bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical research of the influence of the geometric parameters of shadowing fins on the intensity of jet cooling by supercritical carbon dioxide
Authors: Rogalev A N , Kindra V O , Osipov S K , Makhmutov B A , Zonov A S
Published: March 2021

This paper discloses computer simulation results of thermos-hydraulic processes in cooling channels of carbon dioxide turbines used in oxy-fuel power production facilities. Stream cooling systems may be modified by the installation of shadowing ribs on the pressure and suction sides of a hollow blade and this intensifies heat transfer and reduces the cooling agent flow. The heat transfer maximal intensity is obtained at the distance between deflector orifice and shadowing fin of 0.25 orifice diameter. Change of the shadowing fin cross-section shape from oval to circular causes increases of the channel hydraulic resistance for 20–28% and the mean Nusselt number for 8–25%.
A Study of the Short Heat Pipes by the Monotonic Heating Method
Authors: Seryakov AV , Alekseev A P
Published: March 2021

The results of studies using the monotonous heating method in a vacuum adiabatic calorimeter the thermal resistance and heat capacity of short linear heat pipes (HP’s) designed for cooling spacecraft and satellites with strict take-off mass regulation are presented. Experimental results of thermal resistance, obtained at high thermal loads and starts boiling of the working fluid in the HP’s evaporator allow us to determine the evaporator heat capacity by solving the inverse coefficient problem of thermal conductivity equation. This allows us to estimate the thickness of the working fluid layer and the specific heat of evaporation, the heat capacity of the liquid and vapour phase of the boiling two-phase working fluid on the evaporator surface.
Experimental-theoretical approach to calculating the partial density of hydrogen cyanide during fires at energy facilities
Authors: Puzach S V , Boldrushkiev O B , Suleykin E V
Published: March 2021

It is made analysis of toxic effect of hydrogen cyanide on people during fire evacuation at energy facilities premises. The critical value of the partial density of hydrogen cyanide is substantiated. An experimental and theoretical approach is proposed for calculating the partial density of hydrogen cyanide indoor fire. The proposed approach is based on the analytical dependence of the average volumetric partial density of HCN on the change in the volumetric average partial density of oxygen in the premises. The results of experiments on measuring the partial density of HCN in the case of combustion of modern cable products used at energy facilities are presented. The results of experimental and theoretical studies make it possible to determine the time variation of the average volumetric partial density of hydrogen cyanide in a fire in a full-scale premises using the experimental values of the specific coefficients of formation of hydrogen cyanide and oxygen absorption obtained in a small-scale experimental setup, and the change of the volumetric average partial density of oxygen obtained from the solution of the conservation law equation mass of oxygen. It is substantiated that the calculation can also be made without solving the differential equation of the law of conservation of the mass of hydrogen cyanide using only the experimental dependence of the HCN density on the change in O2 density.
Theoretical researches of air permeability during development of cracks in building facilities
Authors: Vorob’eva Y A , Zherlykina M N , Burak E E , Kononova M S , Muravyov AV
Published: March 2021

The article considers a mathematical model of air infiltration through cracks in building envelopes. Air movement for the given flow diagram of a continuous medium is described by the Navier - Stokes equations. As applied to thin layers of the air, assumptions are made that make it possible to compose a system of equations, including equations of dynamics and equations of continuity. The results of assessing the physical deterioration of residential buildings constructed according to standard designs taking into account their number of storeys and wall materials are presented. The influence of various damage to the building on the state of its heat balance is considered. The dependences of reducing thermal protection of building envelopes on the degree of wear in houses made of various materials are revealed. The main recommendations for improving the energy efficiency of buildings are proposed, which allow minimizing heat losses and ensuring comfortable microclimate parameters in the premises.
Particle separation in cyclones of circulating fluidized bed systems
Authors: Ryabov G A , Folomeev O M
Published: March 2021

Circulating fluidized bed (CFB) plants are widely used in energy, petrochemicals, aluminum production (alumina firing), and other industrial sectors. The CFB technology is characterized by relatively high reactor velocity that exceed the transport velocity of medium-sized particles, and the presence of separators (mainly of the cyclone type) with a system for returning trapped particles to the reactor. This ensures a long residence time of the particles in the reaction zone, a high circulation rate, and a stable and relatively low temperature in the reactor. In fact, it is the cyclone capture efficiency that directly determines the multiplicity of circulation and the flow rate of circulating particles and their size characteristics. The report discusses the current state of development and methods for cyclones calculating. Data from our and foreign studies are reviewed and the dependence of the correction on the mass concentration of particles is proposed. A brief description of the test rigs and the results of our own studies of particle separation in cyclones are given. Experimental data on the effect of dust on the capture efficiency are presented in the form of a dependence of the relative entrainment of particles (1-efficiency) on the mass concentration of particles at the entrance to the cyclone. Entrainment is noticeably reduced when the concentration increases, as small particles are attracted by larger ones to the wall of the cyclone.
Application of numerical modelling for determining the optimal position of the suction slot in the steam turbine vane cascade
Authors: Gribin V G , Tishchenko A A , Alekseev R A , Gavrilov I Yu , Popov V V , Tishchenko V A
Published: March 2021

