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A New Structure of Cooling Wall Tube for Supercritical CO_(2)Coal-Fired power Plants

Journal of Thermal Science 2023年第3期32卷 1239-1250页

作者： WANG Yanjuan GAO Shuo JIANG Qiongqiong LI Yi LIU Qibin XU Jinliang The Beijing Key Laboratory of Multiphase Flow and Heat Transfer North China Electric Power UniversityBeijing 102206China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

In terms of developing supercritical CO_(2)(sCO_(2))coal-fired power plants,enhancing cooling wall performance is one of significant factors to improve system *** this paper,a new cooling wall tube structure is proposed to match the non-uniform heat flux(NUH)with the thermal resistance by changing the cooling wall tube eccentricity.A three-dimensional multi-physical coupling model of cooling wall is constructed to compare the novel structure to the conventional *** properties of fluid dynamics,thermal stress,coupled heat transfer and cooling wall deformation are *** contrast to the traditional structure,the maximum temperature and circumferential temperature difference(CTD)of the proposed structure can be reduced by 2%and 27.4%,*** essential working parameters related to the performances of the cooling wall tube are *** maximum temperature of the new structure is reduced by 8-13 K and the maximum thermal stress is reduced by about 10%-15%under all the simulated working conditions when the eccentricity changes from 0 to *** proposed structure can effectively reduce the maximum temperature and circumferential temperature gradient under ***,a novel insight is put out for the design and optimization of the cooling wall tube in coal-fired power plants.

关键词： supercritical carbon dioxide cooling wall tube thermal-hydraulic structural coupling supereritical heat transfer

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Hydrogen production from co-gasification of coal and biomass in supercritical water by continuous flow thermal-catalytic reaction system

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中国高等学校学术文摘·能源与动力工程 2007年第3期1卷 327-330页

作者： YAN Qiuhui GUO Liejin LIANG Xing ZHANG Ximin State Key Lab of Multiphase Flow in Power and Engineering Xi'an Jiaotong UniversityXi'an 710049China School of Environmental and Municipal Engineering Xi'an University of Architecture and TechnologyXi'an 710055China State Key Lab of Multiphase Flow in Power and Engineering Xi'an Jiaotong UniversityXi'an 710049China

Hydrogen is a clean energy *** abundant coal sources and green biomass energy into hydrogen effectively and without any pollution promotes environmental *** co-gasification performance of coal and a model compound of biomass,carboxymethylcellulose (CMC)in supercritical water (SCW),were investigated *** influences of temperature,pressure and concentration on hydrogen production from co-gasification of coal and CMC in SCW under the given conditions (20-25 MPa,650℃,15-30 s) are discussed in *** experimental results show that H2,CO2 and CH4 are the main gas products,and the molar fraction of hydrogen reaches in excess of 60%.The higher pressure and higher CMC content facilitate hydrogen production;production is decreased remarkably given a longer residence time.

关键词： hydrogen production coal CMC supercritical water co-gasification

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EXPERIMENTAL STUDY ON GAS-LIQUID TWO-PHASE flowS IN AN AREATION TANK BY USING IMAGE TREATMENT METHOD

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Journal of Hydrodynamics 2008年第5期20卷 650-655页

作者： CHENG Wen LIU Wen-hong HU Bao-wei WAN Tian State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an 710049 China Environment Research Institute Xi＇an University of Technology Xi＇an 710048 China Environment Research Institute Xi＇an University of Technology Xi＇an 710048 China

Particle Image Velocimetry （PIV） technique was employed to study experimentally gas-liquid two-phase flow in an aeration tank. In terms of the PIV principles, an algorithm of PIV based on the Fast Fourier Transformation （FFT） was worked out. The PIV program was developed and verified, and then was used to measure three kinds of states in the testing device. The program was also used to calculate and analyze the related parameters. The experimental data indicate that the bubbles in testing device have the longest resident time and stronger turbulent intensity for the gas-liquid two-phase flow in a special case （Case 3）, resulting in great increase of the oxygen transferring speed and efficiency, whereby providing the basis for the selection design of aeration tank.

