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No 1 (2023)
Articles
On the Issue of Determining the Efficiency of Expander-Generator Units
Abstract
Methodological issues of determining the thermodynamic efficiency of expander-generator units as separate technological objects, as well as when they are used at enterprises of various types, are considered. It is shown that when determining the thermodynamic efficiency of the use of DGA at thermal power plants (TPP), a systematic approach is required, taking into account the effect of DGA on the efficiency of the main equipment of TPP. Dependences are given that make it possible to determine the effect of DGA on the thermodynamic efficiency of power plants of various types (CPP and CHPP) under various operating conditions.
3-17
The Current State of Development and Prospects for the Creation of Sensors of Thermodynamic Activity of Oxygen in Relation to Reactor Units with a Heavy Liquid Metal Coolant
Abstract
Successful development of the world nuclear energy is not possible without a transition to a new technological platform. The most promising nuclear technology for this today seems to be fast reactors cooled by liquid metal coolants. In 2021, the construction of the world’s first nuclear power plant with a fast reactor BREST-OD-300 began in the city of Seversk, Russia. This reactor, having a number of innovative solutions, uses liquid lead as the primary coolant. Lead belongs to the class of heavy liquid metal coolants and is similar in technological properties to the Pb-Bi eutectic alloy. Since the 60s of the last century, special attention has been paid to the substantiation of the operability and safety of heavy liquid metal coolants in Russia. The key element of the technology of such a coolant is the thermodynamic oxygen activity sensor, which controls the oxidation potential of the coolant and ensures the cleanliness and corrosion resistance of the circuit. This article provides an overview of the main design solutions proposed for the oxygen activity sensor, their analysis is given, and proposals for the development of an improved sensor design that would meet the requirements of large-scale nuclear power are considered.
18-34
Substantiation of Practical Recommendations on the Organization of Optimal Modes of Preliminary Heat Treatment and Combustion of Coal in a Pulverized State
Abstract
Based on the data on the reactivity of coal, a calculated justification of the requirements for the organization of its preparation and combustion processes was carried out, taking into account the initial quality and operating modes of the preparation systems and combustion devices of power steam boilers. The relationship between such operating parameters of the device for preliminary heat treatment of coal as the size of pulverized coal particles, temperature and duration of treatment with the quality of the source fuel has been established in order to ensure stable ignition and completeness of burnout of the products of thermochemical transformation of coal in the conditions of the furnace chamber of the boiler unit. The results of the cycle of analytical studies are summarized and brought to the level of engineering methodology (in the form of a nomogram), which allows determining the optimal values of temperature and time of the process of preliminary heat treatment of coal before combustion in the furnace chamber of a steam boiler based on the known characteristics of the initial fuel (reactivity and particle size). The found operating parameters of the device for preliminary heat treatment of coal ensure the performance of verification (thermal) and design calculations of real fuel-using installations, for example, fuel-free kindling and dust preparation systems. It is established that the most optimal mode of preliminary heat treatment of brown Kansk-Achinsk coals polyfraction, in terms of the efficiency of ignition and combustion of heat treatment products, is 800–850°C with a processing time of 0.6–1.2 s. The results of the calculated studies were confirmed during experimental work on a special laboratory stand, which provides a mode of preliminary heat treatment of coal in a pulverized state in a wide temperature range and afterburning of dust and gaseous heat treatment products under various conditions.
35-50
To the Calculation of the Unsteady Temperature Field of a Cylindrical Body
Abstract
Determining the temperature regime of cylindrical bodies in the initial period of time, i.e. at small values of the Fourier number, is a rather time-consuming task. In the calculation process, it is necessary to take into account a large number of members of the series to obtain the result of the required accuracy. In this case, it is required to calculate the eigenvalues of the characteristic equation for each term of this series. The article offers a fairly simple and effective analytical method for determining eigenvalues with high accuracy. The method is based on the use of a special function, the inverse of the relation of the Bessel functions of the first kind of zero and first order. In this case, the procedure for determining eigenvalues is reduced to a simple fast-converging iterative process. Using this procedure allows you to determine any eigenvalue of the characteristic equation with high accuracy required for engineering calculation. The application of this method in engineering practice significantly simplifies the process of determining the temperature regime of cylindrical bodies, and can also be extended to other tasks.
51-56
Impact of Electrification in the Road Transport Sector on the Level of Electricity Consumption and Daily Load Curve in the UES of Russia
Abstract
The article assesses the impact of potential motor transport sector electrification on the value of the aggregate demand for electricity and capacity in the UES of Russia. Despite official documents suppose quite modest quantitative targets for the electric transport until 2030, in the longer term, a large-scale replacement of oil fuel with electricity will have a significant effect on reducing greenhouse gas emissions, but will also require a more intensive development of generating and network capacities in the electric power industry. The scenaric forecast for the development of electric transport is made with the allocation of three segments - cars, trucks and buses, which allows taking into account the characteristics of electricity consumption characteristic of each of them. Another important result is an assessment of the possible extent of the influence of electric transport on the configuration of a typical daily load curve. The paper considers various modes of using infrastructure for electric transport charging, which result in different daily load curves. It is shown that, depending on the scales of electric transport development, their annual electricity consumption in the country will lay in the diapason from 168 to 460 TWh. At the same time, depending on the charging mode of electric vehicles, the additional power demand will vary from 26 to 74 million kW, and the amplitude of fluctuations in the hourly loads of electric vehicles will vary from two to four times.
57-71
Determination of Electrodynamic Forces between Coaxial Coil Turns with Current of Various Configuration
Abstract
Determination of electrodynamic forces, as may be required for various practical purposes, is based on known calculation recommendations for mutual inductance coefficients, including the calculation methods with special functions, like complete elliptic integrals of the 1st and the 2nd kind, as well as spherical Legendre functions of the 2nd kind with half-integer index [1–5]. Some examples of practical tasks requiring these calculations are the assessments of mutual inductances in non-contact chargers, as well as the assessments of electrodynamic interactions in the windings of transformers, inductors, various solenoid-based loading devices, electric drives, etc. These applications are discussed in numerous publications and guides, e.g. [6–9].
72-78
Памяти академика Российской академии наук Ашота Аракеловича Саркисова
79-80