The numerical investigations of liquid film development in the last stages of steam turbines were performed. This data was used to suggest the position of the suction slot used to evacuate the liquid phase from the turbine flow path. The object of study is a periphery 2D section of vanes cascade. The movement of coarse droplets in the blade passage was simulated. Their collision with the blade surfaces results in the appearance of additional sources of mass and momentum for liquid film. The influence of theoretical Mach number on the features of liquid film formation was studied. The distributions of main characteristics, reflecting the formation of the film, have been obtained. They were used to analyse the liquid phase flow along the surfaces and to point out base recommendations about the location of the suction slot.
Evaluation of the dynamical characteristics of fluid flow caused by collapse of a non-spherical near-surface bubble
Authors: Le T C , Melikhov V I , Melikhov O I , Yakush S E
Published: March 2021

The paper is devoted to numerical study of the influence of the initial shape of a vapor bubble on the surface impact of the water jet emerging due to the bubble collapse. This problem is relevant to spreading of high-temperature melt under a layer of subcooled water. The vapor bubbles formed on the melt-water interface, upon complete penetration in water, are condensing rapidly to produce high-velocity water micro-jets directed towards the melt. Impact of these jets causes upward melt splashing. Superposition of these processes forms a dynamic layer where melt is mixed with water; the presence of this premixed layer can be a pre-requisite for steam explosion. In this work, numerical modelling by the boundary element method is performed for the collapse of a bubble of an oblate spheroid. It is shown that the water jets generated in this process possess the impulse comparable to that generated by a collapsing spherical vapour bubble of the same volume. By the numerical simulations and subsequent estimates it is obtained that collapse of non-spherical bubbles near the melt-water interface produces melt splashes of the height of few centimetres, which is sufficient for the occurrence of steam explosions.
A review to the specific problems of nano thermal physics
Authors: Khvesyuk V I , Barinov A A , Liu B , Qiao W
Published: March 2021

The paper is devoted to three current problems that related to thermal transfer in the solid-state nanostructures. The first task is the analysis of interaction of phonons with rough solid boundaries, the presence of which leads to a significant increase in the resistance to heat transfer in nanostructures. This fundamental problem is discussed in a connection to the theoretical formulation of rough interface between solids. The second task is exploring methods to calculate diffusion and heat transfer in solids within the framework of detailed consideration of phonon interaction processes. The development of the computational model that adequately represents the physics of interaction processes and allows to calculate thermal properties that are in a good agreement with experimental data remains open. The third task is to calculate the thermal bound-ary conductance. The problem is solved by considering the processes of scattering and refraction of elastic waves at the interface. For the first time, the dispersion properties of elastic waves are taken into account in the problems of this kind. The result is the applicability of the new model in a much wider temperature range than in the existing models.
An experimental study of heat transfer and pressure drop during flow boiling of R134a and R236fa in a microchannel system
Authors: Shamirzaev A S
Published: March 2021

An experimental study was made of heat transfer and pressure drop during the boiling of R134a and R236fa refrigerants in a system with two slotted microchannels. A copper block with two microchannels 2.05 mm wide, 0.4 mm deep, and 16 mm long was used as an experimental test section. The mass velocity varied from 500 to 2000 kg/m2s, the initial subcooling was from 40 °C to 0 °C. Data analysis showed that, when the flux of R236fa refrigerant becomes saturated, nucleate bubble boiling is absent. In the case of R134a saturated flow boiling, suppression of nucleate bubble boiling was observed with heat flux increasing.
Analytical study of the velocity and pressure of the electrovortex flow in hemispherical bowl in a Stokes approximation
Authors: Malyshev K Yu , Mihailov E A , Teplyakov I O
Published: March 2021

The problem of an electrovortex flow in a hemispherical bowl with an internal electrode is considered. In the framework of the Stokes approximation, analytical expressions for the velocity and pressure fields are obtained. Two types of boundary conditions were used: non-leakage on the entire boundary (with no-slip condition on the free surface and partly slip on the electrodes) and an approximate adhesion condition on the electrodes. The non-leakage condition corresponds to the homogeneous Dirichlet boundary condition for the vector potential and the vorticity on the entire boundary. An approximate adhesion condition is posed using the Thom difference approximation. The analytical expressions for the velocity and pressure fields are written uniformly for both types of boundary conditions.
Maps of hydrodynamic regimes of evaporation and boiling in the thin horizontal liquid layer on the modified surface
Authors: Shvetsov D A , Pavlenko A N , Brester A E , Zhukov V I
Published: March 2021

