Article
Thermodynamics
Vatsal Jayantilal Bhuva, Jash Pranav Jani, Abhay Patel, Nishant Tiwari
Summary: A numerical study on two-phase flow boiling in raccoon and straight microchannels is conducted, showing the presence of flow boiling instability and the impact of bubble dynamics on the process. Analysis of Eotvos and Weber numbers is used to study bubble behavior and shape, and the influence of different parameters such as waviness and mass flux on bubble flow patterns is investigated. The study also observes the effect of forces on bubble coalescence under varying waviness and mass flux conditions.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Qun Han, Zhaoxuan Liu, Yongping Chen, Wenming Li
Summary: In this study, a novel tesla-type copper microchannel configuration was explored to inhibit vapor backflow and promote two-phase transport simultaneously in the forward direction. The effect of this configuration on two-phase mixing in the backward direction was also investigated. Experimental results show that both critical heat flux (CHF) and heat transfer coefficient (HTC) are significantly increased due to the effective suppression of vapor backflow and enhanced two-phase mixing. At a mass velocity of 360 kgm-2 s-1, CHF and HTC increase by 88.4% and 86.8% respectively.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Yuanzheng Lv, Guodong Xia, Lixin Cheng, Dandan Ma
Summary: Experiments were conducted in two parallel rectangular multi-microchannels using HFE-7100 for flow boiling, revealing significant differences in heat flux and pressure drop under different aspect ratios, with the minimum heat flux decreasing as the aspect ratio decreases. The physical mechanisms of unstable vapor liquid two phase phenomena were analyzed based on a simplified mathematical model, suggesting that a wide flat regime in the hydrodynamic curves may decrease such phenomena.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Mechanics
Justin Broughton, Yogendra K. Joshi
Summary: Microchannels are a potential solution for high-heat-flux thermal management, with methods like constricted inlet, expanding, and auxiliary jetting microchannels examined to mitigate thermohydraulic instabilities. Computational fluid dynamics and heat transfer analyses show improvements in thermal and pressure performance, consistent with experimental results. Bubble dynamics and visualization provide insights into underlying physics, with performance differences investigated and compared with existing literature.
Article
Thermodynamics
Wenming Li, Chen Li, Zuankai Wang, Yongping Chen
Summary: In this study, a novel capillary structure made from micro-pinfin fence has been explored and fabricated in microchannels to rectify the chaotic and unstable two-phase flows during boiling processes. The results demonstrate a highly stable and efficient single annular two-phase flow regime, along with sustainable thin film evaporation and a highly desirable V-shaped heat transfer coefficient curve. The experimental results show significant enhancements in heat transfer rates and critical heat fluxes compared to smooth microchannels.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Jeongmin Lee, Issam Mudawar, Mohammad M. Hasan, Henry K. Nahra, Jeffrey R. Mackey
Summary: This study investigates the near-saturated flow boiling of FC-72 in microgravity using Computational Fluid Dynamics (CFD) and validates the results against experimental data. The study reveals different flow mechanisms such as bubble nucleation, growth, and vapor blankets, while also noting the uniformity of wall temperature along the heated length.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Yun Li, Huiying Wu, Yuanpeng Yao
Summary: Counter-flow stepped microchannels show significant improvements in critical heat flux, heat transfer coefficient, and pressure drop compared to traditional parallel-flow microchannels, effectively suppressing boiling instability.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Yi Yuan, Li Chen, Chuangde Zhang, Xiaoyu Li, Wen-Quan Tao
Summary: This study numerically investigates the subcooling flow boiling heat transfer characteristics in a manifold microchannel (MMC) using a phase change model. The results show that a lower subcooling promotes nucleate boiling but leads to earlier increase in thermal resistance. Optimal channel height and outlet/inlet width ratio optimize the heat transfer performance. Moreover, a new heat transfer correlation is developed, which significantly improves the prediction accuracy of nucleate boiling in MMC compared to existing correlations.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
D. C. Moreira, V. S. Nascimento Jr, S. G. Kandlikar, G. Ribatski
Summary: The development of high heat flux cooling technologies has led to investigations in flow boiling in microchannels. A recent study introduced new heat sinks with asymmetric Dual-V microchannels and a tapered microgap, which demonstrated boiling inversion in flow boiling experiments using water. However, water may not meet certain cooling requirements, and the use of refrigerants is necessary. This study focused on flow boiling experiments with the Hydro-Fluoroolefin R1336mzz(Z) in copper heat sinks combined with a tapered manifold, and evaluated the effects of various parameters on heat transfer performance.
