Hydraulic Installation Research Articles

Hydraulic Studies of a Model for the Additional Spillway at the Maina Hydraulic Installation (Left-Bank Variant)

The paper presents the results of hydraulic studies of the model for the left-bank variant of the additional spillway in the Maina hydraulic installation performed with the aim of justification of the designed discharge capacity. Similarity criteria of hydraulic modeling and calculation results are given.

Study of Temperature Memory Effect During the Thermal Cycling in Hydraulic Systems

Abstract The effects of thermal cycling in an experimental hydraulic installation of trained shape memory alloy actuators are discussed. After being trained in air for up to 500 flection–deflection cycles during cooling–heating, respectively, with a load fastened at their free ends, the lamellar elements developed two way shape memory effect by reducing their curvature during heating and by recovering it during cooling. Temperature variations versus time were recorded during thermal cycling performed in oil, revealing the influences of: (i) the number of training cycles, (ii) overheating caused by oil thermal-inertia, and (iii) heating interruption during martensite reversion to parent phase. The effects of the number of training cycles, corroborated with heating interruption, were revealed by differential scanning calorimetry both before and after functioning in oil. Heating interruption, associated with temperature memory effect, caused the occurrence of two martensite populations during subsequent cooling, as substantiated by optical and atomic force microscopy.

The Role of Microorganisms in Elevating the Turbidity of Dam Seepage Water

Studies at one of the earthen dams of the Volga – Kama cascade of dams revealed an elevated removal of suspended particles in seepage water, resembling the process of mechanical erosion. Comprehensive studies show that active microbiological processes occur in dam bodies. Elevated turbidity of seepage water was caused by microbiological processes. Microorganisms are also capable of adversely affecting the physical and mechanical properties of soil and promote the risk of reducing the stability of hydraulic engineering installations. In this regard, there is a need to develop a method to study the extent of microbiological process hazard and to incorporate it into regulatory documents.

Technical Condition of Earthen Dams at Nizhegorodskaya HPP After 60 Years of Operation

The complex of hydraulic engineering installations includes five earthen dams. All facilities are of Class I. The diagnostic parameters of dam operation and technical condition monitored via in-situ observation for seepage mode, seepage strength, settlement, static stability, etc. generally meet design assumptions and safety criteria. Despite individual defects and signs of “aging” identified over the period of earthen dam operation, these are currently in a satisfactory and operable state. The long, 60-year operating period of the dams with no serious overhauls or emergencies has demonstrated the high reliability of the facilities, the correctness of the design and technological solutions adopted and implemented in the construction, and the high professional level of their operation in close cooperation with science.

Signals features extraction in liquid-gas flow measurements using gamma densitometry. Part 2: frequency domain

Knowledge of the structure of a flow is really significant for the proper conduct a number of industrial processes. In this case a description of a two-phase flow regimes is possible by use of the time-series analysis e.g. in frequency domain. In this article the classical spectral analysis based on Fourier Transform (FT) and Short-Time Fourier Transform (STFT) were applied for analysis of signals obtained for water-air flow using gamma ray absorption. The presented method was illustrated by use data collected in experiments carried out on the laboratory hydraulic installation with a horizontal pipe of 4.5 m length and inner diameter of 30 mm equipped with two 241Am radioactive sources and scintillation probes with NaI(Tl) crystals. Stochastic signals obtained from detectors for plug, bubble, and transitional plug – bubble flows were considered in this work. The recorded raw signals were analyzed and several features in the frequency domain were extracted using autospectral density function (ADF), cross-spectral density function (CSDF), and the STFT spectrogram. In result of a detail analysis it was found that the most promising to recognize of the flow structure are: maximum value of the CSDF magnitude, sum of the CSDF magnitudes in the selected frequency range, and the maximum value of the sum of selected amplitudes of STFT spectrogram.

Research of flow parameters in a blow off of a hydraulic installation

The paper deals with conditions and parameters of water flow in a blowoff of a hydraulic installation and adjacent area of a discharge channel. The authors point out the significant impact of forms and geometric sizes of outlet structures, as well as stilling structures on the linkage parameters of outlet water flow. The article presents results of research of the impact of a baffle on the water flow in discharge outlet and outlet canal and shows a possibility of hydraulic conditions improvement in discharge canal due to water-diverting wall construction. The authors conclude that deletion of a water-diverting wall in an outlet section of discharge outlet should be proved by technical and economic estimation.

