Subjects -> PHYSICS (Total: 857 journals)
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    - THERMODYNAMICS (30 journals)

THERMODYNAMICS (30 journals)

Showing 1 - 29 of 29 Journals sorted alphabetically
Advances in Heat Transfer     Full-text available via subscription   (Followers: 26)
Applied Thermal Engineering     Hybrid Journal   (Followers: 41)
Araucaria. Revista Iberoamericana de Filosofía, Política y Humanidades     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 9)
Chemical Thermodynamics and Thermal Analysis     Open Access   (Followers: 7)
Condensed Matter Physics     Open Access   (Followers: 2)
Diffusion Foundations     Full-text available via subscription   (Followers: 4)
European Journal of Mechanics - B/Fluids     Hybrid Journal   (Followers: 5)
Experimental Heat Transfer     Hybrid Journal   (Followers: 17)
Experimental Thermal and Fluid Science     Hybrid Journal   (Followers: 34)
Fluids     Open Access   (Followers: 1)
Heat and Mass Transfer     Hybrid Journal   (Followers: 28)
Heat Transfer Engineering     Hybrid Journal   (Followers: 37)
High Temperature     Hybrid Journal   (Followers: 2)
HTM Journal of Heat Treatment and Materials     Full-text available via subscription   (Followers: 3)
International Journal of Thermodynamics     Open Access   (Followers: 11)
International Journal of Thermophysics     Hybrid Journal   (Followers: 7)
Journal of Thermodynamics & Catalysis     Open Access   (Followers: 6)
Journal of Chemical Thermodynamics     Hybrid Journal   (Followers: 4)
Journal of Low Temperature Physics     Hybrid Journal   (Followers: 8)
Journal of Non-Newtonian Fluid Mechanics     Hybrid Journal   (Followers: 16)
Journal of Thermal Science     Hybrid Journal   (Followers: 21)
Journal of Thermal Spray Technology     Hybrid Journal   (Followers: 5)
Journal of Thermodynamics     Open Access   (Followers: 7)
Journal of Thermophysics and Heat Transfer     Hybrid Journal   (Followers: 93)
Low Temperature Physics     Hybrid Journal   (Followers: 6)
Metal Science and Heat Treatment     Hybrid Journal   (Followers: 36)
Quantitative InfraRed Thermography Journal     Hybrid Journal  
Thermophysics and Aeromechanics     Hybrid Journal   (Followers: 6)
Similar Journals
Journal Cover
International Journal of Thermophysics
Journal Prestige (SJR): 0.417
Citation Impact (citeScore): 1
Number of Followers: 7  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1572-9567 - ISSN (Online) 0195-928X
Published by Springer-Verlag Homepage  [2468 journals]
  • An Equation of State for the Thermodynamic Properties of Fluid n-Butane in
           the Critical Region

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      Abstract: Abstract An equation of state that predicts the critical thermodynamic behavior of n-butane is formulated. This equation takes into account the global behavior that includes the singular thermodynamic behavior asymptotically close to the critical point and the crossover to the regular thermodynamic behavior far away from the critical point. The formulated equation is based on the transformation of a truncated classical Landau expansion and represents the thermodynamic properties of n-butane in a wide range of temperatures and densities around the critical point. A comparison of the pressure P–ρ–T data measured by Beattie and co-workers and those calculated with the crossover EOS is made. Finally, the specific heat at constant volume, Cv, for n-butane along the critical density within a restricted temperature interval around the critical point is presented.
      PubDate: 2024-04-09
       
  • Biosurfactant Augmented Characterization and Heat Transport Assessment of
           MWCNT-H2O Nanofluid in Solar Collector