The paper reports the results of the study of evaporation and boiling regimes of a thin horizontal liquid layer on a modified surface. The formation of various structures was observed at the different heat fluxes, pressures, and heights of the liquid layer. The paper presents maps of the hydrodynamic regimes of evaporation and boiling of thin liquid layers on a modified surface. The regions of existence of various structures observed in the layer are indicated depending on the pressure and heat flux. The results are compared with the calculation dependencies.
An review for the heat transfer researches of Hypervapotron in the ITER first wall
Authors: Wang Youpeng , Dedov AV
Published: March 2021

For the steady running of the first-wall (FW) in international thermonuclear experimental reactor (ITER), it’s essential to introduce highly effective heatsinks which can bear high heat flux and remove it up to 30MW m-2. Hypervapotron (HV) is one of the most promising devices in which the subcooled boiling plays a significant role. In this work, notable conclusions drawn by other researchers have been summarized, like “Vapotron effect” and “appearance of vortex”. Characteristics of different HV fabrications were compared at the same time. Especially, aiming at the optimization of Hypervapotron test section for FW in ITER, a series of selected HV heat transfer experiments were analysed thoroughly, including the working fluid parameters, structures of test section, CHF test results, etc. The most reasonable and reliable design of the test sections and corresponding parameters were chosen and optimized.
Experimental determination of the pressure drop and temperature fields in the working section of the fuel assembly model with microfuel
Authors: Mirnov S V , Komov A T , Varava A N , Dedov A V , Zaharenkov A V , Smorchkova Yu V , Tupotilov I A
Published: March 2021

The paper describes an experimental stand and a working area on a model of fuel assembly with microfuels cooled by a single-phase coolant flow at high pressures. The experiments were carried out in a wide range of operating parameters of the coolant coolant pressure p = (2 ÷ 7) MPa; mass flow rate of the coolant Gwater
= (0.05 ÷ 0.5) kg/s. The experiments were carried out on the working area of the body, which is made of high-temperature ceramics. The results of pressure losses and temperature distribution of balls along the length and radius of the filling are obtained. It is shown that the hydraulic resistance coefficient obtained on the basis of experimental data is in good agreement with the Bogoyavlensky formula. Significant temperature stratification is observed along the radius of working section.
Plasma chemical reactions initiation in supersonic jets by a high-voltage electron beam
Authors: Zarvin A E , Khudozhitkov V E , Dubrovin K A , Kalyada V V , Yaskin A S
Published: March 2021

The results of the study of processes occurring in supersonic flows of gas mixtures under the influence of high voltage electron beam are presented. The research was performed on the gas-dynamic complex of experimental installations located in the Department of Applied Physics of Novosibirsk State University. Spectral methods and molecular beam mass spectrometry were used to diagnose the processes. A significant difference in the clustered argon mass spectra was found in comparison of spectrum recorded during ionization by a quadrupole mass spectrometer own ionizer and spectrum obtained with the transport of ions formed by an electron beam in the jet through a skimmer to the mass spectrometer detector (without using an ionizer of spectrometer). The second variant of gas flow ionization presents the possibility of registering the mass spectrum of a hydrocarbon series with features indicating the occurrence of heavier hydrocarbons in the jet. The mechanism of intracluster energy exchange with the transfer of excitation initiated by electrons with subsequent intense radiation at certain wavelengths of a neutral argon atom was detected and identified.
Heat conductivity of copper-zinc catalysts used for producing methyl alcohol
Authors: Tilloeva T R , Safarov M M , Taurov E Sh
Published: March 2021

The paper presents the results of an experimental study of the thermal conductivity of copper-zinc catalysts in a wide range of temperature changes and various concentrations of component components, which ranged from 10 to 90%. To achieve this goal, we used a device developed on the basis of the method of monotonous heating to measure the thermal conductivity of samples depending on changes in the experimental temperature up to 400K. Based on the results obtained using the law of corresponding states, the corresponding empirical equations were derived that allow calculating the thermal conductivity of experimentally unexplored samples with an error of no more than 4%.
Results of steel 20Kh13 samples with combined hardened-structured surface erosion tests
Authors: Mednikov A F , Tkhabisimov A B , Kachalin G V
Published: March 2021

