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Uncertainty analysis of molten corium In-Vessel Retention under External Reactor Vessel Cooling

International Journal of Advanced Nuclear Reactor Design and Technology 2023年第4期5卷 159-167页

作者： Wu, Shihao Wang, Dong Zhang, Yapei Zhou, Yukun Tian, Wenxi Qiu, Suizheng Su, G.H. School of Nuclear Science and Technology Shaanxi Engineering Research Center of Advanced Nuclear Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

External Reactor Vessel Cooling (ERVC) is a key measure to realize molten corium In-Vessel Retention (IVR). The uncertainty of severe accident in core leads to the uncertainty of molten pool parameters in lower head, which may threat the reliability of successful implementation of IVR. In this study, an uncertainty analysis is employed to ensure the reliability of ERVC technology to IVR with the final two-layer molten pool configuration of AP1000.600 simulations are performed to determine the effect of five key parameters. As long as parameters are within high probability density range, lower head can remain intact, and safety margin is greater than 15 %. For influence level and correlation of parameters, the order on metal layer is: Decay heat > Fe mass > UO2 mass > Zr oxidation fraction > Emissivity of metal layer. The results can provide guidance for subsequent research direction and optimal design of mitigation measures. © 2024 Xi'an Jiaotong University

关键词： Uncertainty analysis

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The evaporation of nanoscale sodium liquid film on the non-ideal nanostructure surface: A molecular dynamics study

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International Journal of Advanced Nuclear Reactor Design and Technology 2023年第1期5卷 1-8页

作者： Wang, Zetao Ye, Tianzhou Guo, Kailun Tian, Wenxi Qiu, Suizheng Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Lab of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an710049 China

The nanoscale liquid sodium film inside the microporous wick structure is of great importance to understanding the evaporation mechanism of the sodium heat pipe. The novel optimized wick structure is made of several layers of special screen. The surface of each screen exhibits a nanostructure type. Some non-ideal nanostructures may result from experimental faults or limits. And they will have an effect on the evaporation of film. In the present study, molecular dynamics is adopted to investigate this effect. The simulation system consists of the liquid sodium film and the solid surface. The flat surface is set as the reference. Based on the three non-ideal shapes of deposition, the sinusoidal nanostructures, conical nanostructures, and spherical nanostructures are built. The results indicate that the evaporation is suppressed by the above nanostructure surfaces. The weakening effect is through three forms: the potential gradient of the liquid film is intensified and the evaporation difficulty is increased;the heat transfer in the solid-liquid contact region is impeded;the collision heat transfer inside the liquid film is affected due to the delay of the aggregation variation between liquid atoms. © 2023 Xi'an Jiaotong University

关键词： Heat pipes

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Numerical simulation and structural optimization of spiral finned tube thermal energy storage

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International Journal of Advanced Nuclear Reactor Design and Technology 2023年第3期5卷 123-136页

作者： Ma, Yunfei Meng, Yu Li, Jingyu Chen, Weixiong Yang, Xiaohu Li, Shaodan Chong, Daotong Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Wuhan Second Ship Design and Research Institute Wuhan430205 China

Thermal energy storage (TES) has emerged as a promising solution to enhance nuclear safety by passively removing decay heat during reactor shutdown and accidents, thus preventing overheating of the reactor core and protecting the integrity of containment barriers. The research of TES with different structures has broad application prospects and practical significance. In this study, the melting process of phase change material (PCM) in various TES structures was simulated by the numerical simulation method in two and three dimensions. The mechanism of gravity-driven natural convection enhancing heat transfer was revealed. The effects of different TES structures, fin pitch, fin height, and fin thickness on heat transfer performance were studied. The results showed that many vortices formed by liquid PCM are the main reason for enhancing the natural convection. Adding fins could greatly accelerate the heat storage process. The melting time of PCM in annular and spiral finned tube TES was 47.3% and 61.3% less than that in smooth tube TES, respectively. In the present study, the heat transfer effect was enhanced as the spiral fin pitch became small, the fin height increased and the fin thickness increased. Two opposite effects of fin structure on the natural convection were revealed: (1) positive effect provided by heat transfer enhancement and (2) negative effect produced by blockage. © 2023 Xi'an Jiaotong University

关键词： Phase change materials

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Extra contribution to the crystal stability of insensitive explosive TATB: The cooperativity of intermolecular interactions

