https://www.elibrary.ru/title_about_new.asp?i
2687-1300
Materials Science. Power Engineering
25
2
2019
1-193
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
Borovkov
Alexey
Peter the Great St. Petersburg Polytechnic University, Russia
Russia, 195251, St.Petersburg, Polytechnicheskaya, 29
Voynov Igor B.
Peter the Great St. Petersburg polytechnic university
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