Article
Thermodynamics
Fikret Alic
Summary: This paper investigates the thermal system of two concentric hollow cylinders, exploring the effects of different heating and insulation configurations on thermal entropy and entransy efficiency. The study reveals the differences in thermal entropy and entransy efficiency between the inner and outer cylinders and establishes the relationship between the two.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Mechanics
Sushant Shekhar
Summary: The study focuses on numerically investigating the deformation in a thermoelastic material with voids and a single relaxation time, considering the dependence of modulus of elasticity and thermal conductivity on reference temperature. Two cases of linear and quadratic dependency have been studied, using the finite element method with isoparametric finite elements. The comparison between finite element method and Laplace/Fourier transformation shows the former's advantage in predicting deformation accurately. The impact of thermal relaxation time on various results is observed and discussed.
MECHANICS BASED DESIGN OF STRUCTURES AND MACHINES
(2022)
Article
Thermodynamics
Rajesh Mishra, B. K. Behera, Miroslav Muller, Michal Petru
Summary: This study examined the thermal insulation properties of nonwoven samples embedded with silica aerogel using finite element simulations and experimental measurements. The results showed a high correlation between the FEM based simulations and experimental measurements, providing theoretical support for the use of aerogel blankets in house buildings at sub-zero temperatures.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Dongliang Ding, Qiuyu Zhang, Guangzhao Qin, Yanhui Chen
Summary: Thermal conductivity of polymer composites with oriented anisotropic fillers is accurately predicted using a super-cell model with off-set fillers based on a hexagonal prism primitive-cell. The model systematically evaluates the impact of various factors on the anisotropic thermal conductivity of polymer composites and shows excellent agreement with experimental results. This work provides a practical means to predict thermal conductivity and has guiding significance for designing thermal management materials.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Construction & Building Technology
Aatef D. Hobiny, Ibrahim A. Abbas, C. Alaa A. El-Bary
Summary: This article explores the issue of semiconductors half-space comprised of materials with varying thermal conductivity. The problem is studied within the framework of the generalized thermoelastic model under one thermal relaxation time. Numerical solutions are obtained using the finite element method, and the analytical solution is found using the eigenvalue approach and Laplace transform. Comparisons between numerical findings and analytical solutions are used to examine the accuracy of the proposed approach.
STEEL AND COMPOSITE STRUCTURES
(2023)
Article
Materials Science, Composites
Jiale Wu, Xupeng Song, Yangzhi Gong, Wei Yang, Lin Chen, Shaojian He, Jun Lin, Xingming Bian
Summary: The thermal conductivity of Al2O3/SIR composites was studied with the changes in volume fraction, particle size, and binary filling schemes, proposing the particle contact probability to quantitatively characterize the formation probability of heat conduction path. Increasing the volume fraction of fillers leads to higher contact probability of filler particles, thus enhancing the thermal conductivity of the composites.
COMPOSITES SCIENCE AND TECHNOLOGY
(2021)
Article
Computer Science, Interdisciplinary Applications
Seong-Sik Han, Hyun-jin Eom, Min-Su Lee, Tai-Hong Yim, Heung-Kyu Kim
Summary: This study proposes a new metal-based material design with properties comparable to wood by architecturing of metal sheets. Through Design of Experiment (DOE) and finite element analysis, the effect of design variables on material properties was evaluated, with verification of prediction reliability through comparison with experimental results. The study demonstrates the potential of using architecturing of metal sheets to develop new materials with desired properties while incorporating the advantages of metal such as fire resistance and recyclability.
