Article
Energy & Fuels
Amin Shahsavar, Abbas Goodarzi, Pouyan Talebizadehsardari, Mulsum Arici
Summary: This study investigated the phase change process in a double-pipe latent heat storage system with sinusoidal wavy fins, which resulted in significant efficiency improvements. The best wave profile was determined to have a wave-amplitude of 2 mm and a wavelength of 1 mm. Additionally, the characteristics of the water flow in the system were found to impact performance.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Energy & Fuels
Babak Mohammad Olfat, Faramarz Talati
Summary: This paper investigates the effect of fins on heat transfer enhancement in latent heat thermal energy storage systems containing phase change materials (PCMs) and aims to find the reasons behind the insufficiency of fins in some cases. Through simulations under different boundary conditions and the introduction of the bypassed energy fraction criterion, conclusions were drawn regarding the performance of fins under different conditions.
JOURNAL OF ENERGY STORAGE
(2021)
Article
Thermodynamics
Zhenqiang Ma, Linfeng Li, Liyi Zou, Huachen Liu, Yuanyuan Li, Xiaomin Cheng
Summary: The use of molten chloride salt as a high-temperature phase change thermal storage material was investigated in this study. By reacting citric acid with sodium chlorite, a flaky carbon morphology was generated in the molten salt to improve its heat transfer performance. The modified molten salt showed a higher latent heat of phase change and thermal conductivity compared to the undoped molten salt. Additionally, the combination of ANSYS simulations and temperature measurements indicated that radiation heat transfer effectively improved the temperature distribution of the molten salt at high temperature. This study may contribute to the understanding of heat transfer behavior in molten salt and its application in concentrated solar power generation.
APPLIED THERMAL ENGINEERING
(2023)
Article
Energy & Fuels
Mingzhen Wang, Eric Hu, Lei Chen
Summary: This paper presents a novel technology to improve the energy efficiency of refrigeration and air-conditioning systems by applying a condenser cooling approach. By integrating an innovative thermal diode tank with the system, it is possible to lower the water temperature below the ambient temperature. The study shows that larger day/night ambient temperature differences and higher TS/Qc values can enhance the system's performance and energy saving percentage.
Review
Energy & Fuels
Kin Yuen Leong, Syafawati Hasbi, Balamurugan A. Gurunathan
Summary: Phase change materials (PCMs) are used for storing thermal energy due to their high latent heat and low thermal conductivity. This review discusses factors affecting solidification and melting of PCM in a triplex-tube heat exchanger, including flow rate, temperature, fins, position, heating and cooling, etc. It is found that using fins and nanoparticles in the triplex tube can enhance solidification and melting of PCM.
JOURNAL OF ENERGY STORAGE
(2021)
Article
Green & Sustainable Science & Technology
Jerzy Woloszyn, Krystian Szopa
Summary: The objective of this research is to design a new latent heat thermal energy storage system with improved thermal conductivity and reduced melting and solidification time. Numerical experiments comparing different designs show that the proposed system significantly reduces melting and solidification time compared to traditional systems, and achieves the highest efficiency.
Article
Thermodynamics
Mingzhen Wang, Eric Hu, Lei Chen
Summary: This paper presents the development and validation of simulation models for a Thermal Diode Tank (TDT) with a Radiation-enhanced Heat Pipe (RTDT). The results show that the RTDT can generate colder water and has double the heat transfer capacity compared to the Convection TDT (CTDT). Increasing the heat pipe condenser area significantly enhances the performance of the TDT, especially for the RTDT.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2023)
Article
Energy & Fuels
Ramalingam Senthil, Banumathi Munuswamy Swami Punniakodi, Dhinesh Balasubramanian, Xuan Phuong Nguyen, Anh Tuan Hoang, Van Nhanh Nguyen
Summary: Thermal energy storage plays an important role in storing heat energy. This study simulates different arrangements of heat transfer tubes to analyze the melting of phase change material (PCM), and finds that the optimal tube location can shorten the melting time.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Article
Energy & Fuels
Chunyu Zhu, Chengzhi Zhao, Zihe Chen, Ruijie Zhu, Nan Sheng, Zhonghao Rao
Summary: The study developed a novel 3D porous carbon scaffold consisting of SiC-wrapped biomass carbon fibers to enhance the thermal conductivity and shape stability of paraffin PCM, resulting in improved heat transfer and anti-leakage properties of the composite materials.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Energy & Fuels
Zihe Chen, Ruijie Zhu, Nan Sheng, Chunyu Zhu, Zhonghao Rao
Summary: This study uses wood carbon as a porous support and modifies it with silicon carbide nanowires to improve the thermal conductivity and leakproof performance of paraffin wax phase change composites. The nanowire network in the wood carbon provides additional capillary absorption force and exhibits anisotropic thermal conductivity enhancement.
