Article
Thermodynamics
Yudong Ding, Wenhe Zhang, Bin Deng, Yuheng Gu, Qiang Liao, Zhenze Long, Xun Zhu
Summary: Tubular heat exchangers with vertically oriented 3-D finned tubes were studied for their heat dissipation characteristics under non-forced convection. Results showed that a fin height of 7 mm achieved the highest Nusselt number, which was 207% higher than smooth tubes. The Nusselt numbers increased with fin height and decreased axial fin pitch, minimally affected by fin width and circular fin pitch. The most important geometric parameter affecting heat dissipation is fin height.
Article
Thermodynamics
Utkarsh Deep Tiwari, Parmod Kumar
Summary: This study investigates the film boiling heat transfer phenomenon for elliptical heaters arranged in a tandem and subjected to cross-flow of saturated liquid at near critical pressure conditions. The effects of vertical spacing, aspect ratio, degree of wall superheat, and Reynolds number are studied on bubble departure dynamics and heat transfer characteristics. It is found that the bubble departure size from the bottom heater remains almost unchanged, but the departure frequency increases with higher Reynolds number and degree of superheat. The bubble size and departure frequency of the top elliptical heater vary significantly with aspect ratio, pitch, Reynolds number, and degree of superheat. The time-averaged heat transfer coefficient increases with increasing pitch distance, aspect ratio, Reynolds number, and degree of superheat, but the rate of increase diminishes at high degree of superheat.
APPLIED THERMAL ENGINEERING
(2023)
Article
Nuclear Science & Technology
C. W. Hollingshead, A. Rashkovan, D. R. Novog
Summary: This study examines the impact of buoyancy-driven flows from lower cylinders in a tube array on the heat transfer of higher-elevation cylinders through experimental and numerical analyses. Mechanistic models are developed to understand the velocity and temperature behavior of the plume, and a predictive model is proposed to estimate the heat transfer performance of higher-elevation cylinders. The results show good agreement with experimental data and literature.
NUCLEAR ENGINEERING AND DESIGN
(2022)
Article
Energy & Fuels
Orhan Kalkan, Ali Celen, Kadir Bakirci
Summary: The thermal performance of a LiFePO4 pouch type battery under different discharge rates was experimentally and numerically investigated. It was found that natural convection cooling is not sufficient for the battery at high discharge rates.
JOURNAL OF ENERGY STORAGE
(2021)
Article
Engineering, Chemical
Liuyun Xu, Feng Wu, Haibo Ren, Wenjing Zhou, Yuan Yan
Summary: The erosion of immersed tube was studied using experimental and simulation methods, revealing severe erosion mainly at the lower sides. The DDPM method was able to simulate the erosion law of the immersed tube. A new dimensionless parameter, It, was defined to characterize the erosion state, showing that particle flow characteristics and fluidization degree have direct and inverse relationships with erosion rate. Additionally, simulation results showed that the erosion rate of EA type elliptical immersed tube was 53.68% lower than circular immersed tube.
Article
Energy & Fuels
Sami Missaoui, Zied Driss, Romdhane Ben Slama, Bechir Chaouachi
Summary: This study focuses on improving the accuracy of numerical results and reducing computational time by studying a heat pump water heater with helically coiled tubes. The effects of time step size on results are analyzed, with validation performed by comparing simulated and experimental results.
JOURNAL OF ENERGY STORAGE
(2021)
Article
Nuclear Science & Technology
Chunhui Dong, Shikang Chen, Ronghua Chen, Wenxi Tian, Suizheng Qiu, G. H. Su
Summary: This study numerically investigated the natural convection around the dome, a key part of the PAS, and found that the lift-off point moves towards the bottom of the dome and the eddy under the buoyant plume grows larger as the Ra increases, which enhances heat transfer. The heat transfer along the dome surface with different truncation angles was also studied, and a heat transfer correlation considering the influence of truncation angle was proposed based on the simulated results. This study provides a better understanding of natural convection around the dome of PAS and offers more predictive value in improving nuclear safety.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2023)
Article
Thermodynamics
Hakim Kebabsa, Mohand Said Lounici, Ahmed Daimallah
Summary: The study introduces a novel concept of annular tower solar chimney power plant to improve the performance of the divergent tower system, showing a significant increase in power output. Simulation results indicate a strong sensitivity of flow behavior, power output and thermal efficiency to the changes in exterior and interior tower radius, with the best performance observed at the exterior radius of 17m and interior radius of 13m.
