Archives of Thermodynamics最新文献_第8页

Partially transient one-dimensional thermal-flow model of a heat exchanger, upwind numerical solution method and experimental verification 换热器部分瞬态一维热流模型、迎风数值求解方法及实验验证

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2022.144406

D. Kardaś, Izabela WARDACH-ŚWIĘCICKAa, Artur Grajewski, A. Grajewski

{"title":"Partially transient one-dimensional thermal-flow model of a heat exchanger, upwind numerical solution method and experimental verification","authors":"D. Kardaś, Izabela WARDACH-ŚWIĘCICKAa, Artur Grajewski, A. Grajewski","doi":"10.24425/ather.2022.144406","DOIUrl":"https://doi.org/10.24425/ather.2022.144406","url":null,"abstract":"Shell and tube heat exchangers are commonly used in a wide range of practical engineering. The key issue in such a system is the heat exchange between the hot and cold working media. An increased cost of production of these devices has forced all manufacturing companies to reduce the total amount of used materials by better optimizing their construction. Numerous studies on the heat exchanger design codes have been carried out, basically focusing on the use of fully time-dependent partial diﬀerential equations for mass, momentum, and energy balance. They are very complex and time-consuming, especially when the designers want to have full information in a full 3D system. The paper presents the 1D mathematical model for analysis of the thermal performance of the counter-current heat exchanger comprised of mixed time-dependent and time-independent equations, solved by the upwind numerical solution method, which allows for a reduction in the CPU time for obtaining the proper solution. The comparison of numerical results obtained from an in-house program called Upwind Heat Exchanger Solver written in a Fortran code, with those derived using commercial software package ASPEN, and those obtained experimentally, shows very good agreement in terms of the temperature and pressure distribution predictions. The proposed method for fast designing calculations appears beneﬁcial for other tube shapes and types of heat exchangers.","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":"48068674","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

Passive cooling through the atmospheric window for vehicle temperature control 通过大气窗进行被动冷却以控制车辆温度

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2021.138108

U. Khan, R. Zevenhoven

{"title":"Passive cooling through the atmospheric window for vehicle temperature control","authors":"U. Khan, R. Zevenhoven","doi":"10.24425/ather.2021.138108","DOIUrl":"https://doi.org/10.24425/ather.2021.138108","url":null,"abstract":"One of the most energy-intensive activities for a vehicle is space air conditioning, for either cooling or heating. Considerable energy savings can be achieved if this can be decoupled from the use of fuel or electricity. This study analyzes the opportunities and eﬀectiveness of deploying the concept of passive cooling through the atmospheric window (i.e. the 8– 14 µ m wavelength range where the atmosphere is transparent for thermal radiation) for vehicle temperature control. Recent work at our institute has resulted in a skylight (roof window) design for passive cooling of building space. This should be applicable to vehicles as well, using the same materials and design concept. An overall cooling eﬀect is obtained if outgoing (long wavelength greater than 4 µ m) thermal radiation is stronger than the incoming (short wavelength less than 4 µ m) thermal radiation. Of particular interest is to quantify the passive cooling of a vehicle parked under direct/indirect sunlight equipped with a small skylight, designed based on earlier designs for buildings. The work involved simulations using commercial computational ﬂuid dynamics software implementing (where possible) wavelength-dependency of thermal radiation properties of materials involved. The ﬁndings show that by the use of passive cooling, a temperature diﬀerence of up to 7–8 K is obtained with an internal gas ﬂow rate of 0.7 cm/s inside the sky-light. A passive cooling eﬀect of almost 27 W/m 2 is attainable for summer season in Finland. Comparison of results from Ansys Fluent and COMSOL models shows diﬀerences up to about 10 W/m 2 in the estimations.","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":"49517077","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

An experimental study of solar air heater using arc shaped wire rib roughness based on energy and exergy analysis 基于能量和火用分析的弧形丝肋粗糙度太阳能空气加热器实验研究

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2021.138112

Harish Kumar Ghritlahre

{"title":"An experimental study of solar air heater using arc shaped wire rib roughness based on energy and exergy analysis","authors":"Harish Kumar Ghritlahre","doi":"10.24425/ather.2021.138112","DOIUrl":"https://doi.org/10.24425/ather.2021.138112","url":null,"abstract":"In the present study, energy and exergy analysis has been evaluated for roughened solar air heater (SAH) using arc shaped wire ribs. To achieve this aim, two diﬀerent types of ﬂow arrangement have been considered. These arrangements are: apex upstream ﬂow and apex downstream ﬂo. In addition to this, a smooth duct SAH has been used for comparative study. The experiments were performed using the mass ﬂow rate of 0.007– 0.022 kg/s on outdoor condition at Jamshedpur city of India. The absorber plate roughness geometry has been designed with relative roughness height 0.0395, rib size 2.5 mm, relative roughness pitch 10 and arc angle 60 ◦ . The energetic and exergetic performances have been examined on the basis of the ﬁrst and second law of thermodynamics. According to the results, there is observed to be the maximum thermal eﬃciency and exergy eﬃciency as 73.2% and 2.64%, respectively, for apex upstream ﬂow SAH at 0.022 kg/s, while, at same mass ﬂow rate the maximum thermal eﬃciency and exergy ef-ﬁciency is obtained as 69.4% and 1.89%, respectively, for apex downstream ﬂow SAH. In addition to this, results reported that the maximum outlet temperature and temperature diﬀerence observed at lower mass ﬂow rate. Also examined the outlet air temperature of SAH with various mass ﬂow rates is very important for both analysis.","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":"47027594","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

Research on oxy-fuel combustion power cycle using nitrogen for turbine cooling 利用氮气进行涡轮冷却的全氧燃烧动力循环研究

IF 0.9

Archives of Thermodynamics Pub Date : 2023-07-20 DOI: 10.24425/ather.2020.135859

V. Kindra, Rogalev, O. Zlyvko, A. Zonov, M. Smirnov, Ilya

引用次数: 4

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

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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