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Defence Technology（防务技术） 2023年第7期25卷 88-98页

作者： Zhi-xiang Zhang Yi-tao Si Tao Yu Wei-peng Lai Yi-ding Ma Mao-chang Liu Ying-zhe Liu Bo-zhou Wang State Key Laboratory of Fluorine&Nitrogen Chemicals Xi'an Modern Chemistry Research InstituteXi'an710065PR China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an710049PR China

An in-depth analysis on the cooperativity of intermolecular interactions including hydrogen bonding andπ-π stacking in 1,3,5-triamino-2,4,6-trinitrobenzene(TATB) crystal was studied. Two quantities, cooperativity rate and energy, were defined to evaluate the nature and strength of cooperativity in a series of clusters diverging from 1D to 3D prototypes. The origin and mechanism of the cooperative effect were settled to demonstrate that the nature of cooperativity is determined by whether the non-covalent interactions compete or promote with each other, which is manifested by the changing trend of electron transfer. There exists obvious cooperative effect in intra-layer and inter-layer structures as they own the equivalent non-covalent interactions, while anti-cooperative effect is also observed if two interactions correlate with each other. On the whole, in the process of crystal formation, the apparent cooperativity is the check and balance of the two effects, which is capable to support a global interaction among all of molecules and contribute to the stabilization of system. Based on the results, one may get a new insight to understand the relationship between non-covalent interactions and low impact sensitivity.

关键词： Cooperativity Non-covalent interaction Low-sensitivity Explosives Charge transfer

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A direct polymeric carbon nitride/tungsten oxide Z-scheme heterostructure for efficient photocatalytic hydrogen generation via reforming of plastics into value-added chemicals

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Rare Metals 2024年第8期43卷 3771-3783页

作者： Rui-Zhe Wang Zhi Lin Yi-Qing Wang Kai-Ni Zhang Ge-Hong Zhang Jie Zhang Samuel S.Mao Shao-Hua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China School of Civil and Architecture Engineering Xi'an Technological UniversityXi'an 710021China Department of Mechanical Engineering University of California at BerkeleyBerkeleyCA94720USA

To promote charge transfer and separation for efficient photocatalysis,a direct Z-scheme heterostructure was constructed by coupling polymeric carbon nitride(PCN) and WO_(3).Interestingly,the obtained PCN/WO_(3)Z-scheme heterostructure could photocataly tic ally produce hydrogen and value-added chemicals(e.g.,formate and acetate) by reforming of plastic polylactic acid(PLA) in alkaline aqueous *** optimizing WO_(3) contents and reaction conditions,the obtained PCN/WO_(3)heterostructure exhibits much increased photocatalytic activity for PLA photoreforming under visible light,with hydrogen evolution rate reaching 402.90 μmol·g~(-1)·h~(-1),which is 3.5 times that of *** is revealed that the Z-scheme charge transfer between PCN and WO_(3) mainly contributes to the promoted charge separation and thus the improved photocatalytic ***,with h+and·OH experimentally evidenced as the predominant active species,a possible reaction pathway for the reforming of PLA into value-added chemicals(e.g.,formate and acetate)over PCN/WO_(3) Z-scheme heterostructure is cleared by monitoring the reaction intermediates and *** work paves a carbon neutrality and scalable route toward the synergistical production of hydrogen and value-added chemicals by utilizing and recycling plastic waste.

关键词： Carbon nitride Z-scheme heterojunction Plastic waste conversion Photocatalytic H_(2)production Value-added chemicals

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Temperature dependence photoluminescence properties of ZnSe-based core-shell quantum dots

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Optics Express 2025年第11期33卷 22588-22597页

作者： Zhang, Tingting Ma, Qing Li, Qingping Huang, Lanting Feng, Yuqiong Duan, Hongwei Chen, Xinlei Li, Qinghua Jin, Xiao Bai, Jinke Xu, Bing Key Laboratory of Environmentally Friendly Functional Materials and Devices School of Physics Science and Technology Lingnan Normal University Guangdong Zhanjiang524048 China School of Energy and Power Engineering Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Department of Materials and Chemical Engineering Taiyuan University Taiyuan030032 China

Heavy metal-free ZnSe-based core-shell quantum dots (QDs) are promising emitting material for achieving violet-blue luminescence. Investigating the temperature-dependent variations in the photoluminescence (PL) properties of ZnSe-based QDs will enhance our understanding of the intrinsic factors that influence their diverse luminescence characteristics. Here we select the optimally synthesized ZnSe core QDs with three diameters (4.1, 5.2, and 8.3 nm) and ZnSe/ZnS core-shell QDs to study their temperature-dependent photoluminescence properties. As the sample temperature is increased, the PL intensity decreases, the emission energy redshifts, and the spectral become broader. We observe a reduction in the exciton-longitudinal optical (LO)-phonon coupling constant from 21.7 meV to 16.1 meV as the diameter of ZnSe core QDs increased from 4.1 nm to 8.3 nm. This decrease is associated with a narrower homogeneous broadening of the emission spectrum. Besides, the epitaxial growth of a ZnS wide bandgap shells onto the ZnSe core QDs can effectively isolate the photogenerated excitons away from the inorganic-organic interface, thus reducing the PL peak width and increasing the exciton binding energy of the QDs. Our research provides a valuable addition to the existing studies on the photoluminescence properties of ZnSe-based core-shell QDs. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Atomic emission spectroscopy

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Heavy Metal Migration Characteristics of Co-Combustion between Sewage Sludge and High Alkaline Coal on Circulating Fluidized Bed

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Journal of Thermal Science 2022年第6期31卷 2178-2188页

作者： LI Yaode YANG Dong ZHOU Xihong DONG Le SUO Lihui SUN Wenbo State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi'an Jiaotong UniversityXi'an 710049China College of Energy&Power Engineering Northeast Electric Power UniversityJilin 132000China

The migration characteristics of heavy metals in co-combustion of sewage sludge and high alkali coal in circulating fluidized bed were studied by experiments and simulations. Temperature plays a crucial role in thermodynamic equilibrium distribution and migration characteristics of heavy metals. At the temperature range of 700℃-1200℃, Hg is completely gaseous and the proportion of Pb, Ni, and Cd in the gas phase is also high. As is mainly elemental in the system, and the proportion of Cr in the solid phase is large. Zn compounds are diverse and mostly solid materials. The volatility of Cu is not strong, and it will become gaseous when the temperature exceeds 1700℃. The proportion of heavy metals in the gas phase decreases as the excess air ratio increases. In an oxygen-rich atmosphere, most of Zn and Ni are converted to oxides;Pb and Cd are converted to crystalline silicate;Cu is converted to partial aluminate;Cr compound is decomposed to form Cr_(2)O_(3);they are good for the solidification and controlling of heavy metals. The elemental Hg is converted to HgCl_(2) and the elemental As is converted to AsCl_(3). Temperature also has a great influence on the volatilization rate of heavy metals. The higher the temperature, the shorter the time they reach the maximum volatility.

关键词： co-combustion heavy metal migration circulating fluidized bed sewage sludge high alkali coal

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Operando modeling and measurements:powerful tools for revealing the mechanism of alkali carbonate-based sorbents for CO_(2)capture in real conditions

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Frontiers in Energy 2023年第3期17卷 380-389页

作者： Tianyi CAI Mengshi WANG Xiaoping CHEN Ye WU Jiliang MA Wu ZHOU School of Energy and Power Engineering Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China Key Laboratory of Energy Thermal Conversion and Control of the Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China Key Laboratory of Thermal Control of Electronic Equipment and Advanced Combustion Laboratory of the Ministry of Industry and Information Technology School of Energy and Power EngineeringNanjing University of Science and TechnologyNanjing 210094China

Alkalicarbonate-based sorbents(ACSs),including Na_(2)CO_(3)-and K2CO_(3)-based sorbents,are promising for CO_(2)***,the complex sorbent components and operation conditions lead to the versatile kinetics of CO_(2)sorption on these *** paper proposed that operando modeling and measurements are powerful tools to understand the mechanism of sorbents in real operating conditions,facilitating the sorbent development,reactor design,and operation parameter *** reviewed the theoretical simulation achievements during the development of *** elucidated the findings obtained by utilizing density functional theory(DFT)calculations,ab initio molecular dynamics(AIMD)simulations,and classical molecular dynamics(CMD)simulations as *** hygroscopicity of sorbent and the humidity of gas flow are crucial to shifting the carbonation reaction from the gas-solid mode to the gas-liquid mode,boosting the ***,it briefly introduced a machine learning(ML)approach as a promising method to aid sorbent ***,it demonstrated a conceptual compact operando measurement system in order to understand the behavior of ACSs in the real operation *** proposed measurement system includes a micro fluidizedbed(MFB)reactor for kinetic analysis,a multi-camera sub-system for 3D particle movement tracking,and a combined Raman and IR sub-system for solid/gas components and temperature *** is believed that this system is useful to evaluate the real-time sorbent performance,validating the theoretical prediction and promoting the industrial scale-up of ACSs for CO_(2)capture.

