International Journal of Thermophysics最新文献_第3页

Stability Optimization of Al2O3/SiO2 Hybrid Nanofluids and a New Correlation for Thermal Conductivity: An AI-Supported Approach 基于ai的Al2O3/SiO2杂化纳米流体稳定性优化及导热系数新相关性研究

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-12-18 DOI: 10.1007/s10765-024-03487-0

Fevzi Sahin

{"title":"Stability Optimization of Al2O3/SiO2 Hybrid Nanofluids and a New Correlation for Thermal Conductivity: An AI-Supported Approach","authors":"Fevzi Sahin","doi":"10.1007/s10765-024-03487-0","DOIUrl":"10.1007/s10765-024-03487-0","url":null,"abstract":"<div><p>Due to their high thermal conductivity compared to traditional coolants, nanofluids are preferred; however, their high thermal conductivity alone is meaningless without ensuring their stability. Therefore, when determining the appropriate mixing ratio (hybrid ratio) for hybrid nanofluids, which are starting to replace mono nanofluids today, the primary factor to consider should be stability. In this study, sedimentation and zeta potential measurements, which are methods for evaluating stability, were used to assess the stabilities of mono Al<sub>2</sub>O<sub>3</sub>/water and SiO<sub>2</sub>/water nanofluids with mass fractions of 1 %, 2 %, and 3 %, as well as hybrid Al<sub>2</sub>O<sub>3</sub>/SiO<sub>2</sub>/water (2 % to 1 %, 1 % to 2 %) nanofluids together for the first time in the literature, and the optimum Al2O<sub>3</sub>/SiO<sub>2</sub> hybrid ratio was determined in terms of stability. The results showed that the optimal hybrid ratios for the stability of Al<sub>2</sub>O<sub>3</sub>–SiO<sub>2</sub>/water nanofluids are 1 and 0.714. Furthermore, the thermal conductivities of stable mono and hybrid nanofluids were measured between 25 and 60 °C, and a new correlation valid for both mono and hybrid nanofluids was proposed by modeling with artificial neural networks (MSE = 8.2175E−5 and <i>R</i><sup>2</sup> = 0.99958), with a maximum deviation ratio of 3.839 % (for mono SiO<sub>2</sub>/water) from the experimental measurements.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142845117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Dynamic Viscosity and Specific Heat Capacity of Near Eutectic Gallium–Indium–Tin Alloy 近共晶镓铟锡合金的动态粘度和比热容

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-12-17 DOI: 10.1007/s10765-024-03471-8

M. H. Buschmann, S. Feja, R. Künanz, C. Hanzelmann, R. Mondragón, L. Hernández, M. J. V. Lourenço, F. J. V. Santos, V. Nunes, M. Alves, C. A. Nieto de Castro

{"title":"Dynamic Viscosity and Specific Heat Capacity of Near Eutectic Gallium–Indium–Tin Alloy","authors":"M. H. Buschmann, S. Feja, R. Künanz, C. Hanzelmann, R. Mondragón, L. Hernández, M. J. V. Lourenço, F. J. V. Santos, V. Nunes, M. Alves, C. A. Nieto de Castro","doi":"10.1007/s10765-024-03471-8","DOIUrl":"10.1007/s10765-024-03471-8","url":null,"abstract":"<div><p>The study presents experimental data of the viscosity and specific heat capacity of the near eutectic gallium–indium–tin alloy. Viscosity data cover the temperature range from the alloy’s melting point of 283.85 K (10.70 °C) to about 370.47 K (97.32 °C). Two independent teams using a capillarity viscosimeter and an oscillating cup viscosimeter obtained almost identical values. Below 373 K (100 °C) the data follow the Arrhenius correlation. Specific heat capacity data result from differential scanning calorimetry measurements and reach from 236 K (− 37 °C) to 340 K (67 °C). The Neumann–Kopp rule gives neither the solid nor the liquid state a satisfactory representation of the data. Approximation functions represent these two regions separately in an excellent manner. The study discusses several issues related to the thermophysical properties, namely melting and crystallisation, and a possible liquid-to-liquid crossover.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Reference Correlations of the Viscosity and Thermal Conductivity of Acetone from the Triple Point to High Temperatures and Pressures 丙酮的粘度和热导率从三相点到高温高压的参考相关性

