Article
Thermodynamics
Lin Li, Wen-Quan Jiang, Yang Li, Shi-Yu Su, Jie-Feng Shi, Fan Yang
Summary: This study investigates the flow and heat transfer characteristics of supercritical pressure methane in a vertical tube, focusing on the mechanism of two-peak wall temperatures occurrence. The M-shape velocity distribution and reversal of radial flow direction play key roles in promoting turbulence and enhancing mixing between hot and cold fluids. A new criterion for predicting critical heat flux causing heat transfer deterioration in supercritical pressure methane is proposed.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Zenan Yang, Xiaobo Luo, Wei Chen, Minking K. Chyu
Summary: By installing a body-centered cubic lattice structure in the tube, the heat transfer deterioration of supercritical CO2 flowing in a vertical tube is suppressed and overall heat transfer is improved. The study shows that the temperature peak decreases and the average Nu number increases significantly in the tube with BCC lattice, indicating enhanced turbulence intensity and energy transport.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Yong Cao, Xiaoxiao Xu, Dan Li, Chao Liu, Chaobin Dang
Summary: This study investigates the heat transfer characteristics of supercritical CO2 (S-CO2) in a smooth tube and a smooth tube with Helmholtz oscillators. The results show that the heat transfer deterioration of S-CO2 can be significantly inhibited by the Helmholtz oscillator. The pulsating flow generated by the oscillator enhances the disturbance between near-wall fluid and core fluid, resulting in more uniform thermophysical properties of S-CO2 and weaker buoyancy effect.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Xiao-jing Zhu, Rui-zeng Zhang, Xin Du, Xiao Yu, Qing-gang Qiu
Summary: An experimental investigation on heat transfer in vertical upward supercritical CO2 flow was conducted, and correlations and buoyancy parameters were evaluated based on the experimental data. A segmented correlation considering buoyancy was proposed to predict the heat transfer behavior.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Runfeng Xiao, Yicheng Zhang, Liang Chen, Junxin Wang, Shuangtao Chen, Yu Hou
Summary: This paper conducts simulations of supercritical heat transfer of R134a in horizontal tubes to study the effects of circumferential heat conduction on heat transfer deterioration and explain the abnormal phenomena of higher temperature distribution in non-gravity supercritical flow. The results indicate that heat transfer deterioration is caused by impaired specific heat and heat conduction in the boundary layer, and the subsequent heat transfer recovery is due to enhanced thermal conduction and turbulent convection. A dimensionless parameter called the Biot number is defined to characterize the thermal resistance ratio of circumferential conduction to convective heat transfer. The redistribution of wall temperature caused by circumferential conduction affects supercritical convection in horizontal tubes, and non-gravity supercritical flow may have higher wall temperature when the Biot number is small. The deterioration of the top surface can be significantly alleviated by using a tube with larger wall thickness or thermal conductivity.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Zenan Yang, Meiyuan Lu, Ben Guan, Haiwei Yang, Weiqiang Pu, Ge Wang
Summary: This paper first proposes a new mechanism of heat transfer deterioration (HTD) in supercritical water (SCW) based on the pseudo boiling theory, and then numerically investigates the mitigation effects of nanoparticles and corrugations on the HTD. The study reveals that the low turbulence intensity and thermal conductivity of the pseudo film induce the HTD, and the pseudo two-phase flow instability affects the growth and dissipation of the pseudo film. With the presence of nanoparticles and corrugations, the wall temperature can decrease by 348 K, the wall temperature peak mitigation ratio is 33.5%, and the maximum heat transfer enhancement is 164%. However, when the corrugations in the corrugated tube have a large pitch, HTD cycles occur and further deteriorate the overall heat transfer performance. The coupling effect of nanoparticles and corrugations effectively suppresses the HTD and HTD cycles.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Qianqian Ren, Qinggang Qiu, Guangyu Qiu, Xiao Yu, Xiaojing Zhu
Summary: In this study, the convective heat transfer characteristics of supercritical CO2 in heated tubes were experimentally investigated. The accuracy of different heat transfer deterioration identification methods was evaluated. The results showed that some methods were not accurate or reliable in reflecting the heat transfer trend, while others produced illogical results or were ineffective in certain cases.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Haisong Zhang, Jinliang Xu, Qingyang Wang
