Article
Thermodynamics
Xingtian Wang, Wensi Yuchi, Junfeng Zhu, Jianan Yao, Liang Cao
Summary: The study showed that the heat transfer performance in spirally fluted tubes is mainly enhanced by generating strong turbulence kinetic energy through impacting the windward side of the flute, as well as by disrupting the boundary layer with the formation of the recirculation zone between the flutes. Variations in flute depth ratio and flute pitch length ratio can affect heat transfer performance, with optimal geometric design parameters being crucial.
JOURNAL OF THERMAL SCIENCE
(2021)
Article
Thermodynamics
Guangyi Xie, Jilin Lei, Xiwen Deng, Dewen Jia, Wei Deng, Xiangsen Jiang, Jun Wen
Summary: The uneven temperature distribution of the piston is a significant cause of piston fatigue failure. This study investigates the effect of inclination angle on the flow and heat transfer characteristics of piston cooling galleries. It reveals that the inclination angle can influence the oil accumulation and circumferential heat transfer performance of the piston cooling galleries, resulting in adjustments to the average steady heat transfer coefficient.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Sheng Zhang, Xiaodong Sun
Summary: This study systematically investigates the convective heat transfer and friction factor characteristics of a medium-Prandtl-number fluid in spirally fluted tubes using computational fluid dynamics. Correlations for convective heat transfer and Darcy friction factor are proposed and validated, aiding in the design improvement of spirally fluted-tube heat exchangers.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2022)
Article
Engineering, Aerospace
Youqian Chen, Yong Li, Dechao Liu, Bengt Sunden, Gongnan Xie
Summary: The study found that acceleration weakens the intensity of the first abnormal heat transfer state of supercritical n-decane, but has almost no effect on the second state; external factors have a significant influence on the heat transfer performance.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Energy & Fuels
Xiuzhen Li, Shijie Liu, Xun Mo, Zhaoyang Sun, Guo Tian, Yifan Xin, Dongsheng Zhu
Summary: A numerical simulation was conducted to explore the hydraulic-thermal performance and convection heat transport development inside spirally corrugated pipes. It was found that the heat transport performance increases with the thread height and Reynolds number, but decreases with the thread pitch. The Nusselt number of the spirally corrugated pipe is 2.77 times that of the plain pipe, while the flow resistance coefficients are 89 to 324% higher. The overall heat transmission performance factor increases in the Reynolds number region of 4000 to 7000 and then decreases in the region of 7000 to 13000. The promotion of convection heat transport is attributed to the secondary flow and vortexes in the pipe.
Article
Thermodynamics
Wenyi Wang, Zuliang Ye, Xiang Yin, Yulong Song, Ce Cui, Feng Cao
Summary: This paper presents a theoretical and experimental study of a spirally fluted tube-in-tube heat exchanger used as a gas cooler in a transcritical CO2 heat pump. The results show that the spirally fluted gas cooler can significantly improve the performance of the CO2 system, and provide guidance for further research.
APPLIED THERMAL ENGINEERING
(2024)
Article
Engineering, Multidisciplinary
C. J. Ho, Chu-Yun Cheng, Tien-Fu Yang, Saman Rashidi, Wei-Mon Yan
Summary: This study explores the cooling effectiveness and entropy production of aluminum oxide-water nanofluid in circular tubes with wall conduction effects. Results show that heat transfer effectiveness ratios increase with higher input temperatures of fluid and nanoparticle concentrations. Additionally, local entropy production ratios are mostly below unity, indicating the beneficial use of nanofluids for reducing system irreversibility.
ALEXANDRIA ENGINEERING JOURNAL
(2022)
Article
Thermodynamics
Xin-ji Chen, Chen Yang, Jing-xian Kong, Feng-lei Wang, Zhi-jiang Jin, Jin-yuan Qian
Summary: This paper studies the application of spirally corrugated tube at low Reynolds number in heat exchangers. It is found that the structure of the tube can evenly distribute solid particles, achieving anti-fouling effect and improving heat exchange efficiency. The thermal-hydraulic characteristics of different sample points are analyzed and four representative sample points are selected. The effects of corrugation pitch ratio and depth ratio on convective heat transfer and fluid resistance are studied.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
M. Isakhani Zakaria, M. A. Akhavan-Behabadi, B. Sajadi, M. Tohidi Moghadam
Summary: In this study, the flow pattern, boiling heat transfer, and pressure drop of R1234yf inside a plain tube were experimentally investigated. The results show that the tube inclination angle significantly affects the heat transfer coefficient and frictional pressure drop, especially at low vapor qualities and low mass velocities.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Energy & Fuels
Haiwang Li, Dawei Zhang, Ruquan You, Yifan Zou, Song Liu
Summary: By using a fluid-thermal-structure coupling simulation method, this study investigated the cooling characteristics and stress characteristics of an impingement/effusion cooling system, including thermal stress and thermomechanical stress. The results showed that the non-uniform temperature field introduced by the cooling structure and the shape of film holes had a significant impact on the stress field distribution. Increasing the blowing ratio improved the overall cooling effectiveness but also increased the maximum thermal stress and thermomechanical stress near film holes. Smaller inclination angles provided better cooling performance but led to more severe stress concentration at the film holes. Cases with inclination angles of 30 degrees and 45 degrees exhibited serious thermal stress concentration near the acute region of the hole.
