Article
Thermodynamics
Kangning Xiong, Shuangfeng Wang
Summary: In this work, a low thermal conductivity and high capillary performance porous mullite ceramics secondary wick was prepared to effectively reduce heat leakage in the evaporator of a loop heat pipe (LHP). The addition of NaHCO3 powder improved the compressive strength and porosity of the ceramics, while the surface structure of the ceramics enhanced the capillary performance. Compared to sintered porous copper powder, the porous mullite ceramics exhibited higher porosity, lower thermal conductivity, and superior capillary rise height.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Zhengang Zhao, Guohong Peng, Yanhui Zhang, Dacheng Zhang
Summary: In this paper, a novel sintered multi-size copper powder wick is designed and experimentally investigated for heat flux management. The results show that the new wick has shorter liquid transfer time, faster dynamic response time, and lower overall thermal resistance compared to single-size copper powder wicks.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Hao Guo, Xianbing Ji, Yuanyuan Gan, Jinliang Xu
Summary: Particle morphology and wettability of porous wick have significant effects on the heat transfer performance of loop heat pipes (LHPs). The capillary performance of dendritic particle wick is better than that of spherical particle wick, and superhydrophilic wick has a higher climbing height compared to hydrophilic wick. The particle morphology also affects the uniformity of the working fluid distribution and the operating temperature of LHPs.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Prem Kumar, Mayur Gachake, Sameer Khandekar
Summary: The study focuses on reducing heat leak in loop heat pipes (LHP) by manipulating the properties of the copper wick, leading to improved thermal performance. It was found that the oxidized copper wick performs better thermally than the pure copper wick, attributed to the lower thermal conductivity of the oxidized porous wick reducing heat leak.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Qifan Li, Zhong Lan, Jiang Chun, Shijun Lian, Rongfu Wen, Xuehu Ma
Summary: A novel micro-grooved wick with multi-scale structures was fabricated and its capillary performance investigated, showing that microstructure features had minimal effect on permeability and composite wick covered by microcavities exhibited superior capillary pumping amount and wicking velocity. In the comprehensive evaluation, the optimized capillary wick with microcavities showed over 260% improvement in capillary performance compared to plain sintered-powder wicks.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Shen -Chun Wu, Zhan-Hui Lin, Shu Lo, Wei-Jhih Lin
Summary: Changing the thickness of the polymer wick can effectively reduce heat leakage in the heat pipe, and a thickness of 2mm achieves the best performance.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Thermodynamics
Yugao Ma, Yingnan Zhang, Hongxing Yu, G. H. Su, Shanfang Huang, Jian Deng, Xiaoming Chai, Xiaoqiang He, Zhuohua Zhang
Summary: Screen-wick heat pipes are efficient passive heat transfer devices with heat transfer capacity determined by capillary pressure and film curvature. A capillary evaporating film model was developed, showing improved prediction of the liquid film characteristics. The wire opening distance and diameter affect capillary pressure and flow path. This work provides reference for operating alkali-metal wick heat pipes.
APPLIED THERMAL ENGINEERING
(2023)
Article
Engineering, Chemical
Bing Cai, Weizhong Deng, Tong Wu, Tingting Wang, Zhengyuan Ma, Wei Liu, Lei Ma, Zhichun Liu
Summary: This study explores the influence of using a pouring silicate wick on the production and performance of loop heat pipes. The results show that the system can operate stably, adapt well to changes in heat load, and have good heat load matching capabilities.
Article
Chemistry, Physical
Im-Nam Jang, Yong-Sik Ahn
Summary: The porosity, permeability, and capillary force of porous sintered copper were studied in relation to copper powder size, pore-forming agent, and sintering conditions. Higher values of porosity and permeability were observed when the copper powder size was uniform or small. The capillary force increased with the addition of more forming agent and was higher with larger and non-uniform copper powder size. The results were discussed in relation to porosity and pore size distribution.