Summary: Supercritical fluids are widely used in power generation systems and the heat transfer deterioration phenomenon is of great importance to their design and operation. However, there is a lack of quantitative models to determine the position of the wall temperature peak during heat transfer deterioration and accurately predict the characteristics. In this study, two correlations were developed based on experimental results for supercritical CO2 in vertical upward tubes. These correlations provide quantitative models for the heat transfer deterioration phenomenon and can benefit the engineering application of supercritical power cycles.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Dan Li, Xiaoxiao Xu, Yong Cao, Chao Liu, Shijie Zhang, Chaobin Dang
Summary: This study investigates the characteristics and mechanisms of self-excited oscillation pulsating flow on heat transfer deterioration of supercritical CO2, finding that this flow significantly improves heat transfer performance, particularly in the region of heat transfer deterioration at the entrance of the heated tube.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Guoqiang Xu, Yinchao Ju, Wei Gao, Jian Fu, Bensi Dong
Summary: Hexamethyldisiloxane (MM) is a suitable working fluid for medium/high temperature supercritical ORC system due to its higher thermostability and lower critical parameters. However, the abnormal heat transfer phenomenon caused by the sharp variation of thermophysical properties near the pseudo-critical temperature poses a challenge for heat transfer design in supercritical ORC system. This study analyzes the distributions of key parameters and identifies the main causes of abnormal heat transfer through experimental and numerical analysis. Dimensionless parameters for buoyancy and flow acceleration are obtained, and their thresholds for influencing heat transfer are determined. The results provide insights into the physical mechanism and prediction of heat transfer characteristics.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Shijie Zhang, Xiaoxiao Xu, Chao Liu, Xiaoxiao Li, Chuang Wu, Chaobin Dang
Summary: This paper investigates the heat transfer deterioration of supercritical CO2 in vertical-downward flow and observes the sudden rise of wall temperature. The effect of operation parameters on the heat transfer deterioration is studied, and a new shear stress redistribution model is proposed considering the thermal acceleration in the boundary layer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Chao Li, Junhong Hao, Xingce Wang, Zhihua Ge, Xiaoze Du
Summary: This paper analyzed the convective heat transfer performance of supercritical carbon dioxide (sCO(2)) in horizontal tubes with variable cross-section under heating conditions through numerical simulation. It found that the diverging tube effectively enhances heat transfer performance, while the converging tube weakens it. The concepts of quasi-air film and eddy blockage were introduced to explain the heat transfer deterioration mechanism near the top bus.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Nuclear Science & Technology
Tanuj Srivastava, Dipankar N. Basu
Summary: The thermalhydraulics of a supercritical natural circulation loop (sNCL) are heavily influenced by the operating conditions and geometric configurations chosen. This study focuses on the identification of a quantifiable criterion for the deterioration in a rectangular loop driven by carbon dioxide. The study identifies four operation regimes based on temperature levels and suggests operating within the enhanced heat transfer regime for better heat transfer. The study also observed the impact of loop inclination on circulation rate and heat transfer deterioration, as well as proposing a buoyancy parameter to predict the appearance of deterioration.
NUCLEAR ENGINEERING AND DESIGN
(2022)
Article
Nuclear Science & Technology
S. Kassem, A. Pucciarelli, W. Ambrosini
Summary: In this paper, the authors use a low-Reynolds number turbulence model to predict heat transfer at supercritical pressure with different degrees of surface finishing. The model is able to reproduce friction factors and is based on a simple description of the effect of wall protrusions on turbulence production in the boundary layer. Sensitivity analysis is conducted to characterize the predictions at different roughness parameter values, especially with respect to the possibility of suppressing deteriorated heat transfer by roughened surfaces. Experimental data on carbon dioxide are used to validate the model's capability to predict wall temperature values with different boundary conditions. The described model shows promise not only in predicting experimentally measured effects, but also in studying the behavior of purposely roughened surfaces to reduce the occurrence of deteriorated heat transfer.
