Енергетика та системи керування (EPECS-2013). – 2013 р.

Permanent URI for this collectionhttps://ena.lpnu.ua/handle/ntb/26744

Матеріали IV Міжнародної конференції молодих вчених EPECS-2013

У збірнику опубліковано матеріали конференції, присвяченої проблемам у галузі енергетики. Видання призначено для науковців, аспірантів, студентів.

Енергетика та системи керування : матеріали IV Міжнародної конференції молодих вчених EPECS-2013, 21–23 листопада 2013 року, Україна, Львів / Міністерство освіти і науки, молоді та спорту України, Національний університет "Львівська політехніка". – Львів : Видавництво Львівської політехніки, 2013. – 104 с. : іл. – (4-й Міжнародний молодіжний фестиваль науки "Litteris et Artibus"). – Паралельний титульний аркуш англійською.

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Вплив гідродинамічних збурень на точність вимірювання швидкості потоку ультразвуковими витратомірами газу
(Видавництво Львівської політехніки, 2013) Роман, Віталій; Матіко, Федір
The modeling of perturbed velocity profile of turbulent gas flow using computational fluid dynamics method (CFD) is carried out. The algorithm for determining the average velocity along the acoustic path is developed using the results of CFD-modeling. The effect of influence of flow profile distortions produced by the fitting "90° elbow" on the average velocity measurement error is investigated for single channel ultrasonic flowmeter with diametrical acoustic channels. Modeling of such flowmeter is carried out for various angles of the plane of diametrical acoustic channel (0°, 45°, 90° and 135°). The dependence of the relative deviation (error) of average velocity on the angle of acoustic channel and on the distance between the flowmeter and the fitting "90° elbow" is investigated. The angle of acoustic channel of ultrasonic flowmeter that provides the minimum error of flow velocity measurement downstream of fitting "90° elbow" is defined. The distance between the ultrasonic flowmeter and the fitting "90° elbow" is defined to provide the velocity measurement error smaller than 0.5%.
Розрахунок теплового пункту з підмішувальними помпами формалізованими методами
(Видавництво Львівської політехніки, 2013) Музичак, Андрій; Павликівська, Христина
Traditionally, the heat points are calculated from pressure at the input without influence of neighboring consumers. This cause errors in the analysis of modes of consumers and does not instrument for improvement modes of heating system as a whole. To eliminate these defects can use formalized methods for the analysis of the theory of hydraulic circuits. The object of research was the development of mathematical model of heating points with mixing pumps and methods of setting up by formalized methods. In these heat points also install the heat flow regulator for automatic control mode. This regulator is an active element. Its hydraulic resistance varies depending on the heat take-off from the network. Calculation of flux-distribution for these heating points must perform two nested iterative procedure. In the inner loop calculate flux-distribution with fixed hydraulic resistance brunches. External process for the algorithm given in this paper corrects resistance regulators to minimize the difference between the current and desired heat-carrying agent. Developed a mathematical model and algorithm are instruments for identifying and providing energy saving modes of heat points and heat supply system as whole.
Алгоритм та програмна реалізація декартового множення як елемент побудови моделі гідрогазодинамічних дросельних схем
(Видавництво Львівської політехніки, 2013) Грудецький, Роман
In the design of modern technological parameters of transducers having trouble choosing scheme of the converters, which would provide the necessary technical and metrological characteristics of them. One such problem is the lack to date methodologies describe outline of transducers that describe the relevant circuit solutions , with which to perform synthesis and optimization of transducers. Proposed to be used for this set-theoretic concept, extending the number of concepts and operations of set theory. This will formalize the description and modeling scheme of the transducers, and on this basis to develop a theory of synthesis circuit solutions that automate the process of decision-making circuit. For a given or re-synthesized circuit building measuring transducer to explore its functionality and specifications. It is necessary to develop a methodology for modeling of converters and make it algorithmization that will implement the following processes on the computer. The result of research is to develop computer-aided design elements mentioned above transducers.
