bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermodynamic analysis and optimization of low-boiling fluid parameters in a turboexpander
Authors: Ovsyannik A V , Kliuchinski V P 
Published: March 2021

Abstract
The influence of the initial parameters of a low-boiling working fluid on the thermodynamic efficiency for two turbo-expander cycles (with a heat exchanger at the outlet of the turbo-expander and without a heat exchanger) is considered. For each of the studied cycles, the dependences of the exergy efficiency on the temperature of the low-boiling working fluid before the turboexpander at a constant pressure and the dependence of the exergetic efficiency on the pressure of the low-boiling working fluid before the turbo-expander at a constant temperature were obtained. The dependences of exergy losses on the elements of the studied cycles on the parameters of a low-boiling working fluid are constructed and their analysis is carried out. For the considered schemes, the dependences of the exergy efficiency on pressure are constructed at various temperatures of the low-boiling working fluid in front of the turboexpander. An analysis of the results showed that at any temperature of a low-boiling working fluid, it is possible to determine the pressure at which the exergy efficiency of the investigated circuit will be maximum. Graphic dependencies are obtained that are characterized, from a thermodynamic point of view, by the optimal parameters of a low-boiling working fluid. Comparison of these dependences revealed that, over the entire range of studied temperatures (from 100 °C to 300 °C), a cycle with a heat exchanger at the outlet of the turboexpander has a large exergy efficiency. These graphical dependencies make it possible to determine the optimal parameters of the working fluid in the turboexpander cycle, as well as to predict the change in the exergy efficiency of the installation with changing parameters of the working fluid.
Experimental studies of sediment formation in channels with annular diaphragms of power plants
Authors: Myraviev A V , Nadeev A A , Dakhin S V , Dubanin V Yu , Naumov A M , Vorob’eva Y A 
Published: March 2021

Abstract
In this paper, we consider measures to reduce the amount of deposits in heat exchange tubes and increase the intensity of heat exchange through the use of annular notches-turbulators in tubes of shell-and-tube heat exchangers.
Optimization of CCGT operating modes at variable loads taking into account equivalent operating hours
Authors: Garievskii M V 
Published: March 2021

Abstract
The optimal control of the operating modes of combined cycle power plants is a difficult scientific and practical task, due to the difficulty of taking into account the real technical condition of the equipment, the particularities of the operating modes of a combined cycle gas turbine (with one or two operating gas turbines) and other factors. To determine the optimal regime of combined cycle unit with heat recovery steam generator at variable loads, the method of calculating equivalent operating hours (equivalent operating time) was used, based on the accumulation of damageability from creep and low-cycle fatigue of the main equipment of the combined cycle unit (gas, steam turbines and heat recovery steam generators). The equivalent operating hours and economic parameters of the 450 MW combined cycle power plant were calculated and the optimal operating mode of the main equipment was determined while reducing the load during night off-peak hours.
Mathematical model of estimation of technical condition and prediction of emergency modes of power equipment of power plants using example of power transformer
Authors: Zenina E G , Strizhichenko A V , Efimov V V 
Published: March 2021

Abstract
This paper analyzes the existing regulatory indicators of the technical condition of power transformers. Causal relationships between measurable parameters and defects in the transformer have been studied to identify vulnerabilities and likely scenarios for an emergency. The technical condition of the transformer was assessed using the method of pairing comparisons. The probability of trouble-free operation of functional nodes and transformer in general has been determined. The impact on all transformer systems in determining its lifespan of congestion and short-circuit currents by introducing congestion ratios has been taken into account.
The technique for increase of generating system technical and economic indexes evaluation accuracy using machine learning
Authors: Arakelyan E K , Boldyrev I A , Evseev K V , Sultanov M M , Yurov V A 
Published: March 2021

