higher pressures and 95, 99 and 99.9% as higher pressures, were studied in this paper.

Numerical analysis of hydrodynamic forces due to flow instability at lift gate

A numerical method, being a combination of the vortex method and the boundary element method, is used here to predict the two-dimensional flow field in the vicinity of an underflow vertical lift gate. In practice, tunnel-type flat-bottomed lift gates experience strong hydrodynamic loading, due to vortex detachment from the gate bottom edge, and near-wake velocity fluctuations. This paper presents a stream function, and velocity and vorticity distributions for two gate gaps. The vortex detachment mechanism is described and the vortex shedding frequency, expressed as a Strouhal number, is presented. The predicted velocity and vorticity fields are then used to calculate the pressure distribution on the gate surface by the boundary element method. The time histories of the lift and drag coefficients are presented. The proposed numerical method has been validated by the measurements of the downpull coefficient for the flow around the lift gate.

Design Guidelines for Spillway Gates

This article discusses the most common types of spillway gates including radial gates, vertical lift gates, and flap gates including inflatable gates, and their application. Design considerations for each type are explained. Design and application considerations for different types of spillway gate operators are also included. Items covered for gates include gate geometry, gate proportions, location of gate hoists, location of gate trunnions, trunnion anchorage arrangements, gate seals and sealing arrangements, use of dogging devices, wave deflectors, flow splitters, corrosion protection including use of cathodic protection, and ice problems associated with spillway gates. Items covered for hoists include selection criteria for hydraulic and mechanical hoists, functional requirements of the hoists, use and type of position indicators, normal speed of opening and closing, use of automatic controls, the need for maximizing the minimum opening, and automatic stopping of the gates at set intervals to prevent unintentional spilling. Permissible leakage rate through the gates is also included.

Pressure fluctuations on gates

Mean and fluctuating pressures on various geometries of vertical-lift gates have been measured and analysed. The influence of various hydraulic parameters and the magnitude of the gate opening on mean and r.m.s. pressure fluctuations and their spatial correlations has been investigated. The variations in the distribution pattern, spatial correlations and intensity of pressure fluctuations have been studied when the gate is forced to vibrate with a single degree-of-freedom in the vertical direction at specified frequencies and amplitude. Total intensity of fluctuating pressures on vibrating gates has been obtained by integrating the r.m.s. pressure fluctuations over the gate thickness. The distinct peak in the total intensity of fluctuating pressure on the gate indicates the presence of a dominant frequency which is considered to be the critical condition for the design of hydraulic control gates.

Self-excited vibrations of vertical-lift gates

(1986). Self-excited vibrations of vertical-lift gates. Journal of Hydraulic Research: Vol. 24, No. 5, pp. 391-404.

Improved design of a deep vertical-lift gate

1. Redesigning of the framework of a deep vertical-lift gate by replacing the multibeam framework by a two-beam and the four-support system by a three-support makes it possible to dispense with grooves in the lower part of the walls of the opening and to eliminate off-design loads in the framework and supports, which increases the operating reliability of the proposed type of regulating gate with increased load-bearing capacity and heads. 2. To increase the load-bearing capacity of the slide supports and their life, to reduce the calculated coefficient of sliding friction, and to eliminate irreversible plastic deformations in the antifriction element from local overloads, it is expedient instead of the traditional supports transferring the load by linear contact of the antifriction slide with the rail to use two-level supports with a deformation compensator of the gate framework. Such supports have contact with the embedded parts along a plane.

Operating experience and design problems of surplusing works of high-head hydroelectric stations

1. When designing new hydrostations it is necessary to provide for permanent surplusing works which are used for temporary diversion during construction. Along with overflow spillways it is necessary to provide deep spillways for discharging floodwaters and for emptying the reservoir. 2. On temporary surplusing works small outlets for fine regulation of the discharge should be provided for along with the large outlets covered by vertical-lift gates. 3. It is necessary to continue the development of high-head counterweight gates and to manufacture prototypes and test them on a high-head stand and under actual conditions for the purpose of their introduction at high-head hydrostations.

Development and improvement of erection of mechanical equipment and metal components of hydraulic structures over the past 50 years

1. The development and improvement of the erection of mechanical equipment and metal components in the USSR over the past 50 years is inseparably linked with the solution of a large number of problems raised by wide hydraulic and hydropower construction. 2. For the erection work stages, the increase in the possibilities of Soviet machinery manufacture is characteristic, and, as a result, there has been a significant expansion of the stock of construction-erection mechanisms and transportation means. 3. For the development of mechanical equipment of high-head hydraulic structures, considerable volumes of analytical, experimental-research, and design work have been carried out. Data for design of the load-carrying elements of gates under dynamic loads have been obtained, and sealing elements, sliding and rolling supports for vertical-lift gates, and support hinges for radial gates have been developed. The coefficients of sliding friction of different types of seals have been experimentally determined, and problems of design, fabrication, and erection of high-head gates intended for operation under heads of up to 200 m have been solved. 4. A general characteristic of modern projects for the carrying out of erection of mechanical equipment and metal components is the striving for maximum reduction of the cost of hydraulic construction and of the times of completion, increase in the reliability and improvement of hydroelectric plant operation conditions, and use of new techniques and work automation. 5. During the past 50 years, the journalGidrotekhnicheskoe Stroitel'stvo has described and summed up the gathered erection experience, and has developed in the reader the capacity to apprehend, understand, and value hydraulic construction.

High-head vertical lift gates

1. The presence of high-head gates whose performance has been verified is presently the main unused potential for improving the layout, reducing the cost, and increasing reliability when designing high-head hydroelectric stations, especially of the Nurek or Rogun type, the construction of which requires driving numerous tunnels for the construction period. 2. During a relatively short period considerable work has been accomplished in the area of creating high-head vertical lift gates, as a result of which it was possible to use them in the construction of such large objects as the Nurek hydrostation. 3. The creation of reliable vertical lift gates requires a qualitatively new approach in their manufacture and assembly. 4. It is necessary to avoid dispersing means and resources for the creation of numerous new types of gates, considering in this case the use of balanced systems the least acceptable of all for vertical lift gates. 5. The emergency-guard ring-follower gate of the spillway of the Inguri hydrostation should be considered the most reliable and most perfect of the gates designed by special designs departments of the State All-Union Construction and Installation Trust (Gidromontazh), which is suitable for use in conduits in both the construction and operating periods.