Archives of Thermodynamics最新文献_第7页

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

Heat and mass transfer mechanism on three-dimensional flow of inclined magneto Carreau nanofluid with chemical reaction 具有化学反应的倾斜磁Carreau纳米流体三维流动的传热传质机理

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2020.133630

引用次数: 2

Irreversible energy degradation in heat transfer between two fluids – analysis on manifolds 两种流体之间热传递中的不可逆能量退化——歧管分析

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2020.135858

Z. Drożyński

{"title":"Irreversible energy degradation in heat transfer between two fluids – analysis on manifolds","authors":"Z. Drożyński","doi":"10.24425/ather.2020.135858","DOIUrl":"https://doi.org/10.24425/ather.2020.135858","url":null,"abstract":"Thermodynamics deals with irreversible transformations of substances. Every thermodynamic property of a substance, as a function of two parameters describing its state, can be illustrated as a simply connected manifold. The term manifold stands for the Methods of Geometrical Representation of Thermodynamic Properties of Substances by Means of Surfaces. Generally, every transformation of a substance changes its energy (or enthalpy) by heat transfer and work done on it. All such changes (transformations) are considered to be irreversible and can be described using appropriate manifolds. Studies show that every transformation is associated with the degradation of energy. Such relations (between heat, work and other forms of energy or enthalpy) can be described by the Pfaff formulas and their integrations. This article discusses the issue of irreversible energy degradation in heat transfer between two fluids. Irreversible heat transfer between separated fluids most often occurs through surface heat exchangers. All such processes are determined by convective heat transfer in thermal boundary layers and conduction through the wall. Consequently, entropy changes of fluids in heat and mass transfer can be observed in these layers. While the entropy rate of the heating fluid is negative and that of the heated medium is positive, the sum of entropy changes of all substances involved in the heat transfer process is always positive. These sums, known as entropy increase (entropy generation), can be interpreted as the measure of irreversible degradation of energy in heat transfer processes. The consequence of this degradation is that an arbitrary engine powered by the degraded (lower-temperature) heat flux will operate at a lower efficiency. The significance of this discussion relates especially to cases in power plants and cooling systems where ∗Corresponding Author. Email: drozd@imp.gda.pl","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":"43014538","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: 0

Numerical study of flow maldistribution in plate heat exchangers used for evaporation process 蒸发用板式换热器内流动不均匀的数值研究

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2019.129994

Paweł Płuszka, Arkadiusz Brenk, Z. Malecha

引用次数: 1

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

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

Energetic and exergetic analysis of a triple-pressure reheat combined cycle power using different primary movers 使用不同原动机的三压再热联合循环动力的能量和运动分析

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2019.129543

A. Almutairi, Hamad Alhajeri, A. Alenezi

引用次数: 0

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

A universal model for solar radiation exergy accounting: Case study of Tunisia 太阳辐射火用计算的通用模型:以突尼斯为例

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2022.141980

D. Lounissi, N. Bouaziz

{"title":"A universal model for solar radiation exergy accounting: Case study of Tunisia","authors":"D. Lounissi, N. Bouaziz","doi":"10.24425/ather.2022.141980","DOIUrl":"https://doi.org/10.24425/ather.2022.141980","url":null,"abstract":"The global solar radiation is the origin for all environmental processes on the earth and the majority of energy sources are derived from it. The data of solar radiation are required for the design and the study of solar application systems. The more important is the quality of the solar radiation which is deﬁned by the maximum work can be provided by the solar radiation. This quality is measured by the exergy content of a solar radiation. In the present work, a universal pattern has been built to provide a prediction of solar exergy dependently to the geographic location. Fitting models have been developed for exergy account depending on geographic location, based on the linear, quadratic, cubic, logarithmic, exponential, power regression. The Petela model is adopted from literature for exergetic eﬃciency accounting of solar radiation. The global solar radiation according to ASHRAE model is expressed dependently of the cosine of zenith angle. The developed model is applied on Tunisia regions to predict exergy solar potential. The studied regions are classiﬁed regarding the exergy account, high, medium and low solar exergy locations. Results show that generally the solar radiation shows a low degree of exergy content, about 7% of diﬀerence.","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":"43652475","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: 5

Generalized thermal microstretch elastic solid with harmonic wave for mode-I crack problem 具有谐波的广义热微拉伸弹性固体I型裂纹问题

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ATHER.2020.133626

K. Lotfy, A. El-Bary, M. Allan, M. H. Ahmed

引用次数: 2