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Journal of Supercritical Fluids 2025年 224卷

作者： Hou, Zhenghui Liao, Haifan Yang, Kuang Bai, Shaozhe Fan, Xinjiang Yang, Chaofan Wang, Haijun State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The heat transfer coefficient is a critical parameter for the design and optimization of supercritical carbon dioxide (sCO₂) heat exchange systems. Based on 20723 data points collected from 22 published studies, existing heat transfer correlations are evaluated, and a new model with improved stability and predictive accuracy is developed. Current correlations for upward vertical sCO₂ flow typically include wall-temperature-dependent parameters, which often lead to issues such as non-uniqueness or the absence of solutions during wall temperature prediction, along with limited accuracy. To address these issues, this study integrates the Buckingham Pi theorem and constructs a wall-temperature-independent heat transfer model using a dimensionless neural network. This approach avoids the problems of multiple or no solutions and achieves high predictive performance, with mean absolute relative errors of 2.83 % for wall temperature and 5.81.% for Nusselt number predictions. Furthermore, the active subspace method is employed to identify four dominant dimensionless groups governing the heat transfer process. These groups can be decomposed into products of commonly known dimensionless numbers. During this process, a new dimensionless number—the buoyancy generation (BG) number—is proposed and defined. This study leverages data-driven dimensional analysis to explore {1. influencing parameters and dominant dimensionless numbers for supercritical heat transfer, offering new insights into the underlying physical mechanisms. © 2025 Elsevier B.V.

关键词： Electric heating

Research on the Solution of the Thermo-Hydro-Mechanical-Chemical Coupling Model Based on the Unified Finite Volume Method Framework

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SSRN 2024年

作者： Zhang, Weitao Han, Dongxu Wang, Bohong Chen, Yu-Jie Jiao, Kaituo Gong, Liang Yu, Bo Qingdao266580 China School of Mechanical Engineering Beijing Key Laboratory of Pipeline Critical Technology and Equipment for Deepwater Oil and Gas Development Beijing Institute of Petrochemical Technology Beijing102617 China National-Local Joint Engineering Laboratory of Harbour Oil and Gas Storage and Transportation Technology Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control Zhejiang Ocean University No.1 Haida South Road Zhoushan316022 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Most existing thermo-hydro-chemical-mechanical (THMC) coupling models for enhanced geothermal systems (EGS) employ a combination of finite volume method (FVM) and extended finite element method (XFEM), facing challenges in framework integration, programming complexity, and solution efficiency. To overcome these limitations, this study develops an innovative FVM-XFVM model based on the embedded discrete fracture model (EDFM) that significantly enhances the THMC coupling modeling process for fractured reservoirs with simplicity and efficiency. Rigorous comparative verification demonstrates the new model maintains accuracy while improving computational performance. For EGS applications, this model effectively captures spatiotemporal dynamics of coupled THMC processes with multi-component water-rock reactions. The approximately 3°C temperature deviation between multi-component and single-component models after long-term operation demonstrates the necessity of incorporating multi-component reactions into THMC models for accurate forecasts. This work substantially improves the predictability and efficiency of long-term heat production forecasts for EGS reservoirs. © 2024, The Authors. All rights reserved.

关键词： Finite volume method

Heavy Oil Upgrading Using Naoh/Cuso4 Composite Catalyst in Aquathermolysis

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SSRN 2022年

作者： Zhou, Yantao Zhao, Qiuyang Miao, Yan Wang, Xuetao Zhang, Yanlong Wang, Yechun Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Xinjin Weihua Institute of Clean Energy Research Foshan528216 China

To obtain an inexpensive and efficient catalyst in the in-situ upgrading of heavy oil, the NaOH/CuSO4 composite catalyst was proposed in this work. Firstly, the experiments found the viscosity of heavy oil increased with addition of CuSO4 under 300°C in aquathermolysis. Then, the addition of NaOH was found to improve the catalyst capacity of CuSO4 significantly. The NaOH/CuSO4 decreased the viscosity by 81.43% under 300°C. The further analysis revealed the Cu atoms of CuSO4 enter into the heavy oil molecules to increase viscosity, and the NaOH inhabits the viscosity increasing reaction. Besides, the Cu and CuOx with a higher catalytic capacity produced with the addition of NaOH. These conclusions are helpful to understand the aquathermolysis upgrading mechanism and develop a type of inexpensive and efficient composite catalyst. © 2022, The Authors. All rights reserved.