JOURNAL OF ENERGY STORAGE
(2022)
Article
Thermodynamics
Meibo Xing, Hongfa Zhang, Hongbing Chen, Ruixiang Wang
Summary: This study experimentally investigated the solidification characteristic of aqueous carbon nanotubes (CNTs) nanofluids with various CNTs sizes and concentrations. The results showed that the addition of surfactant SDBS maintained the suspension stability of CNTs nanofluid and had a positive effect during the nucleation region. Furthermore, it was found that the size of CNTs significantly influenced the solidification characteristics.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Energy & Fuels
Burak Kursun, Mehmet Balta
Summary: Phase change materials (PCMs) are preferred for latent heat storage due to their high energy storage densities and low energy losses. The low thermal conductivity coefficients of PCMs hinder their commercialization and broader applications. Double-pipe energy storage (DPTES) with PCM is suitable for cases where there is a mismatch between the generation and consumption times of thermal energy from sources like solar energy. This study investigates the effects of different inner and outer channel combinations on melting and solidification performance.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Energy & Fuels
Daehyeong Lee, Byeongnam Jo
Summary: This study investigated the thermal energy storage characteristics of nanoparticle-doped binary molten salt nanofluids, with a focus on specific heat and latent heat. The effects of chemical composition on specific heat and latent heat were examined in carbonate salt and nitrate salt nanofluids. The study also discussed the enhancement of specific heat and latent heat by doping nanoparticles into the salt mixtures, with considerations on the formation of a compressed liquid layer near the nanoparticles.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Thermodynamics
Hossein Soltani, M. Soltani, H. Karimi, Jatin Nathwani
Summary: The study investigated the combined effects of using fins and rotation in latent heat thermal energy storage systems, finding that rotational speed has a positive impact on solidification time and heat transfer rate. Additionally, increased rotational speed is directly related to an improvement in heat transfer ratio during the charging and discharging processes.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Multidisciplinary
C. J. Ho, Chu-Yun Cheng, Tien-Fu Yang, Saman Rashidi, Wei-Mon Yan
Summary: This study explores the cooling effectiveness and entropy production of aluminum oxide-water nanofluid in circular tubes with wall conduction effects. Results show that heat transfer effectiveness ratios increase with higher input temperatures of fluid and nanoparticle concentrations. Additionally, local entropy production ratios are mostly below unity, indicating the beneficial use of nanofluids for reducing system irreversibility.