Article
Thermodynamics
Xiaowu Wang, Zhenping Wan
Summary: This paper studies the effects of fiber type and wettability of working fluid on the heat transfer performance of the stainless-steel heat pipe with sintered stainless-steel fiber wick. It is found that the thermal resistance of the heat pipe with turned fiber wick is smaller than those of the heat pipes with drawn fiber wick. Water-ethanol solution is suggested as the working fluid, and a concentration ratio of 9:1 to 13:1 is preferred.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
A. Elkholy, M. Bardoel, J. Durfee, R. Kempers
Summary: The hydraulic performance of heat pipes is characterized by the ratio of wick permeability to effective pore radius, known as K/reff. Mass rate-of-rise (mROR) testing is performed to quantify these values, where the wick is dipped into a liquid reservoir and the liquid uptake is monitored. However, conventional models fail to accurately fit experimental data for additively manufactured (AM) wicks. This study introduces a revised model that accounts for the two wicking behaviors observed in AM wicks, resulting in improved data fitting and measurement of K/reff values.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Miao Liu, Wenjing Ning, Junbo Yang, Yuankun Zhang, Zhuosheng Han, Ge Meng, Chunsheng Guo, Han Lin, Baohua Jia
Summary: This study proposes a novel composite pore former comprising NaCl and g-C3N4 for fabricating high-performance multi-morphology porous wicks. The synergistic effect of these pores increases the wicks' porosity and reduces flow resistance, enabling them to exhibit high comprehensive performance. The wicks also have ultralow thermal resistance and exceptional anti-gravity performance.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Shwin-Chung Wong, Mao-Shen Deng, Min-Chieh Liu
Summary: This study investigates the capillary properties of a flat-plate heat pipe with a sintered composite copper mesh-groove wick and proposes a new formula for calculating its permeability. The experimental results show that the composite mesh-groove wick has a higher maximum heat load compared to another commonly used wick.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
A. Ueno, S. Tomita, H. Nagano
Summary: This study presents thin-loop heat pipes with a thickness of 1mm and a one-way transport length of 200mm. Through experiments, it was demonstrated that the tLHPs are capable of transporting heat up to 12W reliably, operating stably without temperature hysteresis within a range of heat loads.
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2021)
Article
Thermodynamics
Jing Zhang, Li-xian Lian, Ying Liu, Ren-quan Wang
Summary: In this study, the capillary limit of heat pipes was predicted based on capillary rise test, showing that irregular powders outperform spherical powders but the experimental values were approximately 7 to 11W higher than the predicted values. The experimental capillary limit was used to adjust the prediction equation at different working temperatures.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Chemistry, Physical
Xiaoru Zhuang, Xinhai Xu, Lun Li, Daxiang Deng
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2020)
Article
Materials Science, Multidisciplinary
Xiang Huang, Tequila A. L. Harris, Yan Wang, Wei Zhou, Daxiang Deng, Tianqing Zheng
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2020)
Article
Optics
Chenyang Zhao, Yang Li, Yingxue Yao, Daxiang Deng
Article
Thermodynamics
Guang Pi, Daxiang Deng, Liang Chen, Xinhai Xu, Chenyang Zhao
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2020)
Article
Energy & Fuels
Yuhua Wu, Jianpeng Cui, Xinhai Xu, Daxiang Deng
Summary: Concentrated photovoltaic (CPV) has attracted attention for its higher efficiency compared to traditional solar cells by concentrating sunrays. Heat dissipation is a critical challenge for CPV at high concentration ratios, but can be mitigated by adjusting water flow rate and temperature to reduce cell temperature and enhance power output. The overall efficiency of heat sinks is influenced by cooling area and channel numbers.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Thermodynamics
Daxiang Deng, Long Zeng, Wei Sun, Guang Pi, Yue Yang
Summary: A new type of open-ring pin fin microchannels (ORPFM) was proposed for advanced microchannel heat sinks, with inline arrangement showing improved boiling heat transfer, reduced pressure drop, and more stable flow boiling process at high heat fluxes through experimental investigation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Chemistry, Physical
Xiang Huang, Wei Zhou, Daxiang Deng
Summary: Understanding the correlation between pore-scale structure and diffusion transport property is crucial for designing and optimizing the performance of porous fibrous materials for energy applications. The lattice Boltzmann method (LBM) and pore network modeling (PNM) are commonly used modeling techniques, but direct comparisons between them have received little attention. Through simulations, it was found that the effective diffusion coefficients between the two methods were in good agreement when estimating throat radius using the cross-section area equivalent radius.