关键词： Sulfur compounds

Thermal and hydraulic performance of molten salt steam generation system under varying operating conditions in concentrating solar power plants

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Case Studies in Thermal engineering 2025年 72卷

作者： Jiaming Tian Bo Ren Yiran Duan Biao Li Yueshe Wang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China

To conduct the thermal transport characteristics and operational stability of the steam generation system (SGS) under partial load conditions in concentrating solar power (CSP), a real-scale shell-and-tube steam generator hydrodynamics predictive model is developed. This model integrates lumped parameter methods with the finite volume method to account for heat transfer and phase change. Additionally, in accordance with the prevailing water circulation mode in the CSP plant, a typical model of the natural circulation system is established, while optimal stable operating points of the maximum circulation mass {1. rate under varying operating conditions are determined. The results indicate that the inherent stability of the generator strongly lies in the dynamic compromise between its thermodynamic and hydrodynamic characteristics. Under high load conditions, the natural circulation mode demonstrates excellent {1. stability. Operating at lower operating pressures results in greater circulation {1. and a heightened sensitivity to phase changes. Under system pressures of 1..76, 1..08, 8.39, and 6.71.MPa, the recommended circulation ratios are determined to be 5.38, 7.86, 1..95, and 1..07, respectively. Furthermore, the stability of the circulation curve is optimized by adjusting the structural dimensions of the steam generator. The sensitivity to evaporation capacity and heat exchanger effectiveness is assessed.

关键词： Molten salt storage Steam generator Natural circulation mode Concentrating solar power

Experimental Study on Leakage of High-Energy Fluids Through Narrow Elliptical Slits

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SSRN 2024年

作者： Bi, Qincheng Zhang, Tao Zhao, Jinle Wang, Teng Yang, Zhendong Gui, Miao State Key Lab Multiphase Flow Power Engn Xi'an Jiaotong University Shaanxi Xian710049 China Department of Power Engineering North China Electric Power University Baoding071003 China State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China Xi'an University of Technology Shaanxi Xian710048 China School of Nuclear Science and Technology Xi'an Jiaotong University Shaanxi Xian710049 China

This study is focused on the leakage flow rate of high-energy fluid passing through narrow elliptical slits with large aspect ratios, which is an issue in the application of the leak-before-break concept. Experiments were conducted using a high-temperature and high-pressure experimental platform at Xi’an Jiaotong University, where the temperature reached up to 320 ℃ and the pressure reached up to 1. MPa. These temperatures and pressures encompass a wide range of operating conditions (single-phase cold water, liquid-vapor (two-phase) mixture, and superheated steam). A series of narrow elliptical slits with different aspect ratios (528-2083) and hydraulic diameters (226-41. um) were used in the experiments. The experimental results were compared with previous model. Based on the experimental data and the the effects of the aspect ratio, the mathematical model was corrected, and the results obtained from the modified model conform well with the experimental results. © 2024, The Authors. All rights reserved.

