Vol 21, No 1 (2020)

Mechanical engineering and machine science
Computer#aided design of the pump profile with epicycloidal gearing using MathCad tools
Vallejo Maldonado P.R., Romanova V.A., Campos M.d.
Abstract

The article discusses a method for determining the relative eccentricity χ, used in calculating the thermal balance of an internal combustion engine sliding bearing. When performing this calculation, a number of temperature values are set in the bearing oil layer. For each set temperature, the engine oil viscosity value μ and the bearing load factor Ф are determined. To determine the relative eccentricity, graphical dependencies of the load factor on the relative eccentricity are used as input data. The thermal calculation of the sliding bearing showed that the accuracy of determining the relative eccentricity χ is of great importance. Their inaccurate definition leads to a failure of the thermal balance in the bearing. In addition, the method of determining the value of χ by the accepted value of the ratio of the working length of the bearing to the diameter of the connecting rod neck of the crankshaft (graphically) for this calculation is quite time-consuming. For this reason, the graphical method for determining χ has been replaced with an analytical one. Relative eccentricities were obtained using the least squares method. An algorithm has been developed for automated construction of transverse and longitudinal profiles of an oil pump with epicycloidal engagement.

RUDN Journal of Engineering Researches. 2020;21(1):7-13
views
Hydrogen application in internal combustion engines
Asoyan A.R., Danilov I.K., Asoyan I.A., Polishchuk G.M.
Abstract

A technical solution has been proposed to reduce the consumption of basic hydrocarbon fuel, to improve the technical, economic and environmental performance of internal combustion engines by affecting the combustion process of the fuel-air mixture with a minimum effective mass fraction of hydrogen additive in the fuel-air mixture. The burning rate of hydrogen-air mixtures is an order of magnitude greater than the burning rate of similar mixtures based on gasoline or diesel fuel, compared with the former, they are favorably distinguished by their greater detonation stability. With minimal additions of hydrogen to the fuel-air charge, its combustion time is significantly reduced, since hydrogen, having previously mixed with a portion of the air entering the cylinder and burning itself, effectively ignites the mixture in its entirety. Issues related to the accumulation of hydrogen on board the car, its storage, explosion safety, etc., significantly inhibit the development of mass production of cars using hydrogen fuel. The described technical solution allows the generation of hydrogen on board the car and without accumulation to use it as an additive to the main fuel in internal combustion engines. The technical result is to reduce the consumption of hydrocarbon fuels (of petroleum origin) and increase the environmental friendliness of the car due to the reduction of the emission of harmful substances in exhaust gases.

RUDN Journal of Engineering Researches. 2020;21(1):14-19
views
Topological optimization of the “Earring” element
Kamardina N.V., Guseynov R.M., Danilov I.K., Konoplev V.N., Ivanov K.A., Zharko A.S., Polishchuk G.M.
Abstract

In recent decades, computer technologies and software such as computer-aided design (CAD) have been actively developing. Thanks to this, modern machine-building enterprises increase the reliability and quality of their products while reducing their weight and complexity of manufacturing. In order to meet numerous requirements, leading companies are increasingly using topological optimization tools at various design stages. The use of this method for effective product design is growing rapidly, due to the continuously increasing computing power of computers and software capabilities. Modern software for topological optimization allows to design the shape of the part from scratch, setting only the conditions for fixing and touching surfaces, and also allows to improve existing structures by reducing their weight based on the set restrictions (equal strength with the original part, equal deformation, preservation of natural frequency, etc.). However, the result of topological optimization is often a complex spatial structure. Using the example of the “Earring” element, a topological optimization of the structure was performed to ensure that the strength requirements were met and that the minimum mass was obtained. As a result of optimization, the design of a reduced weight compared to the prototype is obtained. The results of the verification calculation showed the sufficiency of the values of the strength reserves of the final design of the “Earring”.

