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Vol. 5, no. 4, 2021




V. A. Pronin, A. V. Kovanov, E. A. Kalashnikova, V. A. Tsvetkov
The prospect of using ozone-safe refrigerants with low global warming potential
in scroll compressors. Part 1

DOI: 10.25206/2588-0373-2021-5-4-9-16
The Montreal Protocol and the Kigali Amendment have determined the need and deadlines of the replacement of hydro
fluorinated refrigerants. Substances of natural origin with a low global warming potential are becoming an alternative to
hydrofluorocarbons that are being withdrawn from circulation. Such an alternative corrects the vector of development of
refrigeration equipment and entails the need to adapt or create new models of equipment taking into account the excellent
properties of new refrigerants. However, the consumer’s choice is still based on the efficiency, cost and reliability of the
equipment. Having studied the possibility of using new refrigerants, in the fields of using a scroll compressor, from the point
of view of the operational properties of substances, we also noted some aspects of the influence of their thermodynamic
and thermophysical properties on the working processes and design of compressor elements. Thus, we present a
comparative analysis of the practical application and further prospects for the using of refrigerants in a scroll compressor,
highlighting the current directions of studying this issue.

Keywords: scroll compressor, refrigerant properties, hydrofluorocarbons, flow rate, energy efficiency, fluid leaks.


A. N. Fot, D. K. Melnikov
Features of calculation of refrigerating machines with combined cooling of condensers
taking into account climatic and economic factor

DOI: 10.25206/2588-0373-2021-5-4-17-23
A method for calculating refrigerating machines with a condensation unit implementing water and air cooling methods is
proposed taking into account the economic and climatic features of the calculated region. Since economic and climatic factors
have different degrees of influence on the energy efficiency and efficiency of refrigerating machines over the entire range of
changing temperatures of cooling media, the results of calculating refrigerating machines according to the proposed methodology
allow making informed decisions about the layout of the condensation unit both at the design stage and at the stage of developing
a program for managing the refrigeration unit throughout the year. A comparative analysis of refrigerating machines with combined
cooling of condensers for the regions of Omsk and Berlin is carried out. The most significant influence of the climatic factor at low
temperatures of the cooling air and the influence of the cost of cooling water at high air temperatures were revealed.

Keywords: combined cooling, condensation unit, water and air cooling, ecology, energy saving, mathematical model,
refrigeration machine.


A. R. Aliev
Automation of technological process of filling chambers during pneumatic vacuum tests
DOI: 10.25206/2588-0373-2021-5-4-24-32
The scheme and technology of the automated process of filling chambers with control gas are considered. Mathematical description
of the functioning of filling system served as a basis for the development of design and analysis procedure of performance
characteristics is constructed.

Keywords: tightness test, pneumatic vacuum tests, filling the chamber with gas, automatic filling mode, automation of
the technological process. 


I. S. Busarov, S. S. Busarov, V. L. Yusha
The effect of deformation of flow part of elastomeric elements of self-acting valves on
characteristics of low-speed long-stroke compressor stages

DOI: 10.25206/2588-0373-2021-5-4-33-38
The results of the study of the influence of changes in the area of the flow section in the seat of selfacting valves with elastomeric
elements on the characteristics of low-speed compressor stages are presented. A method of experimental research of low-speed
compressor stages with the possibility of obtaining instantaneous parameters of the gas state in the working chamber of the stage
and its integral characteristics and an experimental stand for its implementation have been developed. The results of comparative
experimental studies have confirmed the effectiveness of the valve design with a variable cross-sectional area of the seat in
comparison with known designs — an increase in the feed coefficient and isothermal indicator efficiency is at least 10...15%.

Keywords: compressor low-speed stage, experimental research, work processes, self-acting valve, elastomeric seat.


A. M. Kalashnikov, G. I. Chernov, V. L. Yusha
Thermodynamic analysis of expansion process of screw expander in wet steam area
DOI: 10.25206/2588-0373-2021-5-4-39-47
In this scientific work, the process of expansion of wet steam with different values of the inlet degree of dryness in a screw expander
is considered. The study is carried out on the basis of the developed mathematical model, which includes both the basic
thermodynamic equations and the process of heat exchange of the working substance with the environment in the process of
expansion. During the study of the expansion process in the area of wet steam in a screw expander, a mathematical model of this
process is developed. The mathematical model is verified by comparing the results obtained on its basis with the results obtained by
other researchers on an identical object. It can be seen from the results obtained that at values of the initial degree of dryness greater
than 0,01, the distributions of pressures and temperatures practically do not depend on its value. When the initial dryness values are
less than 0,01, it begins to have a significant effect on the distributioof pressure and temperature over the angle of rotation of the
main rotor of the screw expander.

Keywords: thermal energy, heat recovery, screw expander, expander, wet steam.


