International Journal of Thermophysics最新文献

{"title":"The Laser Flash Technique: A Widespread Technology for Measurement of the Thermal Diffusivity of Solids and Liquids","authors":"Juergen Blumm","doi":"10.1007/s10765-025-03510-y","DOIUrl":"10.1007/s10765-025-03510-y","url":null,"abstract":"<div><p>Flash methods such as laser or light flash have developed to be one of the most commonly used techniques for measuring the thermal diffusivity and thermal conductivity of various kinds of solids such as metals, ceramics, polymers, graphite and composite materials. During a flash test, the front side of a plane-parallel specimen is heated by a short laser or light pulse. The resulting temperature rise on the rear surface of the specimen is measured versus time. By evaluating this temperature rise, the thermal diffusivity of material can be determined without requirement for any sensor calibration. Fast measurement times, easy adaption to carrying out temperature-dependent tests, easy specimen preparation, small specimen dimensions, and high reliability are only some of the advantages of this non-contact measurement technique. The method allows also for measurement of the specific heat capacity by a comparative method and therefore, thermal conductivity determination. This requires calibration of the signal height by employing a specific heat capacity standard material with comparable specimen geometries and surface emissivities. Since the introduction of the method in 1961, significant improvements have been made on the hardware, the mathematical treatment of the detector signals and the general instrument operation <i>via</i> the software. Presented in this work is an overview of the working principle, the mathematical background, the general uncertainty of the method, results of comparative tests and some typical application examples for the flash technique.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 3","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107951","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}

{"title":"Transport Property Predictions for CH4/H2/CO/CO2/N2/H2O Mixtures Based on Excluded Volume Without Fitting Parameters","authors":"Ali Aminian","doi":"10.1007/s10765-024-03482-5","DOIUrl":"10.1007/s10765-024-03482-5","url":null,"abstract":"<div><p>The knowledge of viscosity and thermal conductivity of molecular fluids in the dense phase, which could also accommodate mixture properties, are of great importance in chemical, aerospace, and syngas technology. In this study, we tend to offer a formulation that only needs “excluded volume” to calculate the transport properties for polyatomic fluids and fluid mixtures. The formulations allow calculation of transport properties over a wide range of temperature, pressure, and composition including the supercritical region. Based on the Chapman–Enskog equations, the low-density properties were taken to be corrected for the dense fluid region in which it has been proposed an excluded volume term whose value can be calculated using an equation of state, e.g., the Statistical Association Fluid Theory (SAFT) Equation of State (EoS). The models were tested for different mixtures comprising CH₄/H₂/CO/CO₂/N₂/H₂O molecules to calculate their transport properties over the entire fluid phase region. Furthermore, comparisons were made between the predicted values and existing experimental data or extended corresponding–states of law equation for mixtures.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 3","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108119","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}

{"title":"Enhancement of Thermal Conductivity of Paraffin PCM with Metal Foams","authors":"Eleonora Baccega,&nbsp;Laura Vallese,&nbsp;Michele Bottarelli","doi":"10.1007/s10765-024-03500-6","DOIUrl":"10.1007/s10765-024-03500-6","url":null,"abstract":"<div><p>Paraffin PCMs (Phase Change Materials) are widely used for thermal energy storage due to their homogeneity and stability. However, one of their main drawbacks lies in their poor thermal conductivity, usually around 0.2 W·m⁻¹·K⁻¹. In the context of the Horizon Europe project “ECHO” (Efficient Compact Modular Thermal Energy Storage System), the integration of metal foams within paraffin PCM was investigated in order to increase the overall thermal conductivity, thus speeding up the melting and solidification phases. Tests were carried out in a thermostatic bath using at first pure aluminum foam. Then, considering the consistent price these materials usually have, other commercial and much cheaper foams were also tested, namely a stainless-steel foam and a brass one. As expected, pure aluminum had the best performance among the three foams. However, the behavior of the brass foam was quite close to that of pure aluminum, which means that interesting improvements can be achieved even with low-cost materials. As regards the stainless-steel foam, barely any improvement is observed.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 3","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-024-03500-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110067","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}