ALEXANDRIA ENGINEERING JOURNAL
(2022)
Article
Engineering, Mechanical
Rico H. T. Hooijschuur, Niranjan Saikumar, S. Hassan HosseinNia, Ron A. J. van Ostayen
Summary: This paper presents the development and dynamic evaluation of a contactless sensing system for an air-bearing based precision wafer positioning system. The system utilizes a thin film of air to float the substrate and avoid damage and contamination. A cascaded control design is implemented to optimize the performance and handle vibration disturbances. The contactless sensor is analyzed for its performance.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Kh. Hosseinzadeh, M. A. Erfani Moghaddam, SeyedKeivan Nateghi, Mohammad Behshad Shafii, D. D. Ganji
Summary: This study aimed to maximize thermal performance by simulating a curved porous star-shaped enclosure with a rounded cavity. The temperature difference between the inner cavity and outer surface stirred the heat flux. By investigating factors such as porosity, radiation intensity, magnetic field, and natural convection, optimal values were determined.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Chemistry, Physical
M. Habibnia, M. Sheikholeslami, S. M. Tabarhoseini, Ali Taheri, M. Sheykhi
Summary: This study focuses on the evaluation of cutting fluids in the turning process. The results show that employing nanofluid minimum quantity lubrication strategy can lead to an average temperature reduction of about 60% in the cutting tool during Mo40 steel turning. Furthermore, increasing the concentration of the nanofluid can further decrease the temperature.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Physics, Applied
Payam Jalili, Hossein Narimisa, Bahram Jalili, D. D. Ganji
Summary: This study investigated a rotating system of micro-polar nanofluid between two parallel plates under the influence of magnetic and electric fields. The impacts of Nusselt number, skin friction, and Sherwood number on temperature, velocity, and concentration distribution were discussed. The results demonstrated the effects of rotation, Brownian motion, thermophoresis analysis, and Hall current on the micro-polar nanofluid.
MODERN PHYSICS LETTERS B
(2023)
Article
Materials Science, Multidisciplinary
Mehdi Safari, Seyed Mohammad Miralaa, Ricardo Alves de Sousa
Summary: This work experimentally studies the laser forming process of cylindrical surfaces. The effects of process parameters such as laser power, laser scanning scheme, and distance between irradiation lines on the radius of curvature of the laser-formed cylindrical surfaces are examined. The design of experiment (DOE) method based on the Box-Behnken algorithm is employed for investigations. Results indicate that increasing laser power decreases the radius of curvature of a laser-formed cylindrical surface. Additionally, the radius of curvature of the cylindrical surface increases with increasing scanning speed, while it decreases with increasing distance between irradiation lines.
Article
Energy & Fuels
Hossein Nabi, Mosayeb Gholinia, Mehdi Khiadani, Abdellah Shafieian
Summary: This paper investigates the impact of red wine-rGO/H2O nanofluid and paraffin wax on the thermohydraulic properties of a photovoltaic/thermal system. Numerical simulations demonstrate that innovative serpentine tube designs significantly enhance the system's performance. The use of environmentally friendly materials such as red wine-rGO/H2O nanofluid and paraffin wax further improves the electrical and thermal efficiency of the system.
Article
Mathematics, Interdisciplinary Applications
Hossein Jafari, Roghayeh Moallem Ganji, Davood Domiri Ganji, Zakia Hammouch, Yusif S. S. Gasimov
Summary: In this paper, the study of fuzzy differential equations (FDEs) in fuzzy calculus is discussed, which provides a proper model to address real problems with uncertainties. Specifically, a class of fuzzy differential equations (FFDEs) with non-integer or variable order (VO) is considered. The main problem is converted to a new problem by utilizing the r-cut representation and is solved using operational matrices (OMs) based on shifted Legendre polynomials (SLPs), leading to a system of nonlinear algebraic equations. The accuracy of the proposed technique is confirmed with an example.
FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY
(2023)
Article
Thermodynamics
Sajad Khodadadi, Mohammad Hassan Taleghani, Davood Domiri Ganji, Mofid Gorji-Bandpy
Summary: In this numerical study, the effect of bubble injection on the heat transfer rate next to an inclined heated wall is investigated. The solver used is the volume of fluid (VoF) method solver in the OpenFOAM package, extended with an energy equation and Boussinesq approximation to consider natural convection flow. The study explores the influence of parameters such as wall slope angle, contact angle, bubble pair, Bond number, and bubble regimes on the heat transfer rate. The results reveal the importance of wall slope and Bond number in determining the Nusselt number.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Multidisciplinary Sciences
M. Jafaryar, M. Sheikholeslami
Summary: In this paper, the application of new structure and loading Graphene nanoparticles to enhance thermal storage systems has been studied. Aluminum layers were used in the paraffin zone, which has a melting temperature of 319.55 K. The paraffin zone was located in the middle section of a triplex tube, with uniform hot temperatures (335 K) applied to both walls of the annulus. Three container geometries were tested by changing the angle of fins (alpha = 7.5 degrees, 15 degrees, and 30 degrees). A homogeneous model with uniform concentration of additives was assumed for property prediction. The results show that loading Graphene nanoparticles decreases the melting time by about 4.98% when alpha = 7.5 degrees, and the impact of phi improves by about 5.2% when the angle is reduced from 30 degrees to 7.5 degrees. Furthermore, as the angle decreases, the melting period decreases by approximately 76.47%, which is associated with an increase in driving force (conduction) in geometries with lower alpha.
SCIENTIFIC REPORTS
(2023)
Article
Materials Science, Multidisciplinary
Payam Jalili, Ali Ahmadi Azar, Bahram Jalili, Davood Domiri Ganji
Summary: This paper investigates the impact of thermo-diffusion, electrical field, and nonlinear thermal radiation. The analysis of radiation heat transfer in non-Newtonian fluids has significant industrial applications. The Hybrid Analytical and Numerical Method is utilized to examine the thermal nonlinear radiation heat transfer flow in non-Darcy Casson fluid on stretched surfaces.
RESULTS IN PHYSICS
(2023)
Article
Thermodynamics
Bahram Jalili, Hassan Roshani, Payam Jalili, Mohammad Jalili, Pooya Pasha, Davood Domiri Ganji
Summary: This paper investigates the behavior of a 2D steady, laminar, and incompressible viscous fluid between two porous disks under an external magnetic field. The study is divided into two interconnected parts. In the first part, the dimensionless equations of the nanofluid flow between the disks are analyzed using the Akbari-Ganji Method (AGM) and compared with numerical results. The second part focuses on using the Finite Element Method (FEM) in CFD software to study the fluid parameters of two different types of nanotubes.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Mathematics, Interdisciplinary Applications
Marcin B. Kaczmarek, Hassan HosseinNia
Summary: In this paper, a fractional-order extension of a negative position feedback (NPF) controller for active damping is proposed. The controller design is motivated by frequency-domain loop shaping analysis and maintains the high-pass characteristics of an integer-order NPF. Experimental results demonstrate the efficiency and feasibility of the proposed fractional-order controller.
FRACTAL AND FRACTIONAL
(2023)
Article
Thermodynamics
Mehran Ghasemian, M. Sheikholeslami, Maziar Dehghan
Summary: This study applies numerical techniques to assess the integration of twisted tapes in different cross-sectional tubes of Photovoltaic/Thermal (PV/T) collector units, and the impact on system performance. Computational fluid dynamics is used to evaluate PV/T systems with cylindrical, rectangular, and triangular cross-sectional tubes, with and without twisted tapes. Various pitch-to-width ratios (YD) of twisted tapes and total inlet mass flow rates are considered. The analysis of energy and exergy is carried out to evaluate system performance. The results show that the triangular cross-sectional tube is optimal without twisted tapes, but the cylindrical tube with twisted tapes outperforms other designs in terms of electrical and thermal aspects. The addition of a twisted tape in the cylindrical tube increases electrical efficiency by 7.2% and 9%, respectively. Furthermore, integrating twisted tapes with the lowest pitch-to-width ratio reduces surface temperature by 3.2℃ and 17.55℃ compared to systems with cylindrical tubes and PV alone.
