HEAT-AND-POWER ENGINEERING FUNDAMENTALS
Yu.A. Kirsanov*, A.Yu. Kirsanov**
DESCRIPTION OF THE SHORT-TERM PROCESS BY THE EQUATION OF HEAT CONDUCTIVITY WITH FRACTIONAL DERIVATIVES // Transactions of Academenergo. -2020. -№3.-P.P. 7-19.
doi:10.34129/2070-4755-2020-60-3-7-19
e-mail: kirsanov-yury@mail.ru, akirsanov@list.ru
*Institute of Power Engineering and Advanced Technologies of FRC Kazan Scientific Center of RAS, Kazan
**Kazan National Research Technical University named after A.N. Tupolev – KAI «KNRTU–KAI», Kazan
Keywords: thermal conductivity, physical experiment, mathematical models, fractional derivatives, transients, thermal relaxation, thermal damping.
Abstract
The thermal conductivity models of Fourier, Cattaneo-Vernotte, Maxwell-Cattaneo-Luikov and models with fractional time derivatives of temperature and heat flux are considered. An algorithm for the numerical solution of the generalized problem of one-dimensional heat conduction is constructed. The algorithm comprises all the models listed above applying boundary conditions of the third kind and difference analogs of differential operators of the second order of accuracy in coordinate and time. The parameters (Biot number, time of thermal relaxation and thermal damping, indicators of fractional derivatives) that describe experimental transient processes are determined using the listed models applied for both in the center and on the surface of a low heat-conducting body.
V.I. Kruglov, I.I. Sharipov
DETERMINATION OF THERMODYNAMIC PARAMETERS OF POWER SYSTEMS AS A BASIS FOR ASSESSMENT OF THEIR TECHNICAL STATE // Transactions of Academenergo. -2020. -№3.-P.P. 20-28.
doi:10.34129/2070-4755-2020-60-3-20-28
e-mail: sharipov.ii@kgeu.ru
Kazan state power engineering university
Keywords: forecasting of technical condition, thermodynamic parameters, method of group accounting of arguments
Abstract
In the article, the authors present an approach to predicting the failure time of energy systems based on the control of their thermodynamic parameters. Solving this problem can facilitate the transition to an operational strategy based on the actual state. For the forecast has been selected well-proven method of group account of arguments (GMDH), which has found wide application in solving complex scientific and engineering problems. The results of forecasting the failure time of two NK-8-2U gas turbine engines based on the results of measuring the main technical parameters are presented. The calculations were performed in the course of the equivalent-cyclic tests on JSC “Kazan motor building production Association”. The results of calculations showed sufficient accuracy of the forecast (no more than 20-25 hours of operation).
O.N. Filimonova, A.S. Vikulin, M.V. Enyutina
MASS TRANSFER IN A VERTICAL CYLINDRICAL INERT granular LAYER FOR AXIAL FLOW INPUT // Transactions of Academenergo. -2020. -№3.-P.P. 29-41.
doi:10.34129/2070-4755-2020-60-3-29-41
e-mail: olga270757@rambler.ru, mmiler5472@yandex.ru, maryena63@mail.ru
Military Educational and Scientific Center of the Air Force «N.E. Zhukovsky and Y.A. Gagarin Air Force Academy»
Keywords: granular layer, mass transfer, heterogeneous flow, concentration field, pseudo-diffusion model, leveling devices
Abstract
Based on pseudodiffusion model with orthotropic tensor of the dispersion of the tools analyze the impact of heterogeneity of the mass flow of the substance entering the working area of the device with stationary cylindrical granular inert layer of non-stationary boundary value problems for linear differential equations in private derivatives of parabolic type with initial conditions corresponding to the device, leveling heterogeneity. The analytical solution of the formulated problem is obtained by successive application of the semi-bounded integral Laplace transform and the finite integral Hankel transform, are verified the structures of functions describing the input flow as a result of using equalizing systems (distribution grids and scattering disks). Computational experiments allowed us to quantitatively describe the picture of heterogeneity of concentration fields depending on the values of the flow dispersion coefficients and the type of device that equalizes the input flow. It is shown that without equalizing elements, the input stream creates a significant heterogeneity of the concentration field in the apparatus, and the disk has the highest efficiency in this aspect compared to the lattice due to the formation of a more “smooth” input concentration profile. A specific example of evaluating the heterogeneity of concentration fields in the complex cleaning unit of an air separation unit showed the effectiveness of the proposed approach.
