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Numerical Study on Combustion and Heat Transfer Properties Under Oxy-fuel Condition in a 600MW Utility Boiler

Energy Procedia 2017年 105卷 4009-4014页

作者： Debo Li Xuan Liu Chang’an Wang Kai Xu Qiongliang Zha Qiang Lv Yongxin Feng Jun Zhong Defu Che Electric Power Research Institute of Guangdong Power Grid Corporation Guangzhou 510080 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China

Oxy-fuel combustion is recognized as one of the most promising CO 2 capture technologies. Under oxy-fuel combustion, the concentrations of CO 2 and H 2 O are much higher, result in different temperature profiles and heat transfer properties. In this study, a modified computational fluid dynamics (CFD) model-was developed for a 600 MW tangentially-fired boiler. Different oxygen volume fractions and two flue gas recycle modes (dry recycle and wet recycle) were numerically investigated, focusing on the properties of combustion and heat transfer. The results indicate the peak temperature in the burner zone decreases in oxy-fuel combustion, because of the high heat capacity and chemical reactivity of CO 2 . Compared with air-fired combustion, similar total heat transfer rate in furnace can be achieved at 27.0% and 28.3% of oxygen volume fraction for wet and dry recycle. These findings indicate retrofitting an existing boiler with oxy-fuel combustion technology is entirely feasible.

关键词： oxy-fuel combustion WSGGM numerical simulation combustion properties heat transfer properties

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Layered sphere-shaped TiO_2 capped with gold nanoparticles on structural defects and their catalysis of formaldehyde oxidation

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Journal of Environmental Sciences 2016年第1期28卷 77-85页

作者： Chunyan Ma Guanglong Pang Guangzhi He Yang Li Chi He Zhengping Hao Department of Environmental Nano-materials Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power EngineeringSchool of Energy and Power Engineering Xi'an Jiaotong University

We describe here a one-step method for the synthesis of Au/TiO2 nanosphere materials,which were formed by layered deposition of multiple anatase TiO2 *** Au nanoparticles were stabilized by structural defects in each TiO2 nanosheet,including crystal steps and edges,thereby fixing the Au-TiO2 perimeter *** transfer occurred along the gaps between these TiO2 nanosheet layers and in contact with catalytically active sites at the Au-TiO2 *** doped Au induced the formation of oxygen vacancies in the Au-TiO2 *** vacancies are essential for generating active oxygen species（-＊O^-） on the TiO2 surface and Ti^3＋ ions in bulk *** ions can then form Ti^3＋-O^--Ti^4＋species,which are known to enhance the catalytic activity of formaldehyde（HCHO） *** studies on structural and oxygen vacancy defects in Au/TiO2 samples provide a theoretical foundation for the catalytic mechanism of HCHO oxidation on oxide-supported Au materials.

关键词： Layered Au/TiO2 nanospheres Structural defects Oxygen vacancy defects Reaction mechanism Formaldehyde oxidation

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Diffusion-controlled synthesis of Cu-based catalysts for the Rochow reaction

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Science China Materials 2017年第12期60卷 1215-1226页

作者：刘合之李晶纪永军张在磊汪学广钟子宜苏发兵 State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai University State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of Sciences Institute of Chemical and Engineering Sciences Agency for ScienceTechnology and Research (A~*STAR) Institute of Industrial Chemistry and Energy Technology Shenyang University of Chemical Technology

The properties of materials are strongly dependent on their structures. The diffusion effect is a main kinetic factor that can be used to regulate the growth and structure of materials. In this work, we developed a systematic and feasible strategy to synthesize Cu2O solid spheres and hexahedrons by controlling the diffusion coefficients. These Cu2O products can be successively transformed into corresponding Cu hollow spheres and hexahedrons as well as CuO porous spheres and hexahedrons by controlling hydrogen diffusion in hydrazine hydrate solution and controlling oxygen diffusion in air, respectively. The formation of these transformations was also discussed in detail. Tested for Rochow reaction, the as-prepared Cu2O solid and CuO porous spheres exhibit higher dimethyldichlorosilane selectivity and Si conversion than Cu hollow spheres, which is attributed to the active sites for CH3Cl adsorption formed in CuxSi phase after the removal of oxygen atoms in Cn2O and CuO in the formation of dimethylchlorosilane. The present work not only develops a feasible method for preparing well shape-defined Cu2O solid spheres and hexahedrons but also clarifies the respective roles of Cu, Cu2O and CuO in dimethyldichlorosilane synthesis via Rochow reaction.

关键词： cuprous oxide hollow spheres porous spheres surface oxygen vacancies Rochow reaction

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Experimental study on thermal performance of a water/steam cavity receiver with solar simulator

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Energy Procedia 2017年 142卷 265-270页

作者： Zhenjie Wan Mumtaz A. Qaisrani Xuancheng Du Jinjia Wei Jiabin Fang Jian Zhang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 People’s Republic of China School of Chemical Engineering and Technology Xi’an Jiaotong University Xi’an 710049 People’s Republic of China

The performance of cavity receiver plays a fatal role in light-heat conversion process in a concentrating solar power (CSP) plant. In our present work, an experimental platform is designed and built, in which a solar simulator consisting of seven mutually independent xenon lamp units is used for supplying the solar energy needed. The cold start-up and steady state performance of the cavity receiver were studied under 0.5MPa. The results show that for a certain cavity structure, temperatures on boiling panels and thus the heat loss can be affected not merely by the heat flux, other parameters can influence the temperature of absorbing surfaces, such as the heat transfer in the boiling tubes, fluid flow states and the wind effect, so the temperature distribution is highly non-uniform on boiling panels. However, the temperatures of passive surfaces depend greatly on the input solar energy, thus the heat losses of the passive surfaces will vary with the input energy. Overheat occurs if a high heat flux doesn’t have a sufficient heat transfer inside boiling tubes internal. The stagnation zone does exist in the cavity and its boundary varies with a different input energy, thus the convective heat loss can be affected. The cavity receiver thermal efficiency is 72.92% under 0.5MPa, may be the reason behind this low efficiency is the strong cooling wind of the solar simulator.

关键词： Solar energy central cavity receiver start-up thermal performance solar simulator thermal efficiency

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Rambutan-like hierarchically heterostructured CeO2-CuO hollow microspheres： Facile hydrