Archives of Thermodynamics最新文献_第8页

Correlations for the thermal conductivity of selected steel grades as a function of temperature in the range of 0–800°C 选定钢种的导热系数与温度在0-800°C范围内的关系

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2022.143170

Rafał Wyczółkowski

{"title":"Correlations for the thermal conductivity of selected steel grades as a function of temperature in the range of 0–800°C","authors":"Rafał Wyczółkowski","doi":"10.24425/ather.2022.143170","DOIUrl":"https://doi.org/10.24425/ather.2022.143170","url":null,"abstract":"Reliable knowledge of thermo-physical properties of materials is essential for the interpretation of solidiﬁcation behaviour, forming, heat treatment and joining of metallic systems. It is also a precondition for precise simulation calculations of technological processes. Numerical calculations usually require the knowledge of temperature dependencies of three basic thermo-physical properties: thermal conductivity, heat capacity and density. The objective of this work is to ﬁnd a correlation that ﬁts the thermal conductivity of selected steel grades as a function of temperature (within the range of 0–800 ◦ C) and carbon content (within the range of 0.1–0.6%). The starting point for the analysis are the experimental data on thermal conductivity taken from literature. Using the method of least squares it was possible to ﬁt an equation which allows calculating the thermal conductivity of steel depending on the temperature and carbon content. Two kinds of equations have been analyzed: a linear one (a linear model) and a second degree polynomial (a non-linear model). The thermal conductivity obtained by linear and nonlinear models varies on average from the measured values by 3% and 2.6% respectively.","PeriodicalId":45257,"journal":{"name":"Archives of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44178226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Thermal analysis of a gravity-assisted heat pipe working with zirconia-acetone nanofluids: An experimental assessment 氧化锆-丙酮纳米流体重力辅助热管的热分析：实验评估

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2020.133622

Amin Abdolhossein Zadeh

{"title":"Thermal analysis of a gravity-assisted heat pipe working with zirconia-acetone nanofluids: An experimental assessment","authors":"Amin Abdolhossein Zadeh","doi":"10.24425/ather.2020.133622","DOIUrl":"https://doi.org/10.24425/ather.2020.133622","url":null,"abstract":"An experimental investigation was performed on the thermal performance and heat transfer characteristics of acetone/zirconia nanoﬂuid in a straight (rod) gravity-assisted heat pipe. The heat pipe was fabricated from copper with a diameter of 15 mm, evaporator-condenser length of 100 mm and adiabatic length of 50 mm. The zirconia-acetone nanoﬂuid was prepared at 0.05–0.15% wt. Inﬂuence of heat ﬂux applied to the evaporator, ﬁlling ratio, tilt angle and mass concentration of nanoﬂuid on the heat transfer coeﬃcient of heat pipe was investigated. Results showed that the use of nanoﬂuid increases the heat transfer coeﬃcient while decreasing the thermal resistance of the heat pipe. However, for the ﬁlling ratio and tilt angle values, the heat transfer coeﬃcient initially increases with an increase in both. However, from a speciﬁc value, which was 0.65 for ﬁlling ratio and 60–65 deg for tilt angle, the heat transfer coeﬃcient was suppressed. This was attributed to the limitation in the internal space of the heat pipe and also the accumulation of working ﬂuid inside the bottom of the heat pipe due to the large tilt angle. Overall, zirconia-acetone showed a great potential to increase the thermal performance of the heat pipe.","PeriodicalId":45257,"journal":{"name":"Archives of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42515241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

A case study of working fluid selection for a small-scale waste heat recovery ORC system 小型余热回收ORC系统工质选择实例研究

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ATHER.2019.129999

P. Klimaszewski, D. Zaniewski, Ł. Witanowski, T. Suchocki, P. Klonowicz, P. Lampart

{"title":"A case study of working fluid selection for a small-scale waste heat recovery ORC system","authors":"P. Klimaszewski, D. Zaniewski, Ł. Witanowski, T. Suchocki, P. Klonowicz, P. Lampart","doi":"10.24425/ATHER.2019.129999","DOIUrl":"https://doi.org/10.24425/ATHER.2019.129999","url":null,"abstract":"The paper illustrates a case study of fluid selection for an internal combustion engine heat recovery organic Rankine cycle (ORC) system having the net power of about 30 kW. Various criteria of fluid selection are discussed. Particular attention is paid to thermodynamic performance of the system and human safety. The selection of working fluid for the ORC system has a large impact on the next steps of the design process, i.e., the working substance affects the turbine design and the size and type of heat exchangers. The final choice is usually a compromise between thermodynamic performance, safety and impact on natural environment. The most important parameters in thermodynamic analysis include calculations of net generated power and ORC cycle efficiency. Some level of toxicity and flammability can be accepted only if the leakages are very low. The fluid thermal stability level has to be taken into account too. The economy is a key aspect from the commercial point of view and that includes not only the fluid cost but also other costs which are the consequence of particular fluid selection. The paper discusses various configurations of the ORC system – with and without a regenerator and with direct or indirect evaporation. The selected working fluids for the considered particular power plant include toluene, DMC (dimethyl carbonate) and MM (hexamethyldisiloxane). Their advantages and disadvantages are outlined. ∗Corresponding Author. Email: pklimaszewski@imp.gda.pl 160 P. Klimaszewski, et al.","PeriodicalId":45257,"journal":{"name":"Archives of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41673982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Design of thermoelectric radiant cooling – photovoltaic panels system in the building 建筑热电辐射制冷-光伏板系统的设计

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2022.144407

I. Abdulghafor, M. Mnati

{"title":"Design of thermoelectric radiant cooling – photovoltaic panels system in the building","authors":"I. Abdulghafor, M. Mnati","doi":"10.24425/ather.2022.144407","DOIUrl":"https://doi.org/10.24425/ather.2022.144407","url":null,"abstract":"In this study, a theoretical model is presented to investigate the performance of a thermoelectric (TE) radiant cooling system combined with photovoltaic (PV) modules as a power supply in a building with an ambient temperature reaching more than 45 ◦ C. The combined system TE/PV performance is studied under diﬀerent solar radiation by using the hourly analysis program and photovoltaic system software. The thermal and electric characteristics of TE are theoretically investigated under various supplied voltages using the multi-paradigm programming language and numerical computing environment. Also, a theoretical analysis of heat transfer between the TE radiant cooling system and an occupied zone from the side, and the other side between the TE radiant cooling system and duct zone is presented. The maximum power consumption by TE panels and building cooling load of 130 kW is predicted for May and June. The 145 units of PV panels could provide about 50% of the power required by TE panels. The thermal and electric characteristics of TE panels results show the minimum cold surface temperature of 15 ◦ C at a supplied voltage between 6 V and 7 V, and the maximum hot surface temperature of 62 ◦ C at a supplied voltage of 16 V. The surface temperature diﬀerence between supplied current and supplied power increases as supplied voltage increases. At a higher supplied voltage of 16 V, the maximum surface temperature diﬀerence be-tween supplied current, and supplied power of 150 ◦ C, 3.2 A, and 48 W, respectively. The cooling capacity increases as supplied voltage increases, at a surface temperature diﬀerence of –10 ◦ C and supplied voltage of 16 V, the maximum cooling capacity is founded at about 60 W. As supplied voltage","PeriodicalId":45257,"journal":{"name":"Archives of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45561944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Refined multi-phase-lags theory and Thomson effect on a micropolar thermoelastic medium with voids 精细多相滞后理论和微极性热弹性介质中的Thomson效应

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2021.138120

E. M. Abd-Elaziz, M. Othman

引用次数: 2

Development of flow and efficiency characteristics of an axial compressor with an analytical method including cooling air extraction and variable inlet guide vane angle 轴流压气机的流动和效率特性的分析方法，包括冷却空气抽取和可变进口导叶角

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2021.138121

Paweł Trawiński

{"title":"Development of flow and efficiency characteristics of an axial compressor with an analytical method including cooling air extraction and variable inlet guide vane angle","authors":"Paweł Trawiński","doi":"10.24425/ather.2021.138121","DOIUrl":"https://doi.org/10.24425/ather.2021.138121","url":null,"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.","PeriodicalId":45257,"journal":{"name":"Archives of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42500312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Numerical study of heat transfer and aerodynamic drag of the radiator with lamellar split finning 分层翅片散热器的传热和气动阻力数值研究

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2020.132950

引用次数: 0

Implementation of turbulence damping in the OpenFOAM multiphase flow solver interFoam 湍流阻尼在OpenFOAM多相流求解器interFoam中的实现

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2022.140923

J. Polansky, S. Schmelter

{"title":"Implementation of turbulence damping in the OpenFOAM multiphase flow solver interFoam","authors":"J. Polansky, S. Schmelter","doi":"10.24425/ather.2022.140923","DOIUrl":"https://doi.org/10.24425/ather.2022.140923","url":null,"abstract":"In the presented work Egorov’s approach (adding a source term to the ω -equation in the k - ω model, which mimics the damping of turbulence close to a solid wall) was implemented in on the subclass of shear stress transport models. Hence, turbulence damping is available for all shear stress transport type models, including hybrid models that are based on the ω -equation. It is shown that turbulence damping improves the prediction of the axial velocity proﬁle not only for Reynolds-averaged Navier–Stokes simulation but also for detached eddy simulation and delayed detached eddy simulation models. Furthermore, it leads to a more realistic estimation of the pressure drop and, hence, to a more correct prediction of the liquid level. In this paper, simulation results for four diﬀerent turbulence models are presented and validated by comparison with experimental data. Furthermore, the inﬂuence of the magnitude of the damping factor on the pressure drop in the channel is investigated for a variety of diﬀerent gas-to-liquid ﬂow rate ratios. These investigations show that higher gas-to-liquid ﬂow rate ratios require higher damping factors to correctly predict the pressure drop. In the end, advice is formulated on how an appropriate damping factor can be determined for a speciﬁc test case.","PeriodicalId":45257,"journal":{"name":"Archives of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42402623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Development of real gas model operating in gas turbine system in Python programming environment Python编程环境下燃气轮机系统实际燃气模型的开发

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2020.135853

Paweł Trawiński

{"title":"Development of real gas model operating in gas turbine system in Python programming environment","authors":"Paweł Trawiński","doi":"10.24425/ather.2020.135853","DOIUrl":"https://doi.org/10.24425/ather.2020.135853","url":null,"abstract":"Identification of working fluids and development of their mathematical models should always precede construction of a proper model of the analysed thermodynamic system. This paper presents method of development of a mathematical model of working fluids in a gas turbine system and its implementation in Python programming environment. Among the thermodynamic parameters of the quantitative analysis of systems, the following were selected: specific volume, specific isobaric and isochoric heat capacity and their ratio, specific enthalpy and specific entropy. The development of the model began with implementation of dependencies describing the semi-ideal gas. The model was then extended to the real gas model using correction factors reflecting the impact of pressure. The real gas equations of state were chosen, namely due to Redlich–Kwong, Peng–Robinson, Soave– Redlich–Kwong, and Lee–Kesler. All the correction functions were derived analytically from the mentioned equations of real gas behaviour. The philosophy of construction of computational algorithms was presented and relevant calculation and numerical algorithms were discussed. Created software allowed to obtain results which were analysed and partially validated.","PeriodicalId":45257,"journal":{"name":"Archives of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45846944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Challenges in operating and testing loop heat pipes in 500–700 K temperature ranges 在500-700 K温度范围内操作和测试环路热管的挑战

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2022.141978

P. Szymański

{"title":"Challenges in operating and testing loop heat pipes in 500–700 K temperature ranges","authors":"P. Szymański","doi":"10.24425/ather.2022.141978","DOIUrl":"https://doi.org/10.24425/ather.2022.141978","url":null,"abstract":"The potential applications of loop heat pipes (LHPs) are the nuclear power space systems, fuel cell thermal management systems, waste heat recovery systems, medium temperature electronic systems, medium temperature military systems, among others. Such applications usually operate in temperature ranges between 500–700 K, hence it is necessary to develop an LHP system that will meet this requirement. Such a thermal management device require to meet various technical problems and challenges currently existing in the development of LHP working in medium temperatures, including: (1) selection of appropriate working ﬂuid; (2) selection of appropriate LHP construction material; (3) construction of suitable test rig capable of testing at elevated temperatures; (4) development of new testing methods. Currently, there are no proven working ﬂuids that can be used in LHPs in medium temperature ranges. Water can be applicable only at temperatures up to 570 K. Caesium can be applicable at temperatures above 670 K. Organic ﬂuids usually tend to generate non-condensable gasses and/or decompose at elevated temperatures and their viscosity dramatically increases. For halides, most of them are very reactive or toxic and their full property data are not available or the majority of the physical properties are predicted, also live tests and their environmental impact data are not adequate. As for casing/LHP construction material, there are no full chemical compatibility tables with most of the medium temperature working ﬂuids and the reactivity of ﬂuids signiﬁcantly limits the potential materials. Also, testing such an LHP is an endeavour as the reactivity of medium temperature ﬂuids and the use of obscure metals create new chal-∗","PeriodicalId":45257,"journal":{"name":"Archives of Thermodynamics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41323524","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2