Article
Physics, Applied
Xuri Yang, Kai Yue, Dongxu Han, Xinxin Zhang
Summary: The thermal conductivity of phase change materials (PCMs) during phase transitions is crucial for evaluating the thermal performance of energy-saving buildings. A method for measuring the effective thermal conductivity of PCM composites was proposed, and its correctness was verified through experiments. The results showed the variations in effective thermal conductivity during phase transitions.
MODERN PHYSICS LETTERS B
(2022)
Article
Materials Science, Ceramics
Kiyoshi Hirao, You Zhou, Manabu Fukushima, Naoki Wakasugi, Katsuaki Suganuma
Summary: Metalized ceramic substrates are widely used for heat dissipation and electrical insulation in high output power modules due to increasing output power of power devices. However, an accurate method for evaluating the in-plane effective thermal conductivities of such substrates is still missing. In this study, a method was developed to evaluate the in-plane effective thermal conductivities by creating a cavity between the substrate and a cooling plate using a ring-shaped structure. Surface temperature measurements were used to evaluate the thermal conductivities, and the values obtained were consistent with those calculated by the rule of mixtures.
CERAMICS INTERNATIONAL
(2023)
Article
Thermodynamics
Ke-Fan Wu, Tao-Feng Cao, Wen-Bin Li, Hu Zhang, Gui-Hua Tang
Summary: In this study, the quantitative influence of natural convection on measuring the thermal conductivity of liquids with the transient plane source method is evaluated by numerically mimicking the heat transfer process within liquids. The results show that for liquids with lower Prandtl numbers (<10), the thermal conductivity measured by a horizontally placed sensor is more precise. On the other hand, liquids with Prandtl numbers higher than 1000 are less affected by natural convection (<1%). Shorter heating time and proper temperature rise magnitude can suppress the influence of natural convection to some extent.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Construction & Building Technology
Aichun Ma, Chenghan Cai, Jie Yang, Tian Zhou
Summary: The study developed a transient measuring method based on two transient plane heat source methods, which can accurately measure multiple thermophysical properties of building insulation materials. The measured thermal conductivities for different materials had small errors, and the findings can contribute significantly to improving the database of thermophysical properties for building insulation materials.
ENERGY AND BUILDINGS
(2021)
Article
Engineering, Multidisciplinary
Sergejs Tarasovs, Andrey Aniskevich
Summary: The identification of anisotropic thermal conductivity of a material was achieved using the transient plane source method and inverse solution. Through three measurements and transient finite element analysis, the accurate calculation and identification of thermal conductivity were realized. The obtained results were validated and found to be consistent with the results calculated using conventional finite element methods.
Article
Materials Science, Ceramics
Shiqi Li, Yuanbing Li, Nana Xu, Shujing Li, Ni Zhong, Chenzhen Fu, Han Luo, Hailu Wang
Summary: This study demonstrated the synthesis of novel zirconium pyrophosphate (ZrP2O7) ceramic foams with controllable thermal insulating properties using a two-step method. The foams showed high porosity, compressive strength, and thermal conductivity, making them suitable for applications requiring low thermal conductivity.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Physics, Multidisciplinary
Hualin Ji, Liangliang Qi, Mingxin Lyu, Yanhua Lai, Zhen Dong
Summary: To reduce errors in the transient planar source (TPS) method, a finite element model that accurately represents heat transfer process was constructed. The established model had an average error of below 1%, significantly better than the 5% average error of the analytical model. An optimization model of the inverse heat transfer problem with thermal conductivity differential equation constraints was then constructed using probabilistic and heuristic optimization algorithms. An improved Bayesian optimization algorithm, BOAAIP, was proposed, which demonstrated better adaptability and stability compared to a genetic algorithm. The inversion accuracy of the two algorithms was around 3% for thermal conductivity below 100 Wm-1K-1, and the improved Bayesian optimization algorithm was three to four times faster in calculation speed than the genetic algorithm.
