Article
Thermodynamics
Xin Wang, Bo Xu, Zhenqian Chen, Yang Yang, Qian Cao
Summary: The study simulates dropwise condensation heat transfer on different microstructured surfaces using 2D hybrid thermal lattice Boltzmann method, investigating the dynamic behaviors of condensate droplets and analyzing the influence of surface wettability, surface microstructure, and subcooling degree on condensate dynamics and heat transfer performance. The results show that condensate microdroplets preferentially form at the valley or side of micropillar arrays, with superhydrophobic surfaces eventually surpassing hydrophilic and hydrophobic surfaces in condensate mass and rate. The study provides insight into the microscopic mechanism of dropwise condensation heat transfer.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Nanoscience & Nanotechnology
Soumei Baba, Kenichiro Sawada, Kohsuke Tanaka, Atsushi Okamoto
Summary: This study focused on the hierarchical nano/microstructure of Euphorbia myrsinites leaves and successfully mimicked the structure artificially to provide important insights for the development of new engineering materials.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Thermodynamics
Hai Wang, Xin Zhao, Junfeng Wang, Zhentao Wang, Dongbao Wang, Jiameng Tian
Summary: The study developed superhydrophilic and superhydrophobic hybrid surfaces for enhancing condensation heat transfer on copper substrates. The synergistic combination of superhydrophobic and superhydrophilic surfaces was effective in improving droplet nucleation rate, coalescence control, and condensate removal efficiency. Experimental results showed that the SSH-2 surface outperformed the SSH-3 and SSH-1 surfaces in heat transfer performance, with a heat transfer coefficient 1.1 and 1.3 times higher at a surface subcooling of 7.1 K, respectively.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Xifan Fu, Qinpeng Zhu, Denghui Liu, Binghan Liu, Lintao Kuang, Yanhui Feng, Fuqiang Chu, Zhi Huang
Summary: A study on moisture condensation on hybrid superhydrophobic-hydrophilic surfaces revealed the significant impact of wettability difference and microstructure size on condensation efficiency, leading to a 90% enhancement in condensation rate. Detailed analysis of the condensation process provided insights into the enhanced condensation mechanism, proposing effective methods for controlling and optimizing moisture condensation.
Article
Thermodynamics
Marco Tancon, Riccardo Parin, Stefano Bortolin, Alessandro Martucci, Davide Del Col
Summary: Dropwise condensation is a complex phenomenon involving droplet nucleation, coalescence and motion. Limited studies have investigated the effect of vapor velocity on heat transfer coefficient and droplet departing radius during DWC.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Fengyong Lv, Sifan Lin, Hanlu Nie, Zhenbiao Dong, Fang Zhao, Daolai Cheng, Zhiguang Dong, Raza Gulfam
Summary: This study investigates the droplet dynamics and heat transfer performance of a helically-finned hydrophobic tube fabricated using a simple annealing method. The findings show that the heat transfer coefficient of the helically-finned hydrophobic tube can increase by up to 327% compared to a smooth hydrophilic tube at a specific heat flux. Furthermore, the heat transfer coefficient decreases as the subcooling temperature increases, primarily due to slower droplet growth and dripping frequency. The grooves on the helically-finned hydrophobic tube enhance droplet coalescence and sweeping, resulting in improved heat transfer performance. This study provides technological insights to enhance heat transfer performance in industrial condensers.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Chemistry, Physical
Wei Chang, Benli Peng, Ahmed S. Khan, Mohammad Alwazzan, Yunya Zhang, Xiaodong Li, Yan Tong, Chen Li
Summary: The study reveals the significant impact of graphene grain size on the wettability of polycrystalline graphene, showing that the static contact angle and hysteresis on graphene surfaces change with the average graphene grain areas. Furthermore, experiments on water vapor condensation indicate that a larger graphene grain size leads to enhanced dropwise condensation heat transfer rates.
Article
Physics, Fluids & Plasmas
Chia -Ming Chang, Yi-Hsin Lin, Victor Reshetnyak
Summary: The way water condenses on surfaces is crucial for the energy efficiency of heat transfer systems. Controlled manipulation of water condensation on tunable surfaces has potential applications in various fields and offers promising prospects for development.
Article
Chemistry, Multidisciplinary
Bingang Du, Yaqi Cheng, Siyan Yang, Wei Xu, Zhong Lan, Rongfu Wen, Xuehu Ma
Summary: This study explores the importance of controlling vapor nucleation on micro-/nanostructured surfaces and the surface morphology to achieve this. The research found that nanostep morphologies around the top of nanowire bunches can reduce energy barriers and enhance nucleation, thus promoting vapor nucleation and droplet removal.
Article
Thermodynamics
Fengyong Lv, Sifan Lin, Jie Miao, Cong Wang, Zhenbiao Dong, Raza Gulfam
Summary: This study developed slippery lubricant-infused porous surfaces (SLIPSs) on helically-finned grooves of copper tubes (HF-SLIPSs). The high viscosity lubricant (GPL 107) was locked by the nano-pores of the oxidized layer on the grooves. The results show that HF-SLIPSs not only improve droplet mobility and increase condensing area but also provide directional transport tracks, resulting in a short renewal time and enhanced condensation heat transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Chemistry, Multidisciplinary
Jianxing Sun, Xinyu Jiang, Patricia B. Weisensee
Summary: Lubricant-infused surfaces enhance dropwise condensation and heat transfer rates by creating distinct oil-rich and oil-poor regions for water microdroplets to self-propel, but the dynamic interplay between oil film redistribution, droplet self-propulsion, and nucleation process is not fully understood.
Article
Chemistry, Multidisciplinary
Dong Niu, Hongtao Gao, Guihua Tang, Yuying Yan
Summary: In this study, molecular dynamics simulation was used to investigate droplet nucleation and growth in the Ar-Ne mixed system. Different droplet state transition modes were identified, and the interaction between NCG and droplets was considered to explain the wetting state. The disappearance mechanism of the flooding mode on nanostructured surfaces under large amounts of NCG was clarified at the nanoscale, providing insights into the NCG effect on dropwise condensation heat transfer on nanostructured superhydrophobic surfaces.
Article
Chemistry, Multidisciplinary
Younghun Shin, Subin Jeong, Kwon-Yeong Lee, Seeun Woo, Woonbong Hwang
Summary: Condensation is a critical phenomenon in industrial fields, and the condensation heat transfer performance can be improved by regulating the surface topology. This study analyzed the condensation phenomenon of large-area copper tubes and found a correlation between contact angle hysteresis and total heat transfer coefficient.
Article
Chemistry, Multidisciplinary
Abinash Tripathy, Cheuk Wing Edmond Lam, Diana Davila, Matteo Donati, Athanasios Milionis, Chander Shekhar Sharma, Dimos Poulikakos
Summary: Researchers have developed an ultrathin and conductive lubricant-infused surface architecture that greatly enhances heat transfer performance while resisting lubricant depletion, making it perform better in condensation processes.
Article
Thermodynamics
Zhifeng Hu, Zhiping Yuan, Huimin Hou, Fuqiang Chu, X. M. Wu
Summary: An event-driven simulation method is proposed to efficiently simulate multi-scale three-dimensional dropwise condensation, significantly improving computational efficiency. The influence of droplet departure modes on dropwise condensation is discussed, showing the importance of droplet jumping in enhancing condensation heat transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
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)