Global Energy

REV RUS 6-29 Klimenko Aleksandr V. Klimenko Aleksandr V. Borisova Polina N. COMBINED GENERATION OF PRODUCED ENERGY CARRIERS: REVIEW The article presents a review of scientific and technical publications dedicated to one of the possible directions of efficiency improving generation facilities, i.e., the development of multi-generation energy systems. Such systems include energy generation facilities and consumers. This technology is proposed for generation facilities which forced to work in off-nominal conditions during seasonal and daily off-peak periods of electric and thermal loads, which decreases their thermodynamic efficiency. Generation of other produced energy carriers, such as cold, hydrogen, compressed air, etc., is organized together with electricity and heat due to using unclaimed capacities. It allows to provide generation of electricity and heat in the modes close to nominal, and also to organize combined generation of electricity and heat and other produced energy carriers with higher efficiency criteria than with separate generation. Various efficiency evaluation criteria of multi-generation systems are considered, as well as operational features of generation facilities in Russia. 10.18721/JEST.25201 620.91-93:620.97 efficiency improving load curves leveling of generation facilities combined generation of energy carriers efficiency evaluation criteria of multi-generation systems operational features of generation facilities in Russia https://engtech.spbstu.ru/article/2019.108.1/ 1_Klimenko.pdf

RAR RUS 30-41 Shishigin Sergey ctod28@vologda.ru Cherepanov Shishigin IMPULSE METHOD OF MEASURING IMPEDANCE IN GROUNDING SYSTEMS The impulse method is designed for measuring impedances of grounding systems of transmission line towers (TL) with overhead grounding wires exposed to current impulses that are similar in form to the lightning current. Measuring electrodes are arranged in the orthogonal pattern that eliminates inductive noise, but leads to an error of up to tens of percent in soil with high-resistance base. Electrical conductivity of high-resistance soil significantly depends on the frequency or time of impulse impacts. The specific conductivity is maximal at the beginning of the transient process, then decreases monotonically for tens of microseconds, which significantly exceeds the experiment duration. For this reason, direct measurement of steady-state impedance of the grounding system of the TL tower with the overhead grounding wire using the impulse method is impossible. The transient impedance (circuit reaction on the unit step current) is regarded as the grounding system’s main characteristic that defines its stationary, impulse and instantaneous impedance upon exposure to impulse impacts. A simple analytical expression of the transient impedance of a concentrated grounding conductor in high-resistance soil suitable for engineering calculations is obtained. A method for determining the dielectric permeability of soil according to the impulse experiment data is proposed. The developed method has been tested for processing experimental data and for numerical modeling of the TL tower grounding system measurements. 10.18721/JEST.25202 621.316.99 grounding system impedance impulse method soil specific conductivity frequency dependence numerical modeling https://engtech.spbstu.ru/article/2019.108.2/ 2_Shishigin.pdf

RAR RUS 42-53 Kozhukhov Iurii kozhukhov_yv@mail.ru Neverov Vladimir Ivanov Viacheslav M. Kartashov Sergeii V. THE CHOICE OF GEOMETRIC PARAMETERS IN THE OPTIMIZATION OF CENTRIFUGAL COMPRESSOR IMPELLER The article analyzes the significant geometric parameters and the range of their variation in solving the optimization problem of centrifugal compressor impellers using computational fluid dynamics. The study was carried out using the Numeca Fine/Turbo package. The influence of more than 10 geometric parameters on the efficiency and the head of the impeller was considered. The influence of the degree of the investigated optimization parameters was estimated by changing the parameter values in a preset range and analyzing their impact on the efficiency and head of the impeller. As a result, the main geometric parameters of optimization, which should be considered first, were identified. Other parameters do not have to be considered within the optimization problem, and can be assigned standard values. In addition, recommendations on optimal ranges of parameter values were given. 10.18721/JEST.25203 621.515 Impeller centrifugal compressor optimization parameter geometry parameter computational fluid dynamics Numeca Fine/Turbo https://engtech.spbstu.ru/article/2019.108.3/ 3_Kozhuhov.pdf