The work presents the results of erosion tests and metallographic studies of samples from blade steel 20Kh13 with diffusion coating obtained by ion nitriding and samples from nitrided steel 20Kh13 with a relief previously formed on the surface. Studies of the samples resistance to high-speed water droplet erosion were carried out using the unique hydraulic impact rig «Erosion-M» of the NRU «MPEI». It was established that the use of nitriding and nitriding with preliminary surface structuring allows increasing the relative erosion resistance in the area with a maximum wear rate of at least 2 times, and in the area with a steady wear rate of at least 3 times. It was also found that structuring the surface layer before the nitriding process allows reducing the wear rate in the area with a maximum erosion rate compared to the nitrided surface by at least 10%.
Fundamental equation of state developed on basis of Migdal’s phenomenological theory of critical point
Authors: Rykov S V , Kudryavtseva I V , Rykov V A , Sverdlov A V , Ustyuzhanin E E
Published: March 2021

In this work a fundamental equation of state (FEoS) with account taken of requirements of the scale theory of the critical point has been developed. The behavior of the FEOS in the asymptotic vicinity of the critical point is determined by the characteristics of the scaling function a(x) of the Helmholtz scale free energy F. The structure of the function a(x) is calculated on the basis of Migdal’s phenomenological theory and the hypothesis about the identical behavior of the isothermal compressibility coefficient at the critical and near-critical isohors near the critical point (Benedek’s hypothesis). The parameters of the singular component of the FEOS are calculated using the similarity theory. The proposed FEoS has been approved on the example of description of equilibrium properties of the refrigerating agent R1234yf in the range of state parameters: by a temperature from 220 K to 440 K and by pressure up to 40 MPa. The obtained results are discussed.
Study of the phase behavior of n-pentacosane C25H52 by optical method
Authors: Kuryakov V N , Dechabo V A
Published: March 2021

For two samples of n-pentacosane dispersions in water with different average size of the dispersed phase, the melting, crystallization and rotator phase temperatures are determined by optical method. For particles, that have a radius of 100 nm, the temperatures of phase transition correspond with the published data. For particles with a radius, that is not exceeding 50 nm, a significant undercooling of n-pentacosan drops happens.
Justification for effectiveness of stepwise heat supply during preliminary thermal processing of solid organic fuel
Authors: Boiko E A , Strashnikov A V , Shishmarev P V
Published: March 2021

This paper presents the practical justification of the efficiency of the organization of step heat supply in the process of pre-heat treatment of solid organic fuel. Two options were considered heat training: at a constant temperature and with a step-heating.
Processing of radioactive graphite by gas-generating method
Authors: Barbin N M , Kobelev A M , Terent’ev D I
Published: March 2021

Using the method of thermodynamic modeling the composition and quantity of generator gas formed during the processing of radioactive graphite in water vapor in the temperature range from 773 to 1073 K were determined. It has been established that the main components of the gas phase are CO, H2, CO2, CH4, H2O, HCl. The technological scheme and the scheme of a gas generator for the processing of radioactive graphite are developed.
Scientific-Technical and Economic Aspects For Development Of Innovative Reactor Plants For Small And Medium Nuclear Power Plants
Authors: Dmitriev S M , Kurachenkov AV , Petrunin V V
Published: March 2021

The scientific, engineering and production capability that has been developed in our country in the field of nuclear shipbuilding is of exceptional value. In nuclear shipbuilding technologies, a special concept of a modular reactor plant has been formed, which is characterized by an extremely small footprint required to accommodate a steam generating plant in a limited space of the reactor compartment, enhanced reliability and survivability. Based on the experience in creating and improving marine and naval reactor plants, JSC “Afrikantov OKBM” has developed a number of designs of innovative reactor plants for small-and medium-sized nuclear energy sources. The paper describes the basic scientific, technical and economic aspects of developing such innovative reactor facilities as ABV, KLT, RITM and VBER.
Comparative analysis of renewable energy integration in Germany and Russia
Authors: Kozlova Yu A , Fedotova E V
Published: March 2021

The problems and prospects of renewable energy penetration to the Russian regional energy systems are discussed. The comparative analysis of renewable technologies development was done considering Russian and Germany power systems as ones with quite similar initial conditions before the energy transition has been started. Implementation a considerable renewable generation share into a “traditional” power system seems to be perfectly technically feasible still with the state-of-the-art technologies. Substantial organizational, financial and economical efforts seem to be unavoidable. Careful preliminary planing of renewables implementation is crucial to ensure viability of the volatile renewable generation working as a part of the Russian power system.
Mechanisms of vibration damping in heat power engineering structural materials
Authors: Kul’kov V G , Sultanov M M , Chubko Yu M , Syshchikov A A , Kuryanov V N
Published: March 2021

This article explores two models of internal friction in porous materials and ultrafine-grain composite materials. The high-temperature background is described by two straight sections based on the dependence of the internal friction value on the reverse temperature or frequency of vibrations.
Graph-analytical method for determining thermal loads of combined heat and power plant
Authors: Orlov M E , Dolgov M A , Mityakhin D A
Published: March 2021

