Applied sciences

Archives of Thermodynamics

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Archives of Thermodynamics | 2021 | vol. 42 | No 4

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Authors and Affiliations

Tomasz Staśko
1
Mirosław Majkut
1
Sławomir Dykas
1
Krystian Smołka
1

  1. Department of Power Engineering and Turbomachinery, Silesian University of Technology, Konarskiego 18, 44-100 Gliwice, Poland
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Abstract

The development of a reliable mathematical model of an axial compressor requires applying flow and efficiency characteristics. This approach provides performance parameters of a machine depending on varying conditions. In this paper, a method for developing characteristics of an axial compressor is presented, based on general compressor maps available in the literature or measurement data from industrial facilities. The novelty that constitutes the core of this article is introducing an improved method describing the performance lines of an axial compressor with the modified ellipse equation. The proposed model is extended with bleed air extraction for the purposes of cooling the blades in the expander part of the gas turbine. The variable inlet guide vanes angle is also considered using the vane angle correction factor. All developed dependencies are fully analytical. The presented approach does not require knowledge of machine geometry. The set of input parameters is based on reference data. The presented approach makes it possible to determine the allowed operating area and study the machine’s performance in variable conditions. The introduced mathematical correlations provide a fully analytical study of optimum operating points concerning the chosen criterion. The final section presents a mathematical model of an axial compressor built using the developed method. A detailed study of the exemplary flow and efficiency characteristics of an axial compressor operating with a gas turbine is also provided.
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Authors and Affiliations

Paweł Trawiński
1

  1. Institute of Heat Engineering, Warsaw University of Technology, Nowowiejska 21/25, 00-665, Warsaw, Poland
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Abstract

Liquefied natural gas (LNG) is transported by the sea-ships with relatively low pressure (0.13–0.14 MPa) and very low temperature (about 100 K) in cryo-containers. Liquid phase, and the low temperature of the medium is connected with its high exergy. LNG receives this exergy during the liquefaction and is related with energy consumption in this process. When the LNG is evaporated in atmospheric regasifiers (what takes place in many on-shore terminals as well as in local regasifier stations) the cryogenic exergy is totally lost. fortunately, there are a lot of installations dedicated for exergy recovery during LNG regasification. These are mainly used for the production of electricity, but there are also rare examples of utilization of the LNG cryogenic exergy for other tasks, for example it is utilized in the fruit lyophilization process. In the paper installations based on the Brayton cycle gas turbine are investigated, in the form of systems with inlet air cooling, liquid phase injection, exhaust gas based LNG evaporation and mirror gas turbine systems. The mirror gas turbine system are found most exegetically effective, while the exhaust gas heated systems the most practical in terms of own LNG consumption.
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Authors and Affiliations

Ireneusz Szczygieł
1
Bartłomiej Paweł Rutczyk
1

  1. Silesian University of Technology Institute of Thermal Technology, Konarskiego 22, 44-100 Gliwice, Poland
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Abstract

The research provides a thermodynamic analysis of the theoretical model of a ventilation and air conditioning heat pump system with the ventilation air cold energy recovery depending on outside air parameters, the recovery efficiency and characteristics of a premise. A confectionery production workshop was taken as a prototype where technological conditions (temperature and humidity) must be maintained during the warm season. Calculations using the method of successive approximations to estimate air parameters at system’s nodal points were conducted. It allowed to determine theoretical refrigeration efficiency of the studied system and proved advantages of heat recuperation for smaller energy consumption. The model can be applied for design of heating, ventilation, and air conditioning units which work as a heat pump. The studied system has the highest energy efficiency in the area of relatively low environment temperatures and relative humidity which is suitable for countries with temperate continental climates characterized by low relative humidity.
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Authors and Affiliations

Myhailo Kostiantynovych Bezrodny
1
Tymofii Oleksiyovych Misiura
1

  1. National Technical University of Ukraine, Igor Sikorsky, Kyiv Polytechnic Institute, Prosp. Peremohy 37, 03056 Kyiv, Ukraine
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Abstract

This paper presents the results of developing a methodology for assessing and predicting the technical condition of boiler plants and steam turbines. The proposed method is based on generalized experimental data on failures to predict the damage of the principal elements and components of thermal power plants by Monte-Carlo simulation. The proposed method considers the complexity of technological processes, turnaround time, failure rate, and condition of the residual metal life. It allows developing approaches to assessing each element’s safety to obtain a reliable and representative sample of failure statistics to reliability assessment of boilers and steam turbines of thermal power plants. According to the results, the probability of failure operation of steam boilers and turbines is 0.037 in the 100 MW conditions. The obtained results can be used to create predictive models that provide approaches to prolonging the operational state of elements of boiler plants and steam turbines of thermal power plants. It can be used in the implementation of projects of digital energy systems for monitoring and diagnostics of the main power equipment of thermal power plants.
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Authors and Affiliations

Makhsud Mansurovich Sultanov
1
Stepan Anatolyevich Griga
2
Maksim Sergeevich Ivanitckii
1
Anatoly Alekseevich Konstantinov
1

  1. National Research University MPEI, Krasnokazarmennaya 17, Moscow, 111250 Russia
  2. PJSC “Mosenergo”, Vernadsky Avenue 101/3, Moscow, 119526 Russia
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Abstract

The electricity production by combustion of organic fuels, especially coal, increases the atmospheric CO2 content, which contributes to global warming. The greenhouse gas emissions by the power production industry may be reduced by the application of CO2 capture and storage systems, but it remarkably decreases the thermal power plant (TPP) efficiency because of the considerable increase of the auxiliary electricity requirements. This paper describes the thermodynamic analysis of a combined cycle TPP with coal gasification and preliminary carbon dioxide capture from the syngas. Utilization of the heat produced in the fuel preparation increases the TPP net efficiency from 42.3% to 47.2%. Moreover, the analysis included the combined cycle power plant with coal gasification and the CO2 capture from the heat recovery steam generator exhaust gas, and the oxy-fuel combustion power cycle with coal gasification. The coal-fired combined cycle power plant efficiency with the preliminary CO2 capture from syngas is 0.6% higher than that of the CO2 capture after combustion and 9.9% higher than that with the oxy-fuel combustion and further CO2 capture. The specific CO2 emissions are equal to 103 g/kWh for the case of CO2 capture from syngas, 90 g/kWh for the case of CO2 capture from the exhaust gas and 9 g/kWh for the case of oxy-fuel combustion.
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Authors and Affiliations

Vladimir Olegovich Kindra
1
Igor Alexandrovich Milukov
1
Igor Vladimirovich Shevchenko
1
Sofia Igorevna Shabalova
1
Dmitriy Sergeevich Kovalev
1

  1. National Research University “Moscow Power Engineering Institute”, Krasnokazarmennaya 14, Moscow, 111250 Russia
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Abstract

The Rankine cycle steam turbine power plants make a base for world electricity production. The efficiency of modern steam turbine units is not higher than 43–45%, which is remarkably lower compared to the combined cycle power plants. However, an increase in steam turbine power plant efficiency could be achieved by the rise of initial cycle parameters up to ultra-supercritical values: 700–780˚C, 30–35 MPa. A prospective steam superheating technology is the oxy-fuel combustion heating in a sidemounted combustor located in the steam pipelines. This paper reviews thermal schemes of steam turbine power plants with one or two side-mounted steam superheaters. An influence of the initial steam parameters on the facility thermal efficiency was identified and primary and secondary superheater parameters were optimized. It was found that the working fluid superheating in the side-mounted oxy-methane combustors leads to an increase of thermal efficiency higher than that with the traditional boiler superheating in the initial temperature ranges of 700–780˚C and 660–780˚C by 0.6% and 1.4%, respectively.
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Authors and Affiliations

Vladimir Olegovich Kindra
1
Sergey Konstantinovich Osipov
1
Olga Vladimirovna Zlyvko
1
Igor Alexandrovich Shcherbatov
1
Vladimir Petrovich Sokolov
1

  1. National Research University “Moscow Power Engineering Institute”, Krasnokazarmennaya 14, Moscow, 111250 Russia
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Abstract

Steam discharge produces noise due to rapid expansion and a temperature drop of ejected steam. This is why steam silencers are used to change one-stage into multi-stage expansion, which reduces the intensity of pressure and temperature drop during this process and shifts emitted noise into higher frequencies, which are easier to dampen. This paper presents a flow-acoustic numerical model of a steam silencer. It is meant to help to obtain a precise analysis of phenomena occurring in steam silencers and improve the process of designing this type of device. The model described in this paper was based on the parameters of a real working unit manufactured in the Institute of Power Engineering – Thermal Technology Branch. Most of the steam silencers are designed based on construction guidelines that have not been changed for a long time. This restrained an increase in the acoustics efficiency of the steam silencers. An improvement of their flow and acoustic properties allows for the development of smaller, more efficient, and lighter construction. The current version of the model was used for the analysis of flow and acoustic changes which occur after modifying the lower region of a shell of the steam silencer. The proposed modification allowed for a 19% increase in mass flow rate through the silencer and noise reduction in the low-frequency range.
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Authors and Affiliations

