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

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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Experimental investigation of inflow-outflow asymmetry in induced-charge electro-osmosis

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Energy Storage and Saving 2024年第1期3卷 16-22页

作者： Lingqi Zhao Tianwei Lai Yingke Gao Shaohang Yan Mingzhe Liu Yu Hou State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China MOE Key Laboratory of Cryogenic Technology and Equipment Xi’an Jiaotong UniversityXi’an710049China

Induced-charge electro-osmosis(ICEO)is a research hotspot in bioengineering and analytical ***-outflow asymmetry of ICEO was reported in the existing literatures,but systematic study on this phenomenon is *** this experimental study,we found that in strong electric fields,not only the velocity magnitude but also the vortex positions of ICEO are asymmetrical along the inflow and outflow directions because of the pronounced non-uniform surface electrokinetic *** the inflow and outflow directions,the amplitudes of velocities are unequal,ICEO maximum velocity positions change depending on the electric field intensity and sodium chloride(NaCl)***,the distances between vortex centers are *** NaCl solution concentration of 0.001 mol⋅L^(-1),the outflow velocity almost *** asymmetry rises with the increasing electric field *** new discoveries can direct the application of microscale devices.

关键词： Induced-charge electro-osmosis Micro-particle image velocimetry Inflow-outflow asymmetry

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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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NUMERICAL SIMULATION OF SINGLE/TWO-PHASE flow IN A STRATIFIED POROUS BED 31

NUMERICAL SIMULATION OF SINGLE/TWO-PHASE FLOW IN A STRATIFIE...

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2024 31st International Conference on Nuclear engineering, ICONE 2024

作者： Bouloudenine, Aimad Li, Liangxing Xiang, Zutao Shi, Shang Bakar, Muhammad Abu Xi’an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xianning West Road 28 Xi’an City710049 China

ISBN: (纸本)9780791888292

This study investigates the coolability of debris beds formed from Fuel-Coolant Interactions (FCI) within nuclear reactors, a critical safety concern when cooling systems fail, leading to significant core melting in light-water reactors. The research focuses on understanding the flow dynamics within two-layer stratified porous beds, which develop from the mixture of corium and coolant, particularly around the interface between layers. Using ANSYS Fluent software, numerical simulations were conducted to estimate velocity profiles and pressure drops across a stratified porous structure. The Euler-Euler two-fluid model was employed alongside the k-ω-based Shear Stress Transport (SST) turbulence model to separately model turbulence for each phase. The results reveal that lateral flow dynamics are significant as fluids traverse through the porous media, affecting pressure drops across layers with varying permeabilities. Specifically, the pressure drops across the lower-permeability layer decrease while that across the higher-permeability layer increases, highlighting the influence of lateral flows between layers of different particle sizes due to variations in porosity. This lateral flow is most likely formed during the initial stages of fluid movement through the bed. The study underscores the importance of understanding these flow characteristics for both single/two-phase flow to enhance the safety and design of nuclear reactors by improving debris bed coolability predictions. Copyright © 2024 by ASME.

关键词： Computational fluid dynamics

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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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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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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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TiO_(2) nanorods based self-supported electrode of 1T/2H MoS_(2) nanosheets decorated by Ag nano-particles for efficient hydrogen evolution reaction

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Chinese Chemical Letters 2023年第11期34卷 355-359页

作者： Changzheng Lin Yunpeng Liu Yaxing Sun Zhenyu Wang Hao Xu Mingtao Li Jiangtao Feng Bo Hou Wei Yan Department of Environmental Science&Engineering Xi’an Jiaotong UniversityXi’an 710049China School of Physics and Astronomy Cardiff UniversityThe ParadeCardiffCF243AAWalesUnited Kingdom State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China International Research Center for Renewable Energy(IRCRE) State Key Laboratory of Multiphase Flow in Power Engineering(MFPE)Xi’an Jiaotong UniversityXi’an 710049China