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      Abstract: Abstract This study presents a comparative analysis of the thermal performance of a flat plate solar collector featuring deionized water and MWCNT-water nanofluid with Gum Arabic, a bio-surfactant. A two-step method is adopted to formulate the nanofluid, which is utilized as a heat transport fluid to improve the thermal performance of a flat plate solar collector. A zeta potential analyzer is employed to characterize the nanofluid. The collector consists of a copper tube heat exchanger for closed-loop cyclic operation. Temperature, pressure and flow rate measurements are carried out. The comparative collector efficiency is investigated at 0.50 and 0.94 lpm flow rates and at MWCNT concentrations of 0.05 and 0.10 wt%, respectively. The thermal conductivity of the MWCNT-water nanofluid with Gum Arabic bio-surfactant exhibited a higher value than that of the SDS surfactant. The absorbed and removed energy parameters at 0.5 lpm for MWCNT-water (0.10 wt%) are found to be increased by 50.42% and 158.75%, respectively, when compared to the corresponding values obtained for DI water. The distribution of collector efficiency with time during the peak hours with maximum solar radiations suggests that a maximum thermal efficiency of 61% can be achieved for 0.94 lpm and 0.10 wt% of MWCNT nanoparticles.
      PubDate: 2024-04-09
       
  • Enthalpy and Heat Capacity of Cs–Pb Alloys in Solid and Liquid
           States

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      Abstract: Abstract The enthalpy of Cs–Pb system alloys containing 40, 50, 60, and 66.67 at.% Pb have been measured and heat capacity have been determined using high-temperature drop calorimetry method over a temperature range 430–1075 K covering solid and liquid phases. For all alloys, recommended temperature dependences of the studied properties have been developed as well as the enthalpy changes on phase transitions and the liquidus temperature have been determined. The concentration dependence of the heat capacity of Cs–Pb liquid alloys at different temperatures has been constructed, at which the pronounced maximum is observed at a content of 50 at.% Pb. A significant excess of the heat capacity of the studied melts over additive values is revealed. It is shown that the results obtained are consistent with the assumptions in the literature about the formation of structural units with a partially ionic character of interatomic interaction in melts of the Cs–Pb system.
      PubDate: 2024-04-09
       
  • Heat Transfer Performance Study on Several Composite Phase Change
           Materials for Battery Thermal Management

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      Abstract: Abstract Lithium battery temperatures will increase if the heat produced during the charging and discharging procedures is not promptly vented externally. Fewer investigations have been conducted on materials that can retain good flexibility at room temperature and shape stability at high temperatures under the existing thermal management system for phase change materials (PCM). In this study, a particular kind of flexible composite PCM (CPCM) at room temperature is created to address the issue of heat transfer between the PCM and the power battery. The characteristics of hardness, room-temperature flexibility, form stability at high temperature, and thermal conductivity are compared with those of three other thermally induced flexible CPCMs. The flexibility at room temperature of the new CPCM is demonstrated by the results, which makes assembly easier and helps further lower the contact thermal resistance. Charge–discharge test comparisons of the battery modules employing the chosen CPCM and thermally induced CPCM are performed to further evaluate their thermal management capabilities. The thermally induced CPCM exhibits larger maximum temperature profiles at the discharge rates of 1C, 2C, and 3C than the room-temperature flexible CPCM. The variations in maximum temperatures are 0.96, 1.48, and 2.08 °C.
      PubDate: 2024-04-06
       
  • Correct Use of Oscillating-Cup Viscometers for High-Temperature Absolute
           Measurements of Newtonian Melts

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      Abstract: Abstract Oscillating-body viscometers have been used in the past to measure, in an absolute way, the viscosity of molten materials at high temperatures, from salts, metals, alloys, and semiconductors. However, the simultaneous use of basic or incomplete mathematical models, to mimic the experiment, and less careful engineering solutions for the design and operation of the instruments, led in the past to high discrepancies between the data obtained in several laboratories. This was caused by the incorrect use of the method’s theory, less accurate solutions of the complex solutions, that involve solid state and fluid mechanics, and unreal instrument design. From these types of viscometers, oscillating-cup instruments have had the most success in measuring viscosity at high temperatures, and they will be the object of this paper. It was written as a resource for workers interested in transport properties of materials when considering its use for the absolute measurement of fluids viscosity in their work, or in judging the results of others' work when comparing data with their own. The paper starts with the most accurate theory of the method’s description, followed by a discussion of its validity, application to instrument design, and consequent operation. Several constraints were identified and recommendations were made to minimize the effects of failing to satisfy them. Finally, a discussion about the uncertainty budget calculations for a real experiment is made. If all these points are followed in the design and operation of the instrument, results in global uncertainties Ur(η) between 0.02 and 0.04 are possible to obtain, up to high temperatures. If these constraints are not satisfied, erroneous measurements can be made, making comparisons and quality assessment difficult.
      PubDate: 2024-04-05
       
