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
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
R. H. Hernandez, M. Vial
Summary: This study reports experimental results on inclined Rayleigh–Benard convection in a convection cell with moderate aspect ratio using a high Prandtl aqueous solution of glycerol. The aim is to measure the transition from convective to conductive regime by varying the tilt angle of the cell. Flow transitions between different flow patterns are observed by measuring changes in the heat transfer curve and visualizing the flow.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Massimo Corcione, Alessandro Quintino
Summary: This study presents a numerical investigation on Rayleigh-Benard convection in a shallow cavity filled with different metal-oxide water-based nanofluids. The dispersion of nanoparticles into the base fluid enhances the stability of the nanofluid layer and determines the conditions for convection onset.
APPLIED SCIENCES-BASEL
(2022)
Article
Mechanics
Shashwat Bhattacharya, Mahendra K. Verma, Arnab Bhattacharya
Summary: A multivariate regression model and a neural network model were developed in this paper to predict the Reynolds number and Nusselt number in turbulent thermal convection. By comparing with earlier models, it was found that the machine-learning models in this work provided the best match with the experimental and numerical results.
Article
Physics, Fluids & Plasmas
Shenglei Qin, Guoxiang Hou, Liuming Yang, Xu Liu, Haoze Luo
Summary: This paper introduces a simplified lattice Boltzmann method that solves macroscopic equations in a single step. It can accurately simulate thermal flow problems and has good numerical stability.
Article
Mechanics
Jian-Chao He, Yun Bao, Xi Chen
Summary: Direct numerical simulation (DNS) is conducted for non-slip two dimensional (2D) Rayleigh-Benard convection (RBC) with a wide range of Rayleigh number (Ra up to 10^13), Prandtl number Pr 1/4 0.7, and aspect ratio gamma= 1. The thermal dissipation rate shows an evident scaling transition at Ra asymptotic to 10^9. The mean temperature gradient in the thermal boundary layer is the dominant contribution to the transition. The Nusselt number also exhibits the transition at Ra asymptotic to 10^9. Rating: 7/10.
Article
Thermodynamics
Huilin Tong, Zhengyu Wang, Zhengdao Wang, Hui Yang, Yuehong Qian, Yikun Wei
Summary: The joint effect of rectangular-type roughness and horizontal vibration on two-dimensional turbulent Rayleigh-Benard convection is studied using the thermal lattice Boltzmann method. The Nusselt number and plume dynamics of the convection are the main focus, within the ranges of dimensionless vibration frequency 0≤ω*≤1000 and dimensionless roughness height 0≤h*≤0.05. Numerical results show that the Nusselt number is mostly proportional to the roughness height and exponentially related to the vibration frequency. Furthermore, heat transfer is enhanced by 3.06 times under the joint effect of horizontal vibration and rectangular roughness on turbulent Rayleigh-Benard convection. This provides important insights into the mechanism of cooperative heat transfer enhancement.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2023)
Article
Mechanics
Sebastian Moller, Theo Kaeufer, Ambrish Pandey, Joerg Schumacher, Christian Cierpka
Summary: Turbulent superstructures in horizontally extended three-dimensional Rayleigh-Benard convection flows are investigated in controlled laboratory experiments in water at Prandtl number Pr = 7. The experimental results confirm that the superstructure patterns are an important backbone of the heat transfer.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Alessandro De Rosis, Giovanni Giustini
Summary: This paper analyzes the flow and heat transfer regimes in Rayleigh-Benard convection with a melting boundary using numerical simulations. The results provide insight into the complex behavior of thermal convection, melting, and fluid dynamics.
Article
Engineering, Mechanical
Jian-Zhao Wu, Bo-Fu Wang, Quan Zhou
Summary: In this study, direct numerical simulations of turbulent Rayleigh-Benard convection (RBC) were conducted with consideration of both roughness and external vibration. It was found that increasing the vibration frequency greatly enhances the heat transfer after exceeding a critical value, due to the destabilization of thermal boundary layers and the generation of more thermal plumes. Additionally, the vibration-induced heat transfer enhancement significantly affects the scaling behavior between heat flux and Rayleigh number.
