Article
Mechanics
Xueshuo Chen, Jie Wang, Tao Lu, Jiang Sheng, Xue Chen
Summary: The flow characteristics of droplet and sheet flow in horizontal tube falling film were investigated through experiments and simulations. The results provide detailed insights into the flow characteristics and identify the factors influencing the film thickness.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2022)
Article
Thermodynamics
Chuang-Yao Zhao, Qiong-Tao Li, Di Qi, Zeng-Xi Feng, Jun-Min Jiang
Summary: Numerical simulations were conducted to examine the effect of cross-vapor stream on the heat transfer performance of a falling film evaporator. The results showed that the cross-vapor stream caused deflections in liquid film spreading, distinct distributions of heat transfer coefficients and liquid film thicknesses on the tube surface, and asymmetry in the axial-averaged peripheral heat transfer coefficient. Increasing vapor velocity led to three trends of average heat transfer coefficients, and higher liquid flow rates improved the heat transfer performance under cross-vapor conditions.
APPLIED THERMAL ENGINEERING
(2023)
Article
Mechanics
Chuang-Yao Zhao, Qiong-Tao Li, Di Qi, Zeng-Xi Feng, Jun-Min Jiang
Summary: This study developed a three-dimensional model to investigate the hydrodynamics of a falling film on a horizontal tube with a cross vapor stream. The results showed that vapor velocity has a significant impact on film thickness and spreading, leading to film offset.
Article
Thermodynamics
Prudviraj Kandukuri, Sandip Deshmukh, Supradeepan Katiresan
Summary: Gravity-driven horizontal falling-film flow is an innovative technology widely used in various industries. Through experiments and numerical simulations, the flow regimes, flow mechanisms, and parameter details were investigated. The study found that droplet flow has three important phases and increasing Reynolds number leads to increased film thickness and vortices formation.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Mechanics
Yali Guo, Minle Bao, Luyuan Gong, Shengqiang Shen, Kun Zhang
Summary: In this study, numerical simulations were conducted to investigate the film thickness and heat transfer characteristics of a falling film evaporator over a horizontal round tube. The results showed that the film thickness had an asymmetric circumferential distribution, and the heat transfer coefficient reached its maximum value at the impact point. Increasing the spray density, saturation temperature, and longitudinal inter-tube spacing led to an increase in the film thickness and heat transfer coefficient.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2022)
Article
Thermodynamics
Furqan Tahir, Abdelnasser Mabrouk, Muammer Koc
Summary: The study focuses on analyzing the effects of co-current vapor flow on falling film distribution and hydrodynamics in a multi-effect evaporator. It found that vapor flow significantly affects the film distribution on the upper half of the tube, leading to a reduction in average film thickness and wetting time.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Nuclear Science & Technology
Meihui Zhou, Ping Tao, Xichao Di, Jianqiu Zhou
Summary: In this study, a 2D model is used to investigate the influence of co-current gas flow on the hydrodynamic characteristics of falling film outside horizontal pipes. The results show that the gas flow significantly affects the film thickness and motion. Factors such as film flow rate, tube diameter, and distributor height also amplify the impact of gas flow velocity on the falling film. A film thickness correlation is established and provides accurate predictions for both with and without co-current gas flow, with 91% accuracy.
NUCLEAR ENGINEERING AND DESIGN
(2023)
Article
Engineering, Chemical
Hui Han, Zhengxiong Su, Yifan Du, Junqi Wang, Yuxing Li, Liang Liu, Jianlu Zhu
Summary: The influence of surface wettability on the liquid film distribution outside the tubes of a spiral wound heat exchanger was studied, and the effects of tube spacing and Reynolds number on the flow characteristics of the falling film were analyzed.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2022)
Article
Thermodynamics
Qifan Wang, Xuetao Liu, Minxia Li, Dandan Su, Chaobin Dang
Summary: This study investigates the replacement of high-GWP refrigerants with non-azeotropic refrigerants and the reduction in refrigerant charge. A numerical simulation of falling-film evaporation of a non-azeotropic refrigerant outside a horizontal tube was conducted, considering various influencing factors on the heat transfer coefficient. The results indicate that spray height, tube diameter, inlet temperature, Reynolds number, and the mass fraction of R32 in the liquid-phase mixture have significant effects on the heat transfer coefficient.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Review
Thermodynamics
Chuang-Yao Zhao, Di Qi, Wen-Tao Ji, Pu-Hang Jin, Wen-Quan Tao
Summary: This paper provides a comprehensive review of computational studies on falling liquid film flow and heat transfer, covering topics such as two-phase flow, mass transfer models, hydrodynamics, heat transfer, and future technological needs. The use of numerical simulations offers a cost-effective and efficient approach to studying liquid film behavior and performance, with the potential to extract valuable insights for further research and development.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Bo Xu, Chun Jiang, Zhenqian Chen
Summary: The application of horizontal tube falling film evaporation in horizontal single tube and evaporator shows that spray density and temperature have an impact on the total heat transfer coefficient, liquid film thickness varies with tube diameter, and the total heat transfer coefficient increases with the increase in liquid distribution height and density.
