Article
Thermodynamics
Muhammad Nasir, Kazuki Kaito, Anindityo Patmonoaji, Mohammad Azis Mahardika, Yun She, Shintaro Matsushita, Tetsuya Suekane
Summary: X-ray micro-tomography was used to study the pore-scale drying process and characterize the liquid film region and the invasion front. The decrease in saturation is not uniform across the pore size. The invasion front shows a sharp decrease in liquid saturation and the presence of liquid film and multi-pore connected clusters.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Libin Tan, Yuejin Yuan, Zhe Zhao, Yingying Xu, Yueding Yuan
Summary: Drying shrinkage is a complex process influenced by the micro-pore structure of high-moisture porous media. This study established a pore-scale model and conducted pore network simulations to analyze the effects of micro-pore structure characteristics on heat-moisture and stress-strain distributions during drying. The simulation results showed good agreement with experimental measurements and revealed the phenomena of dry spots, wet spots, irregular drying front, and asymmetric shrinkage. Capillary stress was identified as a key factor affecting drying shrinkage.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Engineering, Chemical
Jianlin Zhao, Feifei Qin, Qinjun Kang, Dominique Derome, Jan Carmeliet
Summary: In this work, a hybrid method coupling a pseudo-potential lattice Boltzmann model (LBM) and a pore network model (PNM) is proposed to simulate drying in porous media. By subdividing the porous medium into pore regions and using different models for different types of pores, the hybrid method combines the accuracy of LBM and the efficiency of PNM, leading to significant reduction of computation time in larger porous systems.
Article
Environmental Sciences
Ryan Haggerty, Dong Zhang, Jongwan Eun, Yusong Li
Summary: This study investigates the effect of varying flow rates and bubble sizes on gas-liquid flow in porous media through a horizontal microchannel. A bubble generation system was used to create bubbles with controllable sizes and frequencies, which were then passed through microfluidic channels filled with different sizes of glass beads. Visual analysis of the bubble flow and measurement of pressure data were conducted to determine changes in liquid holdup and hydraulic conductivity. Results showed that larger bubbles resulted in a lower frequency of bubble breakthrough, and increasing flow rates increased changes in liquid holdup during bubble breakthrough. Additionally, both larger bubbles and lower flow rates reduced the relative permeability of each channel.
Article
Thermodynamics
Faeez Ahmad, Arman Rahimi, Evangelos Tsotsas, Marc Prat, Abdolreza Kharaghani
Summary: The study investigates solute transport in capillary porous media during drying, comparing the results of a continuum model and pore network simulations to evaluate the predictive capability of the continuum model. Using Monte Carlo simulations, the heterogeneity of the liquid phase structure is characterized, and the probability of first solid crystals appearing is discussed.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Chemical
Zhenyu Xu, Krishna M. Pillai
Summary: Large opening area and good transportation routes are beneficial for quick-drying performance.
Article
Engineering, Chemical
Ilgar Azizov, Marcin Dudek, Gisle Oye
Summary: This study demonstrates a microfluidic method for investigating the transport of dilute oil-in-water emulsions through porous media. Droplet size has a dramatic effect on pore clogging, with larger droplets facilitating the retention of smaller droplets.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Engineering, Chemical
Hafiz Tariq Mahmood, Evangelos Tsotsas, Abdolreza Kharaghani
Summary: The study examines the role and significance of liquid films in mass exchange under isothermal, slow drying conditions, systematically conducting three-dimensional pore network Monte Carlo simulations. Results show that the pore network model with capillary rings can predict the evolution of wet and dry patches on the medium surface more accurately, compared to classical pore network models without consideration of liquid films.
TRANSPORT IN POROUS MEDIA
(2021)
Article
Environmental Sciences
Senyou An, Muhammad Sahimi, Vahid Niasar
Summary: Hydrodynamic dispersion in flow through porous media is an essential phenomenon in many geosystems. However, limited studies have focused on dispersion in flow of non-Newtonian fluids. This study used pore-scale simulations to investigate the effects of rheology and flow dynamics on hydrodynamic dispersion. Surprisingly, the simulations revealed a non-monotonic relationship between injection rate and dispersivity, highlighting the need for improved theories of transport in porous materials for non-Newtonian fluids.