JOURNAL OF COMPUTATIONAL DESIGN AND ENGINEERING
(2021)
Article
Materials Science, Composites
Ruoyu Huang, Dongliang Ding, Xiaoxiao Guo, Changjiang Liu, Xinhua Li, Gaoxiao Jiang, Yufeng Zhang, Yanhui Chen, Weiwei Cai, Xue-ao Zhang
Summary: Vinyl polydimethylsiloxane (PDMS) composites with spatially aligned carbon fibers (CFs) bridged by Al2O3 particles were fabricated and showed enhanced thermal conductivity. The effects of shape factor, spatial angle, and CF loading on thermal conductivity were quantitatively discussed. It was found that increased CF loading contributed positively to thermal conductivity, while shape factor and spatial angle had a negative effect.
COMPOSITES SCIENCE AND TECHNOLOGY
(2022)
Article
Acoustics
Per Kristian Bolstad, Martijn E. Frijlink, Tung Manh, Lars Hoff
Summary: This study presents a finite element method to estimate the effective medium parameters of 2D and 3D layers of arbitrary composition. The method can capture deviations occurring in coarser composites and demonstrates that void positions influence wave velocity.
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
(2022)
Article
Energy & Fuels
Xiaoming Dong, Cancan Zhang, Yuting Wu, Yuanwei Lu, Chongfang Mu
Summary: This study analyzes the effect of structural and operating parameters on the performance of a molten salt-supercritical CO2 concentric tube heat exchanger using the distributed parameter method. Optimal design and optimization calculations are conducted to improve the heat exchange efficiency.
Article
Nanoscience & Nanotechnology
Xiaoyuan Duan, Shuaishuai Cheng, Rongyao Tao, Zhiyi Zhang, Guizhe Zhao
Summary: This study chemically grafted flexible thio-lene click reaction particles onto the molecular chain of natural rubber, enhancing the filler-matrix interface interaction and dispersibility of the rubber composites. This resulted in improved mechanical properties, reduced heat generation, and enhanced thermal conductivity. Additionally, the study revealed the influence of thermal conductivity and loss factor on tires and provided insights for the preparation of high-performance graphene rubber tires.
ADVANCED COMPOSITES AND HYBRID MATERIALS
(2022)
Article
Mathematics
Aatef Hobiny, Ibrahim Abbas
Summary: This paper investigates the problem of an unbonded material with variable thermal conductivity, with and without the use of Kirchhoff's transformations. The study utilizes the finite element method to solve the problem and discusses the effects of variable thermal conductivity on the solution. The numerical results are presented graphically for temperature, displacement, and stress distributions.
Article
Mechanics
Tao Meng, Chaoqun Peng, Richu Wang, Yan Feng, Xiaofeng Wang, Zhiyong Cai
Summary: A new prediction model was developed to calculate the effective thermal conductivity of ellipsoidal inclusion-reinforced composites by introducing new shape coefficients and interaction coefficients based on Maxwell-Eucken's model. The model was verified using experimental data and finite element simulation, and the results demonstrated high accuracy (<10%) of the prediction model. The analysis of the model revealed an increase in the effective thermal conductivity of composites with an increase in the aspect ratio of ellipsoidal particles when randomly distributed in the matrix. However, when the ellipsoidal particles were non-randomly distributed, the effective thermal conductivity depended on the angle between the heat flux direction and the long axis of the ellipsoid.
COMPOSITE STRUCTURES
(2023)
Article
Materials Science, Multidisciplinary
Yuanyuan Wang, Jijun Zhao
Summary: This study systematically investigates the thermal conductivity of void-containing tungsten, analyzing the relationship between the topological features of void and the thermal response, exploring the effects of void shapes, arrangements, and rotation angles on heat transmission, and comparing the predicted thermal conductivities with experimental data.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Thermodynamics
Chuan-Jin Su, Tian Zhao, Zeng-Yuan Guo
Summary: In this study, a concept of generalized entransy dissipation (GED) is proposed to optimize the heat conduction process with arbitrary boundary conditions. The minimum principle of GED is applied to solve complex optimization problems, and the results show that GED achieves better thermal performance compared to other optimization objectives. The GED-based continuous optimization problems are convex, ensuring the uniqueness and global optimality of the solution.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(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)