RAR RUS 54-67 Avdeev Evgenii E. Bulovich Sergii V. Gorskiy Yurii A. ANALYSIS OF ENTRAINMENT AND DEPOSITION MODELS IN ANNULAR DISPERSED FLOW REGIME A comparative analysis of entrainment and deposition models was carried out using a steady-state one-dimensional three-fluid model with equal pressure in the phases. The predictive ability of the models that take into account both purely hydrodynamic entrainment of droplets and bubble entrainment associated with film boiling in heated channels is analyzed. The calculated hydraulic characteristics of two-phase steam-water flow are compared with known literature data: in the pressure range of 0,98–11,77 MPa, mixture flow rates of 500–3000 kg /(m2s), and vapor quality of 0,08–0,95 for vertical adiabatic channels and in the pressure range of 2,94–10 MPa, mixture flow rates of 500–3000 kg/(m2s) and vapor quality of 0,2–0,65 for vertical heated channels. The results of the analysis helped find the models that predict the literature data in the best way. 10.18721/JEST.25204 536.7; 532.5; 519.6 two-phase steam-water flow dispersed-annular flow regime three-fluid model entrainment and deposition of droplets numerical simulation https://engtech.spbstu.ru/article/2019.108.4/ 4_Avdeev.pdf

RAR RUS 68-77 Nguyen Ngoc Thuan Kapralov Vladimir M. Kolenko Grigorii S. EFFECT OF LOADING FREQUENCIES ON FATIGUE RESISTANCE OF MATERIALS The influence of the loading frequency on the endurance limit, durability and cyclic strength of metals and alloys in the high frequency range depends on several factors: stress level, voltage change, loading method, material structure. With increasing speeds and power of engines and power-driven vehicles, the fatigue strength of parts and components is becoming increasingly important. During operation, parts are exposed to high-frequency cyclic loading, and their service life and reliable operation are determined by fatigue strength in most cases, therefore, it is necessary to conduct fatigue tests in a wide range of loading frequencies. In the general case, the frequency of application of the load ambiguously affects the material’s resistance to fatigue; therefore, different materials in different areas of fatigue failure have differences in their response to a change in the loading frequency. 10.18721/JEST.25205 620.178 high loading frequency fatigue resistance strength endurance limit durability https://engtech.spbstu.ru/article/2019.108.5/ 5_Nguen.pdf

RAR RUS 78-86 Loktionova Elena elena.lokt@yandex.ru Goloshchapova Anastasiia A. Goloshchapova Elena A. FILTRATION MODEL OF HYDRODYNAMIC RESISTANCE OF PRESSURE PIPELINES Pipelines are engineering structures of varying degrees of complexity. Using pipelines made of polymer materials, applying protective coatings to the inner surface of the pipes, using modern and highly reliable pipeline fittings lead to a decrease in energy losses during movement of fluid, increase the service life of pipeline systems and, as a result, reduce the cost of their operation. Hydraulic calculation of pipelines at the stage of their design involves obtaining information about the roughness and resistance coefficients, as well as experimental studies of hydraulic compatibility of the materials used. The transition from traditional assessment of pipeline capacity to the filtration characteristics of the flow is proposed. The results of experimental studies on pipelines with different hydraulic resistances are presented. 10.18721/JEST.25206 621.64 Pressure pipelines energy loss capacity speed index hydraulic resistance porous medium filtration coefficient https://engtech.spbstu.ru/article/2019.108.6/ 6_Loktionova.pdf

RAR RUS 87-104 8840090300 Peter the Great St. Petersburg Polytechnic University, Russia Borovkov Alexey