R. Deeb; A.V. Kolotvin
NUMERICAL INVESTIGATION OF HEAT TRANSFER AND HYDRODYNAMICS FOR IN-LINE DROP-SHAPED TUBES BUNDLE // Transactions of Academenergo. -2020. -№3.-P.P. 42-59.
doi:10.34129/2070-4755-2020-60-3-42-59
e-mail: e.rawad.deeb@yandex.com, kolotvinav@mpei.ru
Damascus University
National Research University (Moscow Power Engineering Institute), Moscow
Keywords: drop-shaped tube, longitudinal spacing, heat transfer, Nusselt number, drop pressure, friction factor, deformation, numerical investigation, CFD.
Abstract:
A numerical study using the software package ANSYS has been conducted to investigate fluid flow and heat transfer characteristics for in-line drop-shaped and circular tubes bundles in crossflow. Reynolds number based on equivalent diameter varied in range of 3×103 ≤ Re ≤ 18.7×103. The longitudinal spacing SL= 37, 46.25 mm, while the transversal spacing ST =37 mm. A mathematical and numerical model has been developed for numerical evaluation of heat transfer and hydrodynamic of a studied bundles. The distribution of the pressure coefficient over a half surface of the circular and drop-shaped tubes of the third row was obtained. Correlations of the average Nusselt number and the friction coefficient for the studied bundles in terms of Re were presented. Results showed that pressure coefficient and heat transfer of drop-shaped tubes depend on position of tubes in tubes bundle. The thermal–hydraulic performance of the drop-shaped tubes bundle is about 1,45~ 2,01 и 1,45~ 2,01 times greater than the circular one for SL= 37, 46.25 mm, respectively.
POWER GENERATION STATIONS
O.V. Pazushkina, M.V. Zolin
EVALUATION OF MODERNIZATION OF INCLUSION OF GAS EXHAUST DEVICES OF VACUUM DEAERATORS // Transactions of Academenergo. -2020. -№3.-P.P. 60-73.
doi:10.34129/2070-4755-2020-60-3-60-73
e-mail: zolinm6@gmail.com
Keywords: thermal power station, thermal deaeration of water, vacuum deaerator, gas exhaust devices, water-jet and steam-jet ejectors.
Abstract
The issue of increasing the reliability of gas exhaust devices remains quite relevant, since a large number of violations of vacuum deaeration of water are associated with their failures. Jet gas removal devices – ejectors, are used as devices for removing non-condensable corrosive gases from vacuum deaerators. The article provides a detailed description of the designs and existing types of steam-jet and water-jet ejectors, provides a classification of ejectors, their scope. Moreover, in this paper, schemes for switching on ejectors are presented, the positive and negative aspects of each of the types of ejectors are considered. In particular, in this work, the scheme of operation of a combined heat and power plant (CHP) with the combined use of steam-jet and water-jet ejectors is considered, and an assessment is made of the modernization carried out at Ulyanovsk CHP-2, associated with an additional installation of a water-jet ejector.
