Article
Thermodynamics
Sufei Wang, Fujun Zhang
Summary: This paper investigates the heat transfer advantages of opposed-piston 2-stroke diesel engines (OP2S) through CFD simulation. The results show that OP2S achieves higher combustion efficiency and significantly reduces heat transfer loss compared to conventional diesel engines (4S) at optimized swirl ratio and injection phase.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Han Jiang, Zhongli Xi, Xiaoqing Zhang
Summary: This research focuses on the modeling of free piston Stirling engines (FPSEs) using network theory and emphasizes the active attribute of Stirling regenerator and differences from thermoacoustic devices. A general heat-dynamics active network model in distributed form is developed, considering the intrinsic attribute and treating nonlinear network parameters. The model is verified and compared with experiments and existing network models, showing improved accuracy and practicality.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Zhen Cao, Bengt Sunden, Zan Wu
Summary: The present study investigates boiling heat transfer enhancement on coated surfaces using mechanistic models. The results show that the coatings on copper surfaces significantly increase the critical heat flux and heat transfer coefficient of deionized water, with the coated surface providing more active nucleation sites. Based on these insights, a heat transfer model is established and the critical heat flux is explored experimentally and theoretically.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Yinglei Guo, Yuhua Lai, Shuai Wang, Lin Wang
Summary: The lattice Boltzmann method is used to investigate the bubble dynamics on the vertical rough heating wall, considering the conjugate heat transfer process. The results reveal the interaction between bubble dynamics and boiling heat transfer characteristics. It is found that the bubble motion and gas-liquid interface are influenced by the wall thermal conductivity, and the wall mixed wettability has an impact on the conjugate heat transfer behaviors.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Nesrine Zahi, Asma Alkabsh, Feriel Bouhjar, Lotfi Derbali
Summary: In this study, a computational model is developed to investigate the fluid flow and heat transfer in a two-dimensional horizontal cylinder filled with an open-cell metal foam block. The results show that the behavior of both hydrodynamics and heat transfer can be controlled by adjusting the porosity, size, and other parameters of the metal foam.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Xiang Wang, Kun Liang, Jing Xu, Jigang Wang, Xinwen Chen
Summary: This paper investigates the bubble dynamics behavior and heat transfer characteristics of pool boiling at sub-atmospheric pressure. The experimental results show that as the boiling pressure decreases, the diameter of bubble departure increases and becomes more circular, while the frequency and aspect ratio decrease. Additionally, the critical heat flux (CHF) decreases with the decline in pressure. At sub-atmospheric pressure, the boiling heat transfer coefficient (HTC) increases with liquid height, while it remains nearly unchanged at standard atmospheric pressure and above.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Vladimir Serdyukov, Georgy Patrin, Ivan Malakhov, Anton Surtaev
Summary: This paper investigated the boiling characteristics of water on a biphilic surface under different pressure conditions. It was found that the fabricated biphilic surface exhibited significant heat transfer enhancement at subatmospheric pressures, as well as stabilized the boiling process.
APPLIED THERMAL ENGINEERING
(2022)
Article
Mechanics
Zheng Zhang, Guanmin Zhang, Min Wei, Yi Zhang, Maocheng Tian
Summary: This study investigates two-phase flow and heat transfer in vertical upward rectangular microchannels using the volume of fluid method and the Lee phase-change mass transfer model. The results reveal the sequential occurrence of different flow patterns with increasing heat flux and establish a phase diagram to predict flow pattern transitions. A new correlation for two-phase flow boiling heat transfer in microchannels is proposed.
