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
Lihui Liu, Yichi Zhang, Guobiao Cai, Peichun Amy Tsai
Summary: The impact of droplets on heated surfaces is crucial in various applications. Temperature variations during impact are significantly influenced by dynamics, with different behaviors observed at different Weber numbers and initial surface temperatures. Temperature changes in both droplets and surfaces are related to the energy conservation principle.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Energy & Fuels
Shiquan Shen, Huan Liu, Yi Liu, Xi Liu, Houzheng Hu, Zhiming Hu, Tianyou Wang
Summary: Emulsion fuel technology is widely recognized as a potential alternative fuel to improve engine fuel efficiency and reduce pollutant emissions without modifying the engine. Micro-explosion in fuel spray has been identified as the key factor in enhancing fuel combustion efficiency and reducing harmful emissions. However, there have been limited studies on the micro-dynamic processes inside emulsion droplets before micro-explosion occurs during heating. Understanding these micro-dynamic processes is crucial for explaining micro-explosion.
Article
Thermodynamics
Yue Ma, Huang Zhang, Qianfeng Liu
Summary: This study experimentally investigates the spreading and splashing behavior of continuous droplets impinging on a heated wall under different conditions. The spreading parameters of the droplets and the relationship between splashing parameters, droplet Weber numbers, and Jacob numbers are analyzed and mathematically fitted.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Engineering, Chemical
Martha L. Taboada, Eva Mueller, Nora Fiedler, Heike P. Karbstein, Volker Gaukel
Summary: The effect of viscosity ratio and emulsion viscosity on oil droplet breakup during atomization was investigated, and a model for predicting oil droplet sizes after atomization was developed.
JOURNAL OF FOOD ENGINEERING
(2022)
Article
Energy & Fuels
Gyu Min Jang, Nam Il Kim
Summary: In this study, the breakup behaviors of n-dodecane water-in-oil emulsion structures on a hot surface were observed and analyzed by varying experimental parameters. The dynamic behaviors of the emulsion droplets after impinging were classified into five regimes, and a simple empirical model for numerical simulation was proposed to explain the breakup mechanism of water-in-oil emulsion on a hot surface.
Article
Engineering, Chemical
Julieta C. Villalobos-Espinosa, Evangelina Garcia-Armenta, Liliana Alamilla-Beltran, Maria Ximena Quintanilla-Carvajal, Ebner Azuara-Nieto, Humberto Hernandez-Sanchez, Maria de Jesus Perea-Flores, Gustavo F. Gutierrez-Lopez
Summary: This study evaluated the effects of a peristaltic pump and a two-fluid pneumatic nozzle on the stability parameters of oil/water emulsions. The results showed that pumping and atomisation led to more homogeneous emulsions with smaller sizes and better stability. This study can contribute to determining operating conditions for encapsulating by spray drying.
JOURNAL OF FOOD ENGINEERING
(2022)
Article
Multidisciplinary Sciences
Mengnan Jiang, Yang Wang, Fayu Liu, Hanheng Du, Yuchao Li, Huanhuan Zhang, Suet To, Steven Wang, Chin Pan, Jihong Yu, David Quere, Zuankai Wang
Summary: This study presents a rational design of structured thermal armours that can inhibit the Leidenfrost effect and maintain heat transfer at higher temperatures. The design includes thermal bridges, an insulating membrane, and vapor evacuation channels, which can generate non-uniform temperature distribution and enhance thermal cooling.
Article
Chemistry, Multidisciplinary
Jiayu Du, Xiong Wang, Yanzhi Li, Qi Min, Xinxin Wu
Summary: Based on the energy conservation approach, a universal model has been developed to predict the maximum spreading factor of liquid droplet impact on a smooth solid surface. Through simulations and experiments, the model effectively reduces computing errors and overcomes limitations of previous models in the viscous regime. It is shown that previous models underestimated the maximum spreading factor due to an overestimation of viscous dissipation. By improving the formulation to compute viscous dissipation, the model has shown good performance in the capillary regime as well.
Article
Thermodynamics
Alexander Ashikhmin, Alexandra Semyonova, Vladislav Fedorov, Sergey Misyura, Maxim Piskunov
Summary: The collision of fuel droplets with the walls of the combustion chamber plays a significant role in the formation of the air-fuel mixture. This study focuses on the hydrodynamic parameters of the drop-wall interaction in the nucleate boiling process of an n-decane-based water-in-oil emulsion, and their influence on heat transfer. Experimental measurements are used to derive empirical models for the contact time of droplets and the heat flux density at the solid-liquid interface during nucleate boiling. These models provide insights into the heat transfer characteristics during the formation of an air-fuel mixture in the combustion chamber of an engine.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Review
Thermodynamics
Chang Cai, Issam Mudawar
Summary: This article provides a systematic overview of the droplet impact on a high-temperature solid surface in the film boiling regime. It discusses the parameters influencing the dynamic Leidenfrost point temperature and reviews the prior theoretical models. The article emphasizes the need for further experimental investigations and the development of an accurate theoretical and experimentally-validated model.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Review
Mechanics
De-yu Tu, Qing-min Pan, Jian-hong Zhou, Baohong Tong, Guo-tao Zhang, Wei Wang
Summary: The study reveals three evolutionary processes of spreading, transition, and central jet after hollow oil droplet impacts on heated walls. The spreading length of hollow oil droplets remains similar in different evolutionary processes, while the central height varies. Additionally, the wall heat flux and the position of the maximum heat flux increase with impact velocity.
