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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 flow 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 flow stability. Operating at lower operating pressures results in greater circulation flow and a heightened sensitivity to phase changes. Under system pressures of 13.76, 11.08, 8.39, and 6.71 MPa, the recommended circulation ratios are determined to be 5.38, 7.86, 11.95, and 16.07, 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

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Curvature-property coupling governed heat transfer deterioration in supercritical helically coiled tubes: Mechanistic insights and mitigation strategies via structural parametrization

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International Journal of Thermal Sciences 2025年 215卷

作者： Chang, Fucheng Xin, Jiaxing Wu, Xiaoyi Li, Liwei Li, Huixiong Zhu, Yanlin National Key Lab of Aerospace Power System and Plasma Technology School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710049 China China Special Equipment Testing and Research Institute Beijing 100029 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an 710049 China Shanghai Nuclear Engineering Research & Design Institute Co. Ltd Shanghai 200233 China

The unique thermo-hydrodynamic coupling phenomena in the helically coiled tube (HCT) handling supercritical fluids present both opportunities and challenges for next-generation compact heat exchangers. While the pronounced thermophysical property variations near pseudo-critical temperatures (T_pc) and curvature-induced secondary flows synergistically enhance heat transfer coefficient (HTC), their nonlinear coupling mechanisms may unexpectedly provoke severe heat transfer deterioration (HTD). Through systematic numerical investigations, this study reveals that circumferential wall temperature inhomogeneity (CWTI) exhibits an inverted N-shaped evolution, providing valuable insights for thermal homogenization design near T_pc. The secondary flow Reynolds number (Se), quantifying secondary flow intensity, shows a monotonic increase with decreasing coil diameter (D_c) or inner diameter (D_i), reaching saturation in high-enthalpy regions. Notably, CWTI demonstrates non-monotonic behavior, achieving minimum values near T_pc before manifesting distinct rebound characteristics near T_pc conditions. Parametric analysis establishes that: (1) Elevating heat flux (q) increases Se, reducing D_c boosts it by 50.3 %, and decreasing D_i raises it by 60.0 %. (2) HTD predominantly initiates at the outer wall under high-q conditions, with D_c reduction achieving HTD suppression and 26.9 % enhancement in the local HTC;(3) Reducing the D_i results in a reduction of maximum CWTI by 22.5 %–28.6 %, suggesting that structural parametrization effectively mitigates wall temperature non-uniformity, thus suppressing the HTD. While centered on supercritical water, the dimensionless scaling relationships demonstrate extendibility to other media, with the curvature-property coupling mechanism both elucidating fundamental interactions and guiding robust heat exchanger design. © 2025 Elsevier Masson SA

关键词： Heat transfer deterioration Helically coiled tube Structural parametrization Supercritical fluid Thermo-hydrodynamic coupling

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A review of engine application and fundamental study on turbulent premixed combustion of hydrogen enriched natural gas

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Science China(Technological Sciences) 2014年第3期57卷 445-451页

作者： WANG JinHua WEI ZhiLong ZHANG Meng HUANG ZuoHua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

The application and fundamental study on turbulent premixed combustion of hydrogen enriched natural gas is reviewed in this *** include the combustion characteristics of direct injection engine fueled with hydrogen enriched natural gas,visualization study of direct injection combustion of hydrogen enriched natural gas using a constant volume vessel,and the fundamental study of turbulent premixed combustion of hydrogen enriched natural *** effect of additional hydrogen on the combustion process of natural gas engine is investigated from the fundamental view of the interaction between combustion reaction and turbulent flow.

关键词： natural gas hydrogen direct injection combustion turbulent premixed combustion OH-PLIF engine

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Corrigendum to “Experimental study on flow boiling and circumferential non-uniform heat transfer characteristics in helically-coiled tube under coupled heat transfer conditions” [Appl. Therm. Eng. 258(Part C) (2025) 124844]

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Applied Thermal engineering 2025年 261卷

作者： Hengyuan Wang Qiyu Xuan Hailin Lei Xi Li Zhibin Li Huixiong Li State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China

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Study on thermo-fluid-chemical coupling simulation and characteristic fields evolution during in-situ pyrolysis of tar-rich coal

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International Journal of Heat and Fluid flow 2025年 116卷

作者： Meijing Chen Yongbo Du Chang’an Wang Yujie Hou Tianlin Yuan Liujun Chang Lei Deng Defu Che State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China