Article
Materials Science, Multidisciplinary
Daxiang Deng, Jian Zheng, Xiaolong Chen, Wei Sun
Summary: This study developed a facile and scalable thermal oxidation method to prepare CuO nanowires on the electrodischarge machining (EDM) processed V-shaped microgrooves. The formation of nanowires was influenced by both annealing temperature and time, and all the nanowire samples showed hydrophobic properties.
CURRENT APPLIED PHYSICS
(2021)
Review
Thermodynamics
Daxiang Deng, Long Zeng, Wei Sun
Summary: This paper comprehensively reviews recent advancements in flow boiling enhancement and fabrication of enhanced microchannels. It emphasizes the flow boiling enhancement performance of these enhanced microchannels in microchannel heat sinks, while also discussing their advantages and disadvantages after summarizing the classification and manufacturing methods of enhanced microchannels.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Mechanical
Long Zeng, Daxiang Deng, Ningbo Zhong, Guisen Zheng
Summary: A unique microchannel heat sink design with inline and staggered open-ring pin fins was developed for high heat flux devices. The open-ring pin fins induced flow separations and convergences, leading to enhanced heat transfer performance. The staggered configuration showed slightly better heat transfer performance than the inline configuration, making it more favorable for heat dissipation in high heat flux devices.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Thermodynamics
Zhi-Jia Xu, Man-Si Luo, Qing-Hui Wang, Hao Zhao, Ying-Jun Wang, Da-Xiang Deng
Summary: This paper proposes a shape optimization method to optimize the shape of the evaporator wick in CPVC, based on the study on the minimization of the maximum pressure drop. By analyzing sensitivity information, the side shape of the wick block is changed, reducing the maximum pressure drop and providing a more scientific and objective alternative for the design of wicks in CPVC.
APPLIED THERMAL ENGINEERING
(2022)
Article
Chemistry, Physical
Xiang Huang, Wei Zhou, Daxiang Deng, Bin Liu, Kaiyong Jiang
Summary: A stochastic pore network modeling method with tailored structures was proposed to investigate the impacts of surface microchannels on the transport properties of porous fibrous media. Results showed that microchannels increased permeability of flow while smaller pores provided higher resistance for better catalyst support. This work suggests that the modeling framework is promising for the design optimization of cross-scale porous structures.
Article
Engineering, Manufacturing
Da-Xiang Deng, Jian Zheng, Xiao-Long Chen, Guang Pi, Yong-Heng Liu
Summary: A laser-micromilling process was developed to fabricate micro pin fins on inclined V-shaped microchannel walls for enhanced heat sinks. The height of the pin fins increased with scanning speed but decreased with line spacing. Optimal processing parameters were found to be a laser output power of 21 W, scanning speed of 100-300 mm/s, and line spacing of 2-5 μm.
ADVANCES IN MANUFACTURING
(2022)
Article
Energy & Fuels
Liang Chen, Daxiang Deng, Qixian Ma, Yingxue Yao, Xinhai Xu
Summary: Efficient cooling is crucial for high concentration photovoltaic (HCPV) cells to maintain their electrical performance and extend their lifetime. In this study, a novel microchannel heat sink with serpentine reentrant microchannels (SRM) was developed for efficient cooling of HCPV cells. The SRM design effectively reduced cell temperatures and improved temperature uniformity, resulting in increased output power and electrical efficiency for the HCPV cell module.