关键词： gas-liquid two-phase flow Particle Image Velocimetry （PIV） Fast Fourier Transformation （FFT） aeration tank

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POD analysis on vortical structures in MVG wake by Liutex core line identification

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Journal of Hydrodynamics 2020年第3期32卷 497-509页

作者： Xiang-rui Dong Xiao-shu Cai Yinlin Dong Chaoqun Liu School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Key Laboratory of Multiphase Flow and Heat Transfer in Shanghai Power Engineering Shanghai 200093China Department of Mathematics University of Central ArkansasConway 72035USA Department of Mathematics University of Texas at ArlingtonArlington 76019USA

The Liutex core line method, first combined with the snapshot proper orthogonal decomposition (POD), is utilized in a supersonic micro-vortex generator (MVG) wake flow at Ma = 2.5 and Reθ = 5 760 to reveal the physical significance of each POD mode of the flow field. Compared with other scalar-based vortex identification methods, the Liutex core line identification is verified to be the most appropriate approach that is threshold-free and provides full information of a fluid rotation motion. Meanwhile, the Liutex integration is employed to quantitatively track the evolution of the vortices in MVG wake and is applied to the determination of the effective control section of the MVG wake for the optimization study of MVG design. The physical mechanism of each POD mode for multi-scale and multi-frequency vortical structures is investigated by using Liutex core line identification to give some revelations. For the mean mode (mode 0) indicating the time-averaged velocity flowfield of the MVG wake flow, a pair of primary counter-rotating streamwise vortices and another pair of secondary vortices is uniquely identified by two pairs of Liutex core lines with Liutex magnitude. In contrast, mode 1 is featured by a fluctuated roll-up motion of streamwise vortex, and the streamwise component of the MVG wake is demonstrated to be dominant in terms of the total kinetic energy contribution. Meanwhile, a dominant shedding frequency of St = 0.072 is detected from the temporal behavior of mode 2, which has the organized arc-shaped vortex structures shedding from MVG induced by the K-H instability. Additionally, mode 4 subjects to low-frequency oscillations of the wall vortices and thus takes a relatively lower frequency of St = 0.044.

关键词： Proper orthogonal decomposition(POD) vortex identification Liutex vortex core lines micro-vortex generator(MVG)

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Significant heat transfer enhancement for R123 condensation by micromembrane cylinder

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Chinese Science Bulletin 2014年第23期59卷 3676-3685页

作者： Jian Xie Feng Xing Jinliang Xu Huan Liu The Beijing Key Laboratory of Multiphase Flow and HeatTransfer North China Electric Power University

Renewable energy or low grade energy utilizations need high performance of phase change heat exchangers. Suspending micromembrane cylinder in tube(called modulated heat transfer tube) increases the void fractions or vapor qualities near the tube wall to significantly enhance heat transfer. The R123 condensation heat transfer with horizontal position was investigated. The results for the bare tube and modulated heat transfer tube were tested case by case. It is found that the modulated heat transfer tube significantly enhance the condensation heat transfer, with the heat transfer enhancement factors(EF)covering the range of 1.118–2.124. The comprehensive performance evaluation criteria(PEC) had the range of0.71–1.66, with most of runs behaving PEC larger than *** the two-phase outlet conditions, the EF values are increased with increases in the vapor mass fluxes, Gxin,where G is the mass flux and xinis the inlet vapor mass quality. The EF values are inversely related to Gxinfor the subcooled liquid outlet cases. The enhanced heat transfer mechanisms are analyzed with the observed images together with the discussion of pressure and velocity distributions.

关键词：强化传热 R123 凝结质量通量膜冷凝传热综合性能蒸汽质量

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Study on boiling heat transfer mechanism based on microlayer evaporation theory 6

Study on boiling heat transfer mechanism based on microlayer...

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6th International Conference on Fluid Mechanics and Industrial Applications, FMIA 2022

作者： Dong, Wu-Han Gao, Ming Shen, Zhong-Xiang Zhang, Li-Xin Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China

Based on dynamic microlayer evaporation model. Heat transfer mechanism of nuclear boiling and microlayer thickness under single bubble on heated surface. It has a lot to do with the temperature of the wall. Therefore, this paper studies the mechanism of bubble microlayer and makes comparative analysis with its experiments. It is helpful to master nuclear boiling heat transfer more comprehensively. In the study of individual bubble microlayer thickness. The effects of time and radius on wall temperature are considered in this paper. The theoretical formula of initial thickness of microlayer is deduced. The theoretical formula is compared with the experimental data of microlayer evaporation under the nucleation bubble. It was found that the experimental data fell within ±25% of the formula range. It is consistent with the previous experimental research. © Published under licence by IOP Publishing Ltd.

关键词： Evaporation

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Nanomaterials for renewable hydrogen production,storage and utilization

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Progress in Natural Science:Materials International 2012年第6期22卷 522-534页

作者： Samuel S.Mao Shaohua Shen Liejin Guo Lawrence Berkeley National Laboratory and Department of Mechanical Engineering University of California at Berkeley.BerkeleyCA 94720United States Lawrence Berkeley National Laboratory and Department of Mechanical Engineering University of California at Berkeley.BerkeleyCA 94720.United States International Research Center for Renewable Energy.State Key Laboratory of Multiphase Flow in Power Engineering.Xi'an Jiaotong University International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong University

An ever growing demand for energy coupled with increasing pollution is forcing us to seek environmentally clean alternative energy resources to substitute fossil *** rapid development of nanomaterials has opened up new avenues for the conversion and utilization of renewable *** article reviews nanostructured materials designed for selected applications in renewable energy conversion and *** review is based on the authors’ research,with particular focus on solar hydrogen production,hydrogen storage and hydrogen *** topics include photoelectrochemical(PEC) water splitting and photocatalytic hydrogen production, solid-state hydrogen storage,and proton exchange membrane fuel cells(PEMFCs).It is expected that the rational design of nanomaterials could play an important role in achieving a renewable energy based economy in the coming decades.