Article
Construction & Building Technology
M. Sheikholeslami, Z. Khalili
Summary: A new configuration of photovoltaic-thermal unit with a thermoelectric layer has been proposed to enhance electrical performance. The system includes a circular duct with a turbulator and a mini channel with jet impingement for hybrid nanofluid flow. By selecting the turbulator with the highest revolution, the electrical efficiency improves by about 1.41% and useful heat increases by about 5.72%. The best case equipped with confined jets achieves an electrical performance of 15.50% and a thermal performance of 85.30%, with a temperature uniformity improvement of about 46.89%.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Construction & Building Technology
M. Sheikholeslami, Hazim R. A. Al-Hussein
Summary: This study combines Trombe wall with paraffin layer and fins for solar energy saving and ventilation purposes. Alumina nanoparticles are loaded into pure paraffin to enhance the performance. Two heat generation terms are added to consider solar irradiation, and temperature equations with heat sources are applied for modeling different layers. The impacts of fins' thickness, length, and paraffin layer's position are investigated. The system with Y-shaped fins shows higher liquid fraction and lower heat loss, leading to a 28.41% increase in heat capacity at 17:00 with the best configuration.
JOURNAL OF BUILDING ENGINEERING
(2023)
Article
Thermodynamics
Mahsa Taghavi, Swapnil Sharma, Vemuri Balakotaiah
Summary: This study investigates the natural convection effects in the insulation layers of spherical storage tanks and their impact on the tanks' performance. The permeability and Rayleigh number of the insulation material are considered as key factors. The results show that as the Rayleigh number increases, new convective cells emerge and cause the cold boundary to approach the external hot boundary. In the case of large temperature differences, multiple solutions may coexist.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyang Xu, Fangjun Hong, Chaoyang Zhang
Summary: This study introduces a self-induced jet impingement device for enhancing pool boiling performance in high power electronic cooling. Through visualization and parametric investigations, the effects of this device on pool boiling performance are studied, revealing the promotion of additional liquid supply and vapor exhausting. The flow rate of the liquid jet is found to positively impact boiling performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Wenchao Ke, Yuan Liu, Fissha Biruke Teshome, Zhi Zeng
Summary: Underwater wet laser welding (UWLW) is a promising and labor-saving repair technique. A thermal multi-phase flow model was developed to study the heat transfer, fluid dynamics, and phase transitions during UWLW. The results show that UWLW creates a water keyhole, making the welding environment similar to in air laser welding.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Xingrong Lian, Lin Tian, Zengyao Li, Xinpeng Zhao
Summary: This study investigates the heat transfer mechanisms in natural fiber-derived porous structures and finds that thermal radiation has a significant impact on the thermal conductivity in low-density regions, while natural convection rarely occurs. Insulation materials derived from micron-sized natural fibers can achieve minimum thermal conductivity at specific densities. Strategies to lower the thermal conductivity include increasing porosity and incorporating nanoscale pores using nanosize fibers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Yasir A. Malik, Kilian Koebschall, Stephan Bansmer, Cameron Tropea, Jeanette Hussong, Philippe Villedieu
Summary: Ice crystal icing is a significant hazard in aviation, and accurate modeling of sticking efficiency is essential. In this study, icing wind tunnel experiments were conducted to quantify the volumetric liquid water fraction, sticking efficiency, and maximum thickness of ice layers. Two measurement techniques, calorimetry and capacitive measurements, were used to measure the liquid water content and distribution in the ice layers. The experiments showed that increasing wet bulb temperatures and substrate heat flux significantly increased sticking efficiency and maximum ice layer thickness.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinqi Hu, Tongtong Geng, Kun Wang, Yuanhong Fan, Chunhua Min, Hsien Chin Su
Summary: This study experimentally examined the heat dissipation of vibrating fans and demonstrated its inherent mechanism through numerical simulation. The results showed that the flow fields induced by the vibrating blades exhibited pulsating features and formed large-scale and small-scale vortical structures, significantly improving heat dissipation. The study also identified the impacts of different blade structures and developed a trapezoidal-folding blade, which effectively reduced the maximum temperature of the heat source and alleviated high-temperature failure crisis.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Dan-Dan Su, Xiao-Bin Li, Hong-Na Zhang, Feng-Chen Li