ANNALS OF NUCLEAR ENERGY
(2023)
Article
Thermodynamics
Zenan Yang, Xiaobo Luo, Ge Wang, Ben Guan, Haiwei Yang
Summary: This study numerically investigates the effects of nanoparticles on the heat transfer performance of supercritical CO2. The results show that increasing the nanoparticle concentration further suppresses local temperature peaks and improves heat transfer enhancement. Detailed flow field analysis reveals that reducing the density gradient in the buffer layer significantly improves heat transfer performance, and the convective heat transfer benefits from the decreased specific heat and improved thermal conductivity of the nanofluid. High-density nanoparticles play a more effective role in mitigating the HTD phenomenon.
NUMERICAL HEAT TRANSFER PART A-APPLICATIONS
(2022)
Article
Thermodynamics
Xueli Wang, Jinjia Wei, Yueping Deng, Zan Wu, Bengt Sunden
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2018)
Article
Thermodynamics
Zan Wu, Bengt Sunden
HEAT AND MASS TRANSFER
(2019)
Review
Thermodynamics
Wei Wang, Zan Wu, Bingxi Li, Bengt Sunden
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2019)
Article
Mechanics
Zan Wu, Zhen Cao, Bengt Sunden
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2019)
Article
Thermodynamics
Xueli Wang, Zan Wu, Jinjia Wei, Bengt Sunden
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2019)
Article
Thermodynamics
Zhen Cao, Zan Wu, Anh-Duc Pham, Yanjie Yang, Sahar Abbood, Peter Falkman, Tautgirdas Ruzgas, Cathrine Alber, Bengt Sunden
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2019)
Article
Chemistry, Physical
M. Hernaiz, V Alonso, P. Estelle, Z. Wu, B. Sunden, L. Doretti, S. Mancin, N. Cobanoglu, Z. H. Karadeniz, N. Garmendia, M. Lasheras-Zubiate, L. Hernandez Lopez, R. Mondragon, R. Martinez-Cuenca, S. Barison, A. Kujawska, A. Turgut, A. Amigo, G. Huminic, A. Huminic, M-R Kalus, K-G Schroth, M. H. Buschmann
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2019)
Article
Energy & Fuels
Zan Wu, Zhen Cao, Bengt Sunden
Article
Thermodynamics
Jin-yuan Qian, Zan Wu, Qian-Kun Zhang, Zhi-Jiang Jin, Bengt Ake Sunden
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2019)
Article
Engineering, Aerospace
Tong Zhang, Shanshan Geng, Xin Mu, Jiamin Chen, Junyi Wang, Zan Wu
INTERNATIONAL JOURNAL OF AEROSPACE ENGINEERING
(2019)
Article
Thermodynamics
Zhen Cao, Zan Wu, Bengt Sunden
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2019)
Article
Thermodynamics
Zhen Cao, Zan Wu, Anh-Duc Pham, Bengt Sunden
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2019)
Proceedings Paper
Energy & Fuels
Zan Wu, Zhen Cao, Anh Duc Pham, Bengt Sunden
INNOVATIVE SOLUTIONS FOR ENERGY TRANSITIONS
(2019)
Proceedings Paper
Energy & Fuels
Zhen Cao, Zan Wu, Sahar Abbood, Bengt Sunden
INNOVATIVE SOLUTIONS FOR ENERGY TRANSITIONS
(2019)
Article
Nanoscience & Nanotechnology
Jin Wang, Guolong Li, Jing Luo, Zan Wu, Bengt Sunden
JOURNAL OF NANOFLUIDS
(2019)
Article
Energy & Fuels
Shitong Fang, Houfan Du, Tao Yan, Keyu Chen, Zhiyuan Li, Xiaoqing Ma, Zhihui Lai, Shengxi Zhou
Summary: This paper proposes a new type of nonlinear VIV energy harvester (ANVEH) that compensates for the decrease in peak energy output at low wind speeds by introducing an auxiliary structure. Theoretical and experimental results show that ANVEH performs better than traditional nonlinear VIV energy harvesters under various system parameter variations.