关键词： Nanomaterials Renewable energy Hydrogen production Fuel cell Hydrogen storage

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Continuous hydrogen production by biomass gasification in supercritical water heated by molten salt flow: System development and reactor assessment

Continuous hydrogen production by biomass gasification in su...

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作者： Xiao, Peng Guo, Liejin Zhang, Ximin Zhu, Chao Ma, Shaohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an 710049 Shaan Xi Province China

Hydrogen production by biomass gasification using solar energy is a promising approach for overcoming the drawbacks of fossil fuel utilization, but the storage of discontinuous solar flux is a critical issue for continuous solar hydrogen production. A continuous hydrogen production system by biomass gasification in supercritical water using molten-salts-stored solar energy was proposed and constructed. A novel double tube helical heat exchanger was designed to be molten salts reactor for hydrogen production. Model compounds (glycerol/glucose) and real biomass (corn cob) were successfully gasified in this molten salts reactor for producing hydrogen-rich gas. The unique temperature profiles of biomass slurry in the reactor were observed and compared with that of conventional electrical heating and direct solar heating approaches. Product gases yield, gasification efficiency and exergy conversion efficiency of the reactor were analyzed. The results showed that the performances of reactor were determined by feedstock style, biomass concentration, residence time and biomass slurry temperature profiles. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Biomass

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Photocatalytic water splitting on BiVO_(4):Balanced charge-carrier consumption and selective redox reaction

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Nano Research 2023年第4期16卷 4568-4573页

作者： Xiangjiu Guan Li Tian Yazhou Zhang Jinwen Shi Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi’an Jiaotong UniversityXi’an 710049China Suzhou Academy of Xi’an Jiaotong University Suzhou 215123China State Key Laboratory for Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Surficial redox reactions play an essential role in photocatalytic water splitting,and are closely related to the surface properties of a specific *** this work,using monoclinic BiVO_(4)decahedral single crystals as a model photocatalyst,we report on the interrelationship between the photocatalytic activity and the surficial reaction sites for charge-carrier *** controlled hydrothermal synthesis,the ratio of{010}to{110}facets on BiVO_(4),which respectively serve as reductive and oxidative sites,is carefully *** results show that superior photocatalytic water oxidation could be obtained on BiVO_(4)decahedrons with a medium ratio of reductive/oxidative sites and that efficient overall water splitting could be achieved via further modification of appropriate cocatalysts in Z-scheme *** excellent photocatalytic performance is attributed to the accelerated selective redox reactions by realizing balanced charge-carrier consumption,which provides insightful guidance for prospering photocatalytic reactions in energy conversion.

关键词： BiVO_(4) photocatalytic water splitting reactive site

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Experimental investigation on the gravity driven discharge of cohesive particles from a silo with two outlets

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Particuology 2024年第6期89卷 11-21页

作者： Li Dai Zhulin Yuan Fengxian Fan Conghui Gu School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China School of Energy and Power Jiangsu University of Science and TechnologyZhenjiang 212100China

An experimental study on the gravity driven discharge of cohesive particles from a silo with two outlets was *** discharge behaviors under the conditions that a single outlet was open and two outlets were open were investigated by varying the moisture content of the particles and the filling height of the particles in the *** results show that the discharge rate of the cohesive particles increases gradually at the beginning,then almost keeps constant,and finally drops *** discharge rate in case of two openings is around 1.1–1.6 times that in case of a single *** filling height leads to lower discharge rate in case of a single opening but results in higher discharge rate in case of two ***,the avalanche dynamics in case of a single opening was examined,and the mixing behavior of the cohesive particles was *** is observed that the discharge flow is promoted by the avalanche phenomenon in the silo,generating a general trend that the normalized mass of discharge increases with the filling height at higher moisture *** case of a single opening,the transition from mass flow to funnel flow favors the particle mixing,resulting in an increasing mixing index as the moisture content *** general,a better performance of mixing can be achieved in case of a single opening compared with in case of two *** study provides vital information for fundamental understanding of the gravity driven discharge of cohesive particles from the silo with multiple outlets.

关键词： Cohesive particles Moisture content Discharge rate Avalanche Mixing

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