Summary: The boiling heat transfer of low-boiling-point working fluid is a common heat dissipation technology in electronic equipment cooling. This study analyzed the interfacial boiling behavior of R134a under different conditions and found that factors such as the initial thickness of the liquid film, solid-liquid interaction force, and initial temperature significantly affect the boiling mode and thermal resistance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyi Wu, Dongke Sun, Wei Chen, Zhenhua Chai
Summary: A unified lattice Boltzmann-phase field scheme is proposed to simulate dendrite growth of binary alloys in the presence of melt convection. The effects of various factors on the growth are investigated numerically, and the model is validated through comparisons and examinations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shaokun Ge, Ya Ni, Fubao Zhou, Wangzhaonan Shen, Jia Li, Fengqi Guo, Bobo Shi
Summary: This study investigated the temperature distribution of main cables in a suspension bridge during fire scenarios and proposed a prediction model for the maximum temperature of cables in different lane fires. The results showed that vehicle fires in the emergency lane posed a greater thermal threat to the cables.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shuang-Ying Wu, Shi-Yao Zhou, Lan Xiao, Jia Luo
Summary: This paper investigates the two-phase flow and heat transfer characteristics of low-velocity jet impacting on a cylindrical surface. The study reveals that the heat transfer regimes are non-phase transition and nucleate boiling with the increase of heat transfer rate. The effects of jet impact height and outlet velocity on local surface temperatures are pronounced at the non-phase transition stage. The growth rates of heat transfer rate and liquid loss rate increase significantly from the non-phase transition to nucleate boiling stage.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Emad Hasani Malekshah, Wlodzimierz Wlodzimierz, Miros law Majkut
Summary: Cavitation has significant practical importance and can be controlled by air injection. This study investigates the natural to ventilated cavitation process around a hydrofoil through numerical and experimental methods. The results show that the location and rate of air injection have a meaningful impact on the characteristics of cavitation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Feriel Yahiat, Pascale Bouvier, Antoine Beauvillier, Serge Russeil, Christophe Andre, Daniel Bougeard
Summary: This study explores the enhancement of mixing performance in laminar flow equipment by investigating the generation of chaotic advection using wall deformations in annular geometries. The findings demonstrate that the combined geometry can achieve perfect mixing at various Reynolds numbers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Hui He, Ning Lyu, Caihua Liang, Feng Wang, Xiaosong Zhang
Summary: This study investigates the condensation, frosting, and defrosting processes on superhydrophobic surfaces with millimeter-scale structures. The results reveal that the structures can influence the growth and removal of frost crystals, with the bottom grooves creating a frost-free zone and conical edges promoting higher frost crystal heights. Two effective methods for defrosting are observed: hand-lifting the groove and airfoil retraction contraction on protruding structures. This research provides valuable insights into frost formation and defrosting on millimeter-structured superhydrophobic surfaces, with potential applications in anti-frost engineering.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Thiwanka Arepolage, Christophe Verdy, Thibaut Sylvestre, Aymeric Leray, Sebastien Euphrasie
Summary: This study developed two thermal concentrators, one with a 2D design of uniform thickness and another with a 3D design, using the coordinate transformation technique and metamaterials. By structuring the thermal conductor, the desired local density-heat capacity product and anisotropic thermal conductivities were achieved. The homogenized thermal conductivities were obtained from finite element simulations and cylindrical symmetry consideration. A 3D concentrator was fabricated using 3D metal printing and characterized using a thermal camera. Compared to devices that solely consider anisotropic conductivities, the time evolution characteristics of the metadevice designed with coordinate transformation were closer to those of an ideal concentrator.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Liangyuan Cheng, Qingyang Wang, Jinliang Xu
Summary: In this study, we investigated the supercritical heat transfer of CO2 in a horizontal tube with a diameter of 10.0 mm, covering a wide range of pressures, mass fluxes, and heat fluxes. The study revealed a non-monotonic increase in wall temperatures along the flow direction and observed both positive and negative wall temperature differences between the bottom and top tube. The findings were explained by the thermal conduction in the solid wall interacting with the stratified-wavy flow in the tube.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