RUDN Journal of Engineering Researches. 2020;21(1):20-26
views
Modeling an effective method to utilize secondary energy resources of a combined cycle gas turbine based on the CCGT-420T
Antipov Y.A., Shatalov I.K., Shkarin K.V., Barybina A.S., Ogneva Y.A., Morozov P.D.
Abstract

Nowadays, improving the efficiency of power plants by utilizing secondary energy resources is gaining more attention in the energy sector. In this paper, the combined cycle gas turbine (CCGT-420T) was considered, where exhaust heat from the main and auxiliary equipment is utilized, and sent to a water supply system through a closed-circuit heat exchanger, as a result, the heat transferred ( Q ≈ 6.4 MW) is rejected into the environment through a cooling tower. Moreover, an effective modelling method for utilizing heat in a closed cycle, using a steam compressing heat pump unit (HPU) is proposed. In addition, a calculation of the effectiveness of utilizing secondary energy resources depending on the number of HPU stages. In addition, the calculation of the effectiveness of the use of secondary energy resources depending on the number of stages of HPU was carried out. Several options of the model were discussed in this work, such as, two-, three-, and four-stage HPU and the coefficient of performance was calculated. Moreover, the work of these compressors for each option of the model was discussed in this work. Finally, the economic benefits of using of a multi-stage HPU instead of a traditional one-stage HPU during the annual operation of the CCGT-420T was discussed.

RUDN Journal of Engineering Researches. 2020;21(1):27-35
views
Earth science
Selection of sites for the construction of radioactive waste disposal points
Pankratov N.S., Belov V.V.
Abstract

The article deals with the selection of sites for the construction of nuclear installations, radioactive waste disposal sites and other facilities for the use of nuclear energy. The review of modern approaches to the selection of sites for placement of near-surface radioactive waste disposal points shows that the system research in this area is not fully presented, and is mainly aimed at solving problems of an engineering-geological nature for the location area, as well as the choice of materials for engineering protection barriers. In this paper, using the example of radioactive waste disposal sites, we review the requirements set by the regulatory documents of the Russian Federation and the International Atomic Energy Agency in the field of site selection. The authors proposed additions to the methodology for selecting sites for the construction of low-and medium-level waste disposal sites based on the system and GIS analysis of the ALARA principles, as well as the method of weighted evaluation of criteria and their pairwise comparisons. The multi-criteria nature of the site selection problem is proposed to be described by GIS analysis of data with drawing the corresponding “limiting” and “preferred” requirements directly on the map of the area, which is shown in the article by the example of selecting sites for radioactive waste disposal points. Taking into account the necessary requirements at various stages of the life cycle, as well as their significance, can be assessed by weighted estimates and pairwise comparisons, followed by their introduction into the GIS analysis. This approach allows to choose rational options for placing potential sites, taking into account the life cycle of the object, in a rational way, with compliance with all necessary regulatory requirements.

RUDN Journal of Engineering Researches. 2020;21(1):36-47
views
Determination of the copper-nickel ores formation sequence of the Kun-Manye deposit (Amur region)
Kotelnikov A.E., Kolmakova D.A., Kotelnikova E.M.
Abstract

The purpose of the article is to determine the sequence of mineral formation of copper-nickel ores of Kun-Manie deposit, which is located in Zeya district of Amur region. Three ore chutes take part in the structure of the deposit. Ore-bearing formations are sheet and sheetlike bodies of ultra-basic composition of the Kun-Manien complex, lying among rocks of crystal foundation of the Early Archean. Among the rocks, hornblende differences of gabbro-pyroxenites and pyroxenites predominate. In addition to nickel, the ores contain a wide range of associated components. The ores oxidation zone within the deposit and the entire ore field is not developed. The relevance of the work is due to the fact that detailed studies of ore minerals have not previously been carried out. The study presented in the work was conducted by polarizing ore microscope on polished ore samples characterizing different zones of the ore body. The result of the study was the establishment of mineral paragenesis and the sequence of mineral formation. It has been determined that the main ore minerals are pyrrhotine, pentlandite, also found - pyrite, chalcopyrite, less often - ilmenite, magnetite, sphalerite, platinum group elements. Ore mineralization formed in two stages. The magmatic stage is an early and main mineral formation phases including pyrite-magnetite, polymetallic and pentlandite associations. The hydrothermal stage is a late phase involving a pyrite association.

RUDN Journal of Engineering Researches. 2020;21(1):48-57
views
Development of methods for equalizing level networks
Esina E.N., Likhodeevskaya V.V.
Abstract

The article is devoted to comparison of methods of calculating the approximate elevations of nodal points when adjusting leveling networks by strict and non-strict methods. Ensuring geomechanical monitoring of the mutual influence of constructed and operated objects is important in the intensive development of underground space of megacities, the construction of unique objects and structures. In the course of the research, mathematical models of level networks were developed and presented in the form of a closed loop and a set of open polygons. Analysis of modeling allows to determine the feasibility of applying the knot method by Professor V.V. Popov instead of the parametric method of adjustment. It is established that the quality of the results of strict equalization depends entirely on the quality of measurements, since deviations from the true values do not exceed the measurement error. The research has shown that it is possible to simplify the processing of monitoring data and evaluation of various configuration options for leveling networks, using algorithms for calculating approximate marks of nodal points. This makes it easier to process monitoring results and evaluate various network configuration options while ensuring the required level of measurement accuracy.