Patryk Gaj
1
Krzysztof Sobczak
2
Joanna Kopania
3
Kamil Wójciak
1

  1. Institute of Power Engineering, Mory 8, 01-330 Warsaw, Poland
  2. Lodz University of Technology, Wólczanska 219, 90-924 Lodz, Poland
  3. Lodz University of Technology, Piotrkowska 266, 90-924 Lodz, Poland
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Abstract

Recent climate changes stimulate the search and introduction of solutions for the reduction of the anthropogenic effect upon the environment. Transition to the oxy-fuel combustion power cycles is an advanced method of CO2 emission reduction. In these energy units, the main fuel is natural gas but the cycles may also work on syngas produced by the solid fuel gasification process. This paper discloses a new highly efficient oxy-fuel combustion power cycle with coal gasification, which utilizes the syngas heat in two additional nitrogen gas turbine units. The cycle mathematics simulation and optimization result with the energy unit net efficiency of 40.43%. Parametric studies of the cycle show influence of the parameters upon the energy unit net efficiency. Change of the cycle fuel from natural gas to coal is followed by a nearly twice increase of the carbon dioxide emission from 4.63 to 9.92 gmCO2/kWh.
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Authors and Affiliations

Vladimir Kindra
1
Andrey Rogalev
1
Olga Vladimirovna Zlyvko
Vladimir Sokolov
1
Igor Milukov
1

  1. National Research University “Moscow Power Engineering Institute”, Krasnokazarmennaya 14, Moscow, 111250 Russia
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Abstract

Besides centrifugal pumps, centrifugal fans are the most common turbomachines used in technical applications. They are commonly used in power engineering systems, such as heat engines and chillers, heating, ventilation, and air conditioning systems, supply and exhaust air systems. They are also used as machines consuming final energy (electricity). Therefore, any improvement in their efficiency affects the efficiency of energy generation and the level of electricity consumption. Many efforts have been made so far to find the most efficient numerical method of modelling flows in fans. However, only a few publications focus on the unsteadiness that may have an impact on device efficiency and noise generation. This paper presents an attempt to identify unsteadiness in the flow through a centrifugal fan by means of computational fluid dynamics and computational aeroacoustics methods. The works were performed using the Ansys CFX commercial software and the results of numerical studies are compared with experimental data.
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Authors and Affiliations

Balazs Pritz
1
Matthias Probst
1
Piotr Wiśniewski
2
Sławomir Dykas
2
Mirosław Majkut
2
Krystian Smołka
2

  1. Institute of Thermal Turbomachinery, Karlsruhe Institute of Technology, Kaiserstraße 12 D-76131 Karlsruhe, Germany
  2. Department of Power Engineering and Turbomachinery, Silesian University of Technology, Poland
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Abstract

As a central goal of the energy transition in Germany, the share of renewable energies is to be increased to over 80% by 2050. Due to fluctuating wind conditions or the day-night cycle, storage systems must be integrated into the supply grid for a continuous regenerative power supply from wind and solar energy. In addition to pumped storage systems, batteries and Power2Gas approaches, compressed gases (optimally air) can also be used for this purpose. The aim of the research and development project presented is to develop such a storage unit with the best possible efficiency and long service life. To this end, basic calculations were first made on possible efficiencies depending on the assumed changes in the state of the working gas. Furthermore a piston compressor for compressed air generation was investigated experimentally with regard to its efficiency. In addition, the compressor was modelled and simulated in a corresponding software. Thus, on the one hand, the efficiency of the existing piston compressor could be determined experimentally and, on the other hand, the simulation model could be assessed with regard to its suitability for the purpose of simulation-based optimization. Measures to increase efficiency can be derived from the results. In addition, it becomes possible to forecast the achievable overall efficiency of such an energy storage system with compressed air.
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Bibliography

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Authors and Affiliations

Dirk Herbert Hübner
1
Sebastian Grün
1
Jan Molter
1

  1. HTW Saar – University of Applied Sciences, Campus Rotenbühl, Waldhausweg 14, 66123 Saarbrücken, Germany
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Abstract