关键词： Aspect ratio

Development and technical progress in large-scale circulating fluidized bed boiler in China

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Frontiers in Energy 2020年第4期14卷 699-714页

作者： Zhong HUANG Lei DENG Defu CHE State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

Circulating fluidized bed(CFB)boilers has realized the clean and efficient utilization of inferior coal like gangue and coal slime,high sulfur coal,anthracite,petroleum coke,oil shale and other *** a country with the largest amount of CFB boilers and the largest installed capacity in the world,China has 4401.0-600 MWe CFB boilers with a total capacity of 82.29 GWe,including 227 units of 1.5 MWe,95 units of300 MWe,and 24 supercritical *** statistics of typical 1.0-300 MWe CFB boilers showed that the average number of unplanned shut-down was only 0.37 times per year,among which the 1.5 MWe was 0.26 times per year and 300 MWe was 0.46 times per ycai*.The auxiliary power ratio of some 300 MWe CFB boilers based on {1.-pattern reconstruction can be reduced to about 4%,which is closed to the same level of pulverized coal(PC)*** paper summarizes the development process and application status of China's large-scale CFB boilers,analyzes the characteristics and technical performance of the iconic units,and introduces solutions to the problems such as water wall wear and bottom ash cooling.

关键词： CFB boiler installed capacity reliability economics ultra-low emission China

EXPERIMENTAL INVESTIGATION ON THE REFLOODING IN A 5×5 ROD BUNDLE 29

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EXPERIMENTAL INVESTIGATION ON THE REFLOODING IN A 5×5 ROD B...

2022 29th International Conference on Nuclear engineering, ICONE 2022

作者： Liu, Weihua Yuan, Hongsheng Wu, Pan Wang, Ting Shan, Jianqiang School of Nuclear Science and Technology Xi'an Jiaotong University No. 28 Xianning West Road Shaanxi Xi'an China China Nuclear Power Technology Research Institute Co. Ltd No.1001 Shangbu Middle Road Futian District Guangdong Shenzhen518026 China The State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an China

In the current study, a series of reflood tests with uniformly power input have been carried out at the 51.;5 rod bundle film boiling test facility of the Nuclear Safety and Operation {1.(NUSOL) of Xi'an... 详细信息

ISBN: (纸本)9780791886410

In the current study, a series of reflood tests with uniformly power input have been carried out at the 5×5 rod bundle film boiling test facility of the Nuclear Safety and Operation {1.(NUSOL) of Xi'an Jiaotong University and the experimental results have been analyzed in detail. The effect of several parameters, including subcooling of coolant (1.K to 75K), coolant flow rate (2.5m/s to 1..0m/s) and input wall linear power density (7 W/cm to 1. W/cm) on quench front of reflooding patterns have been studied. It is observed that the quench front during reflood stage of the rod bundle channel is sensitive to above parameters. Increase in input wall linear power density, and decrease in flow rate and subcooling of coolant results in delayed reflooding. The temperature, heat flux and heat transfer coefficient on the rod surface have been got via the self-development Reflooding Experimental Data Analysis (REDA) code. The data is not only useful for the development of theoretical models for film boiling heat transfer, two-phase void fraction, pressure drop, and rod bundle reflooding prediction, but also can be used as a benchmark data base for evaluating the analysis code of Loss of Coolant Accident (LOCA) in reactor and the design of the residual heat removal system. Copyright © 2022 by ASME.

关键词： Coolants

Numerical Study on Phase-Change Thermal Storage for Thermal Management of Intermittent High-power Devices

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SSRN 2022年

作者： Chen, Liang Fan, Jing Zhang, Pingtao Xiao, Runfeng Si, Yansong Chen, Shuangtao Hou, Yu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Key Laboratory of Icing and Anti/De-Icing China Aerodynamics Research and Development Center Mianyang621000 China