Underground in-situ pyrolysis of tar-rich coal is an effective approach to expand the supply channels of oil and gas while ensuring energy security, and it has currently aroused wide attention in the academic community. The coupling of multiple interdependent physical fields causes the in-situ pyrolysis process and related phenomena. However, existing studies usually only have focused on a single process. The study proposed a three-dimensional (3D) model for the in-situ pyrolysis of tar-rich coal employing external high-temperature fluids. Numerical simulation was used to achieve the transient calculation of the coupling model of chemical reaction, fluid flow, and heat transfer. The impacts of medium type, medium temperature, inlet rate, well patterns, and the number of horizontal fractures were investigated by characterizing the temperature and concentration fields. The results indicate that, under the basic working condition, the pyrolysis reaction of tar-rich coal in the formation has been completed after ∼28.5 months of heat injection. Both N 2 and CO 2 are heat carriers with greater advantages in heat transfer as compared to H 2 O (g). The threshold of injection rate is 5 m·s −1 . The heat transfer effect of coal seams with 4 injection wells is obviously better than that of 1 and 2 injection wells. The number of 3 horizontal fractures is superior to 1 and 2 fractures, which can effectively enhance heat transfer and promote the thermal decomposition. The present study has emphatically investigated the evolution of characteristic fields of tar-rich coal seams under thermo-fluid-chemical coupling conditions during the in-situ pyrolysis process, providing substantial reference significance to guide the in-situ conversion mining.

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Laser-based speciation of acetone oxidation behind reflected shock waves and chemical kinetic modeling

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International Journal of Hydrogen Energy 2025年 141卷 46-58页

作者： Congjie Hong Xin Zhang Jiabiao Zou Zuohua Huang Yingjia Zhang Aamir Farooq State Key Laboratory of Multiphase Flows in Power Engineering Xi'an Jiaotong University Xi'an 710049 People's Republic of China Clean Energy Research Platform Physical Sciences and Engineering (PSE) Division King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia

With the growing global focus on renewable and oxygenated fuels, acetone has attracted significant attention due to its role as a key intermediate in the oxidation of alcohol-based fuels, an efficient hydrogen carrier, and a vital component in hydrogen production via catalytic reforming and biofuel synthesis. A comprehensive understanding of its pyrolysis and oxidation mechanisms is crucial for advancing clean energy technologies and optimizing its utilization in sustainable fuel applications. However, discrepancies persist in existing models regarding the time histories of key species during acetone pyrolysis. In this study, advanced laser diagnostic techniques were employed to measure the time-resolved concentration profiles of various species during acetone oxidation behind reflected shock waves, capturing the dynamic evolution of key intermediates and products such as CO, OH, and H 2 O. By integrating the latest experimental and theoretical studies, including the concentration profiles of key intermediates during pyrolysis, rate coefficient measurements, and ignition delay times, the critical reaction pathways and rate coefficients of acetone were systematically refined. Additionally, previously missing reaction pathways (i.e., CH 2 CO + CH 3 =HCCO + CH 4 ) were incorporated, leading to an improved acetone kinetic model that underwent comprehensive validation against various experimental datasets. The results indicate that the updated model accurately predicts the time-resolved concentration profiles of key species during acetone oxidation and pyrolysis over a wide temperature range, with significant improvements in predicting ignition delay times and laminar flame speeds. This study offers valuable insights for refining acetone kinetic models and establishes a research framework for investigating the complex chemical behavior of ketones and other oxygenated fuels in combustion.

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Constructing electron transport channel of SnO2/BaSO4 on g-C3N4 for enhanced visible-light-driven photocatalytic H2 production

Materials Today Catalysis

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Materials Today Catalysis 2025年 9卷

作者： Dong, Gongyue Guo, Xiaojuan Cheng, Cheng Chen, Feng Zhang, Jinfeng Du, Yanping Meng, Wei Liu, Maochang Shi, Jinwen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Guangdong Provincial Key Laboratory of Multi-energy Complementary Distributed Energy Systems Dongguan University of Technology Dongguan523808 China School of Engineering Lancaster University LancasterLA1 4YW United Kingdom Gansu Company PipeChina Lanzhou730060 China Hunan Provincial Key Lab of Dark Tea and Jin-Hua Department of Material & Chemical Engineering Hunan City University Yiyang413000 China

Graphitic carbon nitride (g-C3N4) is confronted with the issue of poor utilization of photogenerated charge carriers, thereby leading to limited performance of photocatalytic hydrogen (H2) production, which restricts its potential application. Herein, the electron transport material SnO2/BaSO4 was synthesized to integrate with g-C3N4 for addressing the above problem. Various characterizations were conducted to investigate the g-C3N4-SnO2/BaSO4 photocatalyst, and it demonstrated that photogenerated electrons from g-C3N4 expeditiously migrate to SnO2/BaSO4 nanoparticles, which markedly hindered photogenerated carriers’ recombination. Subsequently, the g-C3N4-SnO2/BaSO4 photocatalyst demonstrated promoted photocatalytic H2 production at a rate of 14.2 μmol h−1 under visible-light illumination, which was 2.5 times higher than that of pristine g-C3N4. © 2025 The Authors

