Article
Thermodynamics
Chao Dang, Yi Ding, Zhuoling Qi, Liaofei Yin, Li Jia
Summary: This study experimentally investigated the saturated nucleate pool boiling heat transfer characteristics of copper foam covered surfaces and plain copper surfaces. The results showed that copper foam coating significantly improved the boiling heat transfer coefficient, while increased roughness of plain copper surfaces had minimal effect. Copper foam covered surfaces triggered nucleation at lower wall superheats, depending on the relationship between the size of the copper foam pores and active nucleation sites.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Materials Science, Coatings & Films
Keming Peng, Deping Yu, Peng Zhang, Lechen Wang, Zhihong Liao, Zhengqiang Lu, Ganyang Wu, Chenfei Song, Lu Li
Summary: Plasma selective quenching is a promising technique to enhance the wear resistance of rail surfaces by creating discrete martensitic hardened zones. However, these zones often experience severe cracks and spalling, which may be attributed to their microstructure and hardness. To address this issue, a novel laminar plasma quenching-tempering (LPQT) technique was proposed to modify the microstructure and hardness of the hardened zones. The LPQT technique involves laminar plasma quenching followed by laminar plasma tempering, resulting in improved wear resistance and decreased presence of cracks and spalling in the rail surfaces.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Thermodynamics
Hasan Alimoradi, Mehrzad Shams, Nasser Ashgriz, Ali Bozorgnezhad
Summary: In this study, a new model was developed to investigate the effect of surface roughness on subcooled flow boiling, showing that microstructure surface roughness can decrease wall surface temperature, and increase vapor volume fraction and heat transfer coefficient.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Nanoscience & Nanotechnology
Mikhail Zhukov, Md Syam Hasan, Pavel Nesterov, Mirna Sabbouh, Olga Burdulenko, Ekaterina Skorb, Michael Nosonovsky
Summary: For studying surface roughness, appropriate roughness parameters should be selected based on specific applications. Large datasets representing surface topography exhibit orderliness, which can be expressed in terms of topological features in high-dimensional dataspaces reflecting properties such as anisotropy and the number of lay directions. These features are scale-dependent, impacted by both the sampling length and resolution.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Thermodynamics
Xilin Wang, Lu Liu, Chen Yang, Xinyu Dong, Xueming Yang
Summary: This study investigated the boiling of argon liquid films on heated solid metal copper and heated liquid metal gallium surfaces using molecular dynamics simulation. The effects of liquid film thickness and surface flexibility on boiling were analyzed. The results showed that a thinner liquid film could provide sufficient vaporization energy and promote rapid vaporization, while vapor cavity growth would tear the liquid film, enhancing boiling heat transfer. Comparatively, the generation and departure of vapor cavities on the surface of liquid metal increased surface fluctuation, facilitating heat transfer and leading to more intense boiling. This study contributes to the understanding of the microscopic mechanism of boiling heat transfer on liquid metal surfaces and provides insights for industrial applications.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Nuclear Science & Technology
Shikha A. Ebrahim, Fan-Bill Cheung, Stephen M. Bajorek, Kirk Tien, Chris L. Hoxie
Summary: This study investigates the effects of liquid subcooling, substrate material, and surface micro-structure on film boiling characteristics. The results show that liquid subcooling and substrate material have significant impacts on heat transfer characteristics, while the effect of surface micro-structure on film boiling regime is negligible.
NUCLEAR ENGINEERING AND DESIGN
(2022)
Article
Materials Science, Coatings & Films
Yong Wang, Xibin Wang, Zhibing Liu, Shuyao Liu, Mingming Ren, Zhibin Wang, Xiaofeng Qin, Feng Li, Fengbin Liu, Zuomei Yang, Jiayi Ren, Weidong Shen, Hongtao Chen, Pai Wang
Summary: The initial characteristics of the surface layer following the quenching and tempering treatment of ultra-high-strength steel play a significant role in determining the subsequent precision machining. The machining processes affect both the oxidation of the quenching and tempering treatment and the development of a distinct preferred grain orientation. Decreased surface abrasions transform the oxidation structure and preferred grain orientation enhances the Taylor effect.