Article
Energy & Fuels
Wei Jiang, Shuo Zhang, Teng Wang, Yufei Zhang, Aimin Sha, Jingjing Xiao, Dongdong Yuan
Summary: A standardized method was developed to evaluate the availability of solar energy resources in road areas, which combined the Analytic Hierarchy Process (AHP) and the Geographic Information System (GIS). By analyzing critical factors and using a multi-indicator evaluation method, the method accurately evaluated the utilization of solar energy resources and guided the optimal location selection for road photovoltaic (PV) projects. The results provided guidance for the application of road PV projects and site selection for route corridors worldwide, promoting the integration of transportation and energy.
Article
Energy & Fuels
Chang Liu, Jacob A. Wrubel, Elliot Padgett, Guido Bender
Summary: The study investigates the effects of coating defects on the performance of the anode porous transport layer (PTL) in water electrolyzers. The results show that an increasing fraction of uncoated regions on the PTL leads to decreased cell performance, with continuous uncoated regions having a more severe impact compared to multiple thin uncoated strips.
Article
Energy & Fuels
Marcos Tostado-Veliz, Xiaolong Jin, Rohit Bhakar, Francisco Jurado
Summary: In this paper, a coordinated charging price mechanism for clusters of parking lots is proposed. The research shows that enabling vehicle-to-grid characteristics can bring significant economic benefits for users and the cluster coordinator, and vehicle-to-grid impacts noticeably on the risk-averse character of the uncertainty-aware strategies. The developed pricing mechanism can reduce the cost for users, avoiding to directly translate the energy cost to charging points.
Article
Energy & Fuels
Duan Kang
Summary: Building an energy superpower is a key strategy for China and a long-term goal for other countries. This study proposes an evaluation system and index for measuring energy superpower, and finds that China has significantly improved its ranking over the past 21 years, surpassing other countries.
Article
Energy & Fuels
Fucheng Deng, Yifei Wang, Xiaosen Li, Gang Li, Yi Wang, Bin Huang
Summary: This study investigated the synergistic blockage mechanism of sand and hydrate in gravel filling layer and the evolution of permeability in the layer. Experimental models and modified permeability models were established to analyze the effects of sand particles and hydrate formation on permeability. The study provided valuable insights for the safe and efficient exploitation of hydrate reservoirs.
Article
Energy & Fuels
Hao Wang, Xiwen Chen, Natan Vital, Edward Duffy, Abolfazl Razi
Summary: This study proposes a HVAC energy optimization model based on deep reinforcement learning algorithm. It achieves 37% energy savings and ensures thermal comfort for open office buildings. The model has a low complexity, uses a few controllable factors, and has a short training time with good generalizability.
Article
Energy & Fuels
Moyue Cong, Yongzhuo Gao, Weidong Wang, Long He, Xiwang Mao, Yi Long, Wei Dong
Summary: This study introduces a multi-strategy ultra-wideband energy harvesting device that achieves high power output without the need for external power input. By utilizing asymmetry, stagger array, magnetic coupling, and nonlinearity strategies, the device maintains a stable output voltage and high power density output at non-resonant frequencies. Temperature and humidity monitoring are performed using Bluetooth sensors to adaptively assess the device.