JOURNAL OF THERMAL SCIENCE
(2021)
Article
Engineering, Multidisciplinary
Yingchun Xie, Zuopeng Hao, Jinchi Zhu, Yucheng Xiao, Zhen Xu
Summary: The study investigated the effect of ultrasonic field on the flow characteristics of the falling-film flow in the horizontal tube absorber. The experiments found that ultrasonic power increased the mode transition Reynolds number and improved the uniformity of the liquid film thickness. In addition, the ultrasonic field helped increase the average film thickness outside the tube.
Article
Thermodynamics
Tianjiao Zhang, Liangdong Ma, Jili Zhang
Summary: This study numerically investigates the thickness and wave behavior of a falling liquid film outside a vertical tube in vertical falling film evaporators used in sewage source heat pump systems. The effects of various factors, including annular gap, tube diameter, tube length, spray density, viscosity, and surface tension, are discussed. The simulation results show that spray density and fluid viscosity are the most influential factors affecting the film thickness. Tube length also has a significant impact on the film thickness and should be considered in the film thickness prediction model. Tube diameter and surface tension have little effect on the film thickness but mainly affect the wave amplitude of the liquid film at low flowrate. Furthermore, the annular gap has limited effect on the outlet section of the falling film. Based on the simulation results, a new correlation incorporating tube length is developed to effectively predict the falling film thickness, with a prediction accuracy of within +/- 15% compared to experimental data. This research provides a theoretical basis for the design of falling film evaporators.
HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Huanhao Zhang, Yasu Zhou
Summary: This study investigated the effect of wind speed on the spatial distribution of falling-film in an evaporative condenser. The results showed that wind blowing caused the liquid film to move upwards, resulting in an increase in film thickness in the upper part of the tube and a decrease in the lower part.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Akhil Krishnan Maliackal, A. R. Ganesan, A. Mani
Summary: The study utilized an optical shadow method to evaluate falling film thickness around a horizontal tube, offering a simpler measurement approach and a wider range of investigatable circumferential angles. Results showed that film thickness increases with Reynolds number, with minimal trend changes observed with varying feed inlet temperature.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Fang-Fang Zhang, Geng Chen, Pei Yuan, Chuang-Yao Zhao, Hua-Jie Li, Xiang-Yu Li
Summary: The impingement dynamics of a promising ionic liquid absorbent on heated porous surfaces in absorption refrigeration were studied experimentally, revealing that the residual volume decreases linearly with increasing contact time at 323.15 K and exhibits a polynomial behavior at higher heating temperatures. Compared to deionized water droplets, oscillations and capillary waves were not observed in the studied ionic liquid droplets.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2021)
Article
Thermodynamics
Di Qi, Angui Li, Shixiong Li, Chuangyao Zhao
Summary: This study investigated the influence of airflow uniformity on thermal performance of a multi-pipe earth to air heat exchanger system using a mathematical model and experimental data. The results showed a decrease in heat transfer rate of Z-type earth to air heat exchanger compared to uniform type, and better airflow and thermal uniformity in U-type and L-type designs. Optimum main pipes diameter to parallel pipes diameter ratio was also identified for thermal performance and pressure drop consideration.
APPLIED THERMAL ENGINEERING
(2021)
Article
Energy & Fuels
Di Qi, Chuangyao Zhao, Shixiong Li, Ran Chen, Angui Li
Summary: Earth to air heat exchangers are commonly used in passive buildings for energy savings, but they face challenges with high humidity conditions, especially in greenhouses. Research shows that condensation significantly affects the thermal performance of these heat exchangers, highlighting the importance of considering humidity and condensation in their design.
Article
Thermodynamics
Wei Jin, Junmei Wu, Ning Jia, Jiang Lei, Wentao Ji, Gongnan Xie
Summary: Numerical studies revealed that teardrop and NACA pin-fins exhibit better performance in heat transfer enhancement for turbine blade trailing edge compared to circular, elliptic, oblong, and lancet pin-fins. Under certain spanwise and streamwise spacings, NACA pin-fins show superior cooling effects in the trailing edge of turbine blades.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Pu-Hang Jin, Ibrahim Mostafa, Peng He, Zhuo Zhang, Chuang-Yao Zhao, Wen-Tao Ji, Wen-Quan Tao
Summary: This study investigated the thin liquid film boiling heat transfer characteristics of R134a on plain and finned tubular surfaces. Results show that heat transfer coefficient (HTC) depends on the microstructure and hydrophobic coating, increasing with heat flux until reaching a threshold, beyond which it decreases. The boiling-enhanced surface with reentrant cavities has higher HTC at low heat fluxes, while the condensation-enhanced surface is superior at high heat fluxes exceeding 60 kW m(-2). Hydrophobic coating significantly enhances liquid film boiling heat transfer on boiling-enhanced finned surfaces, particularly at high heat fluxes.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Chuang-Yao Zhao, Zhuo-Liang Yao, Di Qi, Wen-Tao Ji, An-Gui Li, Wen-Quan Tao
Summary: Falling film heat transfer is widely used in refrigeration and desalination systems. Numerical simulations show that bundle effect universally exists in falling film tube bundles and is influenced by liquid flow rate, distributor height, tube pitch, and tube bundle arrangement.