A.A. Filimonova, N. D. Chichirova, A.A. Chichirov, A.A. Batalova, A.G. Filimonov
MODERN OPPORTUNITIES FOR PREPARATION OF ULTRA-PURE WATER FOR FEEDING HIGH-PERFORMANCE BOILER PLANTS // Transactions of Academenergo. -2020. -№3.-P.P. 74-84.
doi:10.34129/2070-4755-2020-60-3-74-84
e-mail: aachichirova@mail.ru
Key words: waste-heat boiler, organic matter, water treatment, thermal power plant
Abstract
The article provides an overview of modern high-performance combined-cycle plants and gas turbine plants with waste heat boilers. The forecast for the introduction of gas turbine equipment at TPPs in the world and in Russia is presented. The classification of gas turbines according to the degree of energy efficiency and operational characteristics is given. Waste heat boilers are characterized in terms of design and associated performance and efficiency. To achieve high operating parameters of gas turbine and boiler equipment, it is necessary to use, among other things, modern water treatment equipment. The article discusses modern effective technologies, the leading place among which is occupied by membrane, and especially baromembrane methods of preparing feed water-waste heat boilers. At the same time, the ion exchange technology remains one of the most demanded at TPPs in the Russian Federation.
POWER AND MECHANICAL ENGINEERING
R.M. Khamidullin
review of models of gradient plasticity theory// Transactions of Academenergo. -2020. -№3.-P.P. 85-98.
doi:10.34129/2070-4755-2020-60-3-85-98.
e-mail: ruslankhamidullin94@mail.ru
Institute of Power Engineering and Advanced Technologies, FRC Kazan Scientific Center, Russian Academy of Sciences
Keywords: dislocations, gradient plasticity, geometrically necessary dislocations, dislocation density, strain gradient.
Abstract
Gradient plasticity theories have potential applications for evaluating the load-bearing capacity of structures, since they more accurately describe stress fields in the crack vertex region by including the influence of dislocation distribution density. Gradient plasticity theories take into account scale effects, assuming that stresses depend not only on deformations, but also on the gradient of deformations. The main idea is that the material is strengthened by changing the total density of dislocations, some of which are derived from the stress gradient. These dislocations begin to play a dominant role in the process of metal deformation at the micro level. This paper provides a literature review of gradient plasticity theories that not only rationalize large-scale effects, but also help to understand the processes occurring in the crack vertex region in the presence of the largest plastic deformation gradients.
ECONOMICS, ECOLOGY, INNOVATIVE TECHNOLOGIES AND PROCESSES IN POWER ENGINEERING
B.Kh.Valiev, A.G.Logacheva, Yu.N. Zatsarinnaya
ENERGY STORAGE SYSTEMS AS A TOOL FOR OPTIMIZING ELECTRICITY COSTS // Transactions of Academenergo. -2020. -№3.-P.P. 99-113.
doi:10.34129/2070-4755-2020-60-3-99-113
e-mail: bulatvaliev98@icloud.com., logacheva.alla@yandex.ru, waysubbota@gmail.com
Kazan State Power Engineering University
Keywords: price categories, energy storage systems, retail market, payment for electricity, storage «behind the meter», cost reduction, lithium-ion battery, payback
Abstract
A key prerequisite for the development of a new electric power industry in Russia is a qualitative change in consumer behavior in the retail sector. For Russian industrial consumers costs of paying for consumed electricity and power during peak hours are quite high. Therefore, they have all reasons to install energy storage devices to reduce those costs. The main mechanisms for cost reducing in this case are the price arbitrage and peak shaving. The price arbitrage means buying electricity during low price hours. The peak shaving means reducing the maximum power during certain hours. We examined a low-power industrial enterprise that purchases electric energy from a supplier at third price category. When consumer uses third price category the overall payment to power supply company consists of bill for electricity and bill for power capacity. The price for electricity varies for each hour of the day. While the price for power capacity is constant during the day the value of power capacity is measured during certain hours. Commercial operator sets the measuring hour for each day of the month. The study considered installation of storage units with power capacity of 10 and 19 kW, energy capacity of 40 and 79 kWh respectively at industrial enterprise. We forecasted the payback of those systems based on the current and forecasted prices for electricity, capacity and lithium-ion batteries in the Republic of Tatarstan. Calculations showed that installation of a storage device at an industrial consumer sight may be economically feasible in the conditions of the Republic of Tatarstan today.