关键词： Barium sulfate

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ȮH insights into the interaction of hydrogen-rich methane and water: Laser absorption experiments and chemical kinetics

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Combustion and Flame 2025年 278卷

作者： Xin Zhang Zilong Feng Congjie Hong Wuchuan Sun Zuohua Huang Yingjia Zhang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 PR China

Flue gas recirculation and steam injection are employed in hydrogen-rich gas turbines to stabilize fuel reactivity and improve cycle efficiency, introducing high water vapor content into the combustion chamber and thereby necessitating an investigation of water-fuel interactions at elevated temperatures. This study employed UV laser absorption diagnostics behind reflected shock waves to conduct in situ measurements of the ȮH concentration time-histories during the oxidation of CH 4 /H 2 /H 2 O/O 2 /Ar mixtures at pressures of approximately 1.3, 5.0, and 15.2 atm and temperatures ranging from 1225 to 1888 K with varying hydrogen blending and water addition ratios. The absorption lineshapes of the ȮH R 1 (5) transition in the A-X(0,0) vibronic band were characterized after broadening and shifting in Ar at different pressures, with diagnostic center wavelengths set at 306.6868 nm (1.3 atm), 306.6874 nm (5.0 atm), and 306.6886 nm (15.2 atm), respectively. The obtained ȮH concentration time-history data were compared in detail with predictions from eight representative reaction kinetic models, and the predictive capability of the models for ȮH behavior was quantitatively assessed using the error function method. NUIGMech1.1 exhibited superior performance in predicting ȮH behavior and was subsequently selected for kinetic analysis to elucidate stage-specific micro-mechanisms and identify key reactions driving the concentration evolution. The activating effect of H 2 on ȮH behavior during CH 4 oxidation was investigated. Results indicate that higher hydrogen levels intensify hydrogen-related reaction pathways, expanding the radical pools (H, ȮH, and Ö), thereby promoting fuel consumption through Ḣ-atom abstraction reactions. Additionally, by introducing weak collision H 2 O* and inert H 2 O**, the thermodynamic and kinetic effects of water were distinguished. The results show that under the current conditions, H 2 O primarily affects ȮH behavior through direct participatio

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Comparison of CO_(2)with H_(2)O as the transport medium in a biomass supercritical water gasification system

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Frontiers of Chemical Science and engineering 2024年第11期18卷 121-133页

作者： Weizuo Wang Bingru Lu Jinwen Shi Qiuyang Zhao Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Supercritical water gasification is a clean technology for biomass conversion and *** supercritical water gasification systems,H_(2)O is often used as the transport *** in the reaction temperature at the gasification area and in the heating rate of biomass may limit the gasification rate and *** this paper,CO_(2)is used as the transport medium due to its relatively low critical point and specific heat ***,a corn stalk gasification system with different transport media is established in this paper,and the influences of various operating parameters,such as temperature,pressure and feedstock concentration,are *** results show that the gas yield in the CO_(2)-transport system decreases by no more than 5 wt%.In addition,thermodynamic analysis reveals that a system with CO_(2)as transport medium consumes approximately 25%less electricity than a system with H_(2)O as the transport *** addition,the reaction heat absorption *** results show the superiority of CO_(2)to H_(2)O as a transport medium.

关键词： biomass supercritical water gasification hydrogen production CO_(2)transport energy and exergy analyses

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Thermal-Hydraulic Calculation and Analysis on Evaporator System of a 1000 MW Ultra-Supercritical Pulverized Combustion Boiler with Double Reheat

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Journal of Thermal Science 2021年第3期30卷 807-816页

作者： WAN Li YANG Dong ZHOU Xihong DONG Le LI Juan State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

A double reheat ultra-supercritical boiler is an important development direction for high-parameter and large-capacity coal-fired power plants due to its high thermal efficiency and environmental *** has developed a 1000 MW double reheat ultra-supercritical boiler with steam parameters of 35 MPa at 605℃/613℃/613℃.Reasonable water wall design is one of the keys to safe and reliable operation of the *** order to examine the thermal-hydraulic characteristics of the double reheat ultra-supercritical boiler,the water wall system was equivalent to a flow network comprising series-parallel circuits,linking circuits and pressure nodes,and a calculation model was built on account of the conservation equations of energy,momentum and *** the iterative solving of nonlinear equations,the prediction parameters of the water wall at boiler maximum continue rate(BMCR),75%turbine heat-acceptance rate(THA)and 30%THA loads,including total pressure drops,flow distribution,outlet steam temperatures,fluid and metal temperatures were *** results of calculation exhibit excellent thermal-hydraulic characteristics and substantiate the feasibility of the water wall design of the double reheat ultra-supercritical boiler.

关键词： double reheat ultra-supercritical boiler water wall flow network method thermal-hydraulic characteristic

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