Wicket Gate Research Articles

Notes: Turbine-Passage Mortality of Juvenile American Shad at a Low-Head Hydroelectric Dam

The immediate (1-h) turbine-related mortality of juvenile American shad Alosa sapidissima at the Hadley Falls Hydroelectric Station on the Connecticut River, Holyoke, Massachusetts, was estimated to be 0% ± 14.5% (95% confidence interval) at the 35% wicket gate opening and 2.7% ± 16.2% at the 100% opening. We used the HI-Z TurbˈN tag-recapture technique, which helped minimize control mortality and maximize recapture rates. Earlier literature estimates of turbine-related mortality (up to 82%) of juvenile alosids in passage through Kaplan turbines, in our view, were substantially overstated due to either low recapture rate, high control mortality, or both.

Optimal design of spiral casing tongue and wicket gate angle by decomposition method

AbstractA method of optimal design of Francis turbine tongue and wicket gate angle for given spiral casing is proposed. The potential flow in the doubly connected domain is decomposed into basic and circulation flows. The intensity of circulation is then calculated by the least‐squares method minimizing the error function equal to the sum of squares of differences between given and calculated circumferential velocities in the outflow boundary nodes. It is shown that the error function has a sharp minimum, which qualifies the proposed method as well defined. For given numerical example, the variations in the outflow velocity angles are much smaller for optimal than for already used non‐optimal design. A finite element method is used, with originally developed pre‐ and post‐processor and frontal solver suited for personal computers.

Experimental Loss Analyses in High-Specific-Speed Hydroturbines with Adjustable Blade Runner. 3rd Report, Runner Friction Losses and Friction Coefficients.

This third report deals with friction losses in adjustable blade runners for axial-flow hydroturbines. A method is proposed to extract the friction coefficient for the runner loss from the measured performance characteristics of bulb turbines. As a result of the loss analysis for two model bulb turbines based on the above method under a wide range of runner vane setting angles and wicket gate openings, an algorithm is presented for computing the friction loss in a runner using the well-established friction coefficient for a flat plate with the same Reynolds number and surface roughness as the blade at the root mean square radius.

Automatic generation control for hydro systems

The authors present the decision of an automatic generation control (AGC) system implemented with digital computers that periodically sample tie-line real power flows, line frequency, and generator power outputs. These analog signals are measured at 2-5 intervals and combined with desired interchange to obtain the area control error (ACE). The ACE digital quantity is allocated to regulating hydro turbines and transmitted via telemetry to the remote terminal units (RTU). The RTUs convert the raise/lower megawatts (MW) into timed relay contact closures to the governor which result in wicket gate open/close movement to change the generator output power. The output power of each generator is monitored by the digital AGC, which closes a feedback loop around the governor-turbine-generator to assure that the desired power level is attained. The feedback loop design, which is essentially a sampled-data control, is described. Additional feedback loops due to the ACE and load regulation are also analyzed. A method for allocating water usage between reservoirs on a generator command-time basis is presented. The theoretical designs are verified by online measurements.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Load-level-sensitive governor gains for speed control of hydrogenerators

The application of load-level-sensitive gains to proportional-plus-integral speed control of hydrogenerators is discussed. Appropriate root configuration gain functions of wicket gate position are derived for isolated resistive loads. Computer programs are used to calculate these gains from model turbine data and system parameters. Root locus tuning is used to determine appropriate gains for infinite bus loads. Simulations are presented which compare the use of constant gains to the use of these variable gains for isolated resistive and infinite bus loads. Additional resistive load simulations show the effect of a one-second digital filter on the gain function. Results indicate that the variable gain responses resemble 0.707 damping at each load level. Sample speed-transient comparisons between variable and constant gains show decreases of up to 45% in speed peak overshoot and 80% in power settling time. Load and pressure time-responses are included.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Navier-Stokes Computation of Radial Inflow Turbine Distributor

A two-dimensional flow analysis of a radial inflow turbine distributor using full steady-state Reynolds-averaged Navier-Stokes equations is made. The numerical prediction of the total energy loss and the wicket gate torque is compared with experimental data. Also, a parametric study is carried out in order to evaluate the behavior of the numerical algorithm.