ACTA MECHANICA SINICA
(2022)
Article
Chemistry, Physical
Zhen Tian, Zhibo Tang, Cong Qi, Lanqi Chen, Yuwei Wang
Summary: In this study, the heat transfer properties of nanofluid in a novel cavity were experimentally investigated. The results showed that the best heat transfer performance was achieved when the amplitude was 3mm and the wave number was 2. This provides important guidance for the design of cavities in the field of photothermal conversion and cooling of electronic components.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2022)
Article
Thermodynamics
Temiloluwa O. Scott, Daniel R. E. Ewim, Andrew C. Eloka-Eboka
Summary: The use of hybrid nanofluids for convectional heat transfer has shown great potential in improving heat transfer efficiency. This study experimentally investigated the natural convection heat transfer performance of alumina-multiwalled carbon nanotube/water hybrid nanofluids in a square cavity and found that the hybrid nanofluid with a volume concentration of 0.10 vol% exhibited the best heat transfer performance.
EXPERIMENTAL HEAT TRANSFER
(2022)
Article
Thermodynamics
M. Delort-Laval, L. Soucasse, Ph Riviere, A. Soufiani
Summary: This paper investigates the impact of radiative transfer on Rayleigh-Benard convection and provides conclusions through numerical simulations and analysis. The study found that radiation delays the onset of convection at low Rayleigh numbers, but once convection is established, radiation increases convective flux and kinetic energy. Furthermore, radiative transfer contributes specifically to the potential energy balance and the thermal energy balance, weakening at high Rayleigh numbers. The paper also analyzes the effects of radiative transfer on turbulence budgets of mechanical and thermal fluctuations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Nanoscience & Nanotechnology
Shu-Ning Xia, Jian-Zhao Wu, Zhen-Hua Wan, Bo-Fu Wang, Zhi-Ming Lu, Quan Zhou
Summary: The study found that the tilting has significant effects on large-scale circulation, Nusselt number, and Reynolds number. The trend of Nu and Re with tilting angle shows different behaviors compared to classic models.
Article
Energy & Fuels
Yushuai Liu, Yannis Hardalupas, Alexander M. K. P. Taylor
Summary: A new detailed kinetic model for CO2(1B2) chemiluminescence has been proposed, which successfully predicts the chemiluminescent intensity in hydrocarbon flames and shows good agreement with experimental data. The model extends knowledge of CO2(1B2) chemistry by reproducing a wide range of experimental data.
Article
Engineering, Chemical
George H. Downing, Yannis Hardalupas, Justice Archer, Henry E. Symons, Ulas Baran Baloglu, Daniel Schien, Bryan R. Bzdek, Jonathan P. Reid
Summary: This study compares computational simulations and measurements of aerosol dispersion in a ventilated classroom, finding that a newly developed aerosol transport model can accurately simulate dispersion and predict measured concentrations. The experiments highlight how the maximum aerosol concentration within a room can be many times higher than the average concentration, increasing the risk of infection.
AEROSOL SCIENCE AND TECHNOLOGY
(2022)
Article
Food Science & Technology
D. Bikos, G. Samaras, M. N. Charalambides, P. Cann, M. Masen, C. Hartmann, J. Vieira, A. Sergis, Y. Hardalupas
Summary: Micro-aeration modifies the microstructure of chocolate, creating a third phase layer consisting of cocoa butter with higher melting properties. A multiscale computational model is developed to simulate the structural changes and estimate the thermal properties of micro-aerated chocolate. The study reveals a complex thermal mechanism that controls the behavior of micro-aerated chocolate during melting and solidification, resulting in a slower heat transfer.