The prospects of using excess steam from production bleeds-off of turbines for providing peak heating load of combined heat and power plant from peak network heaters instead of inefficient peak water-heating boilers are considered. For efficiency assessment of excess steam application the graph-analytical method is developed, the essence of which consists in construction, comparison and analysis of graphs of process heat and heating loads of combined heat and power plant dependent on the duration of heating period, determination of excess steam amount and possibility of its supply to peak network heaters, thereby reducing fuel consumption at the combined heat and power plant.
Automated design, calculation and production of plate heat exchangers for complex cycle gas turbine plants
Authors: Remchukov S S , Lepeshkin A R , Yaroslavtsev N L
Published: March 2021

The comprehensive methodology of computer-aided design and calculation of plate heat exchangers for complex cycle gas turbine plants has been developed. This method allows obtaining a heat exchanger that provides the best thermal and hydraulic characteristics within the specified limits with minimal participation of the designer. The algorithm for closely linking the design stage with the production technology, which makes it possible to obtain a set of 3D models of technological equipment necessary for the producing of a heat exchanger, has been developed. Experimental studies of the heat exchanger produced according to the proposed method showed a close convergence with the calculated data.
OPTIMIZATION OF PK-14 BOILER INSTALLATION AIR-DUCT AERODYNAMICS USING PHYSICAL AND MATHEMATICAL MODELING
Authors: Zroychikov N A , Kaverin A A , Vasilenko A M
Published: March 2021

The operation of boiler units is often conducted with increased excess air α due to the non-uniform distribution of air between the burners, which leads to an efficiency factor lowering. This problem can be solved by optimizing the design and laying of the air ducts. Selection of the optimal air ducts design is based on the preliminary model investigations. In this paper, the issue of optimizing the air ducts aerodynamics of the PK-14 boiler is studied. The boiler air path is characterized by a significant difference in length and trace configuration for each burner. The situation is complicated by the combined combustion of natural and blast-furnace gas in the boiler furnace. Nonuniformity of air distribution between natural gas burners reaches 20% and between blast-furnace gas burners up to 40%. Thereby in order to maintain stable fuel combustion, it is necessary to increase the excess air to α ≥ 1.3. In this paper, the current and the optimized developed by the authors variant of this air duct section are investigated by the means of numerical simulation. According to the results of numerical modeling, it was found out that the optimized variant allows to achieve the degree of air distribution nonuniformity not exceeding 3% and reduce the aerodynamic drag of the air duct section by 1.6 times. In the future, verification of the numerical modeling results for the optimized variant of air duct on a physical model is assumed.
Combustion chamber development features for converted small gas turbine
Authors: Afanasov Y V
Published: March 2021

Conversion and modernization of a gas turbine engine involves solving a number of tasks, one of which is the development of a combustion chamber for operation on various gaseous fuels. The complexity of solving this problem is associated with a variety of interrelated processes occurring in the CC, which are complex and insufficiently studied. The work on the small-size gas turbine engine CC is even more complicated by the lack of a generally accepted and well-developed finishing technique typical of large gas turbine engines, which is emphasized both in domestic and foreign works. The report considers the main approaches to classifying the dimensions of combustion chambers of gas turbine engines [1] according to various criteria, namely: to the power type size (according to CIAM)Classification based on the reduced air flow through the compressor. The criteria included in the classification are analysed, in relation to the implemented designs, the most objective classification is selected for further consideration of the design of the combustion chamber of a small-sized gas turbine engine when converting it to gaseous fuel. The features and technical limitations of converting the combustion chamber from liquid to gaseous fuel are considered, which is an urgent task against the background of gasification programs of the fuel and energy complex in the Russian Federation. Attention is paid to the factors that have the greatest impact on the environmental characteristics of the converted combustion chambers.
Mathematical Model for Optimizing the Composition and operating Modes of TPP Steam Boilers according to the Environmental Safety Criterion
Authors: Ivanitckii MS , Konstantinov AA , Kuryanova EV , Sultanov MM
Published: March 2021

This paper deals with the problem of optimizing the composition and operating modes of boilers of thermal power plants according to the criteria of environmental performance in accordance with the main changes made to Federal law № 219-FZ of 21.07.2014 «On amendments to the Federal law «On environmental protection» and certain legislative acts of the Russian Federation» and taking into account the new principles of environmental management of energy enterprises. It is proposed to use the minimum value of the total index of harmful combustion products, depending on the type of fuel being burned, as a criterion for the environmental safety of the gas and oil boiler. The contribution of each individual harmful component of combustion products is taken into account based on the determination of specific indicators of the harmfulness of flue gas components. The proposed approach allows us to take into account the influence of important operational and technological factors on the change in total mass emissions of substances and the formation of a total indicator of the harmfulness of flue gases, including the dynamic nature of changes in the load of TPP boilers.
Development of a system of energy technological processing of coal deposits for energy and other industries
Authors: Burakov I A , Burakov A Y , Nikitina I S , Aung H N , Ye V A , Aung K M , Anufrieva EA , Lozenko VM
Published: March 2021

