Article
Thermodynamics
Mostafa Fathi, Mohammad Mahdi Heyhat, Mohammad Zabetian Targhi, Sajjad Bigham
Summary: Porous-fin microchannel heat sinks have the potential to improve the thermal and hydraulic performances of microelectronic cooling systems. However, the reduced effective thermal conductivity of porous fins compared to solid fins can negatively impact the thermal performance of the microchannel heat sinks. This research confirms that replacing solid with porous fins can simultaneously enhance the thermal and hydraulic performances of microchannel heat sinks.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Jian Song, Fei Liu, Yi Sui, Dalei Jing
Summary: This study numerically investigates the hydraulic and thermal performances of trapezoidal microchannel heat sinks, revealing that pressure drop increases with decreasing small-to-large end width ratio. Only TMCHS configurations with PCPFLI and RCCFLI show improved thermal performances as the ratio decreases, with lower thermal resistance and more uniform temperature distribution. The TMCHS with RCCFLI configuration exhibits the best overall thermal performance among the six configurations studied.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Yunfei Yan, Jinhua Wu, Fulei Xu, Yanrong Chen, Ziqiang He
Summary: A drop-pressure microchannel heat sink with gradient distribution pin fin arrays and narrow slots (DP-MCHS-PS) was proposed to improve the excessive pressure drop in microchannel heat sinks (MCHS). The addition of narrow slots in the DP-MCHS-PS resulted in a smaller increase in pressure drop with increasing volume flowrate. Compared to conventional gradient distribution and uniform distribution, the DP-MCHS-PS exhibited a 56.3% and 52.7% decrease in pressure drop, respectively. The study also evaluated the temperature distribution, heat transfer performance, and thermal resistance of the DP-MCHS-PS.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Xinyu Ji, Xiaoping Yang, Yuantong Zhang, Yonghai Zhang, Jinjia Wei
Summary: This article designs and manufactures silicon-based fractal tree-shaped microchannel heat sinks and experimentally studies their heat transfer and pressure drop characteristics. The results show that compared with traditional linear microchannel heat sinks, fractal microchannel heat sinks achieve significant improvements in flow drag reduction and heat transfer enhancement.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Yacine Khetib, Khaled Sedraoui, Abdellataif Gari
Summary: This study numerically investigated a micro-pin-fin heat sink to improve its cooling capability and productivity. It found that the RS configuration had the maximum heat transfer while also yielding the maximum pressure drop.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Nanoscience & Nanotechnology
Oluwasegun S. Omosehin, Adekunle O. Adelaja, Olabode T. Olakoyejo, Manasseh O. Oyekeye
Summary: This paper numerically investigates the effects of hybridization of water-based copper-alumina nanofluid on the thermal performance, pressure drop, and the figure of merit (FOM) inside a three-dimensional microchannel heat sink. The study shows that higher concentrations of copper nanoparticles lead to better thermal enhancement and FOM of the hydridized nanofluid. Additionally, the maximum FOM is favored by a concentration of copper nanoparticles >= 0.75% for Reynolds number of 400 and <0.75% vol. for Reynolds number of 1200.
MICROFLUIDICS AND NANOFLUIDICS
(2022)
Article
Thermodynamics
Yigit Serkan Sahin, Beytullah Ismet Toprak, Ismail Solmaz, Ozgur Bayer
Summary: With the rapid development in the electronics industry, the thermal management of high power density electronic products has become crucial. This study proposes an integrated heat sink composed of aluminum foam and pin-finned heat sink configurations as an effective solution for the thermal management of such electronic products. Through numerical investigation and experimental examination, the integrated heat sink demonstrates favorable heat removal and pressure drop characteristics under various design conditions.