{"title":"Densities, Speeds of Sound and Refractive Indices for Binary Mixtures of Acetonitrile + Alkyl-Substituted Butylbenzenes: Experimental and Modeling Study","authors":"Dana Drăgoescu,&nbsp;Ariel Hernández,&nbsp;Alexander Shchamialiou","doi":"10.1007/s10765-024-03496-z","DOIUrl":"10.1007/s10765-024-03496-z","url":null,"abstract":"<div><p>The experimental data of densities, <i>ρ</i>, speeds of sound, <i>u,</i> and refractive indices, <i>n</i>_D, are reported for three binary mixtures of acetonitrile + aromatic hydrocarbons, namely: acetonitrile + <i>n</i>-butylbenzene, acetonitrile + <i>sec</i>-butylbenzene and acetonitrile + <i>tert</i>-butylbenzene, respectively, at <i>T</i> = (298.15, 303.15, 308.15, 313.15, and 318.15) K, on the entire composition ranges and under atmospheric pressure, <i>p</i> = 0.1 MPa. The values obtained from experimental measurements have been correlated by the Jouyban-Acree model with good accuracy. The excess molar volumes, <span>({V}_{m}^{E})</span>, excess speeds of sound, <i>u</i>^E, excess isentropic compressibilities, <span>({kappa }_{S})</span>, excess molar isentropic compressibilities, <span>({K}_{S,m}^{E})</span>, refractive index deviations, Δ<i>n</i>_D, and excess molar refractions, <span>({R}_{m}^{E})</span>, have been calculated from experimental data. For each of the studied mixtures, the excess or deviation properties have been correlated with the Redlich–Kister polynomial equation and the coefficients of correlations were reported. In this manuscript, Perturbed Chain Statistical Associating Fluid Theory Equation of State (PC-SAFT EoS) was used for modeling the density as predictive approach. On the other hand, PC-SAFT + two models were used for calculate the speed of sound of binary mixtures, and PC-SAFT + four mixing rules were used for compute the refractive index of binary mixtures.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 3","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110038","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}

{"title":"Densities and Viscosities of Polyoxymethylene Dimethyl Ether with Methyl Decanoate, Methyl Dodecanoate, and Methyl Tetradecanoate","authors":"Guofan Jin,&nbsp;Jianrong Shi,&nbsp;Xiaopo Wang","doi":"10.1007/s10765-025-03506-8","DOIUrl":"10.1007/s10765-025-03506-8","url":null,"abstract":"<div><p>Both polyoxymethylene dimethyl ethers (OME_<i>n</i>) and biodiesel are considered as promising alternatives or additives to traditional fuels. The addition of OMEs to biodiesel can realize complementary advantages. The physical properties of OME_<i>n</i>, biodiesel, or OME_<i>n</i>/biodiesel blends are decisive for the performance of internal combustion engines. In this work, density and viscosity of mixtures of OME_<i>n</i> with three typical components of biodiesel (methyl decanoate, methyl dodecanoate, and methyl tetradecanoate) were measured from 303.15 K to 333.15 K at atmospheric pressure. The vibrating-tube method and capillary-tube method were used for the present density and viscosity measurement, respectively. The combined relative uncertainty is 0.1% for density and 1.5% for viscosity (<i>k</i> = 2). The experimental results were fitted by Jouyban-Acree model and McAllister model. Moreover, the excess properties of each mixture including excess molar volume and viscosity deviations were discussed.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 3","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110068","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}

{"title":"Hybrid Nanofluids-Based Direct Absorption Solar Collector: An Experimental Approach","authors":"Gabriela Huminic,&nbsp;Angel Huminic,&nbsp;Claudiu Fleacă,&nbsp;Florian Dumitrache","doi":"10.1007/s10765-025-03507-7","DOIUrl":"10.1007/s10765-025-03507-7","url":null,"abstract":"<div><p>In the last years, studies have demonstrated the potential of hybrid nanofluids to enhance the performance of direct absorption solar collectors. These working fluids containing noble metals (gold, silver) are known for their local surface plasmon resonance which is the main cause for the increased absorption within the solar spectrum. In the current paper, new direct absorption solar collectors prototypes using water-ethylene glycol solution and 0.1 wt.% silver nanoparticles + reduced graphene oxide dispersed in water-ethylene glycol mixture were designed, built, and tested under outdoor conditions, at two flow rates (1.0 and 1.5 l·min⁻¹) and two inlet temperatures (20 <span>(^circ{rm C})</span> and 30 <span>(^circ{rm C})</span>), over several days in September 2023, at Brasov, Romania. The results suggested that by using silver nanoparticles + reduced graphene oxide nanofluid, the efficiency is improved related to water-ethylene glycol solution. The maximum relative enhancement in efficiency was 16.72% related to the base fluid. Also, at 1.0 l·min⁻¹, the instantaneous and accumulative energies delivered were about 13.51% and 42.91%, respectively, higher than the water-ethylene glycol solution. Finally, the current results were compared to other research carried out on full-scale direct absorption solar collectors tested in outdoor conditions.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 3","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-025-03507-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110069","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}