In connection with the forthcoming toughening of environmental requirements, including during the operation of energy facilities, as well as in order to more fully use the resources of the fuel and energy complex and mineral deposits in the Russian Federation, it is proposed to review the principles of developing coal deposits and preparing energy coal and other resources coal deposits for burning at thermal power plants. The main resources of coal deposits considered in this work are steam coal and mine gas, which is present in most coal deposits of the Russian Federation. The gas content of coal seams can reach 35 m3 in terms of 1 ton of dry ashless coal mass. Direct coal combustion at thermal power plants leads to the formation of a large number of emissions of substances that negatively affect the environment. The main emissions from coal flaring are fly ash and slag, toxic sulfur and nitrogen oxides, carbon monoxide and carbon dioxide. The following technologies are used to reduce the amount of these substances in the flue gases: wet and dry scrubber systems, the organization of fuel combustion, aimed at reducing toxin emissions (in particular nitrogen compounds), the use of various types of filters to clean flue gases from volatile ash and slag particles and etc. To increase the effectiveness of the fight against toxic and polluting emissions, the team of authors proposes to use solid fuel pre-processing as part of the operation of the energy technology plant together with the used cleaning systems. The type of energy technology plant, depending on the tasks to be solved within the development region, can be different. To implement the processes of energy technological processing and in the framework of reducing effluents from energy facilities, the issue of the reuse of highly mineralized, oil-contaminated and oiled wastewater from thermal power plants and highly mineralized wastewater from coal deposits, as well as the reuse of spent TPP lubricants in the plant cycle, is being considered. To increase the calorific value of the synthetic gas produced in the plant’s cycle, the issue of its joint combustion with purified mine gas produced in the coal field under development is considered. Mine gas is also cleaned in the plant cycle.
Complex of virtual works on Thermodynamics. Section «Processes of ideal gases and humid air»
Authors: Kuznetsov K I , Ponurovskaya V V , Granchenko P P
Published: March 2021

Two virtual laboratory works are presented in the developed complex: “Measurement of the heat capacity of air” and “Processes in moist air” performed in the Excel 2010 spreadsheet. The works are devoted to the study of processes in ideal gases, in particular in humid air, and are virtual analogues of physical work, on existing stands in the laboratory of technical thermodynamics of the Department of Theoretical Foundations of Heat Engineering MPEI, corresponding to the bachelor’s program in the disciplines “Thermodynamics” and “Technical Thermodynamics”. The presented material is intended to be included in the educational process in case of repair of existing laboratory stands, as well as for distance learning of students
Energy saving in municipal sewage pumping station
Authors: Razakov M , Khohlov V
Published: March 2021

There are a various energy-saving measures for climate control systems in the city sewage pumping station (SPS) are considered in this paper. All consumers and sources of thermal and electric energy in SPS are classified according to various characteristics. There are the positive and negative features of thermal and electrical energy sources are considered. The differences between the set of consumers in the sewage pumping station and the pumping station of the cold water supply system of the settlement are shown by authors. There are possible sources of thermal and electric energy, as well as frequently occurring renewable sources of thermal energy for SPS. It has been shown the search results of all possible energy saving measures that can be used not only in the sewage pumping station, but also in the pumping station of the water supply system of settlements, as well as in pumping stations for reclamation needs in this article. Authors also in this work have considered a number of domestic methods for assessing the energy consumption of a building and assessing the impact of energy-saving measures on the overall energy consumption of a building because at the moment there are not unified techniques on these topics.
Investigation of the open bifunctional cathode for unitized reversible fuel cell: composition and performance
Authors: Ivanova N A , Spasov D D
Published: March 2021

Unitized regenerative fuel cell (URFC) can operate both in energy generation (EG) and in hydrogen production (HP). Using URFC reduces the weight and size characteristics of the power plant compared to a stationary system with the independent fuel cell and the electrolyzer. However, its performance also reduces. In this work, we study URFC with an open cathode, which applied as the anode in HP. In this case, the air inflow to the FC cathode in EG, and oxygen outflow from the anode into the environment in HP. The investigation of the electrocatalysts composition for the bifunctional cathode is carried out. The advantages of using a mixture of Pt40/RGO (RGO – reduced graphene oxide) with Ir-black (3:1) for an open cathode of URFC are shown. The cathode composition presented above doubles the efficiency of URFC in comparison with URFC based on a mixture of Pt-black and Ir-black (2:1).
Physical properties of ceramic material obtained using the carbon residue of municipal solid waste pyrolysis
Authors: Kolibaba O B , Dolinin D A , Gusev E V , Malov A A
Published: March 2021

The main tendency to solve the problem of municipal solid waste in the Russian Federation is the transition from landfill to industrial processing. A promising option is the pyrolysis of solid carbon-containing waste, which allows not only to significantly reduce the amount of waste, but also to obtain alternative types of energy.