Article
Thermodynamics
Morgan Sans, Olivier Farges, Vincent Schick, Gilles Parent
Summary: This paper presents a single Monte-Carlo algorithm that can efficiently solve transient conductive and radiative heat transfers in three-dimensional porous media. The methodology demonstrated in this paper allows for practical and efficient study of geometrical and multiphysical complexities. The algorithm was validated against results obtained from various methods and exhibited significant reduction in computation times. This approach is suitable for linear thermal transfer and numerical characterization of heterogeneous media.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Chemistry, Physical
Wenlong Huang, Yushi Ding, Ying Li, Zezhong Wang
Summary: The new double perovskite-type proton conductor BBT30 exhibits high conductivity at high temperatures, with protonic conduction being predominant. It also has a higher proton transport number in atmospheric conditions compared to other double perovskite-type proton conductors.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Rajeev Gopal, Longan Wu, Youngju Lee, Jinzhao Guo, Peng Bai
Summary: Combining solid-state electrolytes with lithium-metal anodes has the potential to enhance the energy density of lithium-ion batteries. By using a combination of linear sweep voltammetry and electrochemical impedance spectroscopy, the presence of significant polarization in ceramic electrolytes, which is critical for understanding dendrite penetration, has been revealed.
ACS ENERGY LETTERS
(2023)
Article
Engineering, Environmental
Jian Hou, Hongdong Liu, Jiansheng Zhang, Ting He
Summary: In the field of proton exchange membrane fuel cell, accurately determining the thermal conductivity of the composite region is crucial for effective hydrothermal management. This study presents a prediction model based on XCT scans to accurately determine the thermal conductivity, and experimental results showed good agreement with the predicted values.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Materials Science, Multidisciplinary
R. W. Yang, Y. P. Liang, J. Xu, X. Y. Meng, J. T. Zhu, S. Y. Cao, M. Y. Wei, R. X. Zhang, J. L. Yang, F. Gao
Summary: In this study, novel rare-earth-niobate high-entropy ceramic foams with hierarchical pore structures were successfully prepared using a particle-stabilized foaming method. Atomic-scale analysis revealed that high entropy led to atom displacement and lattice distortion. The high-entropy ceramic foams exhibited high porosity and ultralow thermal conductivity, indicating promising thermal insulation properties.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Thermodynamics
Svetozar Malinaric, Ahmed Elkholy
Summary: The new plane source (NPS) method is a new technique for measuring thermal conductivity and thermal diffusivity in solid materials, with results showing a high level of accuracy compared to the step-wise transient (SWT) method.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Materials Science, Ceramics
Xiaoyan Zhang, Jingshu Yuan, Yunji Ding, Bo Liu, Shengen Zhang, Jinlong Yang
Summary: A novel method was proposed for directly growing nanowire-built nanofibrous ceramic foams with tunable hierarchical pores, exhibiting excellent heat insulation and dielectric properties, promising for various applications.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Ceramics
Yibo Fan, Shujing Li, Bo Yin, Yuanbing Li, Zhi Tu, Zhen Cai
Summary: In this study, municipal solid waste incineration fly ash was used to prepare a novel calcium silicate-based foam material with ultra-low thermal conductivity. The addition of foam and borax was found to affect the sintering behavior and microstructural evolution of the foams. The resulting ceramic foams show potential applications in thermal insulation, filtration, and catalyst carriers.
CERAMICS INTERNATIONAL
(2022)
Article
Energy & Fuels
Dominik Appel, Fabian P. Hagen, Uwe Wagner, Thomas Koch, Henning Bockhorn, Dimosthenis Trimis
Summary: Compliance with future emission regulations for internal combustion engines poses challenges in cold start conditions during short-distance drives, affecting pollutant emissions and exhaust gas aftertreatment systems. Examination of exhaust gas and deposit composition in a turbocharged gasoline engine during cold start reveals influences on system performance.
JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME
(2021)
Article
Energy & Fuels
Goncalo P. Pacheco, Rodolfo C. Rocha, Miguel C. Franco, Miguel A. A. Mendes, Edgar C. Fernandes, Pedro J. Coelho, Xue-Song Bai
Summary: Ammonia is considered a promising fuel for decarbonization in the power sector due to its lack of carbon and ability to produce energy with zero CO2 emissions. However, challenges such as low reactivity, low flame speed, and formation of nitrogen oxides and ammonia slip exist during its combustion. The use of rich-to-lean combustion approaches can help mitigate NOx formation and improve combustion efficiency, as investigated experimentally and computationally in this study.
Article
Engineering, Civil
M. Vetter, I Dinkov, D. Schelb, D. Trimis
Summary: Experiments conducted in a 36 m(2) compartment revealed main phenomena of fire and smoke propagation before sprinkler activation and interaction between hot flue gases and water spray. A comparison between standard sprinkler and High-Pressure Water Mist system showed different effects, including flue gas scrubbing and recirculation motion leading to increased smoke obscuration.
FIRE SAFETY JOURNAL
(2021)
Article
Engineering, Chemical
Philip Roessger, Andreas Richter
Summary: This study analyzes the interaction of chemical reactions, particle morphology change, and hydrodynamics in fluidized-bed gasifiers through modeling and experimental validation, providing insights into the effects of particle structure changes on chemical reactions and the impact of initial bed height.
Article
Green & Sustainable Science & Technology
Salar Tavakkol, Thorsten Zirwes, Jordan A. Denev, Farshid Jamshidi, Niklas Weber, Henning Bockhorn, Dimosthenis Trimis
Summary: This study presents numerical simulations of rotary kiln reactors for wet biomass carbonization, utilizing a developed numerical tool to model complex physical processes. By validating the tool on laboratory-scale reactors and conducting simulations on an industrial-scale reactor, the study provides insights into optimizing wall temperatures for biomass conversion to char.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2021)
Article
Thermodynamics
D. Bayer-Buhr, M. Vimal, A. Prakash, U. Gross, T. Fieback
Summary: The thermal accommodation coefficient alpha is assumed to be near unity for most gases, but this study shows its contribution to the effective thermal conductivity of highly porous insulation materials. The study investigates the influence of parameters like temperature, roughness, and contamination on alpha for Ar, N-2, He, and validates the assumptions used for calculations. The results also show the effects of physical adsorption and provide insights into the equivalence of alpha for SiO2 and CaSiO3.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Review
Thermodynamics
Falah Alobaid, Naser Almohammed, Massoud Massoudi Farid, Jan May, Philip Rossger, Andreas Richter, Bernd Epple
Summary: This review provides significant knowledge on the development and application of CFD mathematical models in gas-solid fluidized beds. The review is divided into three parts: mathematical modeling, state-of-the-art studies, and conclusion and prospects. It covers various numerical models, their assumptions, and their application in chemical and energy process engineering. The review also analyzes the pros and cons of applying CFD models to fluidized-bed systems and highlights current research trends and future opportunities.
PROGRESS IN ENERGY AND COMBUSTION SCIENCE
(2022)
Article
Thermodynamics
S. Eichinger, T. Storch, T. Grab, S. Tepel, M. Heinrich, T. Fieback, U. Gross
Summary: This study examines the wetting behavior and evaporation heat transfer of a liquid film inside a circular tube with grooves on its internal surface. The experiments show that the use of internal structures significantly improves the wetting behavior and heat transfer. The amount of capillary transported liquid and the geometry of the grooves are the main factors affecting wetting behavior.