APPLIED THERMAL ENGINEERING
(2022)
Article
Energy & Fuels
Di Qi, Shixiong Li, Chuangyao Zhao, Wenbin Xie, Angui Li
Summary: This paper focused on optimizing the structure of multi-pipe parallel earth to air heat exchangers (EAHE) in greenhouses. By establishing a numerical model and proposing evaluation factors, the research compared the impact of structure parameters on the thermal performance of EAHE. Results indicated that specific spacing between pipes, depth of pipes, and angle of branch pipe entering airflow could achieve optimal heat exchange rate and airflow distribution uniformity.
Article
Thermodynamics
Guo-Hun Chong, Xiao-Dong Lu, Wen-Tao Ji, Li Chen, Chuang-Yao Zhao, Wen-Quan Tao
Summary: Research has shown that coupling the three-dimensional micro-finned tube with a polymer coating can significantly enhance the condensing heat transfer of low surface tension substances, with a condensing heat transfer coefficient up to 28 times larger than a smooth tube. This approach shows great potential for applications in surface treatment of micro-fins in the future.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Review
Construction & Building Technology
Chuang-Yao Zhao, Li-Wen Liang, Di Qi, Wen-Tao Ji, Wen-Quan Tao
Summary: This paper provides a comprehensive summarization of the research progress on the influence of gas flow on the hydrodynamics and heat transfer in falling film heat exchangers. It aims to offer guidance on how to maximize the positive effect or minimize the negative impact of gas shearing on the falling film heat and mass transfer.
BUILDING AND ENVIRONMENT
(2022)
Article
Mechanics
Chuang-Yao Zhao, Qiong-Tao Li, Di Qi, Zeng-Xi Feng, Jun-Min Jiang
Summary: This study developed a three-dimensional model to investigate the hydrodynamics of a falling film on a horizontal tube with a cross vapor stream. The results showed that vapor velocity has a significant impact on film thickness and spreading, leading to film offset.
Article
Thermodynamics
Di Qi, Kexin Liu, Jiajia Guan, Chuangyao Zhao, Angui Li
Summary: This paper evaluated the thermal and airflow performance of a high rack cold store using the Z-score method. The study found that the cooling effect and thermal uniformity were excellent in the vertical wall attached ventilation, and a more uniform and reasonable temperature field could be achieved when the air supply angle was -90 degrees. The optimal air supply velocity was found to be 11.7 m/s.
APPLIED THERMAL ENGINEERING
(2022)
Article
Mechanics
Chuang-Yao Zhao, Zhuo-Liang Yao, Di Qi, Wen-Tao Ji, Wen-Quan Tao
Summary: This study numerically investigates the hydrodynamics and thermal performance of turbulent falling films in horizontal tube bundles. It finds that the Standard k-omega model is suitable for reproducing the heat transfer characteristics of turbulent falling films, and that different bundle arrangements and flow regimes have varying effects on the heat transfer coefficient.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2023)
Article
Thermodynamics
Chuang-Yao Zhao, Qiong-Tao Li, Di Qi, Zeng-Xi Feng, Jun-Min Jiang
Summary: Numerical simulations were conducted to examine the effect of cross-vapor stream on the heat transfer performance of a falling film evaporator. The results showed that the cross-vapor stream caused deflections in liquid film spreading, distinct distributions of heat transfer coefficients and liquid film thicknesses on the tube surface, and asymmetry in the axial-averaged peripheral heat transfer coefficient. Increasing vapor velocity led to three trends of average heat transfer coefficients, and higher liquid flow rates improved the heat transfer performance under cross-vapor conditions.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Wen-Tao Ji, Shi-Ming Xiong, Li Chen, Chuang-Yao Zhao, Wen-Quan Tao
Summary: The study investigated the nucleate pool boiling heat transfer of R1234ze(E), R1233zd(E) and R134a outside two reentrant cavity tubes with different fin densities. It found that the combination of R134a and R13234ze(E) outside Tube-B1 exhibited almost equivalent boiling heat transfer performance and the highest averaged overall heat transfer coefficient. Additionally, it was observed that at higher heat flux, boiling heat transfer showed weak dependence on the surface structures.
INTERNATIONAL JOURNAL OF REFRIGERATION
(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)