  • Measurement and Empirical Models of Thermal Conductivity of
           Trifluoroiodomethane (CF3I)

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      Abstract: Abstract This research is focused on the experimental measurement of the thermal conductivity of CF3I and the subsequent development of empirical models, which are integral to engineering system design calculations. CF3I is identified as a potential key component in the formulation of future refrigerant mixtures, owing to its non-explosive nature, low toxicity, and minimal contribution to ozone layer depletion and global warming. Its applicability is further reinforced by its advantageous thermodynamic properties, including a low boiling point and a high critical temperature, making it a vital constituent in refrigerant mixtures. The study employs the well-established transient hot-wire method to measure the thermal conductivity of CF3I in both its liquid and vapor phases. This method is characterized by the sequential arrangement of two platinum wires which are linked in parallel to nullify any impacts from axial heat conduction. Experimental data were methodically gathered across a range of temperatures, spanning from 311 K to 374 K for the liquid phase and from 312 K to 394 K for the vapor phase, under varying pressures from 1.5 MPa to 4.0 MPa and 0.5 MPa to 3.0 MPa, respectively. The combined uncertainties associated with these measurements were meticulously calculated, amounting to 1.8% for the liquid phase and 2.0% for the vapor phase. Furthermore, the research advanced to the development of thermal conductivity models for CF3I, employing both the Extended Corresponding States method and the modified Residual Entropy Scaling method. These models effectively encapsulate the empirical findings, fitting within the established uncertainty limits with reasonable extrapolating behavior. Critically, these models are expected to play a pivotal role in predicting the thermal conductivity of refrigerant mixtures that incorporate CF3I as a component, marking a significant contribution to the field of refrigerant technology.
      PubDate: 2024-03-27
       
  • Fourier Transform Thermoreflectance Method Under Front-Heat Front-Detect
           Configuration

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      Abstract: Abstract The thermoreflectance method, which can measure thermal diffusivity in the cross-plane direction of thin films, mainly has two possible configurations; rear-heat front-detect (RF) and front-heat front-detect (FF) configuration. FF configuration is applicable to a wide variety of thin films including thin films deposited on opaque substrates, but this configuration has some problems in determination of the thermal diffusivity. One of the main problems is the effect of the penetration of pump beam and probe beam in thin film, which affects the initial temperature distribution near the sample’s surface after pulse heating. Several studies have tried to analyze the effect but there have been no practical analytical solutions which can solve this problem in FF configuration. In this paper, we propose a new analytical solution which considers the penetration of pump beam and probe beam into thin film, and by applying Fourier expansion analysis which we developed in a previous study to thermoreflectance signals, we have determined the thermal diffusivity of thin film in the thermoreflectance method under FF configuration. We measured platinum thin films with different thickness under both FF and RF configuration and obtained consistent thermal diffusivity values from both configurations.
      PubDate: 2024-03-25
       
  • Thermodynamic Property Measurements of Binary Refrigerant Blends
           HFO1123 + R290

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      Abstract: Abstract PVTx properties of 0.80 mass fraction HFO1123 + 0.20 mass fraction R290 and 0.65 mass fraction HFO1123 + 0.35 mass fraction R290 refrigerant blends were measured in the temperature range from 300 K to 400 K and at pressures up to 6.9 MPa by the isochoric method along 6 isochores for each blend including the vapor and liquid phases. The expanded uncertainties in temperature and pressure are estimated to be 5 mK and 1.0 kPa (k = 2). The relative expanded uncertainties in density and mass fraction are estimated to be 0.15% and 0.0005 (k = 2), respectively. Saturated densities of these blends were directly measured in the temperature range between 319 K and 342 K by the visual observation of the meniscus disappearance, and also determined from the inflection points of the PVTx isochore-lines. Finally, the critical points of the blends were determined by the consideration of the meniscus disappearing level as well as the intensity of the critical opalescence as Tc = 334.91 ± 0.01 K, ρc = 402 ± 3 kg·m−3 and Pc = 4392 ± 3 kPa for 0.80 mass fraction HFO1123 + 0.20 mass fraction R290, and Tc = 340.94 ± 0.02 K, ρc = 357 ± 3 kg·m−3 and Pc = 4429 ± 5 kPa for 0.65 mass fraction HFO1123 + 0.35 mass fraction R290. A Helmholtz energy equation of state (EOS) was compared with the experimental data, and is in good agreement with the obtained PVTx property data with an absolute average deviation (AAD) of 1.1% for 0.80 mass fraction HFO1123 + 0.20 mass fraction R290, and that of 0.7% for 0.65 mass fraction HFO1123 + 0.35 mass fraction R290 in density. In addition, vapor-liquid equilibrium data of HFO1123 + R290 blends were obtained from 263 K to 323 K based on the recirculation method. A mixing parameter of a simple cubic EOS was determined, and the EOS represents the VLE data with an AAD of 0.73% in pressure and 0.010 mol·mol−1 in mole fraction.
      PubDate: 2024-03-25
       