APPLIED THERMAL ENGINEERING
(2022)
Article
Chemistry, Analytical
Million M. Afessa, Paulo Debiagi, Ana Isabel Ferreiro, Miguel A. A. Mendes, Tiziano Faravelli, A. Venkata Ramayya
Summary: This study investigates the pyrolysis characteristics of khat stem and coffee husk in Ethiopia and proposes the utilization of these residues for local sustainable economies and environmental issue solutions. The pyrolysis kinetic parameters are estimated using different model-free approaches, and empirical models are developed for comparison and error analysis. The CRECK-S-B model shows good agreement with experimental data and accurately predicts the composition and distribution of pyrolysis products. The findings highlight the potential of these residues and provide insights for waste management and resource utilization.
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2022)
Article
Energy & Fuels
Andre A. V. Lisboa, Raquel Segurado, Miguel A. A. Mendes
Summary: Water stress is a significant issue in developing regions. To address this problem, it is crucial to develop low-cost and low-tech solutions. Seawater desalination using solar stills, which rely solely on solar radiation, can be a viable option for rural coastal areas. This study aims to enhance the water yield of solar stills by proposing an alternative thermal model. The parametric analysis suggests that factors such as water depth, structure design, insulation, incident solar radiation, and temperature difference can improve the water yield.
Article
Engineering, Environmental
S. Koch, F. P. Hagen, L. Buettner, J. Hartmann, A. Velji, H. Kubach, T. Koch, H. Bockhorn, D. Trimis, R. Suntz
Summary: The aim of this study is to investigate the impact of global operating parameters on the reactivity of soot particles in a turbocharged 4-cylinder GDI engine. The results reveal that engine speed has only a slight effect, while a reduction of air/fuel ratio or an increase of brake mean effective pressure significantly reduces the soot oxidation reactivity. The quality of the fuel/air mixture is identified as a significant parameter influencing soot reactivity.
EMISSION CONTROL SCIENCE AND TECHNOLOGY
(2022)
Article
Energy & Fuels
Rodrigo V. Santos, Miguel A. A. Mendes, Carlos Alexandre, Manuela Ribeiro Carrott, Abel Rodrigues, Ana F. Ferreira
Summary: This study evaluated the effectiveness of lab-produced biochar mixed with silica-based sand in improving soil moisture dynamics. The results showed that the application of biochar increased soil water retention and plant available water. The findings suggest that carbonaceous feedstock has the potential to improve soil water relations, which is important for agricultural land use.
Article
Green & Sustainable Science & Technology
Philip Roessger, Ludwig Georg Seidl, Fred Compart, Johannes Hussler, Martin Graebner, Andreas Richter
Summary: This study investigates the integration of biomass and waste into the high-pressure partial oxidation process, using their respective pyrolysis oils as feedstocks for methanol production. Technological, economic, and environmental optimization is applied to show how blend variations and operating conditions affect gasification performance and production costs. The results indicate that different feedstock blends are optimal depending on the chosen objective functions.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Thermodynamics
Christoph Wieland, Christof Weis, Peter Habisreuther, Dimosthenis Trimis
Summary: This study investigates the combustion reactions and heat transfer processes inside porous burners using a three-dimensional direct pore level simulation method. The results indicate that the specific surface area of the porous structure is a significant factor affecting the radiation efficiency.
COMBUSTION AND FLAME
(2022)
Article
Mechanics
Feichi Zhang, Simon Wachter, Thorsten Zirwes, Tobias Jakobs, Nikolaos Zarzalis, Dimosthenis Trimis, Thomas Kolb, Dieter Stapf
Summary: The study investigates the effect of scaling up gas-assisted coaxial atomizers on liquid breakup and spray characteristics. Atomizers with increased sizes were designed and experimentally investigated for different liquid mass flow rates. Results from experiments and simulations show that the breakup morphology remains almost unchanged with the degree of upscaling, but the breakup length increases considerably. This is attributed to the decreased gas flow velocity at the nozzle exit, resulting in decreased momentum exchange between the phases. The obtained results allow for estimating the liquid breakup characteristics when considering the influence of nozzle upscaling.
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)