Article
Thermodynamics
Han Yong, Li Jia-ni, Zhang Chong, Zhu You-jian, Wu Xue-hong, Lv Cai, Zhang Zhen-ya, Zhang Can-can
Summary: In this study, the flow and heat transfer characteristics of twisted petaloid spirally wound tubes were numerically analyzed. The results show that the integration of centrifugal force and torsional force induces a secondary flow, enhancing the heat transfer performance.
APPLIED THERMAL ENGINEERING
(2023)
Article
Green & Sustainable Science & Technology
Weixiu Shi, Xuebing Liu, Xiaoyang Su, Hongdi Chen, Lisheng Pan
Summary: Pulsating heat pipe (PHP) is an efficient heat transfer technology used in heat dissipation and energy utilization. Factors affecting its heat transfer include working fluid, filling ratio, and inclination angle. The cooling capacity of the cooling water system at the condensing section is an important factor affecting the starting and operating of PHP. Studying PHP under different cooling water flow rates is significant for enhancing its performance.
Article
Thermodynamics
Chunhui Dong, Guoqing Lu, Ronghua Chen, Kui Zhang, Changliang Liu, Wenxi Tian, Suizheng Qiu, G. H. Su
Summary: Passive Containment Air-cooling System (PAS) is an important passive system in modular small nuclear reactors. This study experimentally investigated the mixed convection heat transfer characteristics of atmospheric air in PAS and proposed a new heat transfer correlation. The research findings are significant for the safety and optimal design of PAS.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Nuclear Science & Technology
Boyang Cao, Yi Li, Yan Sun, Haozhi Bian, Ming Ding
Summary: This experimental study conducted on a 3 x 3 tube bundle with diameters of 12-19 mm revealed the significant variations in the heat transfer coefficient with different pressure ranges, diameters, and inclination angles. The findings suggest that the diameter and inclination angle play an important role in the condensation heat transfer within tube bundles.
ANNALS OF NUCLEAR ENERGY
(2022)
Article
Thermodynamics
Dongnan Cai, Xiaoxiao Xu, Shijie Zhang, Chao Liu, Chaobin Dang
Summary: The study focuses on the heat transfer deterioration and flow instability of supercritical CO2 in a tube, where experiments show that flow instability occurs in upward flow tubes due to buoyancy effects and changes in heat transfer modes.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Yunxia Ma, Fei Liu, Honggang Pan, Hongjian Zhang, Shuxia Yan, Ailing Zhang
Summary: This paper proposes a dynamically tunable and switchable perfect infrared absorber that exhibits excellent electrical regulation performance and high absorptance. The absorption mechanism is explained using a multiple interference model, and it is proven to be polarization insensitive.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
F. J. dos Santos, G. S. M. Martins, M. Strobel, L. Beckedorff, K. V. de Paiva, J. L. G. Oliveira
Summary: This study investigates the effects of inlet conditions and plate's features on the thermal-flow performance of a gasket plate heat exchanger (GPHE) and assesses the impact of a modified tightening distance on its performance. No systematic study on the combined effects of inlet conditions and assembly accuracy on GPHE performance has been conducted before.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Alok K. Ray, Dibakar Rakshit, K. Ravi Kumar, Hal Gurgenci
Summary: The low thermal conductivity of phase change materials limits the heat transfer rate and application of latent heat storage systems. This numerical study examines the impact of two passive heat transfer enhancement techniques on the thermal performance of a latent heat storage system. The results show that the orientation and position of the heat transfer fluid tube have significant effects on the charging duration, while the discharging duration remains unchanged. The combined effect of orientation and eccentricity reduces the charging duration, but increases the discharging duration compared to the concentric domain.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Yalu Han, Yanlong Wang, Chenyang Liu, Xinmin Hu, Yin An, Zhengcai Li, Jiaxun Jiang, Lizhi Du
Summary: This paper investigates the calculation method of thermal conductivity in NAPLs-contaminated soils. By establishing NAPLs-contaminated soil models and using the Lattice Boltzmann Method (LBM) for calculation, an optimized three-dimensional model with high computational accuracy and efficiency is obtained. The study also finds that saturation and Nz parameters have a significant impact on calculation time, while the thermal conductivity of the two-dimensional model is more sensitive to anisotropy. The influence of porosity and NAPLs content on thermal conductivity should be considered during in-situ thermal desorption.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Mostafa Taha, Song Zhao, Aymeric Lamorlette, Jean-Louis Consalvi, Pierre Boivin
Summary: For the first time, large-eddy simulations (LES) of the near-field region of large-scale fire plumes were performed using a pressure-based Lattice Boltzmann method (LBM) with low-Mach number approximation. The simulations showed quantitative agreement with experimental data and were consistent with previously-published numerical studies. The study demonstrated the computational efficiency of the proposed LBM solver in tackling fire-induced flows, suggesting LBMs as a good alternative candidate for modeling fire-related problems.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Weixin Zhang, Yehang Xie, Yuqiang Ding, Zhao Liu, Zhenping Feng