Machines utilising renewable energy constantly undergo research aimed at raising their efficiency. One of them is a Savonius wind turbine, where scientists propose adjustments to improve its aerodynamic properties. At present, their assessment is usually performed by means of transient computational fluid dynamics simulations with two- or threedimensional models. In this paper, the overset (chimera) mesh approach was applied to investigate the performance of a Savonius wind turbine equipped with deformable blades. They were continuously deformed during rotation by a dedicated mechanism to increase a positive torque of the advancing blade, and meanwhile, decrease a negative torque of the returning blade. A quasi-two-dimensional model with a two-way fluid-structure interaction method was applied, where the structural solver determined blade deflection caused by the predefined deformation mechanism and aerodynamic loads, whereas the coupled computational fluid dynamics solver determined the transient flow. The deformable blades rotor performance was calculated and compared with a conventional rigid Savonius turbine, both simulated using the overset mesh approach. The average value of the power coefficient achieved a 55% rise in the case of deformable blades turbine. Additionally, to validate the overset method, its results were compared with the classical sliding mesh method for a conventional rigid rotor.
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Bibliography

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Authors and Affiliations

Emil Marchewka
1
Krzysztof Sobczak
1
Piotr Reorowicz
1
Damian Stanisław Obidowski
1
Krzysztof Jóźwik
1

  1. Lodz University of Technology, Institute of Turbomachinery, Wólczanska 219/223, 90-924 Łódz, Poland
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Abstract

The geometry and operating parameters have an important influence on the performance of ejectors. The improvement of the refrigeration cycle performance and the design of the ejectors for the compression energy recovery requires a detailed analysis of the internal ejector working characteristics and geometry. To this aim, an experimental investigation of an ejector refrigeration system is conducted to determine the effect of the most important ejector dimensions on ejector working characteristics and system performance. Different dimensions of ejector components are tested. The influence of the ejector’s geometrical parameters on the system performance was analysed. The experiments with respect to the variation of ejector geometry such as the motive nozzle throat diameter, the mixing chamber diameter and the distance between the motive nozzle and diffuser were carried out. There exist optimum design parameters in each test. The experimental results show that the performance (entrainment ratio and a compression ratio of the ejector) increases significantly with the position between the primary nozzle and the mixing chamber. A maximum entrainment ratio of 57.3% and a compression ratio of 1.26 were recorded for the different parameters studied. The results obtained are consistent with experimental results found in the literature.
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Authors and Affiliations

Philippe Haberschill
1
Ezzeddine Nehdi
2
Lakdar Kairouani
2
Mouna Abouda Elakhdar
2

  1. University of Lyon, CNRS, INSA-Lyon, CETHIL UMR5008, F-69621, Villeurbanne, France
  2. Research Lab Energetic and Environment, National Engineering School of Tunis, Tunis El Manar University, Tunisia
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Abstract

The placement of the battery box can have a massive impact on the aerodynamics of an electric vehicle. Although favourable from the viewpoint of vehicle dynamics, an underbody battery box may impair the vehicle aerodynamics. This study aims to quantify the effect of an underbody battery box on the drag force acting on an electric vehicle. Four different variants of the vehicle (original variant, lifted suspension, lifted suspension with an underbody battery box) are investigated by means of computational fluid dynamics. The underbody battery box was found to induce flow separation, resulting in a massive increase in drag force. As a solution, a battery box fairing was designed and tested. The fairing significantly reduced the increase in drag. The results of this study could contribute to the design of more stable and aerodynamically efficient electric vehicles.
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Authors and Affiliations

Jakub Bobrowski
1
Krzysztof Sobczak
1

  1. Institute of Turbomachinery, Lodz University of Technology, 217/221 Wolczanska, 93-005 Łódz Poland
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Abstract

