Article
Thermodynamics
Stephen Adeoye, Yoav Peles
Summary: Flow boiling of carbon dioxide with a micro impinging jet was experimentally studied. The effects of heat flux, radial position, mass flux, and pressure on the heat transfer coefficient were investigated. Results showed an increase in the heat transfer coefficient with heat flux, mass flux, and pressure up until the critical heat flux condition. In contrast, the heat transfer coefficient declined with radial position characterized by a pronounced influence of the jet hydrodynamics.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Jeongmin Lee, V. S. Devahdhanush, Steven J. Darges, Issam Mudawar
Summary: This study investigates the effects of compressible volume location on flow instabilities in micro-channel thermal management systems, showing different pressure oscillation phenomena caused by accumulators at different positions. Spectral analysis of pressure signals identifies the most stable operation location.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Jie Li, Dalin Zhang, Wang Yubing, Weijian Chen, Guangya Zhu
Summary: This paper investigates the flow boiling pressure drops in a mini channel with micro pin fin arrays and explores the effects of different structural parameters on its flow performance. The experimental results reveal that smaller channel width and greater diamond angle result in larger pressure drops.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Marius Vermaak, Daniel Orejon, Jaco Dirker, Khellil Sefiane, Josua P. Meyer
Summary: The fluid instability during flow-boiling of Perfluorohexane in a flat horizontal micro/mini channel was experimentally investigated. The results showed that the flow instability was most severe when the heated surface was horizontal and increased with higher mass and heat fluxes. Flow instability often led to improved heat transfer performance.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
V. S. Devahdhanush, Yuchuan Lei, Zhenqian Chen, Issam Mudawar
Summary: This study compares the advantages and disadvantages of micro- and macro-channel flow boiling for high-heat-flux cooling applications, finding that micro-channels have better heat transfer performance but come with increased pressure drop and power requirements, and are prone to choking.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Haein Jung, Seunghyun Lee
Summary: This study presents a new mechanistic model for predicting density wave oscillation (DWO) of flow boiling in horizontal micro-channel heat sinks, using both flow visualization results and transient experimental data. The model consists of two sub-periods, flow surge and reversal, and establishes a set of 1D transient conservation equations. It simulates a full cycle of flow oscillation and shows good agreement with measured oscillation frequencies.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Stanislawa Halon, Zbigniew Krolicki, Remi Revellin, Bartosz Zajaczkowski
Summary: Flow boiling in micro channels is a promising solution for electronics cooling, but its development is hindered by the lack of understanding of heat exchange mechanisms and instabilities. This study experimentally determined the dominant heat transfer mechanism of R245fa in micro channels and investigated the impact of inlet restrictions on thermal performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Yohei Kubo, Sayaka Yamada, Hideki Murakawa, Hitoshi Asano
Summary: Frictional pressure drop and flow patterns of vertically upward boiling flows in semi-circular mini-channels were experimentally investigated using R-245fa as the working fluid. It was found that the gas Weber number increased with increasing mass flux and decreasing hydraulic diameter, and nucleate boiling leading to strong fluctuation of the gas-liquid interface was observed in the 0.55 mm channel.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Jiaxuan Ma, Wenming Li, Dawei Tang, Chen Li
Summary: This study evaluates the impact of micro-slots on the flow boiling characteristics in a microchannel heat sink. The results show that the interconnected microchannels with micro-slots have significantly improved heat transfer coefficients and critical heat flux compared to plain wall microchannels.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Ilhwan Yeo, Seunghyun Lee
Summary: This study computationally investigates the transport phenomena and heat transfer mechanisms of R-134a flow boiling in large length to diameter micro-channel heat sinks, developing a two-dimensional computational model and using a 2D CFD solver based on OpenFOAM. The accuracy of the developed CFD model was assessed by comparing channel wall temperatures with experimental results, revealing good agreement for cases without dry-out. However, nonuniform film evaporation led to unexpected temperature rise and compromised accuracy under asymmetric heating conditions.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Wenming Li, Jiaxuan Ma, Chen Li