Article
Thermodynamics
Qing-Hui Wang, Zhan-Hui Wu, Zhi-Jia Xu, Xiao-Lin Fang, Hao Zhao, Ying-Jun Wang, Da-Xiang Deng
Summary: This study proposes an optimization method based on design of experiments and response surface methodology, using a decoupling strategy to optimize the groove parameters of the composite porous vapor chamber. The results show that the groove parameters have a nonmonotonic effect, with groove depth having the greatest influence on thermal hydraulic characteristics. The optimal groove parameter configuration can reduce the maximum temperature, maximum temperature difference, and liquid pressure drop, providing a more objective and scientific design method for CPVC structural parameters.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Cong Li, Jiali Wang, Chenhui Wang, Yanke Jin, Yina Yao, Rui Yang
Summary: This study investigates the impact of NaCl water droplets with various concentrations on a heated surface. The results show that the impact patterns can be categorized into different types, and models are established to predict the spreading behavior of droplets with different concentrations. Additionally, high concentration droplets exhibit more violent boiling and have lower residual energy and rebound time.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
C. Barrera, V. Castro, F. Escudero, J. J. Cruz, I. Verdugo, J. Yon, A. Fuentes
Summary: This study focuses on the characterization of soot maturity and sooting propensity of anisole fuel in a controlled laminar coflow diffusion flame. The results show that the spatial distribution of soot volume fraction is enhanced near the flame centerline, while soot production is promoted near the flame wings. The temperature increase also affects the maturity of soot particles.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Roman W. Morse, Jason Chan, Tiago A. Moreira, Jared J. Valois, Evan T. Hurlburt, Jean-Marie Le Corre, Arganthael Berson, Kristofer M. Dressler, Gregory F. Nellis
Summary: This study investigates the dryout of liquid film and the role of disturbance wave frequency. Experimental results indicate that the heat transfer coefficient associated with optimal boiling conditions is maximized when the surface is dry 5% of the time, independent of pulse amplitude and frequency. Liquid-film measurements, dryout statistics, and direct observation suggest that disturbance-wave frequency can be manipulated by density-wave oscillations in the flow field.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
E. J. Vega, J. M. Montanero
Summary: In this study, we experimentally investigated the bursting of a bubble covered with a surfactant. We found that the bubble bursting time is longer compared to a surfactant-free bubble due to interfacial elasticity. Furthermore, the Marangoni stress drives liquid flow that allows the jet to escape from the end-pinching mechanism within a certain surfactant concentration range.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Guofu Sun, Yi Zhan, Tomio Okawa, Mitsuhiro Aoyagi, Akihiro Uchibori, Yasushi Okano
Summary: Experiments were conducted on liquid jets ejected from oval nozzles to investigate the effects of nozzle orifice shape on jet behavior. The study found that the liquid jet exhibited different characteristics at different liquid flow rates. Correlations were established to predict the liquid jet state and characteristics of the secondary droplets produced during jet impact onto a solid surface. This research extended the available knowledge on liquid jet behavior.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Jeonghoon Lee, Laurent Zimmer, Takeshi Saito, Shinji Nakaya, Mitsuhiro Tsue
Summary: This study investigates the effects of spatial resolution on DMD amplitudes and spatial mode strengths, and proposes scaling factors to correct for the resolution differences. The results show that the proposed scaling factors successfully normalize the amplitudes and spatial modes, allowing for quantitative comparison of data obtained with different spatial resolutions. This study is significant for analyzing spatiotemporal data in various fields.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Yanli Zhao, Shibing Kuang, Xiaoliang Zhang, Mingjun Xu
Summary: This study experimentally investigates the dynamic process of water droplet impacting different wood surfaces and analyzes and discusses the impacting phenomena, phenomena distribution, droplet spreading dynamics, and maximum spread factor. The results show that the impacting process can be distinguished by Weber numbers and Reynolds numbers, and can be predicted by mathematical expressions.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Aakhash Sundaresan, Atul Srivastava, Callum Atkinson
