Vol 23, No 3 (2022)


The relevance of using the renewable fuels for power grids

Razuvaev A.V., Redko I.Y., Krasnoludskiy N.V., Kostin D.A.


The paper presents the analysis and efficiency of using the cogeneration power plants and alternative energy sources. The documents on the relevance of introducing the energy-efficient measures in the economies of various countries are given. The prospects of using the alternative and renewable fuels considering the effectiveness of their use in various power systems and grids are well substantiated. Such measures contribute, on the one hand, to saving the hydrocarbon fuels extracted from the ground and to extending their use, and, on the other hand, to the development and application of the alternative power grids with the use of the renewable fuels. Firewood can serve as such a fuel. The characteristics of the firewood in the corresponding tables are described. It provides the opportunity for evaluating the efficiency of the woodfired power plant depending on the type of the firewood and the territory of growing the firewood at the development stage. Moreover, the characteristics of the firewood make it possible to estimate its necessary amount and the territory for storing and harvesting. Based on the obtained data, the authors conclude that it is necessary to develop and establish the power plants based on the reciprocating steam engines for various small and medium-sized enterprises. Design proposals for the power plant based on the reciprocating steam engine are briefly present-ed and the economic effect of its use on site is estimated.

RUDN Journal of Engineering Research. 2022;23(3):191-197
pages 191-197 views

Minimax adaptive filtering algorithm nonlinear systems with Volterra series of the second order

Sidorov I.G.


The study solves the problem of filtering nonlinear systems based on the minimax adaptive algorithm of nonlinear systems by Volterra series of the second order, provided that the autocorrelation functions of the useful signal and interference are known with some errors according to the criterion of the maximum standard error of filtering. The author analyses the stationary performance of a minimax adaptive Volterra filter of the second order with the least mean square (LMS) with a constant step size of µ with a time-varying setting. A quantitative assessment of the steadystate excess root-mean-square error (RMSE) has been established, in which the contribution of incorrect gradient adjustment and tracking error is well characterized. Then the optimal step size is set for a time-varying secondorder minimax Volterra filter. Thus, we can study the correlation between the excess MSE and the optimal step size, on the one hand, and the parameters of a time-varying nonlinear system, on the other hand. A simple solution with minimal root-mean-square error for the minimax Volterra filter is obtained, based on the assumption that the input signal of the filter is Gaussian. In addition, we propose an iterative factorization method for developing a subclass of minimax Volterra filters, which can greatly simplify filtering operations. In addition, an adaptive algorithm for the Volterra filter is investigated, as well as its average convergence and asymptotic excess root-mean-square error. Finally, the usefulness of the Volterra filter is demonstrated by its use in studies of nonlinear drift oscillations of moored vessels exposed to random sea waves.

RUDN Journal of Engineering Research. 2022;23(3):198-206
pages 198-206 views

Algebraic ship hull surfaces with a main frame from three plane curves in coordinate planes

Krivoshapko S.N.


One of the important problems of naval architects and designers is a choice of rational ship hull shape. A choice of ship hull form is based often on empirical formulae or on designers’ intuition. In the study, a method of determination of generalized explicit algebraic equations of theoretical ship hull configuration with three main cross sections given in advance and coinciding with waterline, main buttock (keel line), and midship section that are taken in the form of superellipses or in the form of any algebraic curve. Presented three of algebraic equations of surfaces with the same frame from three plane curves describes infinite number of ship hull surfaces. Having the same three plane curves one can get three algebraic surfaces of different order. The optimal shape, including cylindrical fragment or the ship hull shape containing two different - stern and bow - parts, joining along midship section, can be chosen with the help of methods of computer modelling with the application of artificial intellect using the materials of the paper. One can apply given results for the design of underwater apparatus on the early stage of the design.

RUDN Journal of Engineering Research. 2022;23(3):207-212
pages 207-212 views

Investigation of the influence of the degree of contact of rolling surfaces on contact stresses in ball radial bearings

Belousov Y.V., Kirilovskiy V.V., Rekach F.V.


The study is devoted to the determination of the coefficients of the degree of contact of rolling surfaces, considering the tolerance field of rolling bodies, as well as the influence of the coefficients of the degree of contact on the maximum contact stresses in ball radial bearings. A method has been developed for determining the maximum value of the coefficient of the degree of contact of rolling surfaces of ball radial bearings, taking into account the tolerance field of rolling bodies. It is established that the coefficient of the degree of contact of the rolling surfaces for each bearing size with a certain radius of the raceways is located in a range that depends on the limiting dimensions of the rolling elements. It is shown that the coefficient of the degree of contact of the rolling elements with the tracks of the outer ring, with the same auxiliary value, considering the sum and difference of the curvatures of the rolling surfaces, is greater than the inner one. Therefore, in order to reduce contact stresses on the outer ring of the bearing, the radius of its raceway can be made smaller than the inner one. A method has been developed for calculating the maximum contact stresses on the raceways of radial ball bearings, taking into account the coefficient of the degree of contact of rolling surfaces and the tolerance field of rolling bodies, which allows calculating contact stresses for radial ball bearings of any size at any coefficients of the degree of contact of rolling surfaces.

RUDN Journal of Engineering Research. 2022;23(3):213-223
pages 213-223 views

Probabilistic assessment of the permeability of the deposits of the upper part of the Tyumen suite of the Shaim oil and gas region

Strakhov P.N., Markelova A.A.