Article
Environmental Sciences
Avihai Tsinober, Uri Shavit, Ravid Rosenzweig
Summary: We numerically investigate the effect of hydrodynamic dispersion on convective dissolution of carbon dioxide in saline aquifers. The transport equations are solved to describe the dissolution process and analyze the influence of dispersion on the wavenumber and dissolution flux. The results show that dispersion decreases the dissolution rate and reduces the finger wavenumber. New empirical scaling laws are developed based on the simulated results to predict the dissolution rate and wavenumber.
WATER RESOURCES RESEARCH
(2023)
Article
Thermodynamics
Puxian Ding, Kai Chen, Xiaoqing Zhou
Summary: This study compares the performance of different scale-resolving simulation (SRS) models in resolving turbulent flow structures and forced convection around a wavy cylinder. The results show that the production-limited DDES (PL-DDES) model is superior to the SST scale adaptive simulation (SAS) and the SST delayed detached-eddy simulation (DDES) models on a coarse grid resolution. The study also investigates the turbulent flow and mixed convection around the cylinder using the PL-DDES model and identifies the effects of buoyancy on the flow structures in contra flow and parallel flow.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Zhenhong Luo, Kun Liang, Xinwen Chen, Zhaohua Li, Xiang Wang, Hang Zhou, Yucheng Wang
Summary: This study investigates the heat transfer performance of spray cooling in non-boiling regions under vibration using numerical methods. Experimental results show that the film thickness and film velocity vary with frequency, affecting the heat transfer coefficient. Larger vibration amplitudes result in a decrease in the heat transfer coefficient.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Mechanics
Hideyuki Sugioka, Atsushi Miyauchi
Summary: In this study, a thermally driven water pump using fixed oblique beam structures with bubbles in the nucleate boiling region was proposed. The use of six fixed oblique beams along a circular fluidic channel resulted in a net flow of an average flow velocity of approximately 40 mm/s and an average volume flow rate of approximately 10,000 mm(3)/s (approximately 0.01 l/s) at a superheat of approximately 22 K. These findings should contribute to the effective utilization of unused heat such as factory waste heat and environmental energy.
Article
Mathematics
Shenglin Zhu, Jinfeng Wang, Jing Xie
Summary: This study investigated the heat transfer and pressure drop characteristics of R290 flow boiling in a corrugated tube using CFD. The results showed that the corrugated structure significantly enhanced heat transfer efficiency and reduced the required heat transfer area, leading to cost reduction.
Article
Thermodynamics
Rahul Ryan Savio, Subhani Shaik, Rajendran Senthil Kumar
Summary: The study investigated the impact of changing the orientation of a square cylinder around its central axis on heat flow and flow characteristics, and found that a 45-degree rotation angle provides the most optimal and efficient means of heat transfer at higher Rayleigh numbers.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
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
Mathematics, Applied
Navid Dehdashti Akhavan, Foued Abroug, Lionel Arnaud, Kamel Hooman
Summary: This study evaluates the thermal and hydraulic performance of microchannel heat sinks using supercritical carbon dioxide (s-CO2) as a coolant compared to conventional liquid coolant (water). The results show that s-CO2 offers higher overall heat transfer coefficient and lower friction factor, enhancing cooling efficiency in high-heat flux heat sinks.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2023)
Article
Thermodynamics
Lianying Zhang, Qingzeng Zhang, Xiaohu Yang, Kamel Hooman
Summary: This study analyzes the insulation performance and buried depth of heating pipelines and their impact on energy loss, and calculates and evaluates the optimal insulation thickness, energy-saving effect, and payback period. The sensitivity analysis shows that insulation and fuel have a greater influence on the optimum insulation and payback period than the buried depth.