APPLIED THERMAL ENGINEERING
(2023)
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
Sunjae Kim, Nishad Damle, Issam Mudawar, Jason Hartwig
Summary: With the growing interest in space exploration, there is a high demand for cryogenic technologies involving two-phase flow and heat transfer. However, the unique thermal properties of cryogenic fluids introduce distinct flow boiling fluid physics and energy transport phenomena. Understanding the unique two-phase physics in cryogenic flow boiling remains a challenge, and the lack of readily available microgravity cryogenic steady-state heat transfer data hinders the assessment of gravitational effects on cryogenic flow boiling. This study aims to elucidate the gravitational effects on two-phase fluid physics and heat transfer by conducting the first-ever experimental measurement of cryogenic flow boiling performance using a steady-state heated method in a reduced gravity environment.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Ali H. Al-Zaidi, Mohamed M. Mahmoud, Tassos G. Karayiannis
Summary: This paper presents an experimental study on flow boiling patterns, heat transfer rates, and pressure drop in multi-microchannels evaporators made of copper and aluminium. The results showed that aluminium heat sinks have comparable thermal performance to that of copper heat sinks.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Odumuyiwa A. Odumosu, Huashi Xu, Tianyou Wang, Zhizhao Che
Summary: Flow boiling in microchannels utilizes the latent heat of the fluid and can efficiently remove heat. Numerical simulations provide detailed information about the flow and vapor bubble dynamics, which cannot be obtained experimentally. This study focuses on the growth of vapor bubbles in straight and wavy microchannels using numerical simulations. The results show that the wavy structure of the microchannel enhances bubble growth and wall heat transfer due to deformation, expansion, and perturbation of the bubbles. The local Nusselt number in the wavy channel can be up to 2.6 times higher than in the straight channel.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Zhijie Gao, Sihui Hong, Chaobin Dang
Summary: Upward-facing pooling boiling enhancement employing micro-structure has been extensively studied, yet rarely applied in microgravity or nuclear industry. To solve the challenge of vapor removal and liquid replenishment without buoyancy force, this study introduced additional pressure induced by microchannels to achieve spontaneous bubble removal and liquid replenishment. Experimental results showed that channeled surfaces had a lower onset of nucleate boiling superheat and significantly improved heat transfer coefficients compared to plain surfaces. The proposed enhancement mechanism, which relied on separate vapor-liquid flow paths, demonstrated high and consistent heat transfer performance under various pressure conditions and even in downward-facing situations.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Ziliang Rui, Fei Zhao, Hong Sun, Li Sun, Hao Peng
Summary: This paper presents experimental research on a microchannel flow boiling system for thermal management in electronic devices. The flow boiling characteristics of HFE7100 in two novel microchannel structures, namely microchannel with Tesla valve (MCTV) and microchannel with sector bump (MCSB), were studied under different operational conditions. The effects of mass flow rate, inlet temperature, and heat flux on the flow boiling characteristics were analyzed, and it was found that MCSB demonstrated superior thermal-hydraulic performance compared to MCTV. The study also identified reasons for this performance difference, including the ability of MCSB ribs to segment bubble and vapor slug, as well as the smoother geometry and higher local flow velocity near the rib in MCSB.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2023)
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
Energy & Fuels
Jose Loyola-Fuentes, Luca Pietrasanta, Marco Marengo, Francesco Coletti
Summary: This study trains three classification algorithms using experimental data and selects the best algorithm based on their classification accuracy. The results show that the machine learning approach can reduce the uncertainty in flow pattern classification and improve flow regime predictions.