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-12-04 DOI: 10.1007/s10765-024-03465-6

Sofia G. Sotiriadou, Eleftheria Ntonti, Marc J. Assael, Marcia L. Huber

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A Breakthrough in Penta-Hybrid Nanofluid Flow Modeling for Heat Transfer Enhancement in a Spatially Dependent Magnetic Field: Machine Learning Approach 空间依赖磁场中强化传热的五元混合纳米流体流动模型的突破：机器学习方法

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-12-04 DOI: 10.1007/s10765-024-03467-4

Shabbir Ahmad, Kashif Ali, Hafiz Humais Sultan, Fareeha Khalid, Moin-ud-Din Junjua, Farhan Lafta Rashid, Humberto Garcia Castellanos, Yashar Aryanfar, Tamer M. Khalaf, Ahmed S. Hendy

{"title":"A Breakthrough in Penta-Hybrid Nanofluid Flow Modeling for Heat Transfer Enhancement in a Spatially Dependent Magnetic Field: Machine Learning Approach","authors":"Shabbir Ahmad, Kashif Ali, Hafiz Humais Sultan, Fareeha Khalid, Moin-ud-Din Junjua, Farhan Lafta Rashid, Humberto Garcia Castellanos, Yashar Aryanfar, Tamer M. Khalaf, Ahmed S. Hendy","doi":"10.1007/s10765-024-03467-4","DOIUrl":"10.1007/s10765-024-03467-4","url":null,"abstract":"<div><p>A versatile penta-hybrid nanofluid has been successfully developed by combining silver (Ag), single-walled carbon nanotubes (SWCNTs), titanium dioxide (TiO<sub>2</sub>), copper (Cu), and iron oxide (Fe<sub>3</sub>O<sub>4</sub>) nanoparticles with a base fluid. This nanofluid is utilized in a range of advanced applications, including coatings, sensors, energy storage, water purification, enhanced heat transfer, biomedical uses, and lubricants. The synergistic properties of these nanoparticles significantly enhance the performance of the base fluid, offering substantial benefits across various industries. Therefore, this study delves into the influence of localized magnetic fields, augmented by machine learning, on vortex dynamics under the light of penta-hybrid nanofluid flow, confined in a horizontal cavity with a 2:1 aspect ratio. The Stream-Vorticity formulation tackles the dimensionless governing partial differential equation. Single-phase model has been employed to model the nanofluid. An Alternating Direction Implicit (ADI) technique has been employed to address the governing equations. The research highlights a significant increase in the Nusselt number (<i>Nu</i>) with intensified magnetic fields. Additionally, introducing more nanoparticles enhances <i>Nu</i> with varied effects for different particles. Silver (Ag) and Copper (Cu) exhibit the highest increase in Nu (53%), indicating robust thermal-fluid coupling, while Titanium Dioxide (TiO<sub>2</sub>) shows lower increases (37%), implying weaker coupling in the flow. These findings hold relevance for diverse applications, including transportation, energy, medical technology, materials science, and fundamental physics.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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A Comprehensive Numerical Analysis on the Thermo-hydraulic Performance of U-Bend Tube with Spherical Dimple of Shell-and-Tube Heat Exchanger Subjected to Uniform/Non-uniform Magnetic Fields 均匀/非均匀磁场作用下管壳式换热器带球形凹窝u型弯管热工性能综合数值分析

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-12-02 DOI: 10.1007/s10765-024-03452-x

