MODELS FOR MAXIMUM PROBABLE FLOW CALCULATION AND THE TIME DISTRIBUTION ANALYSE – PART I
This paper presents an approach to estimate the maximum flow calculation and the time distribution analyse for different rivers from Romania.
Keywords: maximum probable flow calculation, time distribution, maximum probable rain
Cuvinte cheie: Viitura maximă probabilă, distribuție în timp, precipitația maximă probabilă
MODELS FOR MAXIMUM PROBABLE FLOW CALCULATION AND THE TIME DISTRIBUTION ANALYSE – PART I
THE LOAD CAPACITY OF A HYDROELECTRIC
POWER PLANT BY THE LAKE TO DOWNSTREAM
In the paper presents the results of measurements of the tailrace of the hydroelectric power Șugag underground HPP (high head cents) to determine the maximum power that can be achieved with the safe operation of the plant by Şugag HPP capacity transport manifold run it. The paper presents how to perform monitoring and protection system for monitoring water levels in tailrace.
Keywords: hydroelectric power plant, hydraulic turbine, efficiency, run gallery
Cuvinte cheie: centrală hidroelectrică, turbină hidraulică, randament, galerie de fugă
THE STRESS DETERMINATION FOR WATER
INTAKES WITH PIPES INSIDE PILES
This paper presents the initial stress calculations performed in order to validate a future innovative solution which incorporates both the sluices and the water intake with the supply pipes embedded within the concrete piles.
A brief calculus was done to estimate the supplementary forces involved in the dam stress. It starts from simplifying assumptions in order to estimate the stress supported by the concrete piles. The obtained results will be furthermore used to determine if the envisaged solution requires special methods of foundation or structural reinforcement.
Keywords: water intakes, supply pipes, dam cells, dams
Cuvinte cheie: prize de apă, conducte de alimentare, pile, baraje
THE USE OF NUMERICAL METHODS FOR ESTIMATING
THE CONTRACTION COEFFICIENT OF AN ORIFICE
This paper presents one of the numerical methods that integrate the Navier-Stokes equations, namely the method of finite differences, in order to determine the flowing through a tank and the contracted section of the liquid passing through an orifice.
Keywords: flow coefficient, current lines, orifice, numerical methods
Cuvinte cheie: coeficient de debit, linii de curent, orificiu, metode numerice
THEORETICAL ASPECTS REGARDING THE STRENGTH CALCULATION AND THE DEFORMATIONS OF THE HORIZONTAL TURBINE RUNNER CHAMBERS
This paper presents main theoretical considerations regarding the strength calculation and the deformations of the horizontal axial turbine runner chambers – upstream bulb. The most suitable functional and constructive solutions – for those bulb turbines which designed at Hydro-Engineering, the runner chamber has the lower half embedded in the concrete, and the upper half of this is fixed through a bolted threaded connection and threaded studs. The strength calculation of the deformations is made only for the upper half of the runner chamber.
The establishment of the fundamental equations regarding the strength and deformation calculations have been made taking into account the theory of the plane and curved plates of S. Timoshenko. For solving the equations and avoiding the in determinations it has been used the energetic method (Castigliano’s method). Considering the stressing types that are applied to the upper half of the runner chamber in the paper, it is shown the forces and moments that is stressing the threaded connection of the upper half in relation to the lower half which embedded in the concrete
Keywords: turbine, runner, deformation, bulb
Cuvinte cheie: turbină, rotor, deformaţie, bulb
CONSIDERATIONS REGARDING THE BUTTERFLY VALVE MODEL DESIGN TO PERFORM THE EXPERIMENTAL RESEARCH
The paper presents a model of butterfly valve designed to perform experimental research in the laboratory to determine the functional parameters of industrial (prototype) butterfly valve. The model is designed considering the Froude similarity criterion based on the geometric dimensions and the design of the prototype valve having a nominal diameter of 4.9 m and operates at a pressure of 17.1 bar. The paper presents adaptations designed model can be mounted on the test bench for hydraulic turbines and experimental research can be obtained putting in optimal conditions.
Keywords: Butterfly valve model, testing stand, experimental research, similitude criterion
Cuvinte cheie: model de vană fluture, ştand se încercări, cercetări experimentale, criterii de similitudine
CONSIDERATIONS REGARDING THE EXPERIMENTAL RESEARCH PERFORM BY AN BUTTERFLY VALVE MODEL
The paper presents experimental research performed on a model of butterfly valve in the test stand of the testing laboratory to determine the functional parameters of a prototype butterfly valves ND 4900 mm who operating at a pressure NP17 bar. The valve model is designed and executed based on design and the size butterfly valve prototype applying Froude similarity criterion. It is presented the test stand and the experimental research results obtained regarding to determining the hydraulic resistance coefficient and consequently the flow coefficient and the determination of forces and moment coefficients, the coefficient of cavitation and vibration level.