Article
Mechanics
D. J. Bouchard, M. Andredaki, A. Georgoulas, M. Marengo, S. Chandra
Summary: Experimentalists face limitations in deriving information from drop impact experiments on porous surfaces due to short timescales and the opaque nature of porous materials. Numerical simulations can provide additional information such as velocity and pressure profiles, as well as quantification of fluid volume flow rates into pores. Ethanol drops cleave at all tested conditions, while water drops only cleave at higher conditions. Numerical simulations reveal that the lower surface tension of ethanol leads to further spreading, less recoil, and less liquid above the gap, promoting cleaving.
Article
Thermodynamics
Andrzej I. Nowak, Luca Pietrasanta, Cezary Czajkowski, Marco Marengo, Slawomir Pietrowicz
Summary: Passive two-phase heat transfer systems, such as pulsating heat pipes, have promising thermal management applications in the space sector. This research investigates the effect of inertia on flow patterns to improve modeling tools for pulsating heat pipes operating under reduced gravity.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Ali Ahmed Alqahtani, Stuart Edwardson, Marco Marengo, Volfango Bertola
Summary: The heat transfer performance of a flat-plate, flexible polypropylene pulsating heat pipe (PHP) was experimentally evaluated. The bending angle and the reciprocal positions of the heat sink and source were found to have minimal effect on the thermal performance, but may affect the start-up of the PHP.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Konstantinos Vontas, Nicolas Miche, Marco Marengo, Anastasios Georgoulas
Summary: This study investigates the effect of solid surface thermophysical properties on flow boiling heat transfer characteristics within micro-channels using numerical simulations. The results show that materials with higher thermal conductivity exhibit higher heat transfer coefficients, indicating the significant influence of solid surface properties on heat transfer in flow boiling.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Ning Qian, Marco Marengo, Jiajia Chen, Yucan Fu, Jingzhou Zhang, Jiuhua Xu
Summary: This study investigates the thermal performance of a single-loop oscillating heat pipe (OHP) under rotation conditions. The results show that the heat transfer capacity of OHPs filled with acetone and methanol improves with increasing centrifugal acceleration, while the thermal performance of an OHP filled with water peaks at a rotation centrifugal acceleration of 30 m/s(2). The centrifugal acceleration promotes movements of the working fluid and improves the heat transport capacity.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Ning Qian, Fan Jiang, Marco Marengo, Jiajia Chen, Yucan Fu, Jingzhou Zhang, Jiuhua Xu
Summary: This study investigates the start-up behavior of oscillating heat pipes (OHP) under axial-rotation and highlights the importance of start-up speed on grinding efficiency and quality. It is found that OHP filled with acetone has the shortest start-up time, and the cold air pressure and centrifugal acceleration significantly affect the start-up time.
APPLIED THERMAL ENGINEERING
(2023)
Review
Thermodynamics
Marco Bernagozzi, Anastasios Georgoulas, Nicolas Miche, Marco Marengo
Summary: Electric vehicles are seen as a potential solution for reducing greenhouse gas emissions and addressing global warming. Battery thermal management is critical for the performance and sustainability of electric vehicles. Current technologies for battery thermal management in commercial vehicles include air and liquid cooling. This review focuses on the potential use of passive thermal devices called heat pipes for battery thermal management, analyzing different types of heat pipes and methods for removing excess heat. The review aims to collect research results, identify strengths and weaknesses, and propose future research directions for heat pipe battery thermal management systems.
APPLIED THERMAL ENGINEERING
(2023)
Article
Mechanics
Sarvin Naji, Arvin Rahimi, Vahid Bazargan, Marco Marengo
Summary: In this study, a microfluidic chip using a non-embedded co-flow-focusing geometry was numerically simulated to improve droplet generation throughput. An artificial neural network model was trained to optimize the device geometry and flow rate, resulting in remarkable reduction of computation time. Additionally, a periodically switched laser simulation successfully predicted droplet generation frequency.
Article
Thermodynamics
Ning Qian, Fan Jiang, Marco Marengo, Yucan Fu, Jiuhua Xu
Summary: Grinding of difficult-to-machining materials generates excessive heat. Radial-rotating oscillating heat pipe (RR-OHP) can enhance heat transfer and control the temperature during grinding. Experimental results demonstrate that RR-OHP improves heat transfer efficiency in grinding process significantly.