  • Measurements of the Viscosity of Hydrogen and a (Hydrogen + Methane)
           Mixture with a Two-Capillary Viscometer

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      Abstract: Abstract Measurements of the viscosity of pure hydrogen and a binary (hydrogen + methane) mixture with a nominal composition 90 mol % hydrogen are presented. The measurements were conducted with a two-capillary viscometer relative to helium along three isotherms of (298.15, 323.15, and 348.15) K and at pressures of up to 18 MPa. Expanded relative combined uncertainties in viscosity range from (0.65 to 2.7) % (k = 2) for the hydrogen data, and from (0.91 to 3.2) % (k = 2) for the (hydrogen + methane) data. The viscosity data are compared to experimental literature data and viscosity correlations implemented in the NIST REFPROP v10.0 database. Good agreement between this work’s data, literature data, and the viscosity correlation was achieved for pure hydrogen. The (hydrogen + methane) mixture was compared to the Extended Corresponding States (ECS) model implemented in REFPROP v10.0. Relative deviations between the experimental data and the ECS model exceed the experimental uncertainty and were found to exhibit a positive trend with increasing density and a weakly pronounced negative trend with increasing temperature. No experimental literature data are available at overlapping state regions. Nonetheless, deviations to the ECS model imply reasonable consistency of this work’s data and literature data. In addition to experimental viscosities, experimental zero-density viscosity ratios of the fluids under investigation and helium are reported. Fairly good agreement within the experimental uncertainty of this work with a highly accurate literature value and a value obtained from accurate ab initio calculated data was achieved for hydrogen.
      PubDate: 2024-03-18
       
  • Thermophysical Properties for Alkylphosphonate and Alkylphosphate
           Compounds

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      Abstract: Organophosphorus compounds have a wide range of applications; they are commonly used as drugs or pesticides or in the production of ion batteries. However, some organophosphorus compounds, which were developed as warfare nerve agents, are neurotoxic and potentially lethal to living organisms. On the basis of the literature search, certain properties of these compounds are not well known. Knowledge of thermodynamic properties and the availability of reliable data are fundamental in the development of methods for detecting, treating, and safely analyzing decontamination. For research purposes, substitutes, called simulants, which have similar molecular structures and properties but are less toxic, are often employed. This work presents a thermodynamic study of four organophosphorus nerve agent simulants: trimethyl phosphate, triethyl phosphate, dimethyl methylphosphonate, and diethyl methylphosphonate. Differential scanning calorimeter and a Tian–Calvet type calorimeter were used to analyze their phase behavior and measure the liquid heat capacities, respectively. Vapor pressures were experimentally determined with the static method. Ideal-gas heat capacities were calculated using the R1SM approach, which combines the rigid rotor–harmonic oscillator model, the one-dimensional hindered rotor model, and the mixing model. The results obtained were compared with the data from the literature and simultaneously correlated to obtain a highly reliable thermodynamic description. Graphical
      PubDate: 2024-03-15
       
  • The Study of Thermodynamic Properties of Diethylene Glycol Monobuthyl
           Ether with 2-Alkanols (C3–C6) with Use of PC-SAFT Modeling at Different
           Temperatures