Latent heat thermal energy storage (LHTES) is an effective approach for thermal management of intermittent high-power output electronics. The limited heat absorption power due to the low conductivity of phase change material is an urgent problem for LHTES. This paper investigates a finned tube heat exchanger with dual-side phase change heat transfer, i.e., LHTES of paraffin RT60 on the fin side and condensation of low-pressure water on the tube side. The proposed model couples the three-dimension enthalpy-porosity model on the fin side with the one-dimension homogeneous flow model on the tube side, yielding the solutions of the dynamic process of the LHTES. The heat-charging power and storage effectiveness of LHTES with single-phase and two-phase heat transfer fluids (HTFs) on the tube side are compared and discussed under different condensation pressures and mass flow rates. Heat transfer on both the fin and tube sides are critical for the LHTES performance, and the use of two-phase HTF on the tube side can enhance the heat-charging power by 21..5% and raise the storage effectiveness by 33.5%. The storage effectiveness decreases with the increase of condensation pressure while the mass flux of tube-side HTF does not have an obvious effect on the storage effectiveness. The maximum power density (1.3 kW/L) of LHTES is obtained when the condensing pressure is 90 kPa and the mass flow rate is 0.045 kg/s. It is indicated that dual-side phase change heat transfer to storage energy can provide a compact and efficient thermal management solution for intermittent high-power devices. © 2022, The Authors. All rights reserved.

关键词： Temperature control

Waste Tire-Derived Graphene Modified Carbon as Anodes for Sodium-Ion Batteries

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SSRN 2024年

作者： Zhou, Ziyi Wang, Silang Wen, Bo Xiao, Jiyuan Yang, Guorui Ding, Shujiang School of Chemistry Engineering Research Center of Energy Storage Materials and Devices Ministry of Education "Four Joint Subjects One Union" School Enterprise Joint Research Center for Power Battery Recycling & Circulation Utilization Technology Xi’an Jiaotong University Xi’an710049 China Xi’an Key Laboratory of Solid Waste Recycling and Resource Recovery State Key Laboratory of Multiphase Flow in Power Engineering Department of Environmental Science and Engineering Xi’an Jiaotong University Xi’an710049 China

The rational disposal of waste tires poses a ubiquitous challenge globally. Pyrolytic carbon black, a solid by-product produced through pyrolysis, has great application prospects. Carbon-based materials are regard as the most potential commercial anode materials for sodium-ion batteries (SIBs) ， which features cheap, environmentally friendly, and low reaction potential. In this study, three-dimensional vertical graphene composite (TCBp@VGSs) was synthesized from waste tires. The graphene with higher defectiveness offers an increased number of active sites for Na+, while the vertically aligned graphene facilitates rapid electron transfer. As a result, the TCBp@VGSs electrode demonstrates the ability to maintain a reversible capacity of 252.7 mA h g-1.after 1.0 cycles at a current density of 0.2 A g-1. Furthermore, it exhibits a sustained rate performance of 1.5.4 mA h g-1.at a current density of 5 A g-1. Moreover, even after 1.00 cycles at a current density of 1.A g-1. a reversible capacity of 1.1.5 mA h g-1.is retained, showcasing good stability and a significantly higher capacity compared to TCBp-1.00. This study introduces novel approaches for the high-value utilization of solid-phase by-products from waste tires, offering certain economic benefits, and contributes fresh insights into the advancement of SIBs anodes. © 2024, The Authors. All rights reserved.

关键词： Graphene

Under-Deposit Corrosion Behavior and Dynamic Deliquescence Properties of Ammonium Salts Covered on Pipelines and Components in a Crude Oil Distillation Column: Experimental and Theoretical Studies

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SSRN 2022年

作者： Li, Ruidong Chen, Jukai Wang, Yueshe State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi'An710049 China School of Chemical Engineering & Technology China University of Mining and Technology Xuzhou221116 China

Electrochemical experiments based on the interdigital electrodes of SAE 1.20 steel and atomic simulation were performed to investigate the under-deposit corrosion behavior and dynamic deliquescence properties of ammonium salts. In-situ electrochemical measurements demonstrate that the deliquescence of ammonium salts affects the evolution of the interface, and the surface characterization results proved that the critical state of moisture absorption leads to the most severe corrosion. Additional ab initio molecular dynamics simulations suggest that the H transport chain impacted by the hydrolysis of NH4+ leads to a variation in the charge state of the system, which may triggering corrosion. © 2022, The Authors. All rights reserved.

关键词： Steel corrosion