WATER RESOURCES RESEARCH
(2022)
Article
Energy & Fuels
Lianwei Xiao, Guangpu Zhu, Lei Zhang, Jun Yao, Hai Sun
Summary: This study systematically investigates the impact of disorder on the imbibition process, finding that disorder and wettability have different effects on displacement under different capillary numbers. At low capillary numbers, displacement is governed by wettability; at intermediate capillary numbers, only the largest disorder has a significant influence; at high capillary numbers, disorder greatly affects front morphology and displacement efficiency. The transition from capillary fingering to viscous fingering is observed at intermediate capillary numbers, leading to higher displacement efficiency.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Mathematics
Vladimir A. Shargatov, George G. Tsypkin, Sergey Gorkunov, Polina Kozhurina, Yulia A. Bogdanova
Summary: This study investigates the hydrodynamic stability of liquid displacement by gas in a porous medium, with a focus on the case where a light gas is located above the liquid. The onset of instability and the evolution of shortwave perturbations are analyzed through numerical simulation and a network model. The results demonstrate the anomalous growth of shortwave perturbations, with a reduced growth rate compared to linear analysis.
Article
Water Resources
Milad Hosseini, Majid Siavashi, Milad Shirbani, Mohaddeseh Mousavi Nezhad
Summary: Simulation of flow at the pore scale is crucial for understanding fluid behavior in porous media. This study investigates the effect of the magic parameter on simulation results by considering errors in micro-CT images, and compares the results with the Navier-Stokes method. The study also presents a criterion for estimating the error amplitude of flow characteristics due to micro-CT imaging. The findings show that the magic parameter can accurately simulate complex geometries with minimal error.
ADVANCES IN WATER RESOURCES
(2023)
Article
Water Resources
Nicolas Bueno, Luis Ayala, Yashar Mehmani
Summary: This study investigates the ripening process of bubbles comprised of multiple components using a pore-network model and proposes a theory to predict the probability density function (PDF) of bubble sizes. The research findings reveal that multi-component ripening occurs in two stages - partitioning and coevolution.
ADVANCES IN WATER RESOURCES
(2023)
Article
Computer Science, Interdisciplinary Applications
Yashar Mehmani, Ke Xu
Summary: This article investigates the Ostwald ripening of trapped bubbles in porous media, which is relevant to subsurface and manufacturing applications. Through simulations and theoretical analysis, the article reveals the evolution process of the bubble size distribution from initially non-uniform to stable equilibrium, and finds that the equilibration of bubbles in heterogeneous porous media is slower than in homogeneous media.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Engineering, Chemical
Zhenyu Xu, Krishna M. Pillai
Summary: This study analyzed isothermal drying in single-porosity and dual-porosity porous media using a pore-network simulation. Results showed that higher hydraulic diameter of throats leads to higher drying rates and longer constant drying rate periods.
Article
Chemistry, Physical
Yiguang Zhou, Shuhao Xiao, Jinxia Jiang, Rui Wu, Xiaobin Niu, Jun Song Chen
Summary: The study shows that the Li4Ti5O12/rutile TiO2 heterostructured nanorods exhibit improved high-rate performance and capacity retention, thanks to the constructed interface between the two materials.
Article
Engineering, Chemical
Jialin Men, Subash Reddy Kolan, Ali Massomi, Torsten Hoffmann, Nat Jochen Schmidt, Evangelos Tsotsas, Andreas Bueck
Summary: This study presents the formulation of nanostructured heteroaggregates using the principle of fluidization and demonstrates the feasibility of two technologies, spouted bed and opposed jet fluidized bed. Intraaggregate mixing of constituents is evaluated using SEM-EDX.
CHEMIE INGENIEUR TECHNIK
(2023)
Article
Engineering, Chemical
Yehonatan David Pour, Boris Krasovitov, Andrew Fominykh, Ziba Hashemloo, Abdolreza Kharaghani, Evangelos Tsotsas, Avi Levy
Summary: This study developed a model to investigate the convective heat and mass transfer of an acoustically levitated slurry droplet that evaporates in an atmosphere containing air, water vapor, and soluble gas. The model considered various factors such as acoustic streaming, forced convection, and non-isothermal gas absorption. The results showed that the formation time of a porous shell decreased with increasing sound pressure level (SPL) and increased with increasing frequency.