I. D. Obukhov
Optimization of waste heat recovery system for mobile compressor unit for compressing
natural gas

DOI: 10.25206/2588-0373-2021-5-4-48-54
This paper presents the methodology and results of optimization of the waste heat recovery system (WHRS) of a mobile
compressor unit (MCU) designed to compress natural gas using a computer model in the MatLab with the CoolProp
thermodynamic package. In the course of the study, a computer model of the WHRS is built, a criterion for the efficiency of
recuperation is determined, an optimization problem is formulated and its solution is carried out. The boiling pressure and
mass flow rate of the working fluid in the Rankine cycle are taken as the optimization parameters. With the optimal values of
these parameters, the smallest value of the relative mass fuel consumption of the MCU is achieved, that is, the maximum
recuperation efficiency is achieved.

Keywords: recuperation, Rankine cycle, mobile compressor unit, optimization, natural gas.


A. S. Khrekin, I. V. Baranov, A. A. Nikitin
The analysis of cascade refrigeration machine cycles efficiency using carbon dioxide
DOI: 10.25206/2588-0373-2021-5-4-55-64
The paper analyzes and proves the feasibility of improving the energy performance of low-temperature refrigeration machines
operating on R744 using cascade design with R134a, R1234yf and R717 as refrigerants based on data the scientific study of
two-stage schemes analysis. At present, it is given the existing environmental prohibitions and the growing interest in the creation
of low-temperature refrigeration machines operating on carbon dioxide (R744) in two-stage and cascade schemes, the presented
research supplements the scientific literature on justifying the use of each of them.

Keywords: cascade refrigeration system, global warming potential, upper cascade, transcritical cycle, conventional refrigerants,
 ozone-depleting potential, carbon dioxide, cooling capacity, natural refrigerant, refrigeration unit. 


Y. S. Hu, H. J. Wei, B. Yu, O. X. Yang, J. Wang, J. Wu
Research on the Vapor Injection of Two-stage Rotary Compressor /
trans. from Engl. M. A. Fedorova

DOI: 10.25206/2588-0373-2021-5-4-65-74
In order to understand the vapor injection flow characteristics of two-stage rotary compressor in the course of compression,
mathematical model based on mass conservation equation, energy equation and thermodynamic identity was established and
proved by P-V diagram testing results. Some useful conclusions about pressure in the intermediate chamber and mass flow of vapor
injection in the course of compression were also given out. The results show that, gas backflow between the intermediate chamber
and the vapor injection channel is an important defection of two-stage rotary compressor which can be solved by the application of
injection valve in vapor injection channel. The injection valve can obviously reduce the gas backflow and the power loss in the course
of compression while increasing the pressure fluctuation in the intermediate chamber. Experiments show that the COP of two-stage
rotary compressor with the injection valve increased by over 2% in ASHRAE/T working condition.

Keywords: refrigeration machine, rotary compressor, steam injection, mathematical model, experiment, verification.
Printed by permission from the authors and the Centre for Compressor Technology (International Conference on Compressors
and their Systems. London, 2019).


V. N. Blinov, V. V. Kositsin, A. I. Lukyanchik, P. V. Stepen, P. S. Yachmenev
Research on reliability of pulsed electrothermal propulsion system of nanosatellite
DOI: 10.25206/2588-0373-2021-5-4-75-82
In the paper have been discussed nanosetellite propulsion system normalization actual themes, as well their acknowledgement by
the testing results. To secure needed survival probability P≥0,995, the propulsion system bottlenecks normalized values are defined.
The results of propulsion system fatigue test and reliability evaluation also have been presented. The realized count of propulsion
system pulse mode switching is 15700. The actual value testing propulsion system survival probability is P=0,9979. That confirms
the ability of nanosatellite propulsion system demanded reliability.

Keywords: nanosatellite, resistojet, propulsion system, reliability, survival probability.


V. I. Kuznetsov, V. V. Makarov 
Uniformity of working processes of jet and vortex ejectors, vortex tube and Hartmann–Sprenger pipe
DOI: 10.25206/2588-0373-2021-5-4-83-88
Based on the previously considered physical and mathematical models of jet and vortex ejectors, vortex tube and Hartmann–Sprenger
tube, it makes a conclusion about the identity of the processes of exchange of work and heat in these devices. The influence of viscosity,
tangential stresses, and the gradient of linear and angular velocities on the transfer of kinetic energy from a high-pressure to a
low-pressure gas is shown. The difference of thermodynamic temperatures for heat exchange of high-pressure and low-pressure gases
is taken into account.

Keywords: jet and vortex ejector, vortex tube, Hartmann–Sprenger tube, work exchange, heat exchange, viscosity, tangential stress.


V. I. Trushlyakov, V. A. Urbansky, A. N. Pavlenko, V. E. Zhukov, E. Yu. Sukhorukova
Experimental studies of unsteady processes of cryogenic liquid evaporation in rocket tank model
DOI: 10.25206/2588-0373-2021-5-4-89-98
The program and the methodology of the experiment and the results of the experiment have been developed. The experimental bench
and metrological support have been created, liquid nitrogen (LN) has been considered as a model liquid. A database of heat and mass
exchange process parameters (pressure, temperature) under the modes of tank inflation with helium gas up to 2 atm., given external
thermal loading, pressure relief after reaching 4 atm. up to 1 atm. The technique of processing the results of pressure and temperature
measurements with the assumptions and limitations is given.

Keywords: liquid nitrogen, conductive heating, evaporation, boiling, volumetric boiling, pressurization, helium gas, mass evaporation rate.


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