Forces on Lifting Beams Used with Three‐Leaf Intake Gates

At many hydroelectric plants, crane‐lowered, leaf‐type intake gate systems are relied upon to stop turbine flow after failure of the wicket gates. Unfortunately, intake gate systems of that type have a history of operating problems, such as failure of gate leaves to descend, crane overloading, and failure of the lifting beam to release. A review of that history prompted TVA to investigate the efficacy of its intake gate systems. As a starting point, new model tests of the intake gate system at Melton Hill Dam were performed in 1983, 20 years after completion of the dam. The Melton Hill system used three stacked rectangular leaves in each of three bays for closure of a unit. Each of the nine leaves was lowered into position by the same crane and lifting beam. The original design of the system had been based on model tests, which had not included behavior of the lifting beam. In field tests performed shortly after construction of the dam, the gate leaves seated properly in flowing water but the lifting beam...

Effect of stay vane angle on the performance of hydraulic turbine.

The effects of stay vane angle on the turbine efficiency performance was investigated with a tandem circular cascade comprising stay vanes and wicket gates of a high specific speed Francis turbine. The velocity distributions around the stay various and wicket gates as wall as the variation of angular momentum along the streamline were calculated with the Flow analysis computer program based on the quasi-three dimensional Flow theory for the various combination of the stay vane setting angle and the wicket gate opening. A model Francis turbine having the same configurations of stay vane and wicket gate as those analyzed numerically was tested to measure the turbine efficiency and compare with the results of slow analysis. The measured results showed a good correlation with the calculated results and it made clear that the angle of stay vane affects the turbine efficiency in the region of large wicket gate opening.

Experimental Research on Stress Fluctuations in Runner Vanes of High-head Pump-turbines

By measuring stress fluctuations in runner vanes of a prototype 500 m class Francis-type pump-turbine and a 1/12 reduced scale model of that pump-turbine, it was revealed that the stress fluctuations consist of (1) components of higher harmonics of runner speed n, (2) components whose frequencies are constant, that is, independent of runner speed, and (3) components caused by interference from the wicket gates. The 1st components are generated by an unequal distribution of flow properties on the periphery of the runner. The 2nd components are estimated as components of acoustic resonance in flow paths very close to the runner. Comparisons of the prototype and the model are made about the overall amplitude and amplitudes of major frequency components of the stress fluctuations.

Discharge Computations at River Control Structures

A procedure has been developed by the U.S. Geological Survey to calibrate regulating control structures and determine continuous records of stream-flow on highly-regulated rivers. The hydraulic theory assumes steady unform flow within a computational interval, usually 1 hr. To date, five different types of control have been analyzed, including tainter gates, turbine wicket gates, fixed or emergency spillways, locks, and crest gates. Field variables recorded include headwater stage, tailwater stage, gate positions, turbine scroll case pressure drops, number of lockages, and number of crest gates open. Instrumentation was developed for monitoring the necessary variables. A generalized software package has been developed to compute the continuous streamflow records at these multipurpose structures by utilizing calibration results and in-situ variables recorded by digital recorders. Two typical calibration procedures showing the general accuracy of the computational methods are presented.

Field Investigation and Reduction of Wicket Gate Vibration in a Francis-Type Reversible Pump/Turbine

The profiles of three wicket gates on a Francis-type reversible pump/turbine were modified in the field to reduce vibration levels in the pumping and generating modes of operation. This paper describes the modification and the field tests employed to monitor the changes in the gate torque chracteristics. Static and dynamic components of gate torque were reduced significantly.

“DANUTA,” A Three-Dimensional Finite Element Program Used in the Analysis of Turbomachinery

A three-dimensional structural analysis program (DANUTA), using newly developed subparametric finite elements, is described and applied to the analysis of turbo-machinery components. The hexahedron-shaped element has twelve generalized displacements concentrated at each of the eight corner nodes. The displacement components are represented by a complete third degree polynomial, with some selected terms of the fourth and fifth degree, while the geometry is described by a set of second order parametric interpolation functions. The derivation of the stiffness and consistent load matrices (surface and body forces) is outlined. Numerical results, for cases where a classical solution is available, illustrate the high accuracy of the element. Application of the program to the analysis of spherical valves, turbine runners and wicket gates, as well as machine requirements, automatic data generation and possible further developments are discussed.