The work is devoted to the problem of increasing the reliability of the calculation of the permeability cube in the construction of a threedimensional geological model. The common method of mechanically transferring the relationship between porosity and permeability, obtained on the basis of the approximation of the results of the study of the core, gives too vague result since neither the differences in the sizes of cells and samples, nor the large scatter of the values of the analyzed dependencies are taken into account. Instead, it is proposed to use stochastic methods to calculate permeability histograms for each elementary cell. First, the analysis of the results of determining the petrophysical properties performed in the laboratory is carried out. For rocks with similar porosity values, the probability of occurrence of rocks whose permeability exceeds a number of threshold values is calculated. Then, for each threshold value of permeability, empirical dependences of the probability of exceeding a given value on porosity are determined. At the next stage, the obtained results are adapted to the cell scale. The Monte Carlo method is used. Each cell is represented as a set of a large number of rocks, the sizes of which are close to those of the samples. Each virtual rock is assigned a porosity using a random number generator in such a way that the average value of the cell porosity is stored. For each conditional rock, the probabilities of exceeding the corresponding permeability thresholds are calculated. Based on the porosity cube for each cell, the probability of existence of all permeability ranges is automatically calculated for each cell. The authors provide examples of the implementation of the proposed methodology in the study of terrigenous deposits of the Tyumen suite of the Shaim oil and gas region.

RUDN Journal of Engineering Research. 2022;23(3):224-231
pages 224-231 views

Comparison of innovative gas hydrate extraction technologies in China and Japan

Sun H., Huang Q., Vorobyev K.A.


In the 20th century, great attention in the world was paid to the study, exploration, development of natural gas deposits, which are ordinary (traditional) gas-containing accumulations of hydrocarbons. The limited and irreplaceable resources of free natural gas, the growing demand for this energy carrier inevitably forced in the 21st century to pay attention to the significant potential resources of natural gas contained in unconventional sources. These include coal-bearing methane, shale gas, water-dissolved gases of the underground and aboveground hydrosphere, natural gas hydrates. The authors discuss modern technologies for the development of natural gas hydrates, in particular the pilot development of the Nankai field on the shelf of Japan and a number of large deposits on the shelf of China. The results of scientific research are presented, as well as practical experience in the application of various methods of influencing deposits of unconventional hydrocarbons. The study introduces a number of key technical solutions for the development of gas hydrate deposits, such as sand control during extraction, artificial lifting, geological monitoring and environmental monitoring. The information and regulatory framework of the study reflects the current level of development of science and technology in the development of mineral deposits. The world and domestic experience in the development of technologies for the impact on unconventional hydrocarbon deposits in order to optimize and intensify the production process is reflected.

RUDN Journal of Engineering Research. 2022;23(3):232-245
pages 232-245 views

Phenomenological model of the intensity, duration and frequency of precipitation patterns for the Portoviejo river basin, Ecuador

Mendoza Alava J.O., Zambrano Xavier Horacioa V., Mendoza Cedeño J.J., Sinichenko E.K., Gritsuk I.I.


Phenomenological models represent the behavior of random phenomena in reality, the model and the function it should perform. Similarly, tuning parameters allow us to assess the fit of observed data to a variable in a particular mathematical model and to test the validity of the model for representing a real event. These models, used in the exact and earth sciences, analyze the behavior of complex variables that vary in space and time and are the object of special analysis. The present paper contains statistical and probabilistic analyses of rainfall patterns in the Portoviejo basin over a half-century period. As a result and due to the novelty of the study, a new model of intensity, duration and frequency curves for the most important meteorological stations of the aforementioned basin, such as Portoviejo-UTM and Lodan, was obtained. The data used for the calculation were those provided by the National Institute of Meteorology and Hydrology of Ecuador (INAMHI), the country's state agency for the collection and planning of meteorological data. Calculations were performed separately for the Portoviejo-UTM and Lodan stations. Using the equations obtained, an analysis of the results was done, which made it possible to derive other intensity equations used later in the runoff analysis for the intermediate zones between the two stations considered in this study.

RUDN Journal of Engineering Research. 2022;23(3):246-253
pages 246-253 views

Regularities and geohistorical prerequisites of oil and gas specialization of rift sedimentary basins of Africa

Usova V.M.


Sedimentary basins of Late Phanerozoic rift origin are located in Africa and on its underwater margins. The reasons for the oil and gas specialization of basins of this class remain largely unclear. Patterns have been identified that could be of decisive importance in this regard. The intracontinental basins are characterized almost exclusively by oil deposits. In the pericontinental basins, the value of gas deposits decreased, and oil increased in accordance with the decrease in the time of their reef laying and deflection (from C3, P-J1, K1 to J5-K12). The differentiation of basins into tectonotypes of “incomplete” and “completed” development, as well as the asynchronous deflection of the latter reflected in their oil and gas specialization, correlate accordingly with the size and age of the Pan-African granulite belts in which the basins were laid. Since these belts were the most active core structures, this pattern can be considered as evidence of the influence of their inherited or reborn deep “energy systems” on the processes of rifting and generation of hydrocarbons. The use of seismography data showed that mainly oil and gas-bearing rift basins are located in areas of less and more heated mantle respectively. An example of the probable influence of Cenozoic island volcanism centers on oil and gas basin systems is given. A comparative analysis of geological and geophysical data, including heat flows, leads to the conclusion that the temperature conditions of hydrocarbon formation in the rift basins of Africa were determined by a combination of deep thermal systems of different scales: regional (continent - ocean), subregional (cow-structural) and local (volcanic centers).

RUDN Journal of Engineering Research. 2022;23(3):254-262
pages 254-262 views

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