APPLIED THERMAL ENGINEERING
(2023)
Review
Thermodynamics
Shashank Singh, Anup Malik, Harlal Singh Mali
Summary: This article critically examines the research on modifications in geometry of channels for thermo-hydraulic performance enhancement and aims to determine the best channel configuration with optimal parameters. It explores various designs and their influencing parameters, as well as presents conclusions and potential recommendations for future research.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
D. D. Ma, Y. X. Tang, G. D. Xia
Summary: The sinusoidal wavy microchannels with secondary channels (SWSC) show better heat removal performance in flow boiling studies compared to conventional microchannels, thanks to increased bubble nucleation induced by enlarged surface area and continuous development of thin liquid film due to the introduction of secondary channels. However, the SWSC microchannels suffer from a higher pressure drop penalty.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
D. Sathish Kumar, S. Jayavel
Summary: Incorporating porous fins into a rectangular microchannel heat sink can improve thermal performance, especially when the porosity is 0.4 and permeability is 10-8 m2. The study also shows the importance of slip length in enhancing performance and optimizing fin location for better heat transfer characteristics.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Chenyang Yu, Xu Zhu, Zhigang Li, Yu Ma, Ming Yang, Hang Zhang
Summary: This paper conducts numerical simulations to analyze the flow and heat transfer process in an elliptical pin-fin microchannel heat sink. The effects of different fin sizes, numbers, and flow velocities on the thermal-hydraulic performance of the heat sink are studied. Artificial neural networks are established to predict the average temperature, temperature non-uniformity of the heating surface, and pressure drop of the microchannel. The results show that flow velocity and fin transverse width are the main factors influencing heat transfer and fluid flow.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Rouhollah Moosavi, Mehdi Banihashemi, Cheng-Xian Lin, Po-Ya Abel Chuang
Summary: The study investigates the three-dimensional heat transfer and pressure drop within a microchannel with transverse vortex generator and porous medium. The results show that the convective heat transfer coefficient increases with height and the number of vortex generators, but the pressure drop also increases. By normalizing the changes in heat transfer coefficient and pressure drop using a thermal performance ratio, the microchannel with a combination of vortex generator and porous medium exhibits the highest thermal performance ratio.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Taehoon Kim, Yong-Shik Han, Hwalong You, Changhyun Kim, Minchang Kim, Byung-Il Choi, Kyu Hyung Do
Summary: Despite extensive research on plain-fin heat sinks with impinging flow, few studies have evaluated the impact of flow nonuniformity on their performance. This study developed a novel methodology to assess flow nonuniformity at the heat sink inlet and found that flow uniformity can be improved by increasing the fin height and flow rate. The study also introduced a nonuniformity index-based region map to estimate the heat sink's thermal resistance and pressure drop behaviors under impingement flow.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Chemistry, Physical
Dorsa Sadat Rabizadeh, Majid Abbasalizadeh
Summary: This study aims to investigate the acting mechanism of superhydrophobic surfaces and the factors affecting their performance and efficiency in a three-dimensional flow field. The hydrodynamic performance of a conventional microchannel is numerically assessed with smooth walls and superhydrophobic surfaces at different flow rates. The results show that superhydrophobic surfaces slightly increase the pressure drop in the microchannel, but the increase is not significant. The overall acting mechanism of superhydrophobic surfaces in microchannels is determined by factors such as vortices, periodicity of cavities, and pressure difference.
SURFACES AND INTERFACES
(2022)
Article
Thermodynamics
Fei Liu, Dalei Jing
Summary: The study investigated the hydrothermal performance of symmetric and asymmetric divergent-convergent microchannel heat sinks, finding that smaller inlet-to-middle width ratio results in lower thermal resistance but higher pressure drop in symmetric DCMCHS. Decreasing outlet-to-inlet width ratio improves thermal performance and increases pressure drop in width-asymmetric DCMCHS. Increasing middle cross-sectional width reduces thermal resistance but consumes more pressure drop in width-asymmetric DCMCHS with fixed channel height and outlet-to-inlet width ratio.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Chemistry, Physical
Yulin Wang, Haokai Xu, Wei He, Yulong Zhao, Xiaodong Wang
Summary: This study reconstructs the microstructure of carbon fiber-type GDL with different degrees of aging using a stochastic algorithm, and investigates water transport within the reconstructed GDLs using a multiphase lattice Boltzmann method. The results show that as the GDL ages, its water elimination performance decreases significantly, leading to water retention. The degradation of polytetrafluoroethylene (PTFE) makes the GDL more hydrophilic, causing a more severe water flooding problem. A moderate increase in PTFE content improves GDL antiaging performance, while excessive content reduces the effective porosity and fuel cell performance.
JOURNAL OF POWER SOURCES
(2023)
Article
Chemistry, Multidisciplinary
Shao-Yu Wang, Zi-Jie Wang, Dan-Qi Wang, Yan-Ru Yang, Xiao-Dong Wang, Duu-Jong Lee
Summary: During condensation, applying an external electric field can effectively hinder flooding phenomena and improve the heat-transfer rate by manipulating droplets' motion. Increasing vertical electric field strength hinders vapor motion and decreases collision frequency, while increasing horizontal electric field strength improves condensation performance by enlarging the contacting area. Different electric field frequencies influence growth and nucleation, resulting in various condensation performances.