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      Abstract: Abstract This study investigated the density (ρ), speed of sound (u), and refractive index ( \({n}_{{\text{D}}}\) ) of binary mixtures of diethylene glycol monobuthyl ether (DEGBE) and 2-alkanols (C3–C6) at various compositions and temperatures (T = 298.15, 308.15, 318.15 K) under normal pressure. The experimental data were used to compute derived properties such as excess molar volume ( \({V}_{{\text{m}}}^{{\text{E}}}\) ), excess partial molar volume ( \({\overline{V} }_{{\text{m}},{\text{i}}}^{{\text{E}}}), \mathrm{deviations in}\) isentropic compressibility (Δ \({K}_{{\text{s}}})\) , and in refractive index ( \(\Delta {n}_{D}\) ). These derived properties were fitted with the Redlich–Kister polynomial equation. A digital vibrating-tube densitometer (Anton Paar DSA 5000) was used to measure the density and speed of sound of pure substances and mixtures at different temperatures. The results revealed the intermolecular interactions and structure factors of the binary mixtures. Moreover, the Perturbed Chain Statistical Association Fluid Theory (PC-SAFT) model was applied to predict the density data of binary mixtures and compare them with the experimental data.
      PubDate: 2024-03-11
       
  • Dynamic Light Scattering for the Measurement of Transport Properties of
           Fluids

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      Abstract: Abstract The present article summarizes experimental and theoretical considerations required for a proper use of dynamic light scattering (DLS) for the measurement of transport properties of fluids. It addresses not only recent advancements of the method, but also aims to provide recommendations to researchers who intend to apply the technique in the future. As outlined in this study, DLS is based on the analysis of scattered light governed by microscopic statistical or periodic fluctuations that originate from the thermal movement of molecules and/or particles at macroscopic thermodynamic equilibrium. The dynamics of these hydrodynamic fluctuations in the bulk of fluids or at their phase boundaries are related to the underlying diffusive processes and, thus, to the associated transport properties, and are reflected by the time-dependent correlation function of the scattered light intensity. The fundamentals of this type of detection, known as photon correlation spectroscopy (PCS), will be discussed in the present contribution in some more detail. It is emphasized that the experiments need to be designed carefully in accordance with theory in order to assign the measurement signals to the corresponding hydrodynamic fluctuations. If the necessary conditions are fulfilled, DLS allows the accurate determination of several transport properties including kinematic and dynamic viscosity, thermal diffusivity, mutual diffusivity, and sound attenuation, which may be accessed together with other thermophysical properties such as speed of sound and surface or interfacial tension. In some instances, also the simultaneous determination of several transport properties is possible. With the exception of the sound attenuation, expanded uncertainties for the mentioned transport properties down to 1 % can be achieved for various types of fluid systems over a wide range of thermodynamic states up to elevated temperatures and pressures as well as in the vicinity of critical points. This performance and versatility of the DLS technique is documented in the present study by highlighting measurement examples from recent thermophysical property research on different classes of working fluids relevant for process and energy technology.
      PubDate: 2024-03-11
       
  • Maximizing Thermal Performance of Heat Pipe Heat Exchangers for Industrial
           Applications Using Silver Nanofluids

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      Abstract: Abstract This study analyzes the thermal performance of a specially designed heat pipe heat exchanger (HPHE) containing distinct evaporator and condenser sections and utilizes two convective heat transfer media—deionized (DI) water and silver nanofluids. Low-grade industrial waste heat at 50–60 °C is the primary heat source. The HPHE employs a stainless steel mesh wick and copper fins to promote efficient evaporation and condensation heat transfer (background). The goal was to assess and compare the HPHE's performance in recovering this waste heat using DI water and silver nanofluids as the working fluids (purpose). A custom-built experimental setup allowed careful control and systematic variation of operating parameters, including thermal load (70-90W), and hot and cold fluid mass flow rates (0.2–0.6 kg⋅min−1 and 0.1–0.3 kg⋅min−1). The nanofluid was synthesized robustly, demonstrating remarkable uniformity and stability. The working fluids' heat exchange rates and efficiencies were analyzed and compared based on calculated thermal resistance, overall heat transfer coefficient (U), and effectiveness (ε) values (methods). The nanofluid reduced thermal resistance by 10–15% and improved U and ε by over 60% compared to DI water. A maximum effectiveness of 39.25% proved the HPHE's exceptional waste heat recovery capacity using nanofluids (results). Heat transfer performance escalated with higher thermal loads yet required optimal mass flow rates to balance turbulence and exposure time. The modified HPHE with silver nanofluids shows immense potential for harnessing industrial waste heat through substantially intensified heat exchange rates and thermal efficiency.
      PubDate: 2024-03-09
       