Article
Thermodynamics
Pulak Sen, Sanjib Kalita, Dipak Sen, Ajoy Kumar Das, Bidyut Baran Saha
Summary: In this study, hydrophobic copper micro-structured surfaces were prepared through chemical etching and heat treatment, resulting in different micro-structural features. The experimental results showed that the prepared hydrophobic surfaces have a higher heat transfer coefficient, although the critical heat flux is slightly smaller compared to the bare copper surface. Additionally, the micro-porous surface prepared by a combination of two conventional processes significantly improves heat transfer.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Hui-Chung Cheng, Ho-Ching Lin, Ping-Hei Chen
Summary: The study investigated the effects of charged surfactants in electrolytic pool boiling on heat transfer performance, finding an optimal current for enhancing the heat transfer coefficient. Analysis of bubble behaviors using high-speed images revealed that using charged surfactants in electrolytic boiling significantly increased the heat transfer coefficient due to the number of bubble nucleation sites and bubble departure frequency.
APPLIED THERMAL ENGINEERING
(2021)
Article
Mechanics
Mehran Soleimani, Ali Ahmadpour, Ehsan Amani
Summary: In this study, three-dimensional numerical simulations were conducted to investigate the impact of direct current electric fields on subcooled flow boiling heat transfer in a vertical minichannel. The volume of fluid model was used to represent the liquid-vapor interfaces, and the conservation laws and electrohydrodynamic equations were solved using the finite volume method. Two mass transfer models were evaluated, and a new seeding algorithm was developed based on the physics of bubble formation and departure on heated walls, integrated with the Fourier model. The numerical results showed an early transition from slug to churn/annular flow regimes due to EHD forces, in agreement with experimental observations.
Article
Engineering, Multidisciplinary
Dong Liu, Nannan Sun, Guixiang Zhu, Hengchao Cao, Tie Wang, Guoxin Li, Fengshou Gu
Summary: This study investigates the correspondence between cylinder liner vibration and coolant pressure through vibration cavitation tests, pressure gradient calculations, and visualization observations. The cavitation risk under piston slap is quantitatively analyzed based on a nonlinear structural dynamics model, showing a high risk when the cylinder liner acceleration exceeds 1189 m/s2. The variation in cavitation risk for each cylinder is related to the structural modal characteristics of the crankcase, and the effects of piston-liner clearance and piston pin offset on cavitation risk are also explored.
EKSPLOATACJA I NIEZAWODNOSC-MAINTENANCE AND RELIABILITY
(2023)
Article
Thermodynamics
Lin Lin, Yanxin Hu, Zipei Su, Minghan Zhu, Jin Huang, Changxiang Fan
Summary: The preparation of micro-nano hybrid structured copper surfaces through sandblasting and ultrasonic wet etching techniques has been investigated for its impact on nucleate pool boiling. The study found that the hybrid structure exhibits improved critical heat flux and heat transfer coefficient compared to smooth and individual micro or nano structured surfaces. The enhancement mechanisms are attributed to the combined effects of roughness, surface area ratio, and wettability.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Multidisciplinary Sciences
Jose Pereira, Ricardo Cautela, Ana Moita, Antonio Moreira
Summary: This study aims to evaluate the effect of the size of circular superhydrophobic regions on the bubble dynamics in pool boiling conditions. The experiment found that smaller superhydrophobic spots resulted in more uniform and stable bubbles with higher evaporation mass transfer rates. It also highlighted the possibility of modulating the bubble development according to the design objectives of biphilic surfaces.