Article
Chemistry, Multidisciplinary
Lin Lin, Chuan-Jiang Xu, Xiao-Dong Wang, Duu-Jong Lee
Summary: Wetting and dewetting behaviors of Ag droplets on different Mo surfaces were studied using molecular dynamics simulations. Diffusion energy barriers of Ag droplets on the surfaces were analyzed, revealing the presence of precursor films and adsorption layers. Alloying improved the wetting ability of the Mo(111) surface, which had significant precursor films. The fastest dewetting rate was observed on the surface with the highest adsorption layer density. The same molecular kinetic theory model applied to both wetting and dewetting processes, and higher temperatures reduced the time to reach equilibrium.
Article
Chemistry, Multidisciplinary
Dan -Dan Li, Er-Chao Li, Xiang-Yu Ji, Yan-Ru Yang, Xiao-Dong Wang, Guang Feng
Summary: The performance of supercapacitors with different carbon nanotube (CNT) electrodes in tricationic ionic liquid (TIL) electrolytes was assessed using molecular dynamics simulations. The results showed that the capacitance of the electric double-layer (EDL) in TIL increased with increased CNT curvature, and the capacitance of TIL/CNT systems was higher than that of TIL/graphene systems. Different EDL structures and ion distributions were observed near CNT electrodes in TIL compared to monocationic IL (MIL) electrolytes. The TIL also exhibited higher energy-storage ability at high potentials.
Article
Thermodynamics
Shuo-Lin Wang, Di An, Yan-Ru Yang, Shao-Fei Zheng, Xiao-Dong Wang, Duu-Jong Lee
Summary: Based on the synergistic design concept, double-layered microchannel heat sinks with parallel and symmetric wavy porous fins were developed for pressure drop reduction, heat transfer enhancement, and cooling uniformity improvement. Numerical studies showed that the porous-fin design significantly improved heat transfer performance and reduced pressure drop. The symmetric configuration yielded a higher pressure drop reduction, while the parallel configuration provided higher thermal performance.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Ben-Xi Zhang, Yi-Feng Wang, Yan-Yi Zhang, Xin He, Yan-Ru Yang, Xiao-Dong Wang, Duu-Jong Lee
Summary: The explosive boiling of a Cassie-Baxter (CB) state argon film suspended on nanopillar-arrayed surfaces is systematically studied through molecular dynamics simulations. The onset time of explosive boiling increases with the thickness of the suspended liquid film due to the delayed local accumulation of energy. Although the hydraulic diameter decreases with increased nanopillar height, the onset time remains unchanged. This is because liquid argon atoms cannot infiltrate into nanogrooves, maintaining a constant area for heat transfer.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Engineering, Chemical
Quan Ding, Kai-Qi Zhu, Jiang-Hai Xu, Ben-Xi Zhang, Yan-Ru Yang, Yu-Lin Wang, Zhong-Min Wan, Xiao-Dong Wang, Duu-Jong Lee
Summary: This study simulated the oxygen transport performance of proton exchange membrane fuel cells (PEMFCs) under high pumping power (PP), and proposed a novel bamboo shape flow field to serve applications with intermediate PP.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2023)
Article
Chemistry, Multidisciplinary
Ling-Zhe Zhang, Xu Chen, Yi-Feng Wang, Yan-Ru Yang, Shao-Fei Zheng, Duu-Jong Lee, Xiao-Dong Wang
Summary: This study investigates the dynamic behavior of an off-centered impacting droplet on a superhydrophobic cylinder. The research shows that the introduction of an off-center distance disrupts the symmetry of the droplet, resulting in tilted movement and a direct dripping mode. The study proposes quantitative models for maximum spreading and contact time, highlighting their significance in droplet impact and related applications.
Article
Mechanics
Shu-Rong Gao, Bo-Jian Wei, Jia-Xin Jin, Yi-Feng Wang, Shao-Fei Zheng, Yan-Ru Yang, Xiao-Dong Wang
Summary: This study uses lattice Boltzmann method (LBM) simulation to investigate the impact of a droplet on an inclined hydrophobic surface. The results show that surface inclination has no effect on the contact time, while surface wettability and Weber number significantly influence the receding dynamic. A quantitative relationship is established to calculate the contact time, which can evaluate the anti-freezing, anti-icing, and self-cleaning performance of hydrophobic surfaces.