Article
Engineering, Environmental
Xinyan Li, Shuhao Xiao, Dengji Guo, Jinxia Jiang, Xiaobin Niu, Rui Wu, Taisong Pan, Jun Song Chen
Summary: This study presents a template-free electrodeposition method for the growth of SbBi-Se self-supported nanowall arrays on copper substrates. The resulting heterostructured material exhibits uniformly dispersed phases and interfaces, which facilitate sodium ion diffusion and electronic conduction. The material demonstrates enhanced high-rate performance and superior cyclic retention, making it a promising candidate for sodium-ion battery applications.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Engineering, Chemical
Serap Akbas, Kaicheng Chen, Torsten Hoffmann, Franziska Scheffler, Evangelos Tsotsas
Summary: In this study, an aerosol fluidized bed was used to coat particles with sodium benzoate solution droplets. The coverage of the coated particles was evaluated using scanning electron microscope pictures analyzed by MATLAB image processing. Monte Carlo simulation was employed to describe the coating process. The preferential deposition of droplets on already occupied positions was identified as the main reason for island growth on particles.
Article
Engineering, Chemical
Simson Julian Rodrigues, Nicole Vorhauer-Huget, Thomas Richter, Evangelos Tsotsas
Summary: Tortuosity, an important factor in packed beds or porous media, affects mass transport, thermal and electric conductivity. Current tortuosity models lack consideration for various particle shapes. This study proposes a new model that predicts tortuosity based on sphericity and porosity, demonstrating significant effects on thermal conductivity in different particle shapes. The new model shows superior performance in the porosity range of 0.3 to 0.4, making it an upgrade to the classical Zehner-Bauer-Schlunder (ZBS) model.
Article
Chemistry, Physical
Yi Wang, Zhaohong Li, Xingqun Zheng, Rui Wu, Jianfeng Song, Yulin Chen, Xinzhe Cao, Yao Nie
Summary: Strong metal-support interaction (SMSI) plays an important role in tuning catalytic behavior by facilitating migration of reducible oxides from the support onto loaded metal surfaces and alloying of the guest metal with the metal component in the support. However, the conventional high-temperature redox treatment for SMSI is limited in achieving simultaneous occurrence of oxide migration and alloying mechanisms, which restricts its application in electrocatalysis. In this study, a low-temperature solvothermal-induced SMSI is established in the CeCuOx/C supported Pt system, leading to the partial encapsulation of supported Pt by CeOx and the alloying of Cu2+ in the substrate with guest Pt. This encapsulation and alloying processes significantly improve the catalysis configuration and restructure the geometric/electronic state of interfacial Pt atoms, resulting in enhanced performance for methanol oxidation reaction (MOR).
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Chemistry, Physical
Qi Zhou, Xueqiang Qi, Yiguang Zhou, Junyi Li, Jinxia Jiang, Hanchao Li, Xiaobin Niu, Rui Wu, Jun Song Chen
Summary: Lithium-selenium (Li-Se) batteries have attracted widely attention due to their high volume specific capacity and good electronic conductivity of selenium. However, the rapid capacity fading, high volume changes and shuttle effect of lithium polyselenides (LiPSes) limit its further application. In this study, a zinc-cobalt bimetallic catalysts on nitrogen-doped 3D ordered porous carbon (ZnCo-NC) was constructed and applied as cathode for Li-Se batteries, showing significantly improved performance compared to single-metal counterparts.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Si-Jia Zheng, Hua Cheng, Jin Yu, Qin Bie, Jing-Dong Chen, Feng Wang, Rui Wu, Daniel John Blackwood, Jun-Song Chen
Summary: A three-dimensional ordered porous nitrogen-doped carbon-supported Ni-N-x catalyst has been synthesized by direct pyrolysis of a mixture of SiO2, polyvinyl pyrrolidone, nickel-phenanthroline complex, followed by the removal of the SiO2 templates. The optimized catalyst exhibits a high CO Faradaic efficiency above 85% and a large CO current density of 16.2 mA.cm(-2), demonstrating superior CO2RR performance.