Abstract
This paper addresses the problem of thermal power plant generating unit efficiency evaluation accuracy increase. The comparison of classic regression analysis and artificial neural network regression approaches is described. The feasibility and reasonability of application of the machine learning techniques for generating unit performance prediction and selecting most influential parameters on its efficiency evaluation accuracy are considered.
Evaluation of the Technical Condition of the Turbine Unit During Diagnostics Using Fuzzy Information
Authors: Krokhin G D , Arakelyan E K , Pestunov A I , Mezin S V , Kibireva A E 
Published: March 2021

Abstract
The report is devoted to the problem of applying fuzzy set theory and fuzzy logic methods in models of diagnostics and assessment of the technical condition of TPP equipment using artificial intelligence methods. Are given here: description of fuzzy images; formation of features of fuzzy images; development of criteria for evaluating features; definition of dividing rules for fuzzy images; classification of fuzzy states of the power plant. The simulation algorithm is considered in relation to a heat and power unit with fuzzy input information and a statistical assessment of the adequacy of fuzzy models. The accuracy of the obtained mathematical model is estimated based on the estimation of the degree of dispersion of the obtained regression line relative to its mathematical model, while the adequacy criteria of 2 types (“R” and “D”) are introduced, which help to integrally assess the proximity of mathematical models to the object under study using the selected measure.
Accounting for the heating cycle in the construction of the optimization model of the thermal power station
Authors: Andryushin A V , Arakelyan E K , Neklyudov A V , Yagupova Y Y , Kuznetsova A V 
Published: March 2021

Abstract
Determining the optimal operating mode of equipment is an important task of modern energy. When planning the operating modes of thermal power plants (TPPs) in the short term (from several hours to several weeks), the following requirements are usually taken into account: production and distribution between the generating units of a given amount of electricity, supply of a given capacity in accordance with the schedule for each group of generation supply points, heat supply to external consumers in accordance with the planned schedule of heat supply. Accounting for heat supply to external consumers allows us to consider in more detail the influence of the volume of heat withdrawals on the area of permissible loads of generating units. This article pays special attention to the optimization of equipment operating modes taking into account the volumes of heat withdrawals from generating units.
Determination of power engineering equipment’s defects in predictive analytic system using machine learning algorithms
Authors: Shcherbatov I A , Turikov G N 
Published: March 2021

AbstractAn approach to forecasting of power equipment’s defects and failures is considered in this paper. The main operations of predictive analytic system for forecasting turbine’s regulation system’s defects is represented. Special attention on machine learning models tuning for explored forecast problem is paid. The following machine learning algorithms: Logistic Regression, Random Forest, Extreme Gradient Boosting, ensembles of these algorithms are explored. According to the results of optimal machine learning models determined, their comparison is done and the conclusion on the appropriateness of the use in predictive analytic system is made.
Technology of desorption of dissolved oxygen from water by boiler exhaust gases
Authors: Zamaleev M M , Kamalova R I , Pazushkina O V 
Published: March 2021

Abstract
A new technology of water degassing based on the use of boiler flue gases as a desorbing agent is described. In the process of burning gaseous fuel, almost all oxygen is consumed, which ensures its absence in the composition of exhaust gases. This makes it possible to use the flue gases of a gas-tight boiler as a desorbent in the process of water deaeration and to avoid using steam. The increasing concentration of carbon dioxide in deaerated water is proposed to be reduced by metering an alkaline agent. The article presents the results of evaluating the mass transfer efficiency of water degassing by the proposed method, as well as the results of calculating the theoretically required specific flow rate of exhaust gases for deaeration.
Construction and Analysis of Adaptive Fuzzy Linear Quadratic Regulator
Authors: Kudinov Y I , Duvanov E S , Kudinov I Y , Pashchenko A F , Pashchenko F F , Pikina G A , Andryushin A V , Arakelyan E K , Mezin S V 
Published: March 2021