Signals features extraction in liquid-gas flow measurements using gamma densitometry. Part 1: time domain

Knowledge of the structure of a flow is really significant for the proper conduct a number of industrial processes. In this case a description of a two-phase flow regimes is possible by use of the time-series analysis e.g. in frequency domain. In this article the classical spectral analysis based on Fourier Transform (FT) and Short-Time Fourier Transform (STFT) were applied for analysis of signals obtained for water-air flow using gamma ray absorption. The presented method was illustrated by use data collected in experiments carried out on the laboratory hydraulic installation with a horizontal pipe of 4.5 m length and inner diameter of 30 mm equipped with two 241Am radioactive sources and scintillation probes with NaI(Tl) crystals. Stochastic signals obtained from detectors for plug, bubble, and transitional plug – bubble flows were considered in this work. The recorded raw signals were analyzed and several features in the frequency domain were extracted using autospectral density function (ADF), cross-spectral density function (CSDF), and the STFT spectrogram. In result of a detail analysis it was found that the most promising to recognize of the flow structure are: maximum value of the CSDF magnitude, sum of the CSDF magnitudes in the selected frequency range, and the maximum value of the sum of selected amplitudes of STFT spectrogram.

Application of joint probability approach in derivation of rainfall temporal patterns: case study: Kan Watershed, Iran

Joint probability approach is a superior method of design flood estimation which considers the probabilistic nature of the inputs such as rainfall temporal pattern in the rainfall-runoff modelling. Design flood estimation is one of the major steps in the design and sizing of hydraulic structures and installations. Under the conditions of significant storage capacity or long return periods, use of mathematical models is a common choice for changing of design rainfall to design flood. One of characteristics of design rainfall that cause design flood is distribution of rainfall during the rainy period which is the so-called design rainfall temporal pattern. Design rainfall temporal pattern is a major source of uncertainty in rainfall-based design flood estimation methods. Despite high variability of temporal patterns from storm to storm, an average temporal pattern is used in the design event approach, the recommended rainfall-based design flood estimation method. This paper examines the variability of temporal patterns using joint probability approach. In this study, Monte Carlo simulation technique based on joint probability approach, that considers probability-distributed inputs, model parameters and their correlations, applied to find the probability-distributed rainfall temporal pattern in the study area.

Technical Status of Waterworks and Water Regulating Hydraulic Structure Installations Meliorationuse

The main criteria for determining the reliability of the culvert and water control structures reclamation purposes. The analysis of the technical condition of culverts and water control structures on the basis of which are characteristic of their damage and requirements to ensure their operational reliability. This technique allows to determine the suitability of the building for further use on the basis of visual inspection and robustness of concrete elements of buildings.

Loading Mode and Environment Effects on Surface Profile Characteristics of Martensite Plates in Cu-Based SMAs

The present work reports the influence of the loading mode provided during training under constant stress, in bending, applied to lamellar specimens of Cu-Zn-Al shape memory alloys (SMAs). During training, the specimens were bent by a load fastened at their free end, while being martensitic at room temperature and they lifted the load by one-way effect (1WE), during heating up to austenitic field. On cooling to martensite field, the lower concave surface of bent specimens was compressed, and during heating it was elongated, being subjected to a series of tension-compression cycles, during heating-cooling, respectively. Conversely, the upper convex surface of bent specimens was elongated during cooling and compressed during heating, being subjected to compression-tension cycles. Furthermore, 2WE-trained actuators were tested by means of a hydraulic installation where, this time heating-cooling cycles were performed in oil conditions. Considering that the lower concave surface of the specimens was kept in compressed state, while the upper convex surface was kept in elongated state, the study reveals the influence of the two loading modes and environments on the width of martensite plates of the specimens trained under various numbers of cycles. In this purpose, Cu-Zn-Al specimens, trained under 100-300-500 cycles, were prepared and analyzed by atomic force microscopy (AFM) as well as optical and scanning electron microscopy (OM and SEM, respectively). The analysis also included AFM micrographs corroborated with statistical evaluations in order to reveal the effects of loading mode (tension or compression) in different environmental conditions of the specimens, on the surface profile characteristics of martensite plates, revealed by electropolishing.

Эксплуатационные характеристики фильтровальных перегородок из проволочных сеток с ячейками микронных размеров

Results of pilot studies related to hydraulic resistance of wire woven grids with cells of micron sizes in laminar mode of a filtration have been presented. For assessment of grids hydraulic resistance the permeability coefficient value has been used. To overcome the effect of a large-scale factor on conducted researches results the dimensionless size of this parameter in the form of permeability coefficient relation to a square of the grid cell size is entered. The researches have been conducted on free-flow hydraulic installation by specially developed technique providing high precision determination of this parameter. Influence like wires interlacing at a size of dimensionless coefficient of permeability is established. Nature of influence like wires interlacing at a size of this parameter is confirmed with results of wire grids internal structure analysis. On the basis of obtained data the choice technique like grid has been developed for production of a filtering partition with optimum characteristics at the set size of filtering nominal subtlety. On the basis of porous body channel model the assessment of hydraulic resistance coefficient value of wire grids with various type of wires interlacing has been carried out. Dependence of this parameter on wires interlacing type has been established. Groundlessness of interstice’s tortuosity coefficient use at assessment of grids hydraulic resistance has been shown.