Планування виробничих експериментів для багатофакторного дослідження технології сушіння торфу в парових трубчатих сушарках
(Видавництво Львівської політехніки, 2013) Кулаковський, Леонід; Алтухов, Євгеній
The paper highlights the necessity for planning the experiment in steam pipe dryers of peat for multivariate investigation of the drying process and for further searching power saving regimes of drying. Analysis of plans of experiments allowed to identify the main criteria for the construction plan of the experiment in steam pipe dryer. The basis for the planning of the experiment should take regime maps of tube steam dryers, which provide required quality of a dried peat and changing of control actions carry out in the range of operating conditions. In order to decrease the number of experiments, and also not to rid planning matrix its best features is necessary to develop fractional factorial experiment (FFE) and to identify fractional replica. The optimal experiment’s plan for creating a mathematical model of the drying process is FFE 25-1 with shoulder g=1 and experiments in the center of the plan.
Титульний аркуш до "Енергетика та системи керування - EPECS-2013"
(Видавництво Львівської політехніки, 2013)
Моделювання процесів в теплоенергетиці за допомогою використання дробових похідних
(Видавництво Львівської політехніки, 2013) Кравець, Тарас; Кузнецова, Марта
Symbolic models of technological processes in the heat power engineering, based on classic differential equations, fail to provide certainty in some cases and may contain considerable skewing. The object of this research is dynamic and static processes of heat power systems, that are described by means of differential equations of fraction order, specifically, the processes of temperature alternation in heat-exchange units. The aim of the article is to use the method of reduction of order to provide analytical solution of heat and mass transfer problems in different environments, with different boundary conditions, for flat, cylindrical and spherical surfaces on the edge of heat carriers in motion. The paper reveals, that the use of the theory of fractional estimation to describe the processes of coordinate alternation in heat-exchange units allows finding solution in the cases of other mathematical methods inefficiency.
Математичне моделювання температурного режиму потоку газу в системах його обліку при імпульсних режимах роботи
(Видавництво Львівської політехніки, 2013) Федоришин, Роман; Комарецький, Олександр; Чура, Мар’ян
The mathematical model of the temperature regime of gas flow in a metering system is built based on the law of conservation of energy. Using the developed model the transient processes are simulated and compared to the results of experimental studies. On the basis of verification of the developed model it was defined that the maximum absolute deviation of the simulated values from the experimental results was 0.73 ºC. The developed model provides the possibility to define the systematic error of natural gas flow temperature measurement caused by inertia of the thermometer in pulse regimes of flow. The pulse regime of flow is present in natural gas metering systems installed in boiler houses where the switching on and off of the boiler leads to the pulse regime of gas consumption. Ways to define and eliminate the systematic error of flow temperature measurement caused by inertia of the thermometer in pulse regimes of flow are proposed in this paper in order to improve the accuracy of natural gas metering.
Знаходження сталої часу теплової вимірювальної комірки з метою підвищення швидкодії газоаналітичних приладів
(Видавництво Львівської політехніки, 2013) Макар, Олег; Кріль, Олександр; Кріль, Богдан
In gas analysing equipment heat detectors are widely used for converting thermal physical and mechanical parameters of the gaseous mixture into an electrical signal. Heated by electric current these detectors sense thermal conductivity, heat capacity and project gasous mixture expenditure. Sensitivity and performance velocity are among the main parameters of these detectors determining the irmetrological characteristics. The given paper provides the equation of time constant of the heat measuring cell, common in gas analysing equipment, for the purpose of studying the influence of detectors’ mode changes on the performence velocity of gas analysing equipment.
Design of marketing system of control by energy consumption modes at the retail power market
(Видавництво Львівської політехніки, 2013) Petrova, Kate; Serebrennikov, Bogdan
The methods of managing the modes of electric load for structural levels of the power system were examined. The effectiveness of marketing approach of forming the energy efficient modes of power consumption in transformed model of power market were proved. The levels of segmentation of the retail power market were grounded, the relevant criteria for consumers' segmentation considering their specifics of power consumption mode regulation were determined. The significance of criteria was proposed to consider in calculation of differentiated prices.
Умови реалізації цифрових регуляторів на цифрових системах з обмеженою розрядністю
(Видавництво Львівської політехніки, 2013) Сольський, Мар’ян
The problem of impact of finite-precision data on digital control systems synthesis and practical realization is described. Dependences between the accuracy of elementary first and second order dynamic links coefficients and minimal admissible sampling step were determined and analyzed.