Abstract
The paper proposes a formulation and solution of the LQR control problem based on adaptive fuzzy logic. The designs of regulators are considered. The results of analysis of the quality of transients in control systems with adaptive fuzzy LQR controllers are presented. It is shown that the proposed adaptive fuzzy LQR controller provides a shorter transition time and rise time compared to traditional LQR controllers.
Competitiveness of the combined production of chpp with the best available technologies for the separate production of electric energy and heat
Authors: Beloborodov S S , Dudolin AA 
Published: March 2021

Abstract
Further development of the Russian energy sector involves the use of the best available technologies. An important issue is the identification of bats. Increasing the fuel efficiency of power plants is carried out by increasing the unit capacity of generating equipment, increasing the parameters of the working medium to supercritical and super-supercritical. Unfortunately, when forming the list of bats, performance indicators are not always taken into account in real operating modes of the equipment. The calculations have shown that combined production of PTU-CHP plant with subcritical parameters of the working body on the basis of steam turbines of the type P, T and PT given the mandatory process releases steam into the condenser and the gas turbine CHP based on gas turbines of a small capacity has the best specific fuel consumption for generation of electric energy and heat compared to the separate generation of the best available technologies (BAT).
Features of noise radiation from gas turbines
Authors: Tupov V B , Taratorin A A 
Published: March 2021

Abstract
Gas turbine unit (GTU) is the most intensive source of constant noise during normal operation. The noise of the gas turbine unit is emitted from the compressor intake, from the installation shell and from the chimney mouth of the gas turbine unit. Mathematical models for GTU of various capacities are compiled. It is shown that the determining role plays the noise from combustion. That noise is radiated from the chimney outside. Considered various factors affecting noise emission. Obtained empirical formulas for calculating the noise level at various distances depending on the power of the gas turbine. For the first time indicated the importance of taking into account regional climate factors to determine the required noise reduction from GTU. This is especially important to consider when determining the required reduction at high frequencies. The set of factors considered in this paper allows us to determine the required reduction from the gas turbine. Indicated possible measures to reduce noise from gas turbine unit and bring it to sanitary standards.
Fundamentals of the procedure of a comparative analysis of the thermodynamic effectiveness for power generation facilities in a multigeneration complex with various combinations of their main equipment items
Authors: Petin S N , Korshikova A A 
Published: March 2021

Abstract
A problem is examined of improving the efficiency of power generation facilities during their operation in a multi-generation complex. The efficiency of operation is raised by proper distribution of additional power and heat generating capacities used to cover the consumers’ demand for additional (except for electricity and heat) utilities, among various main equipment items of generation facilities. In this case, electricity and heat generated with a higher efficiency is delivered to the consumers, and electricity and heat with no demand, which have also been generated with a higher efficiency, are utilized at the generation facility to produce other utilities (for example, hydrogen, compressed air, cold, etc.) that are centrally delivered to industrial and social facilities.
Metal-hydride reactor for low rate fuel supply with pressure driven adsorption and cooled by natural convection
Authors: Blinov D V , Borzenko V I , Bezdudny A V , Dunikov D O , Kazakov A N , Romanov I A , Kuleshov V N , Porembsky V I 
Published: March 2021

Abstract
A metal hydride reactor for hydrogen accumulation RHA-1 containing 18 kg of La0.85Ce0.15Ni5 alloy is created. RHA-1 and has maximum hydrogen capacity of 2.7 st.m3 and nominal capacity of 2 st.m3. Experiments have shown that the reactor could be operated using the pressure difference between an electrolyzer (1 MPa) and a fuel cell (>0.2 MPa) with passive cooling/heating of air in indoor conditions. The equilibrium charge rate is 1 st.L/min, the equilibrium discharge rate is 1.3 st.L. The RHA-1 could be used for long term energy storage and in combination with the 100 W PEM fuel cell is comparable with 12V 210Ah electrochemical batteries. The metal hydride/fuel cell system is lighter and more durable than lead acid batteries and cheaper that Li-ion batteries.
Electrode-diaphragm assembly for alkaline water electrolysis
Authors: Kuleshov V N , Kurochkin S V , Kuleshov N V , Blinov D V , Grigorieva O Y 
Published: March 2021