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Peter the Great St. Petersburg polytechnic university Voynov Igor B. voinov@compmechlab.com Rekstin Bakaev Boris V. MODELING OF CHARACTERISTICS OF TWO-STAGE CENTRIFUGAL GAS COMPRESSOR UNIT The study presents the results of CFD calculations of for a flow part of a two-stage 16 MW pipeline compressor. The calculated characteristics of the pressure ratio, efficiency and work coefficient are compared with the characteristics measured at the manufacturer's air test rig. The calculations are performed in two ways, without and with modeling the flow in the "impeller – stator" gaps. In the first case, friction losses of the outer surfaces of the impeller and leakage in labyrinth seals are not taken into account. The «STAGE» interface connects parameters of the flow at the impeller exit and vaneless diffuser inlet. This approach excludes the mixing of high-and low-energy flow zones in the diffusers from the calculation. The calculated characteristics are close in form to the experimental ones, but they are shifted to the area of higher flow rates, differ in efficiency and pressure ratios within the limits unacceptable for using CFD calculations instead of tests. 10.18721/JEST.25207 621.515 centrifugal compressor flow part pressure ratio efficiency CFD calculation https://engtech.spbstu.ru/article/2019.108.7/ 7_Borovkov.pdf

RAR RUS 109-117 Rekstin Galerkin Yuriy galerkin@pef.spbstu.ru IMPROVING METHOD FOR PRIMARY DESIGN OF CENTRIFUGAL COMPRESSOR IMPELLERS A universal modeling method, developed at the Peter the Great St. Petersburg Polytechnic University and successfully used in design practice, uses a flow rate coefficient, a loading factor and compressibility criteria as gas-dynamic design parameters. The main design constraint for the impeller is the hub ratio. The algorithm previously used for initial design of impellers is based on generalizing the design experience and separate calculated experiments. In some cases, significant correction of the dimensions and shape of the impeller is required in subsequent stages of design. To approximate the initial design to the final design, we performed optimal design of 124 radial and axial-radial impellers with flow rate coefficients of 0.015 to 0.15, loading factors of 0.40 to 0.70, hub ratios of 0.25 to 0.40. Geometric parameters are approximated by algebraic formulae and supplemented with recommendations to apply classic formulae of the impeller’s inlet dimensions, which together form the proposed method of initial design. 10.18721/JEST.25208 621.515 2D impeller 3D impeller flow rate coefficient loading factor geometry parameters primary design https://engtech.spbstu.ru/article/2019.108.8/ 8_Rekstin.pdf

RAR RUS 118-131 Nguyen An anquang12a1@mail.ru Lapshin Kirill kirill.lapschin@gmail.com STRUCTURE OF GAS FLOWS IN TURBINE STAGE WITH NEGATIVE GRADIENT OF REACTIVITY DEGREE The study has explored the flow in turbine stages with a negative gradient of degree of reactivity. Stages of this type were created using the tangential inclination of guide blades. The objects of research were two turbine stages. The first stage was a turbine stage with tangential inclination of guide blades. The lines of rounding centers of the radii of output edges of guide blades were rectilinear, lying in the r-u plane of the cylindrical coordinate system and inclined by 23 degrees in the direction of rotation of the rotor at the mean radius. The second turbine stage was created on the basis of the first stage. Тhe two turbine stages differed in that the lines of rounding centers of radii of output edges in the middle part of guide blades were also rectilinear and inclined by 23 degrees at the mean radius in the second turbine stage, but they were smoothly directed to the radius direction r at the root and the periphery. The calculation models of turbine stages were constructed in the Geometry and TurboGrid programs included in ANSYS Workbench. 3D testing gas-dynamic calculations were performed in ANSYS CFX. The pattern of gas flow in the meridian contours of the flow section and the configuration of the current lines on the root, middle and peripheral radiuses were analyzed in nominal mode for the two turbine stages. The graphs of summary characteristics of turbine stages (the efficiency index and the degree of reactivity at the root and periphery) in different modes were presented. The distribution of flow parameters in nominal modes was given by the height of the blade. The conclusion about the rational design of turbine stages with tangential inclination of guide blades were given. 10.18721/JEST.25209 621.438.001.2 axial turbine stages tangential inclination guide blades kinetic energy losses ANSYS CFX https://engtech.spbstu.ru/article/2019.108.9/ 9_Nguen.pdf