Summary: This study presents the first-ever application of an advanced methodology, combining two-color laser-induced phosphorescence and particle image velocimetry, to investigate the heat transfer mechanisms on the surface of a cylinder placed inside a confined square duct. The technique allows for simultaneous measurement of velocity and temperature fields, reducing the complexity and costs associated with separately measuring temperature distributions. Experimental observations show that increasing the mass flow rate enhances heat removal from the cylinder surface, and increasing the cylinder heat input enhances heat transfer in the rear portion of the cylinder.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Harish K. Patel, Sukhjeet Arora, Rutuja Chavan, Bimlesh Kumar
Summary: This study experimentally analyzed the multiscale statistical assessment of scour depth surrounding spur dikes with downward seepage. The research found that seepage affects the morphological behavior and hydrodynamic characteristics of the channel bed, leading to changes in scour formation. The rate of scour depth changes initially increases with higher seepage velocity but eventually becomes constant over time.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Justas Sereika, Paulius Vilkinis, Gediminas Skarbalius, Algis Dziugys, Nerijus Pedisius
Summary: This study experimentally investigated the pulsatile flow structure based on a transitional-type cavity. It was found that the pulsation amplitude has a more significant effect on the dynamics of recirculation zone than the pulsation frequency. Pulsatile flow can reduce the size of the recirculation zone.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Merav Arogeti, Eran Sher, Tali Bar-Kohany
Summary: This study provides a detailed exploration of the events that occur when a droplet hits a dry solid surface of various small sizes, with a focus on the deposition, receding breakup, and prompt splash phases. By utilizing non-dimensional analysis and graphical representation, the boundaries between different events are defined, and criteria for differentiation based on target-to-drop ratio, Reynolds, and Webber numbers are presented.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Tianxiong Li, Fei Wen, Yingchun Wu, Botong Wen, Lei Wang, Jinxin Guo, Xuecheng Wu
Summary: This study investigates the structure of the flow field induced by a strut in a scramjet and its influence on flame stabilization. Experimental and numerical analyses reveal that the flow field exhibits features beneficial for flame stabilization, but the asymmetry of the flow poses a challenge to flame establishment.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Syed Ehtisham Gillani, Yasir M. Al-Abdeli
Summary: This study investigates the asymmetry in bluff-body stabilised annular jets and finds that swirl can significantly mitigate the asymmetry and restore the symmetry of the jets. Moreover, increasing the Reynolds number and the swirl intensity can both decrease the asymmetry of the jets.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Utsav Bhardwaj, Rabindra Kumar, Shyama Prasad Das
Summary: This study presents an experimental investigation on flooding phenomenon in a pulsating heat pipe (PHP) unit cell, and analyzes the impact of flooding on the performance of PHP. The study recognizes three different flooding mechanisms and finds that currently accepted correlations for predicting flooding velocity are inaccurate. The study emphasizes the need for further research on flooding in PHPs.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Yunpeng Xue, Yongling Zhao, Shuo-Jun Mei, Yuan Chao, Jan Carmeliet
Summary: This study investigates the impact of building morphology on local climate, air quality, and urban microclimate. The researchers conducted an experimental investigation in a large-scale water tunnel, analyzing heat and flow fields using Laser-induced Fluorescence (LIF) and Particle Image Velocimetry (PIV). The findings show that factors such as canyon configuration, buoyant force, and approaching flow magnitude significantly influence fluid flow in street canyons, and the morphology of the street canyon dominates ventilation rate and heat flux. For example, changing the aspect ratio of a street canyon can lead to a significant change in air ventilation rate, ranging from 0.02 to 1.5 under the same flow conditions.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)