APPLIED THERMAL ENGINEERING
(2023)
Article
Construction & Building Technology
Roberto Rugani, Marco Bernagozzi, Marco Picco, Giacomo Salvadori, Marco Marengo, Hui Zhang, Fabio Fantozzi
Summary: Personal Comfort Systems (PCSs) create localized comfort environments that satisfy individual needs and reduce energy consumption of main HVAC systems. A study focused on a new type of PCS - a warming desk - that uses conduction and radiation for efficient and effective heat transfer. Results showed that the warming desk provided good overall comfort and thermal sensation, with the ability to adjust the surface temperature for individual preferences. The PCS corrected the ambient temperature by about 7K, creating improved thermal comfort compared to centralized HVAC.
BUILDING AND ENVIRONMENT
(2023)
Article
Energy & Fuels
Konstantinos Vontas, Marco Pavarani, Nicolas Miche, Marco Marengo, Anastasios Georgoulas
Summary: This study investigates the applicability of the Eulerian-Eulerian two-fluid model and RPI model in non-conventional channels through numerical simulations. The model is validated and optimized using experimental data from conventional channels, and the importance of including a bubble coalescence and break-up sub-model is demonstrated.
Article
Materials Science, Multidisciplinary
Ghazal Biglari, Maedeh Saberi, Shervin Issakhani, Omid Jadidi, Jafar Farhadi, Vahid Bazargan, Marco Marengo
Summary: This study investigates the controllable patterning of bio-compatible polymers in the presence of a cross-linker in evaporating bi-dispersed colloidal drops. By changing the concentrations of sodium alginate and calcium chloride, the elemental distribution and deposition uniformity of the final patterns can be significantly altered.
MACROMOLECULAR MATERIALS AND ENGINEERING
(2023)
Article
Thermodynamics
Ning Qian, Yucan Fu, Jiajia Chen, Marco Marengo, Jingzhou Zhang, Jiuhua Xu
Summary: Oscillating heat pipes (OHP) have high heat transport capacity and simple structure, but research on their heat transfer performance under system rotation is insufficient. This study experimentally investigates the thermal performance of a centrifugal-accelerated single closed loop OHP and uses grey system theory to model the thermal performance and predict the heat transfer coefficient. The results show improved heat transfer characteristics with increased centrifugal acceleration, and the prediction model provides reliable guidance for engineering applications of OHPs.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2022)
Review
Thermodynamics
Hafiz Muhammad Ali, Tauseef-ur Rehman, Muesluem Arici, Zafar Said, Benjamin Durakovic, Hayder I. Mohammed, Rajan Kumar, Manish K. Rathod, Ozge Buyukdagli, Mohamed Teggar
Summary: Thermal energy storage is becoming increasingly important due to the challenges posed by intermittent renewable energy and waste heat dissipation. This paper discusses the fundamentals and novel applications of thermal energy storage materials and presents a multi-criteria decision making approach to select suitable materials. Recent advancements include materials with enhanced thermal conductivity and multiple phase change temperatures, as well as the application of nanomaterials and shape-stabilized materials in thermal energy storage.
PROGRESS IN ENERGY AND COMBUSTION SCIENCE
(2024)
Review
Thermodynamics
Xuesong Li, Shangning Wang, Shangze Yang, Shuyi Qiu, Zhe Sun, David L. S. Hung, Min Xu
Summary: This review article summarizes recent advances in flash boiling atomization using experimental approaches. It discusses the gas-liquid characteristics and primary breakup of flash boiling sprays, the characteristics of flash boiling spray plumes, and practical issues in adopting flash boiling atomization. Practical applications of flash boiling atomization in combustors are also presented.
PROGRESS IN ENERGY AND COMBUSTION SCIENCE
(2024)
Review
Thermodynamics
Yusheng Zheng, Yunhong Che, Xiaosong Hu, Xin Sui, Daniel-Ioan Stroe, Remus Teodorescu
Summary: This paper provides a comprehensive review of temperature estimation techniques in battery systems, discussing potential metrics, different estimation methods, and their strengths and limitations in battery management. The challenges and future opportunities in battery thermal state monitoring are also identified and discussed.
PROGRESS IN ENERGY AND COMBUSTION SCIENCE
(2024)