The results of experimental investigations of heat transfer and a friction factor in an air channel of the minichannel heat exchanger are presented. The main aim of the analysis was to examine an influence of geometrical parameters of the fin shape with two geometries on heat transfer and flow characteristics of the air channel. The test rig was designed to monitor the parameters of the airflow during cooling by the minichannel heat exchanger. The analysis was conducted with the airflow in the range of 1–5 m/s. The temperature of the evaporation in a refrigeration system was set at 288.15 K. The energy balance of the refrigeration system was carried out. A numerical model describes the airflow through a part of the heat exchanger. Numerical simulations were validated with the experimental data. Numerical methods were used to evaluate the performance of the system and possibilities to improve the fin geometry. The characteristics of the friction factor (a measure of the pressure loss in the airflow) and the Colburn j-factor (heat transfer performance) were calculated. For the maximal velocity of the airflow, the Colburn factor was equal to 0.048 and the evaporator capacity equaled 1914 W.
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[8] Chan Kang H., Jun G.W.: Heat transfer and flow resistance characteristics of louver fin geometry for automobile applications. J. Heat Transfer. 133(2011), 1–6.
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[17] Kang, Hie-Chan & Jun, Gil.: Heat transfer and flow resistance characteristics of louver fin geometry for automobile applications. J. Heat Transf. 133 (2011), 101802.
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Authors and Affiliations

Michał Jan Kowalczyk
1
Marcin Łęcki
1
Artur Romaniak
1
Bartosz Warwas
1
Artur Gutkowski
1

  1. Lodz University of Technology, Institute of Turbomachinery, Wólczanska 217/221, 93-005 Łódz, Poland

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The list should begin with Latin symbols in alphabetical order followed by Greek symbols also in alphabetical order and with a separate heading. Subscripts and superscripts should follow Greek symbols and should be identified with separate headings. Physical quantities should be expressed in SI units ( Système International d’Unités). In the template a dedicated area is created to put the nomenclature.

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The references should be placed after the acknowledgment section. The references citation in the manuscript body should be numbered: [1], [2], etc. Please use the following style of references in bibliography APA – 7th ed:

Journal citation (APA – 7th ed):
[1] Król, J., & Ocłoń, P. (2019). Sensitivity analysis of hybrid combined heat and power plant on fuel and CO2 emission allowances price change. Energy Conversion and Management, 196, 127–148.
doi.org/10.1016/j.enconman.2019.05.090

[2] Zhou, Y., Bi, H., & Wang, H. (2023). Influence of the primary components of the high-speed train on fire heat release rate. Archives of Thermodynamics, 44(1), 37–61.
doi.org/10.24425/ather.2023.145876

When citing scientific papers, it is needed to provide a DOI identifier if available.
Example of citation:
• Król and Ocłoń [1] studied a hybrid CHP sensitivity on fuel and CO2 emission allowances price change.
• Zhou et al. [2] studied the influence of the primary components of the high speed train on fire heat release rate.

Book citation (APA – 7th ed):
[3] Ocłoń, P. (2021). Renewable energy utilization using underground energy systems (1st ed.). Springer Nature.
Example of citation:
• Ocłoń et al. [3] presented renewable energy systems for heating cooling and electrical energy production in buildings.

Book chapter citation (APA – 7th ed):
[4] Ciałkowski, M., & Frąckowiak, A. (2014). Boundary element method in inverse heat conduction problem. In Encyclopedia of Thermal Stresses (pp. 424–433). Springer Netherlands.
Example of citation:
• Ciałkowski and Frąckowiak [4] presented a Boundary element method application for solving inverse heat conduction problems.

Conference proceedings (APA – 7th ed):
[5] Pourghasemi, B., & Fathi, N. (2023). Validation and verification analyses of turbulent forced convection of Na and NaK in miniature heat sinks. ASME 2023 Verification, Validation, and Uncertainty Quantification Symposium, 17-19 May, Baltimore, USA.
Example of citation:
• Pourghasemi and Fathi [5] validated and verified turbulent forced convection of Na and NaK in miniature heat sinks.
For works originally published in a language other than English, the language should be indicated in parentheses at the end of the reference. Authors are responsible for ensuring that the information in each reference is complete and accurate, including the DOI number.

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Further information

All manuscripts will undergo some editorial modification. The paper proofs (as PDF file) will be sent by e-mail to the corresponding author for acceptance, and should be returned within two weeks of receipt. Within the proofs corrections of minor and typographical errors in: author names, affiliations, articles titles, abstracts and keywords, formulas, symbols, grammatical error, details in figures, etc., are only allowed, as well as necessary small additions. The changes within the text will be accepted in case of serious errors, for example with regard to scientific accuracy, or if authors reputation and that of the journal would be affected. Submitted material will not be returned to the author, unless specifically requested. A PDF file of published paper will be supplied free of charge to the Corresponding Author. Submission of the manuscript expresses at the same time the authors consent to its publishing in both printed and electronic versions.

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