自動改札における乗車経路の判定方法

自動改札における乗車経路の判定方法

Viscount Grey of Fallodon, K. G., F. R. S

Viscount Grey of Fallodon, K. G. was elected into the Royal Society on 26 November 1914 under Statute 12; his proposer was the then President, Sir William Crookes. His citation makes no mention of his ability as a naturalist or of his genius in winning the confidence of wild creatures. I met him first as Visitor of my College, Balliol, and in 19271 took my wife and son Christopher to have tea with him at Fallodon, where his little estate and his ducks were protected against vermin by a high wall with a small wicket gate through which you entered. We left the car outside and rang the bell. Before the door opened we became aware of the peaceful and trustful atmosphere of Fallodon when a small green parrot, like those that live in the walls of the deserted city of Fatehpur Sikri, near Agra, fluttered down on to my wife’s shoulder. We went into Grey's study where a brown squirrel was eating nuts on the writing table.

12) 停車場の設計と旅客の群集流動

Especially in the case of railway stations for high speed city railways, the meaning of station accommodation must be the passage between train and streets because passengers on their way to office or home flow there as a mass in rush hours. So these stations must be designed based on the knowledge of the character of mass flow. The charac ter of passenger's mass flow will be cleared by speed and density with which these passengers walk as a mass. From this standpoint, the author tried to find out the necessary width or number of platforms, shairways, passage and wicket gates.

Test Characteristics of a Combined Pump-Turbine Model With Wicket Gates

Abstract Tests of a wicket-gate pump-turbine model at the Newport News hydraulic laboratory and at the California Institute of Technology are described in this paper. The model was one of a series used in a study of pumps suitable for Grand Coulee. Characteristic curves both as a pump and turbine are illustrated, and expected-performance curves for a prototype stepped up to Grand Coulee conditions are developed from the tests. In conclusion, a summary is given of the advantages of the wicket-gate pump-turbine.

Closure to “Discussions of ‘Test Characteristics of a Combined Pump-Turbine Model With Wicket Gates’” (1942, Trans. ASME, 64, pp. 737–744)

Closure to “Discussions of ‘Test Characteristics of a Combined Pump-Turbine Model With Wicket Gates’” (1942, Trans. ASME, 64, pp. 737–744)

Research Items

Ancestor Worship in Portuguese East Africa* An account of a village temple and ceremonial of WaBarwe ancestor worship by the Rev. D. Shropshire appeared in Man for May. The temple was situated in a banana grove which was entered through a doorway in a decorated bamboo screen. It consisted of a small house, 7 ft. by 5 ft., with a gabled thatched roof. It was built of poles and reeds and had a small wicket gate of reeds. Within the temple were two clay pots sunk in the ground. A large banana leaf lay on the ground in front of them, and two small pieces of bamboo and a calabash hung from the roof. An empty calabash upside down was inserted in the ground. One of the pots was for offerings to the mothers of the forefathers of the head of the village, the other for the mother of his father. In the ritual of worship the head of the village (or in this instance his deputy) swept the floor of the temple and its precincts. He then placed a reed mat in front of the door of the temple and a new large clean banana leaf inside the temple in front of the two pots. At a house in the village a procession was then formed which made its way to the temple, the wife of the representative of the village headman carrying mealie meal on a wooden plate. On arriving at the temple, all knelt and clapped hands ceremonially in greeting to the ancestors. The deputy then entered the temple and sat on the ground. After further clapping of hands he made offerings of the meal, with an invocation, to each of the pots in turn. The procession then returned to the house from which it started. At the time of the great offering and worship of the ancestors at the sowing season, they offer beer, bananas and rice in addition to the mealie meal. They do not pray to the Supreme Being except when out hunting, in prolonged drought or when the medicine man has failed to make a person well. He is too far away, and on ordinary occasions they pray to the ancestors to intercede with him, instead of addressing him directly themselves.

Book Review: The Wicket Gate.

Book Review: The Wicket Gate.