Effects of hydraulic installations on the prevalence of Plasmodium falciparum in the Logone plain in Far North region of Cameroun

The prevalence of Plasmodium falciparum was determined out on 420 persons in two villages of a hydroarranged perimeter and two others out of the water intake perimeter in the Far North region in Cameroon. Thick and thin blood smears were stained with Giemsa. Species-specific densities of plasmodia were estimated under a light microscope at high magnification with thin blood smears for identification of parasite species and thick blood smears for densities by counting the number of parasites on the basis of 8,000 white blood cells / microlitre of blood. Results showed that persons of the hydro-arranged perimeter were significantly infected than those out of the hydro-arranged perimeter. In addition persons from 0 to 11 years were significantly more infected than others in the two perimeters. Females were significantly more infected than males in the hydroarranged perimeter. With or without prevention persons of the hydro-arranged perimeter were significantly more infected than those out of the hydro-arranged perimeter. These results show the importance of the human plasmodia infections and its local variability. These informations were necessary to optimize methods of fight against P. falciparum in the Logone plain and in similar areas.

Hot-water corrosion failure of a hard-drawn copper tube

Deoxidized high phosphorus copper (C12200, DHP-Cu) is the principal construction element in piping in water distribution systems and HVAC (Heating Ventilation and Air-Conditioning) installations due to its excellent thermal and electrical conductivity, formability, corrosion resistance and antimicrobial activity. However, design and installation deficiencies or aggressive environmental parameters, such as improper water quality, may lead to unexpected failures causing material losses and many times property damage incurring high costs of repair. A corroded copper water tube caused leakage in a hot water hydraulic installation. The leakage was reported after approximately 6years in service. Tubes were disconnected from a hydraulic installation and samples were taken for failure investigation. Failure analysis findings suggest strongly that the leakage was caused by tube perforation from the inner waterside due to localized pitting corrosion. The main cause of the accelerated tube pitting corrosion was the improper water chemistry (especially high chlorine content and low pH) inducing chemical attack of copper leading to scale layers of cuprite, chlorides and sulfates.

Flow Model of Pure Water in a Pipeline

Potable water in Tunisia has well defined characteristics. Thus, the Water researches and Technologies Centre-Borj Cedria mainly processing Natural Waters Laboratory, has worked on the physic-chemical quality of the water. As the Higher Institute of Agronomy-chott mariem have studied the phenomena associated with flows. For this work shows that natural water flows that can be generated in a pipeline. During operation of agricultural pumps (centrifugal pumps), the speed of the electric motor increases from zero to the permanent regime speed. This change in regime influences the flow of the hydraulic installation and forced it to follow the starting dynamic law of the motor. Under the effect of the friction force, due to the fluid viscosity, the transient regime is dumped until reaching the normal operating conditions. In this work, we study this phenomenon and see the influence of the pump startup on the hydraulic behaviour of one dimensional flow throw a cylindrical pipe of linear elastic behaviour. The pipe is connected to constant level reservoir at the downstream end. The problem is governed by a two coupled linear hyperbolic partial differential equations which are the equations of continuity and motion. The mathematical model is solved by the method of characteristics where at the upstream end, that is, at the pump station, the boundary condition is given by the differential equation for speed change of the pump motor. A theoretical relationship is introduced to express the motor torque in terms of the time. At the downstream end the discharging reservoir is assumed to be at a constant level. The computed head and discharge time curves, caused by the starting of the pump, are plotted at some cross sections of the pipe. The results show that the evolution of the hydraulic variables is well influenced by the applied motor torque.