Abstract
In connection with the development of hydrogen energy, special attention is currently being paid to the creation of highly efficient water electrolyzers, including electrolyzers with alkaline electrolyte. The main disadvantage of hydrogen production by water electrolysis is its high energy consumption. The present article shows that energy consumption can be reduced by changing of the electrodes and diaphragm layout. The phase inversion method used for the manufacture of polymer-based porous diaphragms for alkaline water electrolysers made it possible to create an electrode-diaphragm assembly, where elements of electrode-diaphragm assembly represent a single element. The comparative research of electrolysis cells with different electrode-diaphragm assemblies and cells of the traditional “zero gap” was carried out.
Two-stage pyrolytic conversion of coffee husk and parchment into synthesis gas
Authors: Faleeva Yu M , Zaichenko V M 
Published: March 2021

Abstract
The paper considers the technology of two-stage pyrolytic conversion of biomass into gaseous fuel. Coffee husk and parchment were used in this study. The experimental data on composition and quantity of the gaseous products formed in the process of thermal treatment of husk and parchment are presented. The results indicated that the method allows obtaining more than 1.34 m3 of synthesis gas, which consists 96-97% of hydrogen and carbon monoxide, with a heating value of about 11.7 MJ/m3. At the same time, 26-29% of the solid residue (biochar) remains with a heating value of 27-31 MJ/kg. The resulting synthesis gas can be used for generating electricity and for producing liquid chemicals.
Recommendations for improving the accuracy of calculations of load losses of electricity in the wires of overhead power transmission lines
Authors: Shchepotin A S , Shvedov G V , Musorina O S 
Published: March 2021

Abstract
The calculations of load losses of electricity in the wires of overhead power transmission lines in the vast majority of cases are carried out by «traditional» methods, in other words without taking into account the change in the resistance of the wires. Such calculations have significant infelicities, and the existing methods of accounting for factors affecting the temperature of the wire are complex, volumetric in calculations, and require comprehensive information about the weather, and therefore are not used in practice. Recommendations for improving the accuracy of afore-referenced calculations through the application of the method of corrective coefficients were developed in this article. The focus is on the practical application of the recommendations.
Elements of energy infrastructure modernization of buildings and cities
Authors: Perepelitsa R R , Sergeeva K D 
Published: March 2021

Abstract
The formation of effective energy technological systems of buildings and cities in new economic conditions requires comprehensive analysis of dynamic of their developing, complex of diverse conditions of their function, diverse factors of their changes. The need for a systematic approach to the analysis of the functioning of complex technical systems is difficult to dispute. Methodologically, the task is to select from the many approaches the most appropriate for achieving the assigned engineering tasks. This implies the need for a comprehensive analysis of the subject area of the studied systems and the choice of the necessary system equipment, commensurate with the complexity of the selected objects. This article presents a number of elements and technologies for the modernization of the infrastructure of buildings and cities, which in practice shows their energy efficiency: fuel cells, recuperators, heat pumps, thermoactive building systems, and a predictive management with using of weather data - an intelligent tool for controlling the building’s air conditioning.
The method for approximate determination of the heat pipes finned radiators optimal geometric characteristics
Authors: Rekunenko E S , Garyaev A B 
Published: March 2021

Abstract
The method is proposed for approximate optimization of the geometric characteristics of heat pipes finned radiators, the heat from which is removed by natural convection. The mass of the radiator is used as the objective function for a given transmitted heat flux from its surface. The mathematical model developed to calculate the optimal geometric characteristics of radiators made of flat round fins, as well as fins made of square plates.
The influence of the geometric parameters of the evaporator on the process of ice formation in the SAR
Authors: Dyadichenko I A , Samson I F 
Published: March 2021