  • On the Importance of Using Reliability Criteria in Photothermal
           Experiments for Accurate Thermophysical Property Measurements

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      Abstract: Abstract The theoretical and experimental foundations of some of the most common frequency-domain photothermal techniques for measuring thermophysical properties of materials are presented. Limitations of these methodologies when used without attention to satisfying the appropriate validity conditions are discussed and their consequences in providing inaccurate and often conflicting quantitative measurements are examined in the form of several case studies in photothermal thermophysics. The importance of adherence to experimental setup configurations and signal generation conditions consistent with photothermal theoretical models used to extract thermophysical properties (diffusivity, effusivity, optical absorption coefficient) is highlighted as an essential requirement for reliable thermophysical measurements.
      PubDate: 2024-03-09
       
  • Analyzing Intermolecular Interactions in 2-Methyl-1-pentanol and C4-C7
           1-Alkanol Mixtures: Thermodynamic and Transport Investigations

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      Abstract: Abstract The current investigation delves into a comparative evaluation of the thermophysical behavior observed in 2-methyl-1-pentanol and short-chain alcohols (C4-C7), from 1-butanol to 1-heptanol over a temperature range of 293.15 to 333.15 K. The primary emphasis of this research centers on analyzing the excess molar volumes and viscosity deviations of these compounds. The findings indicate positive excess molar volumes in the mixtures, which escalate with the elongation of the alkyl chain in the alcohols. Viscosity measurements exhibit deviations from ideal behavior, showing a negative trend that intensifies with longer alkyl chains, indicative of weak molecular interactions between 2-methyl-1-pentanol and the alcohols. Additionally, the study employs the Cubic-Plus-Association (CPA) model to establish correlations among the densities of these mixtures. Remarkably, the model closely aligns with experimental findings, demonstrating a maximum disparity of only 0.57% in the 2-methyl-1-pentanol + 1-pentanol mixture.
      PubDate: 2024-03-06
       
  • Experimental Investigation on Pool Boiling Heat Transfer Performance of
           Superhydrophilic, Hydrophilic and Hydrophobic Surface

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      Abstract: Abstract The recent advances in the growth of heat dissipation from microelectronic devices have led to the two-phase heat transfer method via nucleate boiling for better thermal management. In this study, the effect of surface wettability on the saturated pool boiling heat transfer performance is examined with deionized water. Three types of wettability surfaces are compared, i.e., superhydrophilic (SHPi), hydrophilic (HPi) and hydrophobic (HPo) surfaces. The SHPi surface is prepared by anodic oxidation of the copper surface, while the HPi and HPo surface is prepared by coating Cu–TiO2 and Cu–MWCNTs, respectively, on the copper surface using the electrochemical deposition method. The earliest incipience of nucleate boiling was observed with the HPo surface, while a most delayed onset of nucleation was obtained for the SHPi surface. The critical heat flux is found to be 1012 kW·m−2, 1251 kW·m−2, 1490 kW·m−2 and 1610 kW·m−2 corresponding to the plane copper, HPo, HPi and SHPi surfaces following the ascending order. The improved rewetting of the arid area underneath the formed vapour bubble caused a delay in the dry-out occurrence and resulted in a maximum critical heat flux for the SHPi surface. The maximum heat transfer coefficient of 88.42 kW·m−2·K−1, 64.7 kW·m−2·K−1 and 59.19 kW·m−2·K−1 have been observed for the HPi, HPo and SHPi surfaces, respectively, which translates to an increment of 60.2 %, 17.23 % and 7.25 %, respectively, as compared to plain surface. The SHPi surface induces the rightward shifting of the boiling curve as compared to the plane surface, which gives a lower heat transfer coefficient for a particular heat flux.
      PubDate: 2024-03-06
       
  • Thermal Conductivity of Glycerol at Atmospheric Pressure Between 268 K
           and 363 K by Using a Steady-State Parallel-Plate Instrument