Study of Flow Problems and Those of Soil Compaction in an Agricultural Farm

In agricultural land can be observed problems regarding water and soil. The problems of water flow can cause breaks in pipes, and the problems associated with soil because of the passage of vehicles and lead to compaction, engender changes in soil parameter directly affects the infiltration water and fruit yield regression plants. In this paper, we will study numerically the flow in pipes and soil compaction. So, a first part examines the phenomena of demurrage pumps; when starting a pump, the speed of the electric motor rises from zero up to the permanent regime speed. This change in regime influences the flow of the hydraulic installation and forced it to follow the starting dynamic law of the motor. Under the effect of the friction force, due to the fluid viscosity, the transient regime is dumped until reaching the normal operating conditions. In this work, we study this phenomenon and see the influence of the pump startup on the hydraulic behaviour of one dimensional flow throw a cylindrical pipe of linear elastic behaviour. The pipe is connected to constant level reservoir at the downstream end. The problem is governed by a two coupled linear hyperbolic partial differential equations which are the equations of continuity and motion. The mathematical model is solved by the method of characteristics where at the upstream end, that is, at the pump station, the boundary condition is given by the differential equation for speed change of the pump motor. A theoretical relationship is introduced to express the motor torque in terms of the time. At the downstream end the discharging reservoir is assumed to be at a constant level. The computed head and discharge time curves, caused by the starting of the pump, are plotted at some cross sections of the pipe. The results show that the evolution of the hydraulic variables is well influenced by the applied motor torque. In a second part of the numerical study of soil compaction is developed.

Increasing the Operating Safety of the Machine-Tools by Using Hydro-Pneumatic Accumulators. Modeling - Simulation

This paperwork presents the results of the theoretical and experimental research that has had as object of study the hydraulic installations with hydro-pneumatic accumulators. It presents simulations for determining the performance of some hydraulic safety systems designed for actuating brakes, for ensuring bearings lubrication when the circuit incorporating the pump fails and for lifting loads in emergency situation. A hydraulic installation designed for a grinding machine is presented at the end.

Influence of pump starting times on transient flows in pipes

The purpose of this study is the numerical modelling of the transient flow in a cylindrical pipe caused by the start-up of a centrifugal pump. The pump starting produced by the speed of the electric motor, which rises from zero up to the rated speed, influences the flow in the hydraulic installation and forced it to follow the starting dynamic law of the motor. The governing equations for such flows are two coupled hyperbolic partial differential equations which are the equations of continuity and motion. The head and the discharge are considered as two principal dependent variables. Under the effect of the friction force, due to the fluid viscosity, the transient flow is progressively dumped until reaching the final steady-state flow. Two boundary conditions are considered: a pump with a known motor torque at the upstream end and a constant level reservoir at the downstream end of the pipe. The motor torque is considered for different starting regimes: very rapid, rapid, medium and slow. In order to predict the dynamic behaviour of the flow during the pump start-up transient conditions, the mathematical model is solved by the method of characteristics. The computed head and discharge, caused by the starting of the pump, are presented at some cross sections of the pipe and the results show that the evolution of the hydraulic variables is well influenced by the pump starting time.

Mobilising for water: hydro-politics of rainwater harvesting in Chennai

In 2003–2004, as the Indian city of Chennai faced an unprecedented water crisis, a debate ensued about finding longer-term sustainable solutions, ranging from expensive desalination plants to modest rainwater harvesting schemes. The latter was enforced by an authoritative state and promoted enthusiastically by environmentalists to raise awareness about the city's much-destroyed hydrological ecosystem. In contrast to the state's interpretation reducing it to a compulsory hydraulic installation in individual buildings, environmental NGOs made a concerted effort to develop a more comprehensive intervention in the wider public domain. However, as a dizzying array of socio-political actors came together, concerns emerged about the ability of such a mobilisation to generate a uniform material understanding of rainwater harvesting as a common moral goal. Examining in detail one specific case study of a community-led effort – Puduvellam – this article looks at how, as a grass-roots organisation involved in the restoration of a prominent temple tank in southern Chennai, it rallied support amongst the local (mainly middle-class) residents to create a new topology of ecological consciousness. Its success, however, was only partial and highlights the futility of romanticising rainwater harvesting as an indigenous alternative. More importantly and ironically, its ineffectiveness was enhanced by the crisis itself as it triggered a process of privatisation and commodification of water, with rainwater harvesting eventually being absorbed by the agenda of ‘bourgeois environmentalism’.

Finite element method analysis of pipe material temperature changes influence on line expansion loops in hydraulic installations on modern tankers

Finite element method analysis of main lines of hydraulic central loading system installation expansion loops mounted on product and chemical tankers has been presented in the paper. The axial forces problem in installations mounted along the ship?s open decks executed from hull deformations on waves and thermal stresses is given. Use of ?U? type expansion loops is described. Results of forces in anchor points and stresses of Mises due to expansion loop deformations are shown. Calculations were made by ABAQUS Ver.6.7 FEM computer program.

Fem analysis of pipe material temperature changes influence on line expansion loops in hydraulic installations mounted on modern product and chemical tankers

Fem analysis of pipe material temperature changes influence on line expansion loops in hydraulic installations mounted on modern product and chemical tankers