THEORETICAL AND COMPUTATIONAL FLUID DYNAMICS
(2021)
Article
Thermodynamics
Timothy W. Munuhe, Ruey-Hung Chen, Liang Zhu, Ronghui Ma
Summary: This study investigates the dynamics of CMAS droplets infiltrating porous thermal barrier coatings, finding that the temperature gradient in the coating is critical to the infiltration rate, and heterogeneous structures can reduce damage to the coatings.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Alexandra Semyonova, Nikita Khomutov, Sergey Misyura, Maxim Piskunov
Summary: This paper presents experimental results on the spreading, fingering, and corona-like splashing of water-in-oil emulsion droplets in collision with a solid surface. The effects of Weber numbers, wall temperatures, and the assumptions explaining the behavior of the maximum spreading diameter of emulsion droplets are examined. The results provide insights into predicting the behavior of the corona based on the relationship between the viscous dissipation of the spreading liquid and the energy transferred to the liquid from the wall.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Haixiang Zhang, Xiwen Zhang, Xian Yi, Feng He, Fenglei Niu, Pengfei Hao
Summary: The experimental study demonstrates the significant influence of surface wettability on the spreading and splashing of water droplets, with surface wettability contributing to the lift of the lamella and promoting spreading speed. The spreading velocity of water droplets on superhydrophobic surfaces is much higher than on other surfaces, and splashing behavior is dominated by the force from the surrounding air.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2021)
Article
Chemistry, Physical
Alexander Ashikhmin, Mikhail Andropov, Maxim Piskunov, Pavel Strizhak, Vyacheslav Yanovsky
Summary: This study investigated the thermal stability of fuel microemulsions based on diesel fuel and vegetable additive stabilized by surfactants. The introduction of the bioadditive was found to narrow the range of existence of the microemulsion. The temperature effect on the dynamic viscosity of the microemulsion systems was also analyzed.
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
(2023)
Article
Thermodynamics
Alexandra Semyonova, Nikita Khomutov, Sergey Misyura, Maxim Piskunov
Summary: This paper presents experimental results on the spreading, fingering, and corona-like splashing of water-in-oil emulsion droplets in collision with a solid surface. The effects of Weber numbers, wall temperatures, and the assumptions explaining the behavior of the maximum spreading diameter of emulsion droplets are examined. The results provide insights into predicting the behavior of the corona based on the relationship between the viscous dissipation of the spreading liquid and the energy transferred to the liquid from the wall.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Mechanics
Maxim Piskunov, Nikita Khomutov, Alexandra Semyonova, Alexander Ashikhmin, Sergey Misyura
Summary: This work proposes a mechanism that considers the vortex motion of a liquid inside an emulsion droplet during its collision with a wall. The motion of the liquid leads to increased dissipative energy losses, which affect spreading, corona splashing, and droplet relaxation. The study also found that the equilibrium shape of the droplet during liquid relaxation is influenced by the temperatures of the liquid and wall.
Article
Energy & Fuels
Elena Khan, Kadir Ozaltin, Damiano Spagnuolo, Andres Bernal-Ballen, Maxim V. Piskunov, Antonio Di Martino
Summary: In this study, biodiesel fuel was produced from rapeseed oil and sunflower oil using transesterification reaction. The impact of alcohol type, concentration, and reaction time on the yield and quality of biodiesel was evaluated. Results showed that the optimal conditions for rapeseed oil were a 15:1 molar ratio of alcohol to oil, a 60-minute reaction time, and a temperature of 50 degrees C. For sunflower oil, the best conditions were an 18:1 molar ratio, a 40-minute reaction time, and a temperature of 50 degrees C. Methanol provided the highest yields of biodiesel in both cases, and the obtained products met the required standards and showed similarity to mineral diesel.
Article
Thermodynamics
Alexander Ashikhmin, Alexandra Semyonova, Vladislav Fedorov, Sergey Misyura, Maxim Piskunov
Summary: The collision of fuel droplets with the walls of the combustion chamber plays a significant role in the formation of the air-fuel mixture. This study focuses on the hydrodynamic parameters of the drop-wall interaction in the nucleate boiling process of an n-decane-based water-in-oil emulsion, and their influence on heat transfer. Experimental measurements are used to derive empirical models for the contact time of droplets and the heat flux density at the solid-liquid interface during nucleate boiling. These models provide insights into the heat transfer characteristics during the formation of an air-fuel mixture in the combustion chamber of an engine.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Maxim Piskunov, Alexandra Semyonova, Alexander Ashikhmin, Vladislav Fedorov, Nikita Khomutov, Sergey Misyura
Summary: The experimental study investigates the unstable equilibrium of an emulsion drop's lamella and rim after colliding with a solid surface at high temperatures, taking into account the emulsion concentration and the presence of a stable boundary vapor layer. It reveals the relationship between the delay time of lamella destabilization and the characteristics of diffusive and convective heat transfer. The study also demonstrates the combined effect of Weber number and emulsion concentration on the critical Rayleigh and Marangoni numbers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Energy & Fuels
Alexander Ashikhmin, Nikita Khomutov, Roman Volkov, Maxim Piskunov, Pavel Strizhak
Summary: The effect of coal hydrophilic particles in water-glycerol drops on the maximum spreading diameter along a hydrophobic solid surface was experimentally studied. The analysis of internal flow velocity by Particle Image Velocimetry (PIV) revealed the interrelated influence of Weber numbers and the concentration of coal particles on the maximum absolute velocity of internal flows. At We = 120, the spreading of particle-laden drops was mainly determined by the dynamics of the deformable Taylor rim. An increase in Weber numbers resulted in more noticeable differences in convection velocities in spreading drops. The presence of coal particles caused a general tendency to reduce drop spreading.
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)