RAR RUS 132-140 Ilyinykh Viktor A. STATISTICAL ANALYSIS OF GEOMETRY OF PROFILE PARTS PF SPINDLE UNIT OF MULTI-TASK MACHINES The paper presents the results of study on the accuracy of the geometric shape of shanks (mandrels) of the auxiliary tool in multi-purpose machines using the manufacturing technology with single-axis movement of the cutting tool. Based on the data of mandrel measurements, we constructed the implementations of deviations from the correct geometric shape of the profile curve with an equiaxial contour and found the deviations from the correct geometric shape of the landing surface of the tool mandrels under the action of random and systematic factors within the framework of theory of random stationary processes. It is established that the most rational method of manufacturing mandrels with a profile cross-section curve with an equiaxial contour with the required accuracy of the geometric shape is processing of grinding with a straight flat circle in comparison with the Cup circle. Based on the obtained results, we developed a mathematical model for the geometric shape of the profile connection parts with an equiaxial contour. 10.18721/JEST.25210 621.9.022:519.21 instrumental mandrel accuracy of geometric shape profile joints mathematical model multi-purpose machines https://engtech.spbstu.ru/article/2019.108.10/ 10_Ilinih.pdf

RAR RUS 141-148 Knyazkina Valeriia I. Ivanov Sergey lisa_lisa74@mail.ru DIAGNOSING AND EXTENDING USEFUL LIFE OF TRANSMISSIONS IN MINING EXCAVATORS The study considers the issues related to improving the system for diagnosing the technical condition of mining excavator transmissions and extending the service life of their working fluids based on assessment of magnitude and nature of changes in the acoustic signal D of the ultrasonic range in moving parts of transmission elements during its operation. The quantity and quality of the lubricant determines the value of the indicator D, and allows to make decisions about timely replacement or disposal of used transmission oil when implementing the technology of routine work within the framework of maintenance and repair strategy based on the actual conditions. Recommendations are given for improving the assessment of technical conditions of components and friction pairs of mechanical transmissions of equipment. The results of the experiment on changing the D index in a friction pair as a function of pressure in the contact and the angular velocity are presented. A block for cleaning transmission oil in mining excavator systems is proposed. A description of its operating principles is given. 10.18721/JEST.25211 622.271.4 mining excavator maintenance repair friction units lubrication acoustic signal transmission https://engtech.spbstu.ru/article/2019.108.11/ 11_Knyazkina.pdf

RAR RUS 149-160 Nguyen Ngoc Thuan Kapralov Vladimir M. ANALYSIS OF RESONANCE AND NATURAL FREQUENCIES OF GAS TURBINE BLADES Gas turbine blades operate in a wide frequency range of dynamic loads. Such loads can lead to fatigue deformations and microcracks with time, which changes the dynamic characteristics of the of the blades. The blade is an elastic structure and has a spectrum of natural frequencies and vibration modes. They affect the dynamic properties of the blade itself and its ability to respond to various influences. The study consists in studying the natural frequency and vibration modes of turbomachine blades and in improving the methods of numerical prediction of dynamic response of blades under load, which is an urgent task, as it allows to characterize the dependence of natural frequencies of vibrations on the mode of operation and reliably avoid resonance for engineered blades in actual operating conditions. 10.18721/JEST.25212 620.178 blade modal analysis harmonic response natural frequency gas turbine https://engtech.spbstu.ru/article/2019.108.12/ 12_Nguen.pdf