Keywords: Experimental research, butterfly valve model, testing stand, coefficients
Cuvinte cheie: cercetări experimentale, model de vană fluture, stand de încercări, coeficienţi
BUTTERFLY VALVE DISC SHAPE OPTIMISATION FOR HYDRAULIC RESISTANCE COEFFICIENT 0.07
The paper presents the optimization of butterfly valve disc shape to obtain hydraulic resistance coefficient 0.07 by numerical methods and by experimental measurements realized in Hydro-Engineering Co. Reşiţa. It is presented the test stand, the optimized butterfly valve disc model which measurements were made and the results of model tests. The results of model tests conducted by similarity criterion for butterfly valve with nominal diameter 4900 mm and nominal pressure of 170 mwc consists of determining the hydraulic resistance coefficient and consequently the flow coefficient and the determination of forces and moment coefficients, the coefficient of cavitation and vibration level.
Keywords: disc butterfly valve, hydraulic resistance coefficient, numerical analysis
Cuvinte cheie: disc vană fluture, coeficient de rezistență hidraulică, analiză numerică
LOW FREQUENCY VIBRATION MEASUREMENTS
ON FRANCIS TURBINES
This paper presents an analysis on vibration measurements performed on Francis turbines. Absolute vibration measurements on draft cone tube and proximate measurements on shaft were presented with respect to low frequency phenomena.
Keywords: absolute vibration, kurtosis analysis, relative vibration, draft cone tube
Cuvinte cheie: vibraţii absolute, vibraţii relative, con aspirator, analiza kurtosis
STUDY OF THE EFFECT OF THE FAST FRANCIS TURBINE BLADES’ SPIN AROUND AN AXIS, FOLLOWING CFD ANALYSIS OF FLOW AND RESULTS OF MEASUREMENTS IN THE LAB
The present paper propose an analysis of the rotation around an axis effect of the runner blades that compound the fast Francis turbines in order to increase their energo-cavitational performances. First step was done after the analysis of the runner which resulted from the calculations and hydro-dynamic design. This analysis was performed both theoretically using the finite element software package called CFX Blade Gen, and through experiment within the Test Laboratory for Hydraulic Turbines from Hydro-Engineering. Second step of the research consisted in rotating the blade around the axis with a certain angle in order to increase the absorbed flow, holding the rim and the ring from the initial blade. Rotating was performed in different angles by making the finite element analysis for all the rotating angles. In order to improve the cavitational component it was proposed and realized an extension of the blade with an appropriate covering degree, without any visible effect over the energetic features, these being maintained within the permitted error range that admitted by the IEC 60193 code.
Keywords: blade, runner, Francis
Cuvinte cheie: paleta, rotor, Francis
ASPECTS OF CAVITATION EROSION AT SUCTION
CONES FROM FRANCIS TURBINES
In this article is presented the effect of cavitation applied to the suction cones that equip Francis turbines of HPP Motru. Cavitation erosion is evaluated through in-situ measurements are processed and presented in a new way in this article. It was determined a correlation between various regimes of functioning and the cavitation erosion appeared on the suction cones. Also experimentally was determined optimal maintenance period considering the cavitation attack intensity.
Keywords: cavitation, vacuum con, turbine, Francis, coefficients of cavitation, aeration
Cuvinte cheie: cavitație, con aspirator, turbină, Francis, coeficienți de cavitație, aerare
THE DIMENSIONING OF THE AXIAL TURBINES
In this paper is presented a new method for calculating the axial
hydraulic turbines, whose applicability is demonstrated by a numerical
example. This method is based on the torque developed by the turbine
rotor, which from reasons of simplicity, has been obtained by the
theorem of dimensional analysis. Calculation results with the proposed
method for the flow of small water falls are in a good accordance with
those in the specialty literature. The method should be extended and
verified for large and medium flow and water falling.
Keywords: turbine, rotor, method, calculation, water, hydraulic,
Cuvinte cheie: turbină, rotor, metodă, calcul, apă, hidraulic, axial
MONITORING SYSTEMS IN HAZARDOUS CONDITIONS OF HYDROELECTRIC PUMPED STORAGE (CHEAP)
The primary purpose of modern automation purposes of modern automatic control systems of hydroelectric plants are:
– Automatic adjustment of speed (frequency) and/or power energy group known as Automatic speed control systems (SRAV)
– Automatic adjustment of the voltage generator known as automatic control systems excitation (SRAE)
– Adjust the water level in the reservoir and swirled flow, depending on the spatial requirements
– Protection hydropower group to failures, defects or on the electric or hydraulic side.
Keywords: automatic control systems, automatic adjustment of speed, generator voltage
Cuvinte cheie: sistemelor de conducere automată, reglarea automată a turaţiei, tensiunii generatorului
INTERPRETATION OF INTERFACIAL TENSION ON
MINERAL OILS USED AS CARRIERS OF ELECTRICAL CURRENT OF HIGH VOLTAGE
The interfacial tension against water is a polar soluble contaminants detection and degradation products . This feature is changing fast enough oil to trade vessels iniţial.Determinarea stage is commonly applied oils filled with insulating oil equipment in operation.
