Article
Thermodynamics
Ahmed Kadhim Hussein, Mokhtar Ghodbane, Zafar Said, Rusul Salman Ward
Summary: This paper presents a numerical investigation of natural convection in an inclined rectangular enclosure with a baffle filled with Cu/water and Al2O3/water nanofluids. The study found that the intensity of fluid flow in the enclosure increases with the increase in Rayleigh number, solid volume fraction, baffle length, and aspect ratio but decreases with the increase in inclination angle. The local Nusselt number is found to increase with the rise in Rayleigh number and solid volume fraction but decrease with the increase in aspect ratio and inclination angle.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
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
Physics, Multidisciplinary
Marceau Henot, Nicolas Plihon, Nicolas Taberlet
Summary: The formation of glacier tables depends on the size and thermal conductivity of the cap, which can either stand on an ice foot or sink into the ice block. A one-dimensional conduction model shows that the competition between geometrical amplification and heat flux reduction controls the differential ice melting process. Additionally, a dimensionless number identified by the model controls the onset of glacier tables formation.
PHYSICAL REVIEW LETTERS
(2021)
Article
Thermodynamics
Weitong Liu, Guoqiang Xu, Yanchen Fu, Jie Wen, Nan Zhang
Summary: The study investigates the heat transfer characteristics of supercritical n-decane in a laminar flow tube through numerical simulations. It focuses on the coupling law of forced and natural convection in mixed convection. The effects of heat flux and flow direction on heat transfer are examined. The results show that there is deterioration in forced convection when the wall temperature reaches the pseudo-critical temperature, while heat transfer is continuously enhanced in natural convection. Buoyancy has different effects on heat transfer in upward and downward mixed convection flows.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Rahul Ray, Aurovinda Mohanty, Pandab Patro, Santosh Kumar Senapati
Summary: This study performs a computational analysis on the free convection heat transfer of heat sinks with vertical fins mounted on a vertical base. Four geometrical modifications on the continuous rectangular fins are proposed to enhance the heat transfer rate. The study investigates the thermal performances of six different heat sink configurations and finds that the heat sink with a single slot, with the neck at the base and having interruptions, achieves the maximum heat dissipation.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
S. Y. Misyura, R. I. Egorov, V. S. Morozov, A. S. Zaitsev
Summary: This study experimentally investigated the heat flux, Nusselt number, heat transfer coefficient, and entropy generation under local laser heating at different water layer heights. The results showed that the temperature field on the liquid surface was inhomogeneous and asymmetrical at a layer height of 1.4 mm, while the symmetry of the temperature field increased at a layer height of 4-5 mm. The instantaneous velocity and vorticity fields on the liquid surface were studied using the optical method of Particle Image Velocimetry. It was found that local laser heating caused spatially uneven heat exchange due to the self-organization of various convective vortex structures.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Jiao Li, Siqin Hou, Da Teng, Guoqing Shen
Summary: Acoustic reinforced heat transfer is a method that improves heat transfer efficiency by adjusting the parameters of the acoustic field. Experimental results showed that a heat exchanger with an acoustic field had better heat transfer effect. Parameters such as sound pressure level, acoustic frequency, and inlet temperature of the hot flue gas significantly influenced the enhanced heat transfer effect.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Physics, Applied
Hideyuki Sugioka, Yusuke Someya
Summary: Researchers report a light-driven boat that moves towards the colder end through asymmetrical convection flow. They demonstrate that a floating circular structure consisting of light-reflecting and light-absorbing parts moves towards the light-reflecting end under light irradiation. The device is useful for biomedical applications and water remediation.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Thermodynamics
A. Weppe, F. Moreau, D. Saury
Summary: This paper presents an experimental study on turbulent natural convection air flow inside an enclosure with partially heated inner block. Unsteady boundary conditions are applied on the heated face of the block to simulate industrial unsteady heating or cooling conditions. The maximum Rayleigh number reached is 1.98 x 109, which corresponds to the flow regime encountered in car underhood. A dynamical analysis of the flow is conducted for Rayleigh numbers from 0.25 x 109 to 1.98 x 109, and similarity properties of the ascendant boundary layer are highlighted.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Physics, Multidisciplinary
Felix Schindler, Sven Eckert, Till Zuerner, Joerg Schumacher, Tobias Vogt
Summary: In highly turbulent liquid metal convection experiments, the large-scale flow structure and the turbulent transfer of heat and momentum were directly measured. It was found that the aspect ratio has a significant impact on the scaling laws for heat and momentum transfer.
PHYSICAL REVIEW LETTERS
(2022)
Article
Thermodynamics
Akram H. Abed, Abduljabbar M. Ahmed, Waleed Y. Shehab
Summary: This study aimed to investigate the effect of ultrasonic waves on heat transfer enhancement under a subcooled pool condition. A cylindrical rod was submerged in distilled water and a 1.7 MHz ultrasonic transducer was used to generate ultrasonic waves. Three main parameters were examined, including loaded heat flux, water temperature, and heights. The results showed that imposing ultrasonic waves increased the average heat transfer rate by 133%. Increasing water temperature led to a decrease in heat transfer rate, with the most significant decrease observed at Tw=50°C. The effect of heated surface height was also analyzed, and the ultrasonic waves improved the enhancement factor by 3.52 times at H=65 mm. Empirical correlations were proposed based on the test data to evaluate the benefits of using ultrasonic waves in heat transfer enhancement.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Zuzana Brodnianska, Stanislav Kotsmid
Summary: This paper presents an experimental and numerical study on the heat transfer parameters of a heated tube bank and arc-shaped plate. Holographic interferometry is used to evaluate the local heat transfer coefficients, and numerical simulations are performed using Ansys Fluent software. Different arrangements, such as tube bank with fins and double arc-shaped plate, are considered to improve the heat transfer parameters. The results show that the tube bank achieves a higher average Nusselt number compared to other arrangements, and the double arc-shaped plate and tube bank with fins achieve the highest average heat flux.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Mechanics
Binbin Pei, FangBo Li, Kunpeng Zhao, Liang Zhao, Bofeng Bai
Summary: The study focuses on the dynamics of vortical structures in an isothermal turbulent channel flow at supercritical pressure, revealing the complicated effects of variations in thermo-physical properties. The findings include changes in flow direction and the increase of vortex sheets and tubes near the cold wall, as well as the modulation of typical hairpin vortices. Additionally, the study confirms the increased turbulence anisotropy and stronger vortex stretching in cases with variable properties.
Article
Thermodynamics
Chuan-Chieh Liao, Wen-Ken Li
Summary: This study conducts numerical analysis on the heat transfer performance of natural convection inside a cavity filled with nanofluids of Al2O3-water under an external magnetic field. It is found that the magnetic field angles have a significant impact on the relationship between nanoparticle concentration and heat transfer. The study classifies heat transfer patterns under different magnetic field angles and analyzes the critical Hartmann number, providing a basis for predicting the critical Hartmann number under magnetic field conditions.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Liuwei Wang, Ankang Kan, Wei Yu
Summary: This study investigates the melting heat transfer characteristics of phase change material in embedded fin enclosures under hypergravity using the enthalpy-porosity method. The results show that fins greatly accelerate the melting process and hypergravity enhances natural convection and heat transfer performance.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