Abstract
Fossil resources are the foundation of the global economy. However, the extraction, transportation and consumption of this energy source are harmful to the environment. Economic reasons and the search for new solutions based on energy recovery have generated a growing interest in adsorption technology.
In recent decades, the number of studies on adsorption refrigeration systems has increased significantly, because, unlike vapor compression refrigeration units, they cause less harm to the environment. [1]
Enhancing Slump Flow, Specific Gravity, and Compressive Strenght Material Properties of Self Compacting Concrete (SCC) with Glass Waste Powder
Authors: Noorzyafiqi D , Srisunarsih E , Sucipto T L A , Siswanto B 
Published: March 2021

Abstract
Self Compacting Concrete (SCC) is the latest and advanced technology in the field of concrete technology. SCC is an innovative type of concrete, one of which has properties flowable. In this study, one of the innovations in the use of glass bottles as a substitute some cement for SCC. This research was conducted to determine the effect of glass waste powder as partial substitute for cement on slump flow, specific gravity, and the compressive strength of concrete aged 14 days SCC. The mix design used was Okumura’s Simple Mix Design [1], water-per-powder ratio 0.35, and dosage superplasticizer 1%. Variation of glass waste powder 0%, 5%, 10%, 15%, 20%, 25%, and 30% of the weight of cement, the size of the waste glass powder is through the filter no. 100 and stuck in the filter no. 200. The test object in this study uses a cylinder with diameter 15 cm and height 30 cm. The flowability test is carried out when the concrete is fresh. For hard concrete, specific gravity and compressive strength tests are carried out at the age of 14 days. The result of replacing glass waste powder as a substitute for some cement has a significant effect on the slump flow value of 85%. Slump flow in fresh concrete mixture with various glass waste powder 5%, 10%, 15%, and 20% reach the standard [2]. Replacement of glass waste powder as a substitute for part of cement has a significant effect on the specific gravity concrete amounting to 69.6%. Specific gravity concrete in this study fulfills the requirements for structural normal specific gravity[3]. On the compressive strength of concrete aged 14 days, glass waste powder has a significant effect of 86.2%. Compressive strength has a maximum compressive strength of 35.322 MPa, with an optimal percentage of glass waste powder as a substitute for partial cement is 10.464%.
Effect of concrete strength configuration on the structural behaviour of reinforced graded concrete beams
Authors: Pratama M M A , Umniati B S , Nindyawati N , Margaretha D I , Suhud R K , Puspitasari P , Permanasari A A 
Published: March 2021

Abstract
Earlier experimental studies of graded concrete mentioned that by combining 2 (two) concrete mixes with distinguished strength, it created an advanced material with a higher modulus of elasticity. Research related to the application of graded concrete on beam elements has been conducted several times by researchers and produced numerous important findings. Research using finite element has been conducted to analyse the extensive use of graded concrete when applied to reinforced concrete beams with various configurations. This research aims to validate the findings of previous research in experimental works. Graded concrete beams made of 2 (two) layers of concrete mixes were tested. The difference between the two types of testing beams is in the configuration of concrete placement. The beams were tested under four-point bending procedure to obtain load-deflection data. The results show that the placement of higher concrete strength in the tensile fibres provides a better beam resistance to cracks indicated by an increase in the point at which the steel reinforcement experiences yielding. The greater the tensile strength of the concrete, the concrete will provide a better bonding to the steel reinforcement so that cracks can be minimized. A concave pattern is found in the transition area after the first crack. A noticeable curve pattern becomes apparent at beams composed of low concrete strength, whereas in the beam with high concrete strength only created a linear pattern. In terms of stability and structural strength, GBA has superior performance when compared to GAB. GBA tends to be able to continue to maintain the value of structural rigidity until the beam reaches the ultimate condition. Meanwhile, the GAB instantly loses its stiffness and to experience a sudden collapse.