SURFACE & COATINGS TECHNOLOGY
(2023)
Article
Thermodynamics
Xianqiang Deng, Xiaoxiao Xu, Xiang Song, Qibin Li, Chao Liu
Summary: This paper employs molecular dynamics (MD) simulations to study the influence of lubricant (PEC4) on the boiling heat transfer of CO2 on the structured surface. The results indicate that the structured surface enhances the nucleation boiling of CO2 by providing effective nucleation sites and larger heat transfer areas. However, when the mass fraction of PEC4 is increased, the efficiency of nucleation boiling heat transfer decreases on the structured surface. The presence of PEC4 molecules hinders the movement and phase transition of CO2 molecules, leading to an increase in nucleation temperature and a decrease in heat transfer performance.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Reda A. Khalaf-Allah, Salwa M. Mohamed, Esraa Saeed, Mohamed Tolan
Summary: This paper presents the experimental findings of heat transmission during pool boiling on micro-structured copper heating surfaces modified in different ways. The micro-structured surfaces were created using a wire-cutting machine, laser processing, and sandpaper. Using pure water as the liquid, the heat transfer coefficients of the micro-structured surfaces were estimated through experiments. The results showed that the composite surface modification technology of forming a microscopic structure on the heat source surface achieved a maximum improvement of 51-92%.
APPLIED THERMAL ENGINEERING
(2023)
Article
Engineering, Environmental
S. Keshavarzi, A. Entezari, K. Maghsoudi, G. Momen, R. Jafari
Summary: This study investigates ice nucleation time on superhydrophobic surfaces using both experimental testing and machine learning approaches. The experimental results show that superhydrophobic surfaces with higher roughness parameters have longer ice nucleation times. The predicted ice nucleation time from the machine learning model agrees well with the experimental outcomes. The study also determines the relative importance of different parameters in determining surface icephobicity.
COLD REGIONS SCIENCE AND TECHNOLOGY
(2022)
Article
Food Science & Technology
Masato Ohmura, Kentaro Matsumiya, Maeda Tatsuro, Akio Fujita, Yukako Hayashi, Yasuki Matsumura
Summary: This study analyzed the changes in surface structure and inner microstructure of durum wheat pasta during boiling process using various microscopy techniques. The results showed that the pasta surface became more uneven with increasing boiling time, and gelatinization degree was larger when evaluated by polarized light microscopy. Starch granules began to swell during boiling, and the proportion of gluten network on the outer circumference structure decreased.
LWT-FOOD SCIENCE AND TECHNOLOGY
(2021)
Article
Physics, Fluids & Plasmas
Robin B. J. Koldeweij, Pallav Kant, Kirsten Harth, Rielle de Ruiter, Hanneke Gelderblom, Jacco H. Snoeijer, Detlef Lohse, Michiel A. J. van Limbeek
Summary: This study reveals the early solidification patterns and dynamics of spreading hexadecane droplets, showing that the rapid growth of crystals determines the eventual arrest of the spreading contact line. By combining nucleation theory and scaling relations for spreading, the temporal evolution of the solid area fraction is accurately calculated and in good agreement with observations.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Materials Science, Coatings & Films
Wisanu Boonrawd, Kamal R. Awad, Venu Varanasi, Efstathios Meletis
Summary: Electrolytic plasma processing (EPP) can create superhydrophilic surface profiles on titanium, enhancing cell adhesion and growth to potentially improve bone implant bonding.
SURFACE & COATINGS TECHNOLOGY
(2021)
Article
Thermodynamics
Orr Avni, Tali Bar-Kohany, Eran Sher
Summary: For many applications, a high-quality liquid spray is crucial. Flash boiling atomization is a promising method to generate such fine sprays. This study proposes and theoretically examines a novel method that employs flash boiling mechanism to generate spray. By subjecting the liquid to intense heating and inducing homogeneous nucleation, the liquid is disintegrated into a fine spray.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2022)
Article
Thermodynamics
Mahdi Roodbari, Hasan Alimoradi, Mehrzad Shams, Cyrus Aghanajafi
Summary: This study developed an experimental setup to investigate the pool boiling heat transfer characteristics of dilute dispersions of TiO2 nanoparticles in water-ethylene glycol 50. The results showed that increasing heater surface roughness can enhance BHTC and nucleation site density, while the effect of nanofluid concentration on heat transfer coefficient depends significantly on the surface roughness. Additionally, using TiO2-WEG50 nanofluid was found to increase the surface wettability of the heater.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)