The use of products of the pyrolysis processing of municipal solid waste in the technology for the production of ceramic materials is proposed.

A new ceramic material was obtained in which the solid pyrolysis residue of a mixture of MSW of medium morphological composition was used as a structure-forming additive. The following were experimentally determined: chemical composition of the material, water absorption, mechanical strength, density, heat conductivity, heat capacity. It is recommended to use modified ceramics in the production technology of building products for various purposes.
Analysis of the electric loads of residential and public buildings in urban power supply systems
Authors: Demidenko A S , Kudelina S A , Shvedov G V
Published: March 2021

Accurate determination of the calculated electric loads is a basis for power supply systems design. Values of the calculated loads influence parameters of the electrical grid. That is why the values of the calculated loads should not be exceeded in operation. Calculated electric loads also influence investments in the designed grid. For the most effective usage of the investments, the values of the calculated loads should not be overstated or understated. This article is about the applicability of the problem of the elaboration existing databases used in governing documents. Based on the obtained data, the analysis of the calculated electric loads of public buildings is carried out. Typical daily load graphs at the input of the apartment houses with electric stoves are given. Accurate load graphs at the input of the apartment houses are received, according to the results of measurements for various days of the week. The received load graphs are compared with given graphs from technical literature. We have found that the configuration of the up-dated load graphs of residential buildings significantly differs from the given graphs.
Critical heat flux calculation model for tubes with twisted tapes
Authors: Zakharov S V , Baidakov I L
Published: March 2021

A new method for calculating the heat transfer crisis in tubes with twisted tapes on the basis of the existing physical model of CHF for nucleate boiling is presented. The change of CHF in case of using twisted tapes is taken into account by introducing of correction factors to the existing model. Verification of the present model has been carried by checking out of existing experimental works with data on CHF with a total of 187 points. The model gives good agreement with the experiment in a wide range of parameters.
Control of a local energy complex with renewable energy sources
Authors: Molotov F V , Vaskov A G , Shestopalova T A
Published: March 2021

Local energy complexes are characterized by the fact that they do not have as many energy sources as in the Unified energy system. In this regard, it is required to comply with the standard in quality and reliability of electricity. Given the availability of renewable energy sources in the system, the instability of electricity generation must be compensated for with the help of guaranteed energy sources or storage devices. In this paper, various control algorithms for electric power sources with different guaranteed power and inertia are considered. The proposed algorithms are tested on a physical and mathematical model of a local power system.
Methodological bases of optimization of thermal insulation structures of glass furnaces
Authors: Beknazarian D V , Kanevets G E , Strogonov K V
Published: March 2021

In the construction of modern bathrooms of flaming glass furnaces, glass resistant refractory materials of high quality and a variety of thermal insulation materials are used, which are compounded into multi-layer thermal insulation panels, reducing heat losses. However, increasing the temperature of wall bars when applying thermal insulation sharply reduces their service life due to high-temperature physical and chemical corrosion. Such a contradiction and a wide range of insulation products, as well as various modes of glass melting and intensity of forced cooling of the outer lateral surface of the furnace requires the choice of an optimal set of thermal insulation materials under the chosen conditions of furnace operation to ensure maximum operating life of the unit with maximum efficiency.
Energy saving of high-temperature processes by intensive melt degassing
Authors: Strogonov K V , Zdarov A A
Published: March 2021

The paper considers the possibility of energy saving high-temperature processes for producing melt. Reducing energy consumption is ensured by a set of measures aimed at intensifying the process of degassing of the melt and increasing its efficiency. Presented are modern methods of degassing melts. The main parameters that determine the nature of the movement of gas bubbles in the melt are the Reynolds criterion and the dynamic viscosity of the melt. The viscosity of the basalt melt decreases with increasing temperature. The creation of vacuum conditions in the degassing chamber provides a multiple increase in the rate of degassing of the melt and a decrease in heat loss to the environment.
Development and design of a hybrid power supply system
Authors: Gasho E G , Katkova E Y , Popov D E
Published: March 2021

The work is devoted to the development and design of a hybrid power supply system for Northern climatic conditions on the example of the village of Solovetsky based on non-traditional renewable energy sources and fuel cells.
Methods for determining thermophysical properties of heat protective protections of buildings and high-temperature installations
Authors: Dolinin D A , Wu S K , Davlatov R K
Published: March 2021