Summary: The study introduces a new microchannel configuration by combining capillary micro-pinfin fences and multiple micro-nozzles to enhance flow boiling performance, achieving significant improvements in heat transfer on both DI-water and HFE-7100. Especially, a remarkable enhancement in critical heat flux (CHF) has been achieved, showing promising potential for high-power electronics cooling applications.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Syed Waqar Ali Shah, Xingchi Jiang, Yuanjie Li, Gong Chen, Jian Liu, Yuan Gao, Shakeel Ahmad, Jiyun Zhao, Chin Pan
Summary: Heat dissipation is a crucial challenge for high-power electronics. Microchannel heat sinks, due to their superior heat removal capability and more uniform temperature distribution, are considered a promising option. This study aims to simulate the flow boiling heat transfer in Counter Flow Straight Microchannel (CFSM) pairs and compare it with Co-Current Straight Microchannel (CCSM) pairs. The simulation results show that CFSM pairs have lower void fraction, better heat transfer, and higher Critical Heat Flux (CHF) compared to CCSM pairs.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Nishant Tiwari, Manoj Kumar Moharana
Summary: A three-dimensional numerical study on two-phase flow boiling in a rectangular microchannel with wavy vertical wall configuration was conducted for heat dissipation in high flux electronics devices. The study compared straight and wavy microchannels and investigated the behavior of bubble growth rate and two-phase flow pattern in both. The results showed that smaller bubbles were formed in the wavy microchannel while confined and elongated bubbles were formed in the straight microchannel, leading to flow clogging and premature dryout.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Manolia Andredaki, Konstantinos Vontas, Anastasios Georgoulas, Nicolas Miche, Marco Marengo
Summary: In this paper, the effect of the channel aspect ratio on bubble dynamics and heat transfer characteristics during the early transient stages of bubble growth in confined microchannels is studied using numerical simulations. The results show that the channel aspect ratio has a significant impact on bubble dynamics and heat transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Wei Chang, Kai Luo, Wenming Li, Chen Li
Summary: In this study, the thermal performance of dielectric fluids in microchannel heat sinks was improved by coating nanowires on the microchannels. The enhanced heat transfer rates were achieved by regulating the two-phase regime transition and supporting multiple flow patterns. The results showed improved boiling heat transfer coefficients and critical heat fluxes compared to conventional microchannels.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Marc Hodes, Ravi Mahajan, Zvi Ruder, Terry Simon, Karl Geisler, Michael Ohadi, Joseph Maurer, David Altman, Jim Wilson, Gennady Ziskind, Mark Spector, Ivan Catton, Vijay Dhir, Timothy Fisher, Portonovo Ayyaswamy, Boravoje Mikic
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2021)
Article
Thermodynamics
Majed A. Alrefae, Timothy S. Fisher
Summary: The deposition of graphene on Ni and Cu foils is influenced by factors such as temperature, foil movement, and cooling rate, resulting in growth limitations on Cu foils at lower web speeds and the ability to deposit on Ni foils at relatively higher speeds. By optimizing with a heat transfer model, it is expected to increase the production capacity of graphene in R2R CVD systems.
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2021)
Article
Energy & Fuels
Mostafa Abuseada, Chuyu Wei, R. Mitchell Spearrin, Timothy S. Fisher
Summary: We report a process that converts methane to high-value graphitic carbon and hydrogen gas using simulated solar irradiation. The process involves capturing solid carbon in an easily extractable form through localized solar heating, while maintaining active deposition site density until flow is blocked. This method achieves high methane conversion and hydrogen yield.
Article
Thermodynamics
Akshay Bharadwaj Krishna, Kaiyuan Jin, Portonovo S. Ayyaswamy, Ivan Catton, Timothy S. Fisher
Summary: Heat exchangers are essential in supercritical CO2 Brayton cycles for waste heat recovery. These cycles operate at high temperatures and pressures to achieve higher energy density and thermal efficiency. Accurate estimation of heat exchanger performance is crucial for the design and optimization of sCO2 systems.
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2022)
Article
Thermodynamics
Akshay Bharadwaj Krishna, Kaiyuan Jin, Portonovo S. Ayyaswamy, Ivan Catton, Timothy S. Fisher
Summary: This paper focuses on the performance modeling and correlations of heat exchangers in high-temperature supercritical CO2 Brayton cycles. The developed correlations for heat transfer and friction characteristics offer superior accuracy and versatility. The study validates the correlations using experimental and computational fluid dynamics data and demonstrates their applicability to supercritical CO2 heat exchangers.