Summary: This study investigated the impact of upstream slot leakage on the endwall film cooling characteristics of turbine blades. Pressure Sensitive Paint (PSP) technology was used to measure the film cooling characteristics, and numerical analysis was conducted to evaluate the aerodynamic performance. It was found that increasing the mass flow ratio of the upstream slot enhanced film cooling, decreased aerodynamic losses, and reduced the strength of passage vortex. However, reducing the distance between the slot and the blade leading edge only enhanced film cooling without affecting the leakage coverage area.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Rui Zhang, Zhen-lei Li, Yan-sheng Zhang, Dong Chen, Guo Yuan
Summary: This study discusses the heat transfer behavior of different jet forms on steel tubes. The results show that the annular jet performs better in terms of cooling intensity and uniformity. The cooling performances of the two jet forms are similar when the steel tube size is small. Therefore, the planar jet can be considered for smaller diameters due to its simplicity, low cost, and convenience in application.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
A. R. Khoei, A. M. Orvati Movaffagh, A. Rezaei Sameti
Summary: This paper presents a comprehensive study on the thermo-mechanical characteristics of oxide-coated aluminum nano-powder. It is found that the thermal conductivity of oxide-coated aluminum nano-powder is significantly lower than that of the bulk aluminum, and it is affected by the density and temperature.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Yanjin Wang, Jintao Xiong, Lingyu Chen, Zhihai Lv, Qian Wang
Summary: A solar radiation transfer model for spray cooling double skin facade (SC-DSF) is proposed in this study. The model is validated by experimental results and various influence factors are analyzed. The effectiveness of adjusting droplet coverage rate and size is also evaluated.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Bostjan Zajec, Blaz Mikuz, Anil Kumar Basavaraj, Marko Matkovic, Matej Tekavcic, Martin Draksler, Leon Cizelj, Bostjan Koncar
Summary: We have developed an advanced experimental setup to investigate flow and heat transfer in an annular channel. The setup allows heat transfer measurements and flow visualization using a temperature-controlled inner tube. Measurements can be conducted in both single-phase and two-phase flow regimes. The setup ensures a uniform velocity field in the annular channel using specially designed inlet and outlet headers. The inner copper tube is heated by water and contains turbulators for enhanced heat transfer and thermocouples for temperature measurement. A three-dimensional conjugate heat transfer CFD model has been developed and validated to accurately estimate heat losses in the setup. This study demonstrates the importance of numerical simulations in improving the interpretation of complex experimental results.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Weijie Chen, Ke Wang, Yongqing Wang, Shantung Tu, Zunchao Liu, Huijuan Su
Summary: In this study, a novel gradient porosity transpiration cooling plate structure (GP-TCPS) is proposed to alleviate heat transfer deterioration caused by non-uniform temperature distribution in transpiration cooling plate structure (TCPS). Computational fluid dynamics (CFD) and response surface method (RSM) were used for qualitative and quantitative analysis of the flow and heat transfer of GP-TCPS. The optimized structure of GP-TCPS significantly improves temperature uniformity, injection pressure, and average cooling efficiency compared to traditional TCPS.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
R. Essam, A. Elsaid, W. K. Zahra
Summary: This study presents a novel bioheat model for simulating heat transfer in skin tissue. The model offers an improved representation of thermal dynamics in the skin and has been validated using numerical solutions and experimental measurements. The study highlights the importance of incorporating vascular inlet parameters and thermal relaxation effects in the thermal profile, and suggests potential applications in thermal therapy and wound healing.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Dongbo Shi, Tao Xu, Zifeng Chen, Di Zhang, Yonghui Xie
Summary: The cooling structure design of turbine blades is crucial for the safety and reliability of the gas turbine set. This research investigates different arrangement schemes, including dimple/protrusion arrangements, to enhance the cooling performance. The results show that the arrangement scheme with both passes arranged by dimples has the best comprehensive thermal performance.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Emrehan Guersoy, Hayati Kadir Pazarlioglu, Mehmet Guerdal, Engin Gedik, Kamil Arslan
Summary: The thermo-hydraulic performance of Al2O3/H2O nanofluid with different nanoparticle shapes flowing in a sudden expansion tube with variable sudden expansion inclination angles and elliptical dimpled fins with different diameters were numerically investigated. The results showed that the nanoparticle shapes, sudden expansion inclination angles, and elliptical dimpled fin have significant impact on the thermo-hydraulic performance. This study reveals the novelty and importance of these factors in the research.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)
Article
Thermodynamics
Rukun Hu, Xinyu Huang, Xinyu Gao, Liu Lu, Xiaohu Yang, Bengt Sund
Summary: This study examines the impact of applying bottom cross-cut on PCM's spatial distribution in a horizontal LHTES unit using numerical simulation. The findings show that bottom cross-cut can improve the heat storage rate and natural convection heat transfer gain.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2024)