{"title":"Performance Evaluation of PρT-SAFT, PρT-PC-SAFT, PC-SAFT, and CPA Equations of State for Predicting Density, Thermal Expansion Coefficient, Isothermal Compressibility, Isobaric Heat Capacity, Speed of Sound, and Saturated Vapor Pressure of Three Pure Ethylene Glycols and Their Mixtures","authors":"Arash Pakravesh,&nbsp;Amir H. Mohammadi,&nbsp;Dominique Richon","doi":"10.1007/s10765-025-03505-9","DOIUrl":"10.1007/s10765-025-03505-9","url":null,"abstract":"<div><p>Ethylene glycols are a group of versatile industrial solvents with broad applications across various sectors. Accurate thermodynamic modeling of these compounds is essential for enhancing their utilization and optimizing industrial processes. Among the advanced models available, the Statistical Associating Fluid Theory (SAFT) type equation of state (EoS) stands out for its effectiveness in capturing the thermodynamic behavior of complex fluids. This study employs the PρT-SAFT, PρT-PC-SAFT, PC-SAFT, and CPA EoSs to model pure monoethylene glycol (MEG), diethylene glycol (DEG), triethylene glycol (TEG), and their mixtures. Furthermore, the predictive capabilities of these models are critically evaluated for polyethylene glycol 400 (PEG 400). The performance of the PρT-SAFT, PρT-PC-SAFT, PC-SAFT, and CPA EoSs was evaluated for predicting key thermodynamic properties, including density, thermal expansion coefficient, isothermal compressibility, isobaric heat capacity, speed of sound, and saturated vapor pressure, for pure MEG, DEG, TEG, and PEG 400. Among the models, the PρT-SAFT demonstrated superior accuracy in modeling their properties. Subsequently, the volumetric properties and vapor–liquid equilibrium data of binary mixtures of MEG, DEG, and TEG were predicted using the same EoSs, without incorporating any binary interaction parameters. Under these conditions, the PρT-SAFT achieved the highest accuracy. Furthermore, predictions of the volumetric properties for the ternary mixture of MEG, DEG, and TEG also indicated that the PρT-SAFT outperformed the other models. The overall average absolute deviation percentages for the PρT-SAFT, PρT-PC-SAFT, PC-SAFT, and CPA EoSs across all examined thermodynamic properties and systems were 7.0, 8.2, 22.2, and 30.2, respectively, confirming the robustness of the PρT-SAFT.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-025-03505-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109784","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}

{"title":"Design of Perlite Based Thermal Insulation Plate and Determination of its Physical, Mechanical and Thermal Properties","authors":"Metin Davraz,&nbsp;Murat Koru,&nbsp;Nuri Isildar","doi":"10.1007/s10765-025-03503-x","DOIUrl":"10.1007/s10765-025-03503-x","url":null,"abstract":"<div><p>According to the current fire regulations in Turkey, the use of insulation materials such as EPS, which are commonly employed in building insulation, is limited to buildings up to 28.5 m in height. The regulations mandate the use of Class A fire-resistant thermal insulation materials in high-rise buildings. However, these materials may present challenges in terms of application and sustainability. This study aims to develop a perlite-based thermal insulation board that is Class A fire-resistant, competitive with traditional insulation materials, and possesses optimal physical, mechanical, and thermal properties. In the production of the specimens, expanded perlite, liquid sodium silicate, and silicon powder were used, and tests for apparent density, compressive-flexural strength, capillary water absorption, and thermal conductivity were conducted in accordance with EN standards. In the first stage, the produced specimens were subjected to four different activation temperatures to determine the optimal process temperature. In the second stage, the ratios of perlite, sodium silicate, and water were varied to achieve the mixture design that yielded the highest mechanical properties from the specimens. In the final stage, water-repellent admixtures were incorporated into the batches at mass ratios of 1.5 %, 3 %, 4.5 %, and 6 %. The perlite-based thermal insulation board, which offers optimal properties in the most cost-effective manner, has an apparent density of 127 kg·m⁻³, compressive strength of 266 kPa, flexural strength of 156 kPa, capillary water absorption value of 0.0197 kg·m⁻²·min^−0.5, thermal conductivity of 0.0475 Wm⁻¹·K⁻¹, and a unit cost of 97 $ m⁻³. Consequently, the insulation board developed in this study presents a viable alternative to conventional insulation materials, offering Class A fire resistance.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 3","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-025-03503-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109301","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}