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      Abstract: Abstract The present work reports experimental data for the thermal conductivity of glycerol which is an important fluid in many technical applications. Measurements were performed in an absolute way at ambient pressure using a steady-state guarded parallel-plate instrument (GPPI) with an average expanded (k = 2) measurement uncertainty of 2.3%. For data representation over a temperature range from (268.15 to 363.15) K in steps of 5 K, the thermal conductivities are averaged from measurements at three different temperature gradients for each temperature. The present results indicate an almost constant thermal conductivity of glycerol over the studied temperature range and agree with the sparse experimental data available in the literature. Based on the experimental database including the results from this work, a simple correlation for the thermal conductivity of glycerol at 0.1 MPa as a function of temperature between (268 and 413) K is suggested. The additional study on the influence of water as possible contamination up to water mass fractions of 0.02 on the thermal conductivity of glycerol reveals negligible changes. Overall, the experimental results from this work contribute to an improved data situation for the thermal conductivity of glycerol, particularly in the subcooled liquid region at temperatures below 283 K.
      PubDate: 2024-03-04
       
  • Infrared Directional Spectral Emissivity of Tungsten-Copper Alloy in the
           400–700 ℃ Temperature Range

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      Abstract: Abstract The tungsten-copper alloy is commonly used for the electrical contact in high current vacuum switch, where precise temperature monitoring of the contact is crucial for ensuring stable operation of the switch by radiation thermometry. However, accurate emissivity data of this alloy is necessary when using radiation thermometry for temperature measurement. Thus, the directional spectral emissivity of tungsten-copper alloy is investigated within the temperature range of 400–700 ℃ under vacuum in this work. The hemispherical total emissivity is calculated by numerically integrating the directional spectral emissivity. Experimental results found this tungsten-copper alloy agrees with the theoretical prediction of the electromagnetic theory, that is, the emissivity increases with increasing temperature, and decreases with increasing wavelength. A convergence phenomenon of spectral emissivity occurs when the polar angle exceeds approximately 50°. This means that the normal wavelength dependence undergoes a shift at high polar angles, which is typical behavior of metallic emissivity. Additionally, the effects of thermal cycle, surface roughness, and chemical composition on emissivity are analyzed in detail. Surface stress relaxation process results in a significant decrease in emissivity. Emissivity increases as the surface roughness and tungsten composition of alloy increases. However, the effects of surface roughness and chemical composition on emissivity gradually disappear at long wavelengths and high polar angles.
      PubDate: 2024-03-04
       
  • Synthesis and Thermal Properties of Myristic Acid/Nano-TiO2/Carbon
           Additives Composite Phase Change Materials

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      Abstract: Abstract A novel composite phase change material, myristic acid (MA)/nano-titanium dioxide (nano-TiO2)/carbon additives, was synthesized via a melt blending method, in which MA serves as phase change material, nano-TiO2 acts as support material, and carbon additives are used as thermally conductive enhancer. A series of leakage tests have shown that MA/nano-TiO2 can maintain shape stability during the phase transition when the content of MA in MA/nano-TiO2 does not exceed 50 %. The FT-IR and XRD results demonstrated that there is no chemical reaction among the various components of the MA/nano-TiO2/carbon additive. When the content of MA is 50 %, the melting temperature of MA/nano-TiO2/carbon additives is about 54 °C and the melting enthalpy is about 80 J·g−1. When the content of all three carbon additives, multiwall carbon nanotubes, graphene, and expanded graphite, is 2.5 %, the corresponding thermal conductivity of MA/nano-TiO2/carbon additives is 0.532 W/(m·K), 1.128 W/(m·K), and 1.382 W/(m·K), respectively. The thermal conductivity of these three types of MA/nano-TiO2/additives is 1.23, 2.62, and 3.21 times that of MA/TiO2, respectively. Moreover, the decomposition temperature of these three types MA/nano-TiO2/carbon additives composites is around 245 °C. Therefore, the working ambient temperature of MA/nano-TiO2/additive composites should be lower than 245 °C.
      PubDate: 2024-03-02
       
  • The Four-Sinker Densimeter: A New Instrument for the Combined
           Investigation of Accurate Densities and Sorption Phenomena of Pure Gases
           and Gas Mixtures