INNOVATIVE FOOD SCIENCE & EMERGING TECHNOLOGIES
(2023)
Article
Mechanics
Anjan Goswami, Yannis Hardalupas
Summary: This study investigates the dynamics of the simultaneous impact of two droplets on a dry substrate. A new micro-controlled droplet generator is developed to release two equally sized water droplets simultaneously on-demand. The impact processes for both deposition and splashing of the liquid sheet are analyzed. Simultaneous high-speed imaging provides a quantification of the three-dimensional structure of the sheet morphology, including the temporal evolution of various features.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Materials Science, Multidisciplinary
Dimitrios Bikos, Georgios Samaras, Philippa Cann, Marc Masen, Yannis Hardalupas, Joselio Vieira, Christoph Hartmann, Peter Huthwaite, Bo Lan, Maria N. Charalambides
Summary: This study aims to determine the mechanical properties of chocolate with different levels of micro-aeration under varying modes of deformation. Destructive mechanical experiments are conducted to calculate the Young's modulus, yield, and fracture stress of chocolate. The results show that the Young's modulus of chocolate varies significantly among different mechanical experiments but becomes negligible for the 15% micro-aerated chocolate, suggesting the role of micro-pores in affecting the mechanical behavior of chocolate.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Thermodynamics
Tianyi Wang, Yushuai Liu, Chaoxu Chen, Yannis Hardalupas
Summary: This study applies the technique of two-photon excitation (TPE), planar laser induced fluorescence (PLIF), and optical connectivity (OC) to capture the instantaneous geometry of a liquid jet during atomisation. It demonstrates that a nanosecond pulse laser can excite two-photon fluorescence in a dye-doped water jet. The combination of TPE-PLIF and TPE-OC eliminates the limitations of individual techniques and allows for the quantification of the cross-section structures on the liquid jet surface during atomisation.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2023)
Article
Thermodynamics
A. Sergis, Y. Hardalupas, K. Flinders, D. Hancock, T. Barrett
Summary: This study investigates the morphological and thermal effects of nanoparticle deposition processes on heating surfaces under high heat fluxes. The experiments reveal that nanosuspensions deteriorate cooling performance by forming a porous nanoparticle layer. Increasing nanoparticle concentration helps mitigate the negative thermal effects. The deposited porous layers have the potential to extend critical heat flux in industrial processes.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Mechanics
Tianyi Wang, Yannis Hardalupas
Summary: Liquid jet in crossflow (LJIC) is a process where a high-speed gas crossflow deforms and shears a continuous liquid flow into tiny droplets. This study quantifies the liquid surface motion of LJIC during the primary breakup process, which has not been quantified due to the optical limitation close to the nozzle exit.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2023)
Article
Thermodynamics
M. Iqbal, K. Kouloulias, A. Sergis, Y. Hardalupas
Summary: Nanofluids, colloidal suspensions of nanoparticles and heat transfer fluids, have shown potential for enhanced heat transport in various applications. This study investigates the reported enhancements in thermal conductivity and their alignment with theoretical predictions using a rigorous mathematical analysis method. The results suggest that low nanoparticle concentrations and the use of pH control for electrostatic stabilization, rather than surfactants for steric stabilization, are likely to result in anomalous effects. The findings highlight the importance of understanding the underlying mechanisms of heat transfer in nanofluid preparation.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Engineering, Mechanical
Georgios Samaras, Dimitrios Bikos, Christos Skamniotis, Philippa Cann, Marc Masen, Yannis Hardalupas, Joselio Vieira, Christoph Hartmann, Maria Charalambides
Summary: This article discusses the critical role of structural breakdown of foods in the oral cavity and proposes a computer simulation-based design method to establish the relationship between food mechanical properties and oral behavior. The article introduces a non-local damage approach that overcomes numerical parameter dependency and provides mesh independent results consistent with experimental findings, which is valuable in studying food structure-function relationships.
EXTREME MECHANICS LETTERS
(2023)
Article
Physics, Fluids & Plasmas
Dimitrios Kolokotronis, Srikrishna Sahu, Yannis Hardalupas, Alex M. K. P. Taylor, Akira Arioka
Summary: This study aims to visualize and quantify the relationship between cavitation and liquid flow field in three different injector models. It was found that although bulk cavitation was present, there was no swirling flow structure in the mean flow field at the nozzle exit. However, analysis of the instantaneous liquid velocity data showed that the most energetic mode corresponded to the expected swirling flow structure when bulk cavitation occurred.
Article
Biochemistry & Molecular Biology
D. Bikos, G. Samaras, M. N. Charalambides, P. Cann, M. Masen, C. Hartmann, J. Vieira, A. Sergis, Y. Hardalupas
Summary: This study accurately predicts the temporal and spatial evolution of temperature in chocolate samples using a multiscale finite element model. Experimental and numerical results show that the rate of heat transfer is reduced in micro-aerated chocolate, possibly due to micro-pores acting as thermal barriers.
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)