{"title":"Symbolic-Regression Aided Development of a New Cubic Equation of State for Improved Liquid Phase Density Calculation at Pressures Up to 100 MPa","authors":"Xiaoxian Yang,&nbsp;Ophelia Frotscher,&nbsp;Markus Richter","doi":"10.1007/s10765-024-03490-5","DOIUrl":"10.1007/s10765-024-03490-5","url":null,"abstract":"<div><p>For over a century, cubic equations of state (EoS) have been used to calculate density and phase equilibria of pure fluids and mixtures. Despite a century’s development with hundreds of resulting cubic EoS, their accuracy in liquid phase density calculations is still unsatisfactory. In this work, a new cubic EoS was developed to improve the accuracy of liquid phase density calculation while keeping similar accuracy of other properties. The new cubic EoS, named YFR (Yang-Frotscher-Richter) EoS, was developed based on the functional form of the Patel–Teja (PT) EoS [<i>p</i> = <i>RT</i>/(<i>v</i> − <i>b</i>) − <i>a</i>/(<i>v</i>(<i>v</i> + <i>b</i>) + <i>c</i>(<i>v</i> − <i>b</i>)]. In the PT EoS, parameters <i>b</i> and <i>c</i> are linked to an empirical critical compressibility factor <i>ξ</i>_c, and all these three parameters are constants for a pure fluid. By contrast, in the YFR EoS, <i>ξ</i>_c, <i>b</i>, and <i>c</i> are functions of temperature, and the equations describing this dependency were developed with symbolic regression. This is the key to improving liquid phase density calculation, although it leads to thermodynamic inconsistencies at high pressures. The application range of the new cubic EoS is thus limited to pressures up to 100 MPa. The YFR EoS was developed using nearly all pure fluids available in NIST’s REFPROP 10.0 database, with reference values computed with REFPROP. The average of the absolute value of relative deviations (AARD) of liquid phase densities calculated with the YFR EoS from reference values is approximately 2 %, compared to 3 % when using the Patel–Teja–Valderrama (PTV) EoS and 6 % when using the Peng-Robinson (PR) EoS. The YFR EoS has been implemented in our self-developed OilMixProp 1.0 software package.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10765-024-03490-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109785","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}

{"title":"Thermophysical Properties of the Methyl tert-Butyl Ether + Benzene + n-Hexane Ternary System within the Temperature Range (293.15–313.15) K and Under Ambient Pressure: An Experimental and Modeling Approach","authors":"Altin Gjevori,&nbsp;Artan Llozana,&nbsp;Arbër Zeqiraj,&nbsp;Ariel Hernández,&nbsp;Naim Syla,&nbsp;Fisnik Aliaj","doi":"10.1007/s10765-025-03502-y","DOIUrl":"10.1007/s10765-025-03502-y","url":null,"abstract":"<div><p>Experimental densities and sound speeds at temperatures (293.15, 298.15, 303.15, and 313.15) K and under ambient pressure conditions are reported for the first time for the ternary system {MTBE + benzene + <i>n</i>-hexane} covering the entire composition range. The corresponding binary subsystems have also been studied. The excess molar volume and excess isentropic compressibility, derived from experimental density and sound speed data, were correlated using Redlich-Kister and Cibulka equations for binary and ternary systems, respectively. The composition and temperature dependence of these properties provided insights into the nature of molecular interactions and structural effects within the mixtures. The Perturbed Chain Statistical Associating Fluid Theory Equation of State was used to model the densities of both binary and ternary mixtures using a predictive approach. Schaaff’s Collision Factor Theory and Nomoto’s relation modeled the sound speeds. Further, this work utilized the Jouyban–Acree model to represent the composition and temperature dependence of experimental densities and sound speeds of the studied binary and ternary mixtures. Finally, the ternary excess properties are compared with the predicted values from binary contribution symmetric (Kohler and Muggianu) and asymmetric (Hillert and Toop) geometric models. The accuracy of the theoretical and empirical models was assessed by computing various statistical indicators.</p></div>","PeriodicalId":598,"journal":{"name":"International Journal of Thermophysics","volume":"46 2","pages":""},"PeriodicalIF":2.5,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143108897","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}