Investigation of light intensity and temperature dependency of solar cells electric parameters
(Видавництво Львівської політехніки, 2013) Tobnaghi, Davoud Mostafa; Madatov, Rahim; Farhadi, Payam
In this paper, the performance and overview use of solar cells is expressed. The role of temperature, sunlight intensity on the solar cells electric parameters has been studied. Experimental results the amount of solar cell output parameters variations such as maximum output power, open circuit voltage, short circuit current, and fill factor in terms of temperature and light intensity shows. the most significant is the temperature dependence of the voltage which decreases with increasing temperature. Also output current of solar cells is directly proportional to the light intensity. The best performance of solar panels in sunny and cold day has been suggested. Obtained results could lead to optimal use of solar cells.
Алгоритм роботи комбінованої автономно-мережевої системи електроживлення окремого об’єкта
(Видавництво Львівської політехніки, 2013) Климко, Володимир
In this article an algorithm of work of a combined autonomous and network power supply system of a individual object is considered, and also work of the scheme used in this system is described. For providing the consumer with necessary capacity, it is offered to combine of using of energy of renewable sources, such as wind and solar, and the energy arriving from the centralized network. Use of the electrochemical storage battery as a part of installation for an uninterrupted power supply of object is offered. To management the process of generating of electric power, its distribution between consumers of a certain object, and also optimization of work of elements of installation, the using a controller as a part of a power supply system is offered. The main criterion for the application of the given combined system for ensuring needs of the consumer is direct consumption of the electric energy generated by the wind turbine and the photovoltaic unit. The main goal of this work is improvement an algorithm of work of the combined autonomous and network power system. Relevance of it work consists in using of a new type of the combined power supply system for providing the consumer with qualitative electric energy at any moment.
Оцінка ефективності застосування загущеної присадками індустріальної оливи у вузлах тертя енергетичного устаткування
(Видавництво Львівської політехніки, 2013) Коваленко, Тетяна; Івасик, Ярослав
Polyfunctional lubricant performance properties indicates its significant impact on the longevity and efficiency of work of contact pairs. About 30% of the total energy produced is consumed to friction. The improvement of lubricant and efficiency of lubricating can reduce energy costs by 45%. Therefore, the correct choice of lubricant depends on energy consumption to overcome friction, wear of rubbing surfaces. The most economical way for the improvement of work of the friction units in different environmental conditions is the development of new lubricant compositions with the addition of an effective multifunctional additives as so base oils don't meet all of requirements put forward to them. The polymethacrylate additives with enhanced functionality were obtained in this work. The influence of the concentration of the additives on the viscosity-temperature, depressor and anti-wear properties of industrial oil I-20A were studied. Found that received additives improve the performance properties of oil-20A, respectively, contribute the reliable lubrication of the friction units in power plants at different natural conditions.
Визначення відносного діаметра діафрагми оптимальної за точністю вимірювання витрати природного газу
(Видавництво Львівської політехніки, 2013) Кузик, Володимир; Чабан, Богдан; Лесовой, Леонід
The national literature review showed that the mathematical model for the relative standard diameter of narrowing device calculating because of the introduction of new national standards should be clarified. The components of flowrate measurement error, directly dependent on the design parameters of the standard narrowing devices are found. The optimality criterion for calculating of the structural parameters of the standard narrowing devices for optimal precision flow measurement of natural gas is proved in this paper. An algorithm of calculating of the structural parameters of the standard narrowing devices of differential pressure flowmeter for natural gas measurement, that enhances the accuracy of flowrate measurement by reducing of systematic errors that depend on the design parameters of the standard narrowing devices, was made as well.
Increasing efficiency of radiant heating systems’ work
(Видавництво Львівської політехніки, 2013) Shepitchak, Volodymyr; Zhelyh, Vasyl
The possibility of the application of energy efficient heating systems based on infrared light for heating industrial premises has been analyzed in the article. The experimental studies of temperature condition exposure zone of the rotary infrared heaters. The rotary radiation heater represents the distribution of the exposure intensity depending on the height disposition. The results are presented in graphical interpretation.