关键词： CO_(2)capture carbonation theoretical modeling operando techniques reaction visualization

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EFFECT OF BLENDING STRAW POWDER INTO COAL GANGUE ON LOADING-UP CHARACTERISTICS OF THE CIRCULATING FLUIDIZED BED GENERATOR UNIT

EFFECT OF BLENDING STRAW POWDER INTO COAL GANGUE ON LOADING-...

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ASME 2024 power Conference, power 2024

作者： Zhao, Chenyu Wang, Chaoyang Liu, Ming Liu, Jiping Yan, Junjie MOE Key Laboratory of Thermal Fluid Science Engineering Xi'an Jiaotong University Xi'an China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China

ISBN: (纸本)9780791888186

To increase the contribution to the regional environment, the feasibility of blending agricultural residues was explored by a circulating fluidized bed (CFB) generator unit using coal gangue as the single fuel. In this study, straw powder was chosen to blend into the coal gangue, and the whole thermal system was built as a dynamic model based on self-programming and GSE software. Blending affects the load-increasing process from 75 % to 100 % rated power (Pe) with a load variation rate of 1 % Pe/min. With the blended fuel, the deviation of the output power was almost unchanged, and the maximum deviation of the live steam pressure was reduced by 0.04 MPa. With the blending ratios of 10 % and 20 %, the energy efficiencies of the whole unit were improved by 0.48% and 0.81%, respectively, the accumulative deviations of live steam temperature were reduced by 10.4% and 16.5%, respectively, the accumulative deviations of reheat steam temperature were reduced by 13.3% and 18.2% respectively, and the maximum deviations of bed temperature were increased to 8.9 ℃ and 9.5 ℃ respectively. The increased fluctuations in bed temperature are still far from the safe boundary, so the CFB generator unit can safely load up with the blending ratios of 10 % and 20 %. Copyright © 2024 by ASME.

关键词： Coal

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Impacts of Startup,Shutdown and Load Variation on Transient Temperature and Thermal Stress Fields within Blades of Gas Turbines

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Journal of Thermal Science 2022年第3期31卷 727-740页

作者： CAI Liuxi HOU Yanfang LI Fang LI Yun WANG Shunsen MAO Jingru School of Chemical Engineering and Technology Xi’an Jiaotong UniversityXi’an710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China

Based on the actual operation parameters and temperature-dependent material properties of a gas turbine unit,composite cooling blade model and corresponding reliable boundary conditions were *** thermal-fluid-solid coupling simulations were then comprehensively conducted to analyze the transient flow and the temperature field of the blade under startup,shutdown,and variable loads *** with the obtained transient temperature data,the non-linear finite element method was exploited to examine the effect of these transient operations on the turbine blade thermal stress *** show that the temperature and pressure on the blade surface increase with the load level and vice *** the startup process progresses,the film cooling effectiveness and the heat convection of airflows inside the blade continuously grow;high-temperature areas on the pressure surface and along the trailing edge of the blade tip gradually *** high-temperature zones with the maximum of 1280 K are generated at the air inlet and outlet of the blade platform and the leading edge of the blade *** high thermal stresses detected on the higher temperature side of the temperature gradient are commonly generated in places with large temperature gradients and significant geometry *** the startup/shutdown process,the rate of increase/decrease of the thermal stress is positively correlated with the load variation rate.A slight variation rate of the load(1.52%/min)can lead to an apparent alteration(41%)to the thermal *** operations under action of the variable load,although thermal stress is less sensitive to the load variation,the rising or falling rate of the exerted load still needs to be carefully controlled due to the highly leveled thermal stresses.

关键词： composite cooling blade thermal-fluid-solid coupling method transient temperature field load variation thermal stress

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