Molybdenum disulfide(MoS_(2))has shown significant promise as an economic hydrogen evolution reaction(HER)catalyst for hydrogen generation,but its catalytic performance is still lower than noble metalbased ***,a silver nanoparticles(Ag NPs)-decorated 1T/2H phase layered MoS_(2) electrocatalyst grown on titanium dioxide nanorod arrays(Ag NPs/1T(2H)MoS_(2)/TNRs)was prepared through acid-tunable ammonium ion *** advantage of MoS_(2) layered structure and crystal phase controllability,as-prepared Ag NPs/1T(2H)MoS_(2)/TNRs exhibited ultrahigh HER ***-proposed strategy combines facile hydrogen desorption(Ag NPs)with efficient hydrogen adsorption(1T/2H MoS_(2))effectively circumventes the kinetic limitation of hydrogen desorption by 1T/2H MoS_(2).The as-prepared Ag NPs/1T(2H)MoS_(2)/TNRs electrocatalyst exhibited excellent HER activity in 0.5 mol/L H2SO4 with low overpotential(118 mV *** hydrogen electrode(RHE))and small Tafel slope(38.61 mV/dec).The overpotential exhibts no obvious attenuation after 10 h of constant current ***-principles calculation demonstrates that as-prepared 1T/2H MoS_(2) exhibit a large capacity to store *** protons can be subsequently transferred to Ag NPs,which significantly increases the hydrogen coverage on the surface of Ag NPs in HER process and thus change the rate-determining step of HER on Ag NPs from water dissociation to hydrogen *** study provides a unique strategy to improve the catalytic activity and stability for MoS_(2)-based electrocatalyst.

关键词： Molybdenum disulfide Silver nanoparticles Hydrogen evolution reaction Density functional theory Hydrogen spillover

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Vapor-liquid equilibrium of H2/CO2and H2/N2/CO2mixture, the liquefaction technology related to the supercritical water gasification products 8

Vapor-liquid equilibrium of H2/CO2and H2/N2/CO2mixture, the ...

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8th International Conference on Smart and Sustainable Technologies, SpliTech 2023

作者： Wu, Hongtu Jin, Hui Xi'an Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Shaanxi Xi'an710049 China

ISBN: (纸本)9789532901283

In this paper, the dew point and liquid phase composition of H2/CO2 and H2/CO2/N2 mixtures at phase equilibrium calculated by PR-BM equation and Van Der Waal mixing rule with commercial MATLAB software are introduced, it is of theoretical significance for the wide application of the products of supercritical water gasification. First, the results obtained by the self-programming code are verified with the experimental data, the experimental data and simulation results of two kinds of CO2/H2 mixtures and two kinds of CO2/N2/H2 mixtures were compared. The average percentage deviation was 2.69%, 4.05%, 2.22%, 1.20%, respectively. Thus the absolute deviations of the mixtures are within the acceptable range, therefore, the model proposed in this paper can well predict the dew point of the mixtures composed of H2/CO2 or H2/CO2/***, the dew point and the CO2 content in the liquid phase of common H2/CO2 and H2/CO2/N2 vapor mixtures in supercritical water gasification products were predicted, and a series of analysis and discussion were conducted on the predicted results finally. © 2023 University of Split, FESB.

关键词： Carbon dioxide

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Photochemical Systems for Solar‑to‑Fuel Production

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Electrochemical Energy Reviews 2022年第3期5卷 137-177页

作者： Ya Liu Feng Wang Zihao Jiao Shengjie Bai Haoran Qiu Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina

The photochemical system,which utilizes only solar energy and H_(2)O/CO_(2) to produce hydrogen/carbon-based fuels,is considered a promising approach to reduce CO_(2) emissions and achieve the goal of carbon *** date,numerous photochemical systems have been developed to obtain a viable solar-to-fuel production system with sufficient energy ***,more effort is still needed to meet the requirements of industrial *** this review,we systematically discuss a typical photochemical system for solar-to-fuel production,from classical theories and fundamental mechanisms to raw material selection,reaction condition optimization,and unit device/system advancement,from the viewpoint of ordered energy ***-of-the-art photochemical systems,including photocatalytic,photovoltaic-electrochemical,photoelectrochemical,solar thermochemical,and other emerging systems,are *** highlight the existing bottlenecks and discuss the developing trend of this ***,optimization strategies and new opportunities are proposed to enhance photochemical systems with higher energy efficiency.

关键词： Solar energy Photochemical Hydrogen Carbon-based fuels

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