Emrehan Gürsoy, Engin Gedik, Alina Adriana Minea

{"title":"A Comprehensive Numerical Analysis on the Thermo-hydraulic Performance of U-Bend Tube with Spherical Dimple of Shell-and-Tube Heat Exchanger Subjected to Uniform/Non-uniform Magnetic Fields","authors":"Emrehan Gürsoy, Engin Gedik, Alina Adriana Minea","doi":"10.1007/s10765-024-03452-x","DOIUrl":"10.1007/s10765-024-03452-x","url":null,"abstract":"<div><p>Heat exchangers are widely used in most heat transfer applications, and further improvements are necessary to limit the growing energy demand. In this context, performance improvement studies of shell-and-tube heat exchangers have gained importance. Although many studies have been conducted on this heat exchanger in the literature, research on the Utube channels remain limited. To address this gap in the literature, a detailed investigation of energy, entropy, and exergy analysis was conducted on this geometry using numerical methods. Both passive and active heat transfer enhancement methods were utilized to improve the thermo-hydraulic performance of the U-tube. As a passive method, dimpled fins and MWCNT-Fe<sub>3</sub>O<sub>4</sub>/water hybrid nanofluid at volume fractions of 0.001 and 0.003 were employed. As an active method, DC and AC (f = 2 Hz and square wave) magnetic fields with strengths of B = 0.16 T and 0.30 T were applied. The flow conditions in the analysis corresponded to the laminar flow regime at Dean numbers of 117.1, 175.7, and 234.2. Effects of hybrid nanofluid fractions, U-tube positions, flow regime, magnetic field strength, and current type on each other were discussed and compared in detail with previous results. Findings were carefully evaluated, and conclusions were drawn in the context of similar research. Results indicated that the U-tube position did not affect thermo-hydraulic performance. However, it was calculated that dimpled finned U-tube increased convective heat transfer by up to 30% compared to plain U-tube. Moreover, MWCNT-Fe<sub>3</sub>O<sub>4</sub>/water hybrid nanofluid at 0.003 volume fraction increased this rate by an additional 5.0%.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142761872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Estimation of Effective Temperature-Dependent Thermal Properties of Glass Fiber-Reinforced Polymer for Air‐Core Reactor Insulation: A Case Study Using an Alternative Inverse Approach 用于气芯反应堆隔热材料的玻璃纤维增强聚合物随温度变化的有效热性能估算：使用另一种逆方法的案例研究

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-11-28 DOI: 10.1007/s10765-024-03468-3

Mariana de Melo Antunes, Nícolas Pinheiro Ramos, Luiz Augusto Pereira de Abreu, Hugo Barbosa Faco, Sandro Metrevelle Marcondes de Lima e Silva

{"title":"Estimation of Effective Temperature-Dependent Thermal Properties of Glass Fiber-Reinforced Polymer for Air‐Core Reactor Insulation: A Case Study Using an Alternative Inverse Approach","authors":"Mariana de Melo Antunes, Nícolas Pinheiro Ramos, Luiz Augusto Pereira de Abreu, Hugo Barbosa Faco, Sandro Metrevelle Marcondes de Lima e Silva","doi":"10.1007/s10765-024-03468-3","DOIUrl":"10.1007/s10765-024-03468-3","url":null,"abstract":"<div><p>Fiber-reinforced polymers are crucial for insulating electrical equipment, necessitating accurate thermal property data for an effective thermal analysis. This case study uses a cost-effective method to thermally characterize a glass fiber-reinforced epoxy resin used in air-core reactor insulation. The approach simultaneously estimates temperature-dependent thermal conductivity (<i>k</i>) and specific heat (<i>c</i><sub><i>p</i></sub>) for class H/180 insulation. By analyzing transient heat conduction in a 3D composite sample under vacuum and at various temperatures, the method optimizes sensor placement, enabling accurate property estimation with a single thermocouple. The estimated through-thickness thermal conductivity at room temperature deviates by less than 6% from standard guarded hot plate measurements. The method’s reliability is confirmed by accurately retrieving the applied heat flux using the estimated properties and measured temperature data. The results are valuable for designing accurate simulation models to predict and manage the thermal behavior of air-core reactors, as implemented by GE Grid Solutions in Itajubá, Brazil.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"45 12","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142737169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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A Helmholtz Energy Equation of State for Calculations of Thermodynamic Properties of trans-1,2-Difluoroethene [R-1132(E)] 用于计算反式-1,2-二氟乙烯[R-1132(E)]热力学性质的亥姆霍兹能量状态方程

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-11-28 DOI: 10.1007/s10765-024-03447-8