Article
Chemistry, Physical
Jiaojiao Wang, Yanzhong Li, Lei Wang, Siqi Xia, Jianhua Ren, Hongwei Mao, Yuanyuan Xu
Summary: Understanding bubble dynamics and heat transfer characteristics of hydrogen boiling in microgravity is essential for safe and efficient use of liquid hydrogen in space. The study developed a numerical simulation model to predict the subcooled pool film boiling for liquid hydrogen in different gravities, revealing that poor heat transfer performance is observed in reduced gravity and bubbles may grow larger with decreasing gravity.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Thermodynamics
Enhui Sun, Han Hu, Hangning Li, Jinliang Xu, Guohua Liu
APPLIED THERMAL ENGINEERING
(2020)
Article
Thermodynamics
Zhewen Chen, Yanjuan Wang, Xiaosong Zhang, Jinliang Xu
Article
Chemistry, Multidisciplinary
Xin Yan, Jinliang Xu, Zhijun Meng, Jian Xie, Guohua Liu
Article
Energy & Fuels
Jinliang Xu, Haisong Zhang, Bingguo Zhu, Jian Xie
Article
Thermodynamics
Xin Yan, Jinliang Xu, Zhijun Meng, Jian Xie
APPLIED THERMAL ENGINEERING
(2020)
Article
Thermodynamics
Zheng Miao, Zihang Li, Kai Zhang, Jinliang Xu, Yongpan Cheng
APPLIED THERMAL ENGINEERING
(2020)
Article
Thermodynamics
Yongpan Cheng, Yang Shen, Dong Liu, Jinliang Xu, Yi Sui
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2020)
Article
Thermodynamics
Mingjia Li, Ge Wang, Jinliang Xu, Jingwei Ni, Enhui Sun
Summary: The benefits of large-scale supercritical CO2 coal-fired power plants are analyzed and compared with ultra-supercritical water-steam Rankine cycle coal-fired power plants in terms of energy environment and economy. The results show that the S-CO2 coal-fired power generation system outperforms the USC coal-fired power generation system in terms of energy consumption, resource depletion, environmental impact, and investment cost.
JOURNAL OF THERMAL SCIENCE
(2022)
Article
Thermodynamics
Haisong Zhang, Jinliang Xu, Xinjie Zhu, Jian Xie, Mingjia Li, Bingguo Zhu
Summary: This paper investigates the relationship between pressure drop and heat transfer in supercritical carbon dioxide (sCO(2)), introducing the concept of pseudo-boiling to characterize the flow and heat transfer in the supercritical domain. Different regimes of heat transfer behavior and pressure drops are identified, with a new correlation for friction factors developed to better predict the results in sCO(2) systems.
APPLIED THERMAL ENGINEERING
(2021)
Article
Physics, Multidisciplinary
Guanglin Liu, Qingyang Wang, Jinliang Xu, Zheng Miao
Summary: The study focuses on the subcritical saturated organic Rankine cycle system with four different organic working fluids at various heat source temperatures. It concludes that the efficiency of the two-stage system is affected by the choice of organic working fluids and is higher than that of a single-stage system.
Article
Thermodynamics
Xiongjiang Yu, Jinliang Xu, Guohua Liu, Xianbing Ji
Summary: A new concept of phase-separation evaporator is proposed in this study, where flow instabilities can be suppressed by using gradient pinfin-porous wall microchannels. The high-frequency release of vapor bubbles and stable heat transfer in bare channels enable stable heat transfer under different operating parameters.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Energy & Fuels
Qin Sun, Hao Wang, Kaijun Dong, Tai Lv, Zhibo Kang
Summary: A novel physically separated chilled water storage tank is proposed to replace traditional membrane tanks, and its excellent thermal performance under a large temperature difference is demonstrated in this study. The stability of outlet temperature is better under low-temperature conditions. The full-cycle figure of merit increases significantly, while the percent cold recoverable slightly decreases with increasing temperature difference.
JOURNAL OF ENERGY STORAGE
(2021)
Article
Mechanics
Hao Wang, Jinliang Xu, Xiaojing Ma, Jian Xie
Summary: This study investigates the thermal non-equilibrium process of an FC-72 droplet over a thin oil layer. The droplet radius follows a power law, and the droplet temperature shows nonmonotonic variation. These findings have important implications for applications such as drug delivery.
Article
Thermodynamics
Chunlei Cao, Xiaojing Ma, Xiaotian He, Jinliang Xu, Jian Xie, Guohua Liu
Summary: The study demonstrates that using a soft surface can significantly enhance boiling heat transfer efficiency, especially under saturated boiling conditions. The soft surface can reduce bubble departure size and increase departure frequency, thereby lowering the wall superheating temperature. The formation of elastocapillary waves and dynamic wrinkles can improve heat transfer effect by disturbing the near-wall boundary layer.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
