Article
Thermodynamics
Zufen Luo, Xiande Fang, Chong Li, Xiaohuan Li
Summary: Saturated flow boiling CHF experiments were conducted to investigate the influence of hypergravity on the working fluid R245fa refrigerant flowing inside a horizontal copper tube. The results show that as the inlet vapor quality decreases, CHF increases and outlet vapor quality at CHF decreases. However, for low mass flux and normal gravity, the increase in CHF weakens with decreasing inlet vapor quality, and the deviation between CHF and the corresponding limiting heat flux increases. Increasing gravity level increases saturated CHF and corresponding outlet vapor quality, thus narrowing the deviation. For high mass flux, CHFs under different gravity levels are almost the same and increase linearly with decreasing inlet vapor quality, gradually deviating from the qlim line.
APPLIED THERMAL ENGINEERING
(2023)
Article
Nanoscience & Nanotechnology
Youngsup Song, Shuai Gong, Geoffrey Vaartstra, Evelyn N. Wang
Summary: Boiling is a fundamental process in many applications where surfaces with microcavities or biphilic wettability can enhance heat transfer efficiency. This study investigated microtube structures to simultaneously enhance heat transfer coefficient and critical heat flux, achieving significant improvements compared to smooth surfaces. The combination of micropillars and microtubes further increased critical heat flux by separating nucleating bubbles and rewetting liquids.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Thermodynamics
Mayowa I. Omisanya, Zhihao Chen, Yoshio Utaka
Summary: Flow boiling heat transfer was studied using a different-mode-interacting boiling (DMIB) method to enhance critical heat flux (CHF) and heat transfer coefficient (HTC). The nonuniform surfaces were found to significantly improve CHF under certain conditions, showing the potential for enhanced performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Gangtao Liang, Han Yang, Jiajun Wang, Shengqiang Shen
Summary: This study assesses the pool boiling critical heat flux (CHF) of nanofluids, demonstrating that the maximum CHF ratio of nanofluid to base fluid can reach 4 and 4.6 for different orientations of heaters. The type of heater (wire or block) has a significant impact on CHF, with direct electric-heating wire heaters accelerating nanoparticle deposition. Pressure and nanoparticle size affect CHF, but dispersion level of particles in base fluid plays a more crucial role in determining CHF ratio.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Review
Thermodynamics
V. S. Devahdhanush, Issam Mudawar
Summary: Jet impingement boiling is a thermal management technique with critical heat flux (CHF) as an important safety parameter. This article provides a systematic review of studies in the field of jet impingement CHF, including experimental jet CHF studies, parametric effects, and techniques for increasing CHF.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Yuheng Zhang, Sophie Wang
Summary: The critical heat flux (CHF) is an important parameter in pool boiling that limits the heat flux and temperature. This study proposes a vapor management approach using a chimney-like vapor shroud during the pool boiling process. The results show that the CHF increases with the length of the vapor shroud, reaching a maximum value at a specific gap. The increase in CHF is believed to be caused by improved liquid feeding and vapor release dynamics.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Youngsup Song, Lenan Zhang, Carlos D. Diaz-Marin, Samuel S. Cruz, Evelyn N. Wang
Summary: This study investigates the role of structured surfaces in enhancing critical heat flux (CHF) during pool boiling. The results show that CHF enhancement on structured surfaces cannot be solely explained by roughness or wickability. A unified descriptor, representing the combined effects of thin film density and volumetric wicking rate, is derived and shows a reasonable correlation with CHF values.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Atul Ranjan, Israr Ahmad, Rinku Kumar Gouda, Manabendra Pathak, Mohd Kaleem Khan
Summary: This study reports the creation of Cu(OH)2 nanoneedles on a copper surface using an anodization process, which can enhance critical heat flux (CHF) limit in pool boiling applications by improving surface wettability and wickability. Results show that the anodized surface requires higher wall superheat for nucleation and exhibits a higher CHF value compared to the plain surface.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Engineering, Multidisciplinary
Ho Seon Ahn, Koung Moon Kim, Somchai Wongwises, Dong-Wook Jerng
Summary: This study designs a unique test section to assess the effect of a small flow path and the wall on the critical heat flux (CHF). Contrary to common knowledge, the study finds that the CHF performance is enhanced in a narrowed hydrodynamic flow path between the heater and cylindrical wall.
ALEXANDRIA ENGINEERING JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Ekkachai Martwong, Yvette Tran
Summary: The study reports on the synthesis and temperature-responsive properties of poly(PEGMA) hydrogel thin films. Surface-attached poly(PEGMA) hydrogel films were synthesized using a simple, versatile, and well-controlled thiol-ene click reaction method, with the transition temperature finely tunable by adjusting the number of PEG units. The LCST properties of the hydrogel films are not sensitive to salt, holding promise for applications in biology such as injectable hydrogels, drug delivery systems, microfluidic valves, and flow switches for biotechnologies.
Article
Thermodynamics
Seyed Moein Rassoulinejad-Mousavi, Firas Al-Hindawi, Tejaswi Soori, Arif Rokoni, Hyunsoo Yoon, Han Hu, Teresa Wu, Ying Sun
Summary: This research explores how deep learning can adapt to new datasets with limited data, studying convolutional neural networks and transfer learning. The study found that transfer learning outperforms convolutional neural networks in cases of data scarcity, demonstrating higher accuracy and lower false negative rates.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
P. Liu, Y. S. Guo, W. L. Zheng, Y. T. Song, X. B. Peng, M. Y. Tang, W. H. Wang, S. F. Huang, J. D. Ji, Q. H. Chen, X. Mao
Summary: The novel compound heat transfer tube (CHTT) combining twisted tape inserts and internal thread tube showed better performance in enhancing subcooled critical heat flux (CHF) compared to individual techniques. CHF in CHTT was directly proportional to pitch, mass flux, and pressure, while inversely proportional to twist ratio. Tong-75-II correlation provided the most accurate prediction of CHF in CHTT, with a mean absolute error (MAE) of 32.80% and a root mean square error (RMSE) of 33.72%.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Dong Eok Kim, Junseok Park
Summary: This study directly observed the dynamics of liquid and vapor on boiling surfaces using visible-ray optics. The critical heat flux (CHF) was found to be triggered by a localized dry region. The intense nucleation and coalescence of vapor bubbles hindered heat transfer at high flux levels.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Sreeram Barathula, S. K. Chaitanya, K. Srinivasan
Summary: The present study examines the performance of machine learning methods in classifying the boiling regimes of water based on acoustic characteristics. Pool boiling experiments were conducted on a wire heater at different heat fluxes to generate a dataset. The dataset is divided into three classes: no boiling, nucleate boiling, and critical heat flux. Three machine learning methods, namely binary decision tree, decision tree ensemble, and naive Bayes, were employed. The decision tree ensemble outperformed the other two methods in classifying the boiling regimes with the least classification error and inference time. Accurate classification based on boiling acoustics enhances safety measures in real-time monitoring of cooling systems.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
T. B. Nguyen, Q. Vo, X. Shang, F. Buang, T. Tran
Summary: This study introduces a novel approach of using the dielectrophoretic effect to suppress film boiling behavior and enhance heat transfer rate.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(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)