Article
Thermodynamics
Jun Seok Lee, Man Yeong Ha, June Kee Min
Summary: The study investigated the mixed convection around inclined-pin fins on a heated plate in a vertical channel for different bypass ratios, calculating solutions of three-dimensional governing equations. Flow patterns, temperature distribution, local and average Nusselt numbers were summarized for various parameter variations, providing insights for heat sink design in practical installation conditions.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Gihyun Song, Eun-Seong Moon, Jeong-Jun Park, Sang-Min Song, Se-Jin Yook
Summary: This study analyzed the dissipation performance of a heat sink with pin fins for LED bulb heat sink, finding that low thermal resistance can be achieved with specific fin length and number under certain conditions. The study also derived a correlation equation for predicting the heat sink thermal resistance with satisfactory accuracy within 17.3% error.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Ram Deshmukh, Vaijanath Raibhole
Summary: This study investigates the thermal performance of a heat sink-based model with a drop-shaped pin fin for LED cooling. Experimental and numerical methods were used to analyze the heat transfer coefficient and Nusselt number. The results showed that the best pin fin configuration significantly improved the thermal conductivity of the LED. Comparison with conventional cooling methods highlighted the potential of innovative passive cooling technology for electronic devices such as LED street lights.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2023)
Article
Thermodynamics
Djamel Sahel, Lahcene Bellahcene, Aissa Yousfi, Abdussamet Subasi
Summary: The study investigated the hydrothermal performance of a heat sink with hemispherical pin fins under fully turbulent flow conditions and optimized the fin configuration. Through the perforation technique, the hydrothermal performance of the heat sink was enhanced significantly.
INTERNATIONAL COMMUNICATIONS IN 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
Rahul Ray, Aurovinda Mohanty, Pandab Patro, Kartik Chandra Tripathy
Summary: This study conducts a performance analysis of branched and interrupted fin heat sinks using numerical simulations to explore the possibility of enhancing heat transfer efficiency. The design that places the secondary fins symmetrically and at the farthest position from the base plate shows the best heat dissipation performance.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Gihyun Song, Dong-Hwa Kim, Dong-Hyung Song, Ju-Bin Sung, Se-Jin Yook
Summary: The study focused on managing the temperature of LED light bulbs through the design and application of an appropriate heat sink. It found that a larger number of perforations with a smaller size on the heat sink improved heat-dissipation performance. The thermal resistance varied with factors such as the number of fins, fin inclination angle, and orientation angle of the heat sink, suggesting ways to enhance heat-dissipation efficiency.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Chunquan Li, Xuebin Li, Hongyan Huang, Yuanhao Zheng
Summary: A new microchannel heat sink with embedded modules with ribs and pin-fins is proposed for efficient microchannel heat dissipation. Strategies such as microchannel cooling within low-temperature co-fired ceramic substrates, embedding modules in the substrate, and creating ribs and pin-fins are employed to enhance heat transfer. The study investigates the effects of relative rib height, relative pin-fin height, and relative number of auxiliary channels on heat transfer performance, temperature uniformity, and pressure drop. The performance of the proposed design is compared to other similar designs, showing significant improvements in heat transfer and temperature uniformity with a slight increase in pressure drop.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Aysenur Ates, Behnam Parizad Benam, Vedat Yagci, Muhammed Caglar Malyemez, Murat Parlak, Abdolali K. Sadaghiani, Ali Kosar
Summary: This study investigates the effects of pin fins and tip clearance on flow boiling in heat sinks, showing that distribution pin fins and streamlined pin fin configurations can enhance the heat transfer performance.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Ali Mohammad Ranjbar, Zeinab Pouransari, Majid Siavashi
Summary: This study investigated the turbulent forced convection heat transfer of air in the presence of porous pin fins for cooling thermal parts of devices. Five fin structures, two different fin arrangements, and three various Darcy numbers were examined to analyze the effects of these parameters on the heat sink performance. It was concluded that the decreasing-aligned pin fin configuration with the highest Darcy number provided the best performance among the studied cases.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Zhijian Duan, Gongnan Xie, Bo Yu, Puhang Jin
Summary: The study focuses on designing optimized structures for liquid-cooled microchannel heat sinks with different pin-fin arrays using the topology optimization method for better performance. The goal is to minimize flow energy dissipation and average temperature of the bottom surface to facilitate more efficient design of microchannel heat sinks for electronic chips' cooling.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Swastik Acharya
Summary: This study investigates the thermo-fluidic behavior of a microchannel heat sink with different fin shapes and arrangements. The results show that increasing the number of fins decreases the heater surface temperature, especially for fins with a height over 200 μm. There is no significant difference in heater surface temperature between different fin shapes, but elliptical fins tend to be marginally more effective. Increasing the fin height enhances heat transfer, and staggered fin arrangements provide better heat transfer compared to inline arrangements. Elliptical fins with staggered arrangement result in the least frictional resistance.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Omar A. Ismail, Ahmed M. Ali, Muhammed A. Hassan, Osama Gamea
Summary: This study optimized the geometry of tapered squared cross-section pin-fins in a square base microchannel heat sink (MCHS) using an experimentally validated computational model. Performance analysis of 256 finned MCHS configurations revealed that thermal performance is mainly affected by the area ratio and tapering height ratio, while hydraulic performance is more influenced by the area ratio. A balanced design was identified through genetic optimization, resulting in significantly reduced thermal resistance and pressure losses.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Priscilla Jia Yuan Fok, Pengfei Liu, Ranjith Kandasamy, Teck Neng Wong
Summary: This report explores the use of Bezier curves to create novel pin-fin shapes and evaluates their thermal performance through numerical and experimental investigations. The results demonstrate the flexibility of Bezier curves in producing different pin-fin geometries, with some of the novel shapes exhibiting good thermal performance.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Sheng-Wei Chang, Ali Sadeghianjahromi, Wen-Jenn Sheu, Chi-Chuan Wang
Summary: 3D numerical simulations were conducted to investigate the thermofluids characteristics of oblique fin heat sinks under natural convection. The study identified critical parameters affecting performance, proposed an optimum heat sink configuration, and introduced a novel symmetrical oblique fin design. Experimental verification confirmed that the proposed oblique fin heat sink offers over 3°C reduction in maximum temperature compared to continuous fin heat sinks.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(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)