HEAT TRANSFER ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Sara Behaien, Babak Aghel, Mostafa Safdari Shadloo
Summary: In this study, biogas was upgraded by removing CO2 using three absorbents in a microchannel system. The effects of operating variables were investigated, and a quadratic model was proposed to predict the response. The experimental values matched the model values well.
KOREAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Food Science & Technology
Hadi Hashemi Gahruie, Mohammad Hadi Eskandari, Rohollah Sadeghi, Seyed Mohammad Hashem Hosseini
Summary: The purpose of this study was to investigate the impact of cold plasma treatment on basil seed gum (BSG) and to fabricate functional edible films using the modified BSG. The results showed that cold plasma treatment led to the formation of carbonyl groups in BSG and increased its apparent viscosity. The modified BSG had higher G', G'', and complex viscosity values compared to untreated BSG. Additionally, the modified BSG exhibited enhanced hydrophobicity and lower surface tension. The study also demonstrated the successful use of modified BSG for the preparation of stable edible films incorporating tannic acid and vitamin D-3-loaded nanophytosomes.
Article
Thermodynamics
Michael Opolot, Chunrong Zhao, Partrick F. Keane, Ming Liu, Simone Mancin, Frank Bruno, Kamel Hooman
Summary: Thermal energy storage is increasingly important in a sustainable world due to its potential in capturing waste heat and incorporating in solar power plants. Eutectic Na2CO3-KCl-NaCl phase change material with a melting temperature of 569 degrees C was used in this study, along with a stainless steel wire mesh to enhance heat transfer. Experimental results showed that the charging time was reduced by 35% for the composite case compared to the pure PCM case, and the solidification time in the axial direction was shortened by an average of 10%.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Yueming Yang, Xurong Wang, Kamel Hooman, Kuihua Han, Jinliang Xu, Suoying He, Jianhui Qi
Summary: Recently, the use of additives in the supercritical carbon dioxide (SCO2) power cycle has been shown to effectively improve its efficiency. This study focused on the influence of CO2-based mixtures on the performance of a small-scale radial-inflow turbine (RIT) for SCO2 power systems. The results indicated that adding nitrogen, oxygen, or helium had a negative effect on turbine performance, while an appropriate amount of xenon or krypton improved efficiency. The study also found that higher krypton additions were better suited for higher heat source conditions.
Article
Thermodynamics
Yuxuan Zhang, Xiaoqiang Zhai, Fengyuan Zhang, Zhongbin Zhang, Kamel Hooman, Hai Zhang, Xiaolin Wang
Summary: This article proposes a novel carbon capture capsule inspired by red blood cells (RBC) to enhance CO2 hydrate formation kinetics. Compared to spherical capsules, the RBC-shaped capsule shows a 143% higher gas uptake efficiency. The study also investigates the effects of initial pressure and capsule size on CO2 hydrate formation kinetics.