RAR RUS 161-170 Yagubov Viktor S. Shchegolkov Aleksandr V. ELECTRICAL CONDUCTIVITY AND MECHANICAL CHARACTERISTICS OF COMPOSITES BASED ON CHLOROPRENE RUBBER MODIFIED WITH CARBON NANOMATERIALS The article presents the results of studies of electrical conductivity and mechanical characteristics of adhesive layers formed by chloroprene rubber-based composites containing various concentrations of carbon nanomaterials (CNM). The presented method of manufacturing adhesive composites based on chloroprene rubber contributes to significant reduction in large aggregates of CNM. It was established that all nano-modified adhesive composites have high adhesion to the surface of the glass plate, except for the composites containing 9 wt.% of electrically conductive fillers. Studies have shown that the most durable adhesive compound was obtained using the adhesive composite, modified with 3 wt.% of CNM Taunit-M, while the adhesive composite containing 6 wt.% of carbon black PrinTex XE2B has the lowest specific volume resistance of 1.43 Ω • cm. 10.18721/JEST.25213 678.8 chloroprene rubber carbon nano-compounds ethyl acetate composite electrical conductivity adhesion strength https://engtech.spbstu.ru/article/2019.108.13/ 13_Yakubov.pdf

PER RUS 171-182 Morachevski Andrey morachevski@mail.ru PIONEER OF RUSSIAN THEORETICAL PHYSICS (DEDICATED TO THE 125TH ANNIVERSARY OF BIRTH OF YAKOV ILICH FRENKEL) Yakov Ilyich Frenkel was a theoretical physicist rightfully taking a place of honor among prominent scientists in the entire history of the St. Petersburg Polytechnic Institute (University). He was widely known worldwide. He repeatedly met with the most famous scientist of the 20th century, Albert Einstein (1879–1955), the creator of the special and general theory of relativity, awarded the Nobel Prize in 1921 for his services to theoretical physics. A graduate of the St. Petersburg University, Ya.I. Frenkel, was the first Russian physicist to become a fellow of the Rockefeller Foundation, which allowed him to work in scientific centers of Western Europe, meeting with famous physicists of the time in 1925–1926. Ya.I. Frenkel was invited to give lectures at the University of Minneapolis (USA) in 1930–1931. He also visited a number of other US research centers. From 1921 until the end of his life, Ya.I. Frenkel worked at the Leningrad Polytechnic Institute and at the Ioffe Physical-Technical Institute. In 1929, he was elected a corresponding member of the Academy of Sciences of the USSR, in 1934 he became a doctor of physical and mathematical sciences. In 1947, Ya.I. Frenkel was awarded the Stalin (State) Prize of the first degree for the monograph «Kinetic Theory of Liquids». 10.18721/JEST.25214 51/53(051) Yakov Frenkel corresponding member of USSR Academy of Sciences theoretical physicist winner of Stalin Prize https://engtech.spbstu.ru/article/2019.108.14/ 14_Morachevskiy.pdf

PER RUS 183-189 Evgrafov Alexander .evgrafov@spbstu.ru CONTRIBUTION OF M.Z. KOLOVSKY TO THEORY OF MECHANISMS AND MACHINES Mikhail Zakharovich Kolovsky is an outstanding researcher of mechanics of complex modern machines. His non-linear theory of vibration isolation systems helped to solve the most important problem of protecting electronic equipment of missile systems. He developed a unified and clear methodology for analyzing the dynamics of machines considered as linked dynamic complexes, including the drive, transmission and actuating mechanisms and the control system. Introduced by M.Z. Kolovski, the new definition of the structural group, in which the Assur group is considered as a special case, allowed the development of the theory of L.V. Assur and the study of the modern mechanisms on a single methodological basis, which did not exist in the epoch of L.V. Assur. The methodology developed by M.Z. Kolovski became the foundation for development of such modern academic courses as machine dynamics, the mechanism and machine theory, etc. The given paper presents brief biographical information from the life of M.Z. Kolovsky, and considers scientific ideas developed in his works. 10.18721/JEST.25215 621.01:531.8 M.Z. Kolovsky machine mechanics machine dynamics non-linear theory of vibration isolation systems Kolovsky structural group https://engtech.spbstu.ru/article/2019.108.15/ 15_Evgrafov.pdf