The paper presents two methods for determining the thermal and physical properties of thermal barriers, differing in the range of operating temperatures and the object of which they are an integral part. The first method is based on a non-destructive approach to determining the thermal resistance of the external fencing of buildings, providing comfortable living conditions. The second method is based on taking into account the volumetric absorption of radiation by porous materials used in high-temperature installations, and the quasi-stationary heating mode. The presence of these two factors makes it possible to determine the absorption coefficient of a material located in the field of high-temperature radiation.
Experimental researches of atmospheric sublimation drying and analysis of economic efficiency its applications
Authors: Egorova A I , Vlasenko G P , Nechepurenko N S , Antipov A V , Popov D E , Alyautdinov A R
Published: March 2021

This article presents the results of experimental studies and economic analysis in the field of atmospheric freeze drying (AFD), analyzes the features of the processes of sublimation of polydisperse materials of animal and vegetable origin. Using the results of this work will reduce energy intensity and increase the efficiency of sublimation technologies in industrial production. An economic analysis of the feasibility of atmospheric freeze-drying technology is carried out according to discounted indicators. The values of the terms of the project implementation are obtained and practical recommendations on the modes and parameters of drying are given.
Stability Improvement of Asphalt Concrete Binder Course using LDPE Plastic Waste with Lignin as Coupling Agent
Authors: Afif M R , Huda T , Firdausi M F
Published: March 2021

Development of plastic waste as an asphalt mixture inhibited by its compatibility. In this study, the addition of weight variations modified lignin as coupling agent in Asphalt Concrete-Binder Course (AC-BC) with LDPE mixture was investigated. Asphalt, Polymer Modified Bitumen with and without lignin addition were characterized by physical analysis using Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy. While the AC-BC pavement was analyzed by mechanical analysis using marshall parameter. The addition of plastic to asphalt will form agglomeration and after lignin was added the agglomeration reduced. The reduced formation of plastic agglomeration due to lignin addition in asphalt form Van der Waals reaction was indicated by peaks alteration from 1041.77 cm−1 to 1031.11 cm−1 at the maximum addition of lignin. Moreover, the marshall stability of the AC-BC pavement was enhanced up to 89.5% at optimum lignin addition. Lignin utilization as a coupling agent of asphalt and LDPE can be a solution to the weaknesses of asphalt plastic technology while solving the plastic waste problem.
TVET Institutions’ Perspective on Implementation of Public-Private Partnerships Model in The Southeast Asia Countries
Authors: Towip  , Widiastuti Indah , Saputra Taufik Wisnu , Noviansyah Wahyu , Trianingsih Lilis
Published: March 2021

Youth unemployment is one of the youth problems in Southeast Asia countries. Previous studies found that one of the problems is caused by the skills gap between TVET graduates and industry needs. Strengthening the partnership between TVET institutions and industry is one of the solutions to minimize the skills gap. Many TVET institutions have established partnerships with the industry. Therefore, the present study is aimed to review the partnerships with industry from the TVET institution perspectives. Respondents from different TVET institutions (N = 129) were surveyed to investigate their perceptions of the partnerships with the industry. Quantitatively, the instrument of the survey data is analysed by using SPSS software. Qualitatively, data from open-ended participants’ responses were analysed by qualitative content analysis to explore the findings from the survey. The result showed that the implementation of public-private partnerships has a good performance and improved the skilled workforce in terms of TVET institutions’ perspectives. Other hands, the present study also explored the partnership’s performance in the subjects of demand-oriented, meet the changing skills demand, allow the industry to participate in the development and management of TVET, supported by the regulatory with the systematic framework and go along with a strategic transition from a short-term to long term objective. The areas of partnerships with industry are discussed as well.
Comparative Analysis of Hierarchical Clustering with Improve Feature for Herbs Leaves
Authors: Liantoni Febri , Prakisya Nurcahya Pradana Taufik , Aristyagama Yusfia Hafid , Hatta Puspanda
Published: March 2021

Plants have different leaf morphological characteristics starting from the leaf surface, leaf bone, leaf tips, leaf edges, leaf base, and even leaf color. The study of plants has been progressing rapidly. One of them is the branch of science in plant morphology. Morphological characteristics of leaves are one of the properties possessed by leaves and can be seen clearly. This morphological study learns about the structure of the plant body, especially about the edge leaf shape. This study will be done based on leaf shape. Leaf shape can be used as a reference in the classification process. The classification process requires a good data extraction feature, so it is necessary to improve the feature process at the pre-processing level. Combining the median filter and image erosion is used to improve the feature process. As for feature extraction, the seven moment invariant method is used. The classification method used for grouping is the Hierarchical Clustering. This method consists of four kinds. There are complete link clustering, single link clustering, average link clustering, and centroid linked clustering. Based on the results of experiments conducted, the use of Average Linkage Clustering method obtained clustering accuracy of 87%. It proves that the average method successfully optimizes the result by calculating any distance between points of the cluster. While the smallest accuracy results using complete linkage clustering of 81%.