Article
Thermodynamics
Tian Xiao, Qiaoling Zhang, Xiaohu Yang, Kamel Hooman, Guodong Li
Summary: The study reveals that the solder joint sizes, solder joint skips, solder flux materials, and filling media all have an impact on the thermal conductivity of metal fibrous materials. Increasing solder joint sizes enhances the effective thermal conductivity of porous fibres, while solder joint skips weaken the thermal conductivity. The thermal conductivity of the fibres increases with higher thermal conductivity of solders and decreases when the difference in thermal conductivity between the filling medium and the fibre is reduced.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Green & Sustainable Science & Technology
Mehrdad Mesgarpour, Omid Mahian, Ping Zhang, Somchai Wongwises, Lian-Ping Wang, Goodarz Ahmadi, Sandro Nizetic, Mikhail Sheremet, Mostafa Safdari Shadlooj
Summary: Sedimentation has a direct impact on the thermal performance and efficiency of thermal systems. This study investigates the deposition of nanoparticles inside a tube for possible application in parabolic solar collectors. A combination of lattice Boltzmann and control finite volume methods is used for realistic simulation, and the results are used to train a deep feed-forward neural network to visualize and predict sedimentation behavior. This research provides valuable insights into particle behavior and parameter variation near the surface, and has implications for predicting service periods and cost savings in heat transfer equipment maintenance.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Thermodynamics
Alireza Khoshnood, Mehdi Maerefat, Gholamreza Imani, Kamel Hooman
Summary: This study numerically investigates the effects of the evolving fouling layer at the walls of an EGR cooler on its thermal performance. The possibility of a steady fouling layer formation is also studied. The results show that the thermal performance decreases as the fouling layer grows and a correlation is proposed for the time at which the steady fouling layer occurs based on Reynolds and Darcy numbers.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Xueqiang Li, Zhongyao Zhang, Qihui Wang, Xiaohu Yang, Kamel Hooman, Shengchun Liu
Summary: Air cooling systems are widely used in data centers due to their low cost and reliability. This study compares four airflow management technologies and analyzes their thermal and economic performances.
HEAT TRANSFER ENGINEERING
(2023)
Article
Thermodynamics
Muthamil Selvan Nedumaran, Govindappa Trilok, Nagarajan Gnanasekaran, Kamel Hooman
Summary: A partial filling strategy is used to reduce the cost and weight of foams with fins in this study. A hybrid heat sink with a combination of fins placed at the sidewalls of the enclosure and foams filled at certain heights is analyzed numerically and optimized to determine the guidelines for selecting a preferable pore size and pore density.
HEAT TRANSFER ENGINEERING
(2023)
Article
Thermodynamics
Junfei Guo, Ze Li, Pan Wei, Ling Li, Xiaohu Yang, Ya-Ling He, Kamel Hooman
Summary: The integration of phase change materials (PCMs) and metal foam has garnered significant attention. An adaptive metal foam arrangement strategy, with increasing porosity from inside to outside, has been proposed to address the non-uniformity issue. The simulation and experimental study on a vertical thermal energy storage (TES) tube showed that a smaller difference between the inside and outside subregions, along with a larger porosity difference, led to better thermal performance and faster phase change evolution. The optimal strategy (0.87-0.94-0.97) significantly shortened the melting duration and enhanced the efficiency of vertical metal foam TES systems.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Engineering, Mechanical
Fadhilah Shikh Anuar, Khairul Azhar Mustapha, Fatimah Al-Zahrah Mohd Sa'at, Nurul Hilwa Mohd Zini, Ernie Mat Tokit, Satishwara Rao Narasimmanaidu, Kamel Hooman
Summary: In this study, a new generation of open-cell foam called 3D printed open-cell foam was produced by generating and reconstructing the microstructure of open-cell metal foam. Two different 3D printing technologies, Selective Laser Sintering (SLS) and Fused Deposition Modelling (FDM), were used with nylon powder and plastic acid as materials. The microstructural properties and surface roughness of the 3D printed open-cell foam were investigated and found to be dependent on the printing technologies, materials, and foam size. The SLS technology produced smoother ligament surfaces with fewer residues compared to the FDM technology.
Article
Energy & Fuels
Muthamil Selvan Nedumaran, Nagarajan Gnanasekaran, Kamel Hooman
Summary: This study compares the thermal performance of a modified variable height fin heat sink with conventional constant height fin heat sinks in equal load conditions. The experiments show that the variable height fin heat sink performs better in all load scenarios. A computational model using ANSYS Fluent 19 is also developed to assess the impact of different aspect ratios and fin shapes on thermal performance. The results demonstrate that variable height fin heat sinks provide enhanced melting and solidification for various aspect ratios and fin shapes.
JOURNAL OF ENERGY STORAGE
(2023)