Article
Mechanics
Ben-Xi Zhang, Jiang-Hai Xu, Kai-Qi Zhu, Yan-Yi Zhang, Yan-Ru Yang, Xiao-Dong Wang
Summary: The statics and dynamics of spreading-evaporating nanodroplets under parallel electric fields and free evaporation conditions were investigated through molecular dynamics simulations. The results showed that at a substrate temperature of 320 K, the contact angles on the left and right edges were initially asymmetric and then became symmetric with increasing field strengths, leading to the asymmetric-to-symmetric spreading transition. Under weak evaporation conditions, the asymmetric-to-symmetric spreading transition was triggered by increasing surface wettability at a constant field strength. However, at a substrate temperature of 350 K, the symmetric-to-asymmetric spreading transition appeared first, followed by the asymmetric-to-symmetric transition with increasing field strength. Under strong evaporation conditions, the asymmetric-to-symmetric spreading transition also occurred with increasing surface wettability at a constant field strength.
Article
Chemistry, Multidisciplinary
Xu Chen, Yi-Feng Wang, Yan-Ru Yang, Xiao-Dong Wang, Duu-Jong Lee
Summary: This study investigates the impact of adding ridges to a superhydrophobic cylindrical surface on contact times. It found that at ultralow and medium Weber numbers, the ridges result in longer contact times, while at high Weber numbers, the liquid film above the ridges ruptures, leading to shorter contact times. The study also introduced a criterion, where a value exceeding 2.42 indicates shorter contact times that decrease further with increasing Weber numbers or decreasing droplet diameter.
Article
Chemistry, Multidisciplinary
He-Xiang Liu, Yi-Bo Wang, Shao-Yu Wang, Ke-Chuan Yan, Yan-Ru Yang, Xiao-Dong Wang
Summary: This study investigated the conduction of microscale electrohydrodynamic (EHD) pumps under different working regimes and found that existing theoretical models are not accurate in predicting the electric force of microscale EHD conduction pumps, especially in cases with strong diffusion effects. By revising the expression of heterocharge layer thickness and developing a new theoretical model, the researchers were able to accurately predict the electric force of microscale EHD conduction pumps, even in cases with strong diffusion effects. Additionally, the study showed that microscale EHD conduction pumps are more likely to fall into the saturation regime compared to macroscale EHD conduction pumps, and a new dimensionless number, C (0) (D), was proposed to distinguish the working regimes of microscale EHD conduction pumps.
Article
Thermodynamics
Shao-Fei Zheng, We-Kai Liana, Jia-Xing Meng, He-Chen Wang, Shu-Rong Gao, Yan-Ru Yang, Hai-Wang Li, Bengt Sunden, Xiao-Dong Wang
Summary: This study focuses on optimizing the rib arrangements in cooling passages of a turbine blade cooling unit to improve heat transfer performance. The multi-parameter optimization algorithm is applied to find the optimal designs with different performance indices as objective functions. The results show that using the overall performance factor as the objective function can achieve significant reduction in friction loss with moderate heat transfer loss.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Chemistry, Physical
Yulin Wang, Han Wang, Cheng Wang, Wei He, Yulong Zhao, Xiaodong Wang
Summary: This paper investigates the flow characteristics of water droplets on gas diffusion layer (GDL) surfaces with different roughnesses. The results show that the roughness of GDL surfaces has a significant impact on water droplet flow, with lower Polytetrafluoroethylene (PTFE) content leading to increased surface roughness and longer droplet discharge time, spreading area, and deformation. On the other hand, higher PTFE content results in smoother flow and shorter droplet discharge time. Comparatively, water droplet flow on rough GDL surfaces exhibits longer discharge time, larger spreading area, stronger fluctuations, and larger pressure drop compared to smooth GDL surfaces.
JOURNAL OF POWER SOURCES
(2024)
Article
Thermodynamics
Yi-Bo Wang, Ling-Feng Huang, Ning Lan, Shuo-Lin Wang, Ben-Xi Zhang, Yan-Ru Yang, Xiao-Dong Wang, Duu-Jong Lee
Summary: This study numerically investigated the heat transfer process in a wavy channel enhanced by electrohydrodynamics (EHD), and found that the mechanisms of EHD-enhanced heat transfer differ from a straight channel. Based on the simulation results, strategies for aligning multielectrodes in wavy channels were proposed, and design criteria for enhanced heat transfer performance in discontinuous wavy channels with multiple electrodes were provided.
APPLIED THERMAL ENGINEERING
(2024)