RUDN Journal of Engineering Researches. 2020;21(1):58-65
views
Prospects for production of viscous fluid by electric shaft-driven vane pumps (ESP)
Ageyev S.R., Druzhinin E.Y., Kamaletdinov R.S.
Abstract

The article deals with the prospects of developing significant world reserves of high-viscosity oil. Its production requires specific equipment and technologies, selection of efficient equipment, as well as a special approach in its operation. At the same time it is necessary to take into account the influence of high viscosity on the main characteristics of pumps and on the operating conditions of the equipment in the well. The reasons for unstable operation of the ESP at start-up after long stops are described. The methods of recalculation of characteristics of pumps for oil production of common design are offered. Some results of researches of such pumps on viscous liquid and recommendations on calculation of a flowing part are provided. The possibilities of pumps with open impeller stages and with increased shaft speeds are determined. Additional reasons for decreasing the characteristics of the pump on the viscous fluid, results of the test of stage assembly with measurement of average circumferential components of flow rates at different viscosity of the pumped fluid are given. The possibility of using helico-axial pumps is also considered. Application of modern programs and methods of equipment selection and operation, ESP rotor speed regulation, liquid temperature regulation in tubing and automation of the whole oil production process is recommended. Possible design changes of the ESP in the process of tubing production for the purpose of increasing their efficiency in comparison with the serial pumps are specified. The article can be useful for specialists in design, selection and operation of equipment for high-viscosity oil production.

RUDN Journal of Engineering Researches. 2020;21(1):66-80
views
Civil Engineering (Construction)
Overview of high-strength screw thread reinforcement used in pre-stressed structures
Grishin G.E., Tikhonov G.I., Okolnikova G.E.
Abstract

Article provides an overview of the world and domestic samples of high-strength threaded rebar for pre-stress in concrete structures. First of all, their technical characteristics were analyzed that affect the speed of installation of buildings and structures and the metal content of reinforced concrete structures used in them. We also consider the individual characteristics of the profile of rebar that are specific to individual countries, followed by an assessment of their behavior in reinforced concrete structures. Special attention is paid to domestic developments in this direction, in order to assess the competitiveness of innovative profiles both within Russia and on the world market. One of the most important developments in recent years in our country is the rebar class Av1000P, the history of which described in the second chapter of this review. The reason for the development of this profile was significant problems related to the crack resistance, thrust and endurance of previous types of thread and periodic profiles of high-strength rebar products. In addition to the reinforcement profiles, a high-speed method of joining and anchoring with the help of coupling threaded connections was partially considered, which is only possible on a screw profile armature without labor-intensive threading on rods.

RUDN Journal of Engineering Researches. 2020;21(1):81-93
views
Barite-containing radiation protective building materials
Novikov N.V., Samchenko S.V., Okolnikova G.E.
Abstract

Due to the active development of industries using nuclear technology, the creation of highly effective and cost-effective building materials for protection against hazardous ionizing radiation is of increasing interest. Widespread in the field of radiation-protective building materials are barite-containing concrete. The purpose of this article is to establish the prospects of their use in nuclear facilities, as well as to find ways to improve their technical and operational characteristics. For this an analysis of relevant literature and scientific research in the field of radiation-protective materials and, in particular, barite-containing concrete was carried out. The advantages of barite-containing concrete are high radiation-protective properties, environmental friendliness, high density, as well as economic indicators. The disadvantages are high susceptibility to shrinkage deformation and poor resistance to cyclic temperature effects. The addition of barite to the concrete composition allows to increase the coefficient of linear absorption of γ-rays of the material; also, with the proper selection of the composition, such material may have strength characteristics equal to or superior to the characteristics of concrete with standard compositions. Barite-containing materials have a wide range of applications and can be used both for the production of heavy concrete in the construction of load-bearing structures and in the creation of radiation-protective coatings for walls and floors.

RUDN Journal of Engineering Researches. 2020;21(1):94-98
views

This website uses cookies

You consent to our cookies if you continue to use our website.

About Cookies