Дослідження перенапруг під час дугових замикань на землю в електромережах 35 кВ
(Видавництво Львівської політехніки, 2013) Яцейко, Андрій; Горошко, Олег
In this article it is researched the influence of grounding conditions of neutral of electrical network 35 kV on the level of arc overvoltage due to the theory by: Petersen, Peters - Slep'yan and Belyakov – Dzhuvarly. There were given schematic dependencies of arc overvoltage multiplicities which depend on neutral grounding, given main schematic dependencies of combustion of grounding arc. It is shown that values of arc overvoltages significantly increased with increasing of the value of the capacitive current in the electrical network. Combined condition of neutral grounding reduces the level of arc overvoltages the best. Multiplicity does not exceed 2.4 for all theories for various values of capacitive current.
Role of biomass resources in promotion of renewable energy
(Видавництво Львівської політехніки, 2013) Singh, Tejinder; Dhingra, Arvind
The world especially the developing countries are facing an increasing power crunch. The conventional energy resources are fast depleting and there is an urgent need to find out new avenues of energy to cater to this increasing demand. It is here the energy from biomass finds its place. Although we have been using energy from biomass since the time man learned to burn wood for energy but with the growing technological innovations this energy can be harnessed to meet the growing energy demands. On a worldwide scale Biomass contributes about 12% to today's primary energy supply, rising between 40% and 50% in most developing countries. Biomass fuel obtained from purpose-grown energy crops as well as forests and agricultural waste are being used in power plants and it is very competitive in price and quality with fossil fuels. Applying biomass technology is both an environmental and human necessity, whether on a local scale to get rid of slurries, waste and refuses, or on a global scale to reduce carbon dioxide content in the atmosphere and hence reduce global warming. Scientists are busy in developing different ways of converting biomass into a form that meets our energy needs, while making best use of the available energy. In this paper an attempt has been made to project the biomass conversion and the new emerging techniques of harnessing power from biomass and also from the other biofuels such as Bio-oil and Bioethanol. Hence an attempt has been made through different techniques in this paper that in developing country like India, how much emphasis need to be given on such renewable energy sources for preservation of conventional sources of energy.
Механічне демпфування у системі енергоформуючого керування синхронною машиною з постійними магнітами
(Видавництво Львівської політехніки, 2013) Білецький, Юрій; Щур, Ігор; Щербовських, Сергій
For the control of permanent magnet synchronous motor in electromechanical system an energyshaping control systems have been used. The regulation in such systems is realized by injection of additional damping of current vector projections on dq-axes and some correction coefficient. The energy-shaping control systems with present regulation elements provide worse response compare with classical systems and are hard to be configured. The main aim of this article is to suggest an alternative structure of energyshaping control system without these disadvantages. For this purpose the energy-shaping control system structures with mechanical damping as regulation element are proposed. There are presented the advantages of mechanical damping injection as well. To exam the proposed system work the comparative researches of its work with old structure system work were carried out. So, it might be said that for effective regulation in electromechanical system with permanent magnet synchronous motor the energy-shaping control system can be injected with mechanical damping. Such system provides high response and is simple to configure.
Дослідження впливу поворотної заслінки на гідродинамічний режим нафтопроводу
(Видавництво Львівської політехніки, 2013) Кріль, Сергій; Кріль, Богдан; Кріль, Олександр
The article discusses the positive aspects of the using a butterfly valve to control the outlet pressure of the oil pumping station. Also it emphasizes the importance of the pressure control in oil pipeline to ensure its safe operation. The dependence of the differential pressure on the butterfly valve position, which was experimentally obtained in the oil pipelines in operation, is also analyzed in this article. The uneven impact of butterfly valve on the hydrodynamic regime of the main oil pipeline is demonstrated. The article points out the need to change velocity of the butterfly valve rotary especially in the inefficient and too large throttling areas.
Dynamic simulation of a load system driven by two identical PMDC motors
(Видавництво Львівської політехніки, 2013) Atalay, Ahmet Kubilay; Kocabas, Derya Ahmet; Basdogan, Seda
In this study, dynamic simulation of a load system driven by two identical permanent magnet direct current (PMDC) motor is performed by MATLAB / SIMULINK. In the dynamic simulation, two equivalent motors are tandem operated both at same voltage and different voltages in order to drive a mechanical load. The current of each motor, total induced torque and steady state speed of the entire drive system are obtained. It is seen that, when the motors are supplied by the same voltage they share the load equally. On the other hand, if they are operated with different voltages, the motor which is supplied with lower voltage always operates as a generator and the motor which is supplied with higher voltage is overloaded in order to supply the other one and drive the mechanical load.