Article
Energy & Fuels
Tianshu Dong, Xiudong Duan, Yuanyuan Huang, Danji Huang, Yingdong Luo, Ziyu Liu, Xiaomeng Ai, Jiakun Fang, Chaolong Song
Summary: Electrochemical water splitting is crucial for hydrogen production, and improving the hydrogen separation rate from the electrode is essential for enhancing water electrolyzer performance. However, issues such as air bubble adhesion to the electrode plate hinder the process. Therefore, a methodology to investigate the two-phase flow within the electrolyzer is in high demand. This study proposes using a microfluidic system as a simulator for the electrolyzer and optimizing the two-phase flow by manipulating the micro-structure of the flow.
Article
Energy & Fuels
Shuo Han, Yifan Yuan, Mengjiao He, Ziwen Zhao, Beibei Xu, Diyi Chen, Jakub Jurasz
Summary: Giving full play to the flexibility of hydropower and integrating more variable renewable energy is of great significance for accelerating the transformation of China's power energy system. This study proposes a novel day-ahead scheduling model that considers the flexibility limited by irregular vibration zones (VZs) and the probability of flexibility shortage in a hydropower-variable renewable energy hybrid generation system. The model is applied to a real hydropower station and effectively improves the flexibility supply capacity of hydropower, especially during heavy load demand in flood season.
Article
Energy & Fuels
Zhen Wang, Kangqi Fan, Shizhong Zhao, Shuxin Wu, Xuan Zhang, Kangjia Zhai, Zhiqi Li, Hua He
Summary: This study developed a high-performance rotary energy harvester (AI-REH) inspired by archery, which efficiently accumulates and releases ultralow-frequency vibration energy. By utilizing a magnetic coupling strategy and an accumulator spring, the AI-REH achieves significantly accelerated rotor speeds and enhanced electric outputs.
Article
Energy & Fuels
Yi Yang, Qianyi Xing, Kang Wang, Caihong Li, Jianzhou Wang, Xiaojia Huang
Summary: In this study, a novel hybrid Quantile Regression (QR) model is proposed for Probabilistic Load Forecasting (PLF). The model integrates causal dilated convolution, residual connection, and Bidirectional Long Short-Term Memory (BiLSTM) for multi-scale feature extraction. In addition, a Combined Probabilistic Load Forecasting System (CPLFS) is proposed to overcome the inherent flaws of relying on a single model. Simulation results show that the hybrid QR outperforms traditional models and CPLFS exceeds the best benchmarks in terms of prediction accuracy and stability.
Article
Energy & Fuels
Wen-Jiang Zou, Young-Bae Kim, Seunghun Jung
Summary: This paper proposes a dynamic prediction model for capacity fade in vanadium redox flow batteries (VRFBs). The model accurately predicts changes in electrolyte volume and capacity fade, enhancing the competitiveness of VRFBs in energy storage applications.
Article
Energy & Fuels
Yuechao Ma, Shengtie Wang, Guangchen Liu, Guizhen Tian, Jianwei Zhang, Ruiming Liu
Summary: This paper focuses on the balance of state of charge (SOC) among multiple battery energy storage units (MBESUs) and bus voltage balance in an islanded bipolar DC microgrid. A SOC automatic balancing strategy is proposed considering the energy flow relationship and utilizing the adaptive virtual resistance algorithm. The simulation results demonstrate the effectiveness of the proposed strategy in achieving SOC balancing and decreasing bus voltage unbalance.
Article
Energy & Fuels
Raad Z. Homod, Basil Sh. Munahi, Hayder Ibrahim Mohammed, Musatafa Abbas Abbood Albadr, Aissa Abderrahmane, Jasim M. Mahdi, Mohamed Bechir Ben Hamida, Bilal Naji Alhasnawi, A. S. Albahri, Hussein Togun, Umar F. Alqsair, Zaher Mundher Yaseen
Summary: In this study, the control problem of the multiple-boiler system (MBS) is formulated as a dynamic Markov decision process and a deep clustering reinforcement learning approach is applied to obtain the optimal control policy. The proposed strategy, based on bang-bang action, shows superior response and achieves more than 32% energy saving compared to conventional fixed parameter controllers under dynamic indoor/outdoor actual conditions.