Keywords: interfacial tension, temperature, auto-transformers, oil analysis, hidroscopicitate electrical equipment
Cuvinte cheie: tensiune interfacială, temperatură, analize de ulei, autotransformatoare, hidroscopicitate, echipamente electrice
EXPERIMENTAL STUDY OF THE DIELECTRIC
BEHAVIOR OF DIGLYCIDYL ETHER
OF BISPHENOL ”A” CHARGED
Subject reinforced composite materials are extensively investigated in recent years. This study is deepened to improve the structural and dielectric characteristics of diglycidyl ether of bisphenol A (DEGBE). Dielectric properties were analysed for each batch of material. Microcompozite epoxy samples with good dispersion of nano – particles laden epoxy matrix was prepared and experienced for the dielectric constant (C) , resistance (R ) and impedance (Z) frequency (1kHz, 10kHz) . Measurements were made using a dielectric spectoscropia plateau temperature range of between 20-80 °C . The better dielectric properties of the material corresponding to the nano – fillers in a concentration of 30 % .
Keywords: DGEBA, pozzolan, dielectric constants, microstructure
Cuvinte cheie: DGEBA, rocă vulcanică, constanta dielectrică, microstructură
A MATHEMATICAL APPROACH TO THE LOSSES OF TRANSMISSION LINE UNDER NON-SINUSOIDAL REGIME
In this paper we present a mathematical proof of additional losses in the electrical energy transmission line due to superior harmonics. The proof is based on the Cauchy – Buniakovski – Schwarz inequality, a very important inequality in mathematics. Was considered a simplified model, but the obtained result generalizes to complex electrical circuits. At the beginning of the paper there was a more general overwiev of the issue of technological losses in power transmission line. Finally, we draw the conclusions and we indicate the references.
Keywords: electricity transmission line, transmission line losses, deforming operating system, mathematical proof of additional losses under deforming
Cuvinte cheie: linie de transport a energiei electrice, pierderi pe linia de transport, regim deformant de funcţionare, demonstraţie matematică a pierderilor suplimentare în regim deformant
CORONA PHISICAL MODEL IN ALTENATIVE VOLTAGE
Corona discharge around power lines leads to line parameter alternation as an electric charge is formed around the wires. In transient states, such alternations result in faster damping of oscillations while in steady regime lead to additional energy losses. The paper treats the physical Corona modelling and the analytical transients process of voltages and currents on the proposed model.
Keywords: model, Corona, electronic scheme
Cuvinte cheie: model, efect Corona, schemă electronică
CASLCULUS OF ELECTRIC POWER LOSSES
DUE TO CORONA EFFECT
The paper present the properly designed for Corona model required to produce reasonably close modelling of electric power losses on very high electric lines. Corona modelling has been approached by means of analogue physical or mathematical modelling is treated herewith.
Keywords: power losses, method, Corona, power lines
Cuvinte cheie: pierderi de putere, metodă, efect Corona, linii electrice
STUDY BIOSYSTEMS ELECTRIC FISH (P.E.)
Understanding the phenomena that are specific electrical biosystems, the existence of specialized cells for detecting, measuring and storing electricity, which enable these phenomena. Finding sources of electricity inspired by natural model, but other research direction as the electric discharge and electrical insulation. With the technical model, visualizing electrical discharges of different voltages and currents, check some assumptions-assumptions to an embodiment of the primary data.
Keywords: autologous, non-autologous electrical, impulse nerve, corticalii centers, electric shock, synapses, dendrites, electrical nerve
Cuvinte cheie: autolog16, non-autolog electric, impuls nervos, centri corticali, șoc electric, sinapse17, dendrite, nervi electrici
ANALYSE DE L’ÉNERGIE D’UNE ZONE DE CEE VISANT A APPORTER 45 MW
L’article présente l’analyse énergétique d’une zone territoriale appartenant à une filiale de distribution de l’énergie électrique. L’analyse vise l’évaluation de la puissance générée, consommée et la capacité de distribution du réseau.
Mots-clés: électricité, la production d’électricité, génération, la consommation
Cuvinte cheie: energie electrică, generare, consum
THE IMPLEMENTATION OF ISO ENERGY
MANAGEMENT STANDARD IN ROMANIA
This paper analyses the state of certification for energy management system (EnMS), ISO 50001: 2011, in Romania. The analysis is divided into factors that influence the increase in the number of companies certified to ISO 50001. Relevant information encountered in the training of staff, consulting to document EnMS and certification audit are presented. It is highlighted the importance of energy efficiency and the role of company`s management and other stakeholders.
Keywords: ISO 50001, energy management, energy intensity
Cuvinte cheie: ISO 50001, management energetic, intensitate energetică