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2022)
Article
Thermodynamics
Yuan Hu, Mostafa Abuseada, Abdalla Alghfeli, Saurin Holdheim, Timothy S. Fisher
Summary: This study presents a method for measuring the thermal diffusivity of thin disk samples at high temperatures using a modified angstrom ngstrom's method, along with nondestructive temperature measurements using an infrared camera. The results demonstrate excellent agreement with reference values obtained by other methods, validating the accuracy of the proposed method.
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
(2022)
Article
Physics, Fluids & Plasmas
Majed A. Alrefae, Gayathri Shivkumar, Alina A. Alexeenko, Sergey O. Macheret, Timothy S. Fisher
Summary: In this study, nanocrystalline graphitic films were successfully deposited on Cu foil in a roll-to-roll plasma-enhanced chemical vapor deposition system. The influence of discharge modes on the synthesis of graphitic films was investigated, and electrical and spectroscopic characterizations supported with modeling were performed. It was found that by adjusting the discharge modes, different qualities of nanocrystalline graphitic films could be produced without supplemental heating.
IEEE TRANSACTIONS ON PLASMA SCIENCE
(2022)
Article
Instruments & Instrumentation
Abuseada Mostafa, Alghfeli Abdalla, Timothy S. Fisher
Summary: The paper presents a method for characterizing the output radiative flux of a solar simulator using an inverse mapping technique and custom instruments. This method allows for practical characterization of solar irradiation and provides a cost-effective means of monitoring the performance of solar sources over time.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Correction
Instruments & Instrumentation
Mostafa Abuseada, Abdalla Alghfeli, Timothy S. Fisher
REVIEW OF SCIENTIFIC INSTRUMENTS
(2022)
Article
Materials Science, Multidisciplinary
Mostafa Abuseada, Abdalla Alghfeli, Timothy S. Fisher
Summary: This paper introduces a method to enhance heat spreading capabilities by synthesizing thin graphitic layers on organic substrates through a vacuum deposition process. The use of a light source that can be replaced with solar power enables rapid heating and improves growth rates over larger areas compared to laser processing, mitigating the issue of porosity in graphitic layers. Analysis of the enhanced organic substrates confirms graphitic conversion.
Article
Engineering, Electrical & Electronic
Abdalla Alghfeli, Mostafa Abuseada, Timothy S. Fisher
Summary: This study explores the use of solar-thermal energy to reduce greenhouse gas emissions in industrial processes. Through a solar simulator and a chemical vapor deposition system, high-quality graphene films are synthesized automatically. The results demonstrate the ability of the system to produce high-value products directly from renewable energy sources, and with process control and automation.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B
(2022)
Article
Chemistry, Physical
Mostafa Abuseada, R. Mitchell Spearrin, Timothy S. Fisher
Summary: This article introduces a new solar-thermal methane pyrolysis process that produces hydrogen gas and high-value graphitic carbon product in a fibrous carbon medium. The process reaches steady-state operation quickly and the graphitic product can be easily extracted from the solar reactor.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Engineering, Multidisciplinary
Yuan Hu, Mostafa Abuseada, Abdalla Alghfeli, Saurin Holdheim, Timothy S. Fisher
Summary: This study proposes a Bayesian analysis method that uses a parametric surrogate model in the form of polynomial chaos to accelerate the thermal diffusivity physical model for high-temperature determination. The No-U-Turn sampler is employed to improve the efficiency of the MCMC sampler.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2024)
Article
Energy & Fuels
Mostafa Abuseada, Timothy S. Fisher
Summary: This study presents a scalable route for continuous solar-thermal methane pyrolysis, using a roll-to-roll mode of operation with a fibrous carbon substrate. It converts natural gas into hydrogen and high-quality carbon product with virtually no CO2 emission, offering a promising solution to decarbonize fossil fuels.
Proceedings Paper
Thermodynamics
Ujash Shah, Subramanian S. Iyer, Timothy S. Fisher
Summary: Wafer-scale systems utilize Silicon Interconnect Fabric to achieve high package density and peak heat flux density up to 3 W/mm(2). System requirements vary based on heterogeneous components, with estimated total power delivery of 40 kW and average heat flux density of 1 W/mm(2). Flash cooling enables segmented thermal management with peak heat transfer coefficients of 50,000 W/m(2)K, allowing zonal arrangement of heterogenous dielets.
PROCEEDINGS OF THE TWENTIETH INTERSOCIETY CONFERENCE ON THERMAL AND THERMOMECHANICAL PHENOMENA IN ELECTRONIC SYSTEMS (ITHERM 2021)
(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)