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      Abstract: Abstract An apparatus for high-accuracy gas density and adsorption measurements over the range of temperature from (193 to 423) K and pressure from (0 to 15) MPa is described. This instrument is based on the two-sinker densimetry principle and incorporates a magnetic suspension balance. In addition to the two “density sinkers”, two “sorption sinkers” are weighed to investigate density and adsorption of a gas sample simultaneously. The design of the sinkers increases the resolution of density and adsorption investigations and enables the correction of sorption effects on density measurements. The complete apparatus, including the sinkers, the temperature and pressure measuring systems, and the measurement procedure, is described. For the density range investigated, the uncertainty (k = 2) is between (0.0034 to 0.019) kg \(\cdot\) m−3, corresponding to (0.060 to 0.011)%. The uncertainty (k = 2) in adsorption load is (0.16 to 0.26) \(\upmu\) g \(\cdot\) cm−2. Density measurements at T = (283 and 293) K and pressures up to 10 MPa of high-purity argon and nitrogen validate the instrument for density. Adsorption measurements of high-purity carbon dioxide and propane on a gold surface validate the instrument for adsorption investigation at T = (283 and 293) K and up to the saturation pressure of the investigated gas. The apparatus was used to measure the binary mixture (0.75 \(\text{CO}_2\) + 0.25 \({\text{C}_3\text{H}_8}\) ). In the future, the apparatus will also be used to accurately determine dew-point densities and pressures of pure gases and gas mixtures.
      PubDate: 2024-02-29
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


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  Subjects -> PHYSICS (Total: 857 journals)
    - ELECTRICITY AND MAGNETISM (10 journals)
    - MECHANICS (22 journals)
    - NUCLEAR PHYSICS (53 journals)
    - OPTICS (92 journals)
    - PHYSICS (625 journals)
    - SOUND (25 journals)
    - THERMODYNAMICS (30 journals)

THERMODYNAMICS (30 journals)

Showing 1 - 29 of 29 Journals sorted alphabetically
Advances in Heat Transfer     Full-text available via subscription   (Followers: 26)
Applied Thermal Engineering     Hybrid Journal   (Followers: 41)
Araucaria. Revista Iberoamericana de Filosofía, Política y Humanidades     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 9)
Chemical Thermodynamics and Thermal Analysis     Open Access   (Followers: 7)
Condensed Matter Physics     Open Access   (Followers: 2)
Diffusion Foundations     Full-text available via subscription   (Followers: 4)
European Journal of Mechanics - B/Fluids     Hybrid Journal   (Followers: 5)
Experimental Heat Transfer     Hybrid Journal   (Followers: 17)
Experimental Thermal and Fluid Science     Hybrid Journal   (Followers: 34)
Fluids     Open Access   (Followers: 1)
Heat and Mass Transfer     Hybrid Journal   (Followers: 28)
Heat Transfer Engineering     Hybrid Journal   (Followers: 37)
High Temperature     Hybrid Journal   (Followers: 2)
HTM Journal of Heat Treatment and Materials     Full-text available via subscription   (Followers: 3)
International Journal of Thermodynamics     Open Access   (Followers: 11)
International Journal of Thermophysics     Hybrid Journal   (Followers: 7)
Journal of Thermodynamics & Catalysis     Open Access   (Followers: 6)
Journal of Chemical Thermodynamics     Hybrid Journal   (Followers: 4)
Journal of Low Temperature Physics     Hybrid Journal   (Followers: 8)
Journal of Non-Newtonian Fluid Mechanics     Hybrid Journal   (Followers: 16)
Journal of Thermal Science     Hybrid Journal   (Followers: 21)
Journal of Thermal Spray Technology     Hybrid Journal   (Followers: 5)
Journal of Thermodynamics     Open Access   (Followers: 7)
Journal of Thermophysics and Heat Transfer     Hybrid Journal   (Followers: 93)
Low Temperature Physics     Hybrid Journal   (Followers: 6)
Metal Science and Heat Treatment     Hybrid Journal   (Followers: 36)
Quantitative InfraRed Thermography Journal     Hybrid Journal  
Thermophysics and Aeromechanics     Hybrid Journal   (Followers: 6)
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HOME > Browse the 73 Subjects covered by JournalTOCs  
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JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 3.227.240.72
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-