Ryo Akasaka, Eric W. Lemmon

{"title":"A Helmholtz Energy Equation of State for Calculations of Thermodynamic Properties of trans-1,2-Difluoroethene [R-1132(E)]","authors":"Ryo Akasaka, Eric W. Lemmon","doi":"10.1007/s10765-024-03447-8","DOIUrl":"10.1007/s10765-024-03447-8","url":null,"abstract":"<div><p>This work presents a fundamental equation of state for calculations of the thermodynamic properties of R-1132(E), which is a potential refrigerant for residential or mobile air conditioners. The equation of state has a functional form expressed explicitly in the Helmholtz energy with temperature and density as the independent variables, and the form is fitted to consistent experimental datasets, including the critical parameters, vapor pressure, saturated liquid and vapor densities, <span>((p, rho , T))</span> behavior, vapor-phase sound speed, and ideal gas isobaric heat capacity. The equation of state is valid between temperatures from 240 K and 400 K, with pressures up to 6.5 MPa. In this range, expected relative uncertainties at the 95 % confidence interval (<span>(k=2)</span>) are 0.1 % for liquid densities, 0.4 % for vapor densities, and 0.1 % for vapor-phase sound speeds, except at the saturation states and in the critical region where larger deviations of up to 2 % are possible in densities due to higher experimental uncertainties. The uncertainty in calculated vapor pressures is 0.15 % above 275 K, which is larger at lower temperatures due to their small values. Various plots of derived properties from the equation of state show that the equation exhibits qualitatively correct behavior over wide ranges of temperature and pressure.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"45 12","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-024-03447-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142737231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Correct Use of the Transient Hot-Wire Technique for Thermal Conductivity Measurements on Solids 正确使用瞬态热线技术测量固体导热系数

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-11-28 DOI: 10.1007/s10765-024-03460-x

Konstantinos D. Antoniadis, Marc J. Assael, William A. Wakeham

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Correction to: Optical (n(p, T_{90})) Measurement Suite 1: He, Ar, and (hbox {N}_2) Correction to：光学(n(p, T_{90}))测量套件 1：He、Ar 和（hbox {N}_2)

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-11-28 DOI: 10.1007/s10765-024-03473-6

Patrick F. Egan, Yuanchao Yang

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Developing a Control Strategy for Minimum Airflow Setting Considering CO2 Level and Energy Consumption in a Variable Air Volume System 在考虑二氧化碳水平和能耗的情况下，开发变风量系统中最小风量设置的控制策略

IF 2.5 4区工程技术

International Journal of Thermophysics Pub Date : 2024-11-26 DOI: 10.1007/s10765-024-03474-5

Jong Man Lee, Kwang Ho Lee, Jin Woo Moon, Sang Hoon Lee, Tianzhen Hong

{"title":"Developing a Control Strategy for Minimum Airflow Setting Considering CO2 Level and Energy Consumption in a Variable Air Volume System","authors":"Jong Man Lee, Kwang Ho Lee, Jin Woo Moon, Sang Hoon Lee, Tianzhen Hong","doi":"10.1007/s10765-024-03474-5","DOIUrl":"10.1007/s10765-024-03474-5","url":null,"abstract":"<div><p>In an office building equipped with a Variable Air Volume (VAV) system, this paper introduces a novel method for controlling the minimum supply airflow fraction in each zone’s VAV box, having a capability to consider indoor CO<sub>2</sub> level and energy consumption. The EnergyPlus simulation using the medium office prototype model was employed, which evaluated the performance of the energy and CO<sub>2</sub> concentration for five VAV box airflow control strategies. The paper focuses on CO<sub>2</sub> concentration-based airflow control method and compares it with other four methods including conventional single-max, reduced minimum single-max, demand-controlled ventilation(DCV), and dualmax control methods according to guidelines and common practices. The newly proposed control strategy directly correlates the minimum airflow fraction to CO<sub>2</sub> concentration. A general trend emerged when comparing CO<sub>2</sub> concentrations—lower minimum airflow fractions were associated with higher concentrations. The proposed control method effectively maintained low CO<sub>2</sub> concentrations and enabled a lower airflow fraction contributing to energy consumption reduction. It was confirmed that heating energy consumption in climate zone 4A, 5B, and 6A showed a maximum saving of approximately 30% compared to the conventional single-max and dual max control strategies. It was found that cooling energy consumption in climate zone 4A and 6A can achieve a maximum saving of approximately 10% compared to the conventional control strategies. The proposed CO<sub>2</sub> concentration-based control logic is promising as it not only improves the indoor air quality lowering the CO<sub>2</sub> concentration in the occupied spaces, but also contributes to HVAC energy savings.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"45 12","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142714426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0