Article
Chemistry, Physical
Chuang Fu, Xueqiang Qi, Lei Zhao, Tingting Yang, Qian Xue, Zhaozhao Zhu, Pei Xiong, Jinxia Jiang, Xuguang An, Haiyuan Chen, Jun Song Chen, Andreu Cabot, Rui Wu
Summary: A dual-atom catalyst, Zn/Fe-NC, is synthesized through pyrolysis of PVP coated on Fe-doped ZIF-8, and it shows outstanding activity for oxygen reduction reaction (ORR) with high half-wave potential, excellent stability, and resistance to methanol. Density functional theory calculation reveals that the ORR overpotential is only 0.282 V, and the down-shifted d band center of active Fe affected by Zn alleviates the adsorption of OH* intermediates, thus promoting the overall ORR electrocatalytic activity. Moreover, zinc-air batteries with Zn/Fe-NC catalyst as oxygen cathode demonstrate remarkable power density and specific capacity for practical applications.
APPLIED CATALYSIS B-ENVIRONMENTAL
(2023)
Article
Pharmacology & Pharmacy
Maximilian Thomik, Felix Faber, Sebastian Gruber, Petra Foerst, Evangelos Tsotsas, Nicole Vorhauer-Huget
Summary: This study presents a non-isothermal pore network model with quasi-steady vapor transport and transient heat transfer for primary freeze drying. The physically based model allows for the investigation of correlations between spatially distributed structure and transport conditions. The study focuses on regular pore network lattices with homogeneous and bimodal pore size distributions.
Article
Materials Science, Multidisciplinary
Shuhao Xiao, Jinxia Jiang, Ying Zhu, Jing Zhang, Hanchao Li, Rui Wu, Xiaobin Niu, Jiaqian Qin, Jun Song Chen
Summary: FeSe2-xSx microspheres were prepared by self-doping solvothermal method and gas phase selenization. S doping improved the Na adsorption and lowered the diffusion energy barrier, enhancing the electronic conductivity of FeSe2-xSx. The carbon-free nature of the microspheres resulted in a low specific surface area and high tap density, leading to a high initial columbic efficiency. Compared with pure FeSe2, FeSe2-xSx exhibited a high reversible capacity and enhanced rate performance. Additionally, FeSe2-xSx//NVP pouch cells achieved high energy and volumetric energy densities, demonstrating the potential applications of FeSe2-xSx microspheres.
ADVANCED POWDER MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Zhao Li, Xueqiang Qi, Junjie Wang, Zhaozhao Zhu, Jinxia Jiang, Xiaobin Niu, Andreu Cabot, Jun Song Chen, Rui Wu
Summary: NiN4Cl-ClNC catalysts with atomically dispersed NiN4Cl active sites are prepared through a molten-salt-assisted pyrolysis strategy. The optimized catalyst shows excellent CO2 conversion activity and outstanding stability, delivering a high CO Faradaic efficiency of 98.7% and a remarkable CO partial current density of approximately 349.4 mA cm(-2) in flow-cell. The introduced axial Ni-Cl bond and ClC bond induce electronic delocalization, stabilizing Ni and facilitating the rate-determining step of COOH* formation.
Article
Physics, Applied
Dong Yan, Shuhao Xiao, Xinyan Li, Jinxia Jiang, Qiyuan He, Hanchao Li, Jiaqian Qin, Rui Wu, Xiaobin Niu, Jun Song Chen
Summary: Transition metal sulfides have high potential for sodium storage, but their low conductivity and volume expansion affect their high-rate performance and cycling stability. In this work, a NiS2/FeS heterostructure was constructed by growing Ni-based layered double hydroxide nanosheets on Fe-based Prussian Blue nanocrystals followed by sulfurization. The resulting nanocomposite showed superior rate performance and cycle life compared to the heterostructure-free NiS2 and FeS.
ENERGY MATERIAL ADVANCES
(2023)
Article
Mechanics
Dasika Prabhat Sourya, Debashis Panda, Abdolreza Kharaghani, Evangelos Tsotsas, Pardha S. Gurugubelli, Vikranth Kumar Surasani
Summary: This study employs the Shan-Chen lattice Boltzmann method (LBM) to simulate the drying process of a capillary porous medium, investigating the effects of convection-diffusion conditions on drying kinetics and comparing them with purely diffusion-dominated kinetics. Additionally, the study explores the influence of a temperature gradient on the stability and instability of the drying front, extending the capabilities of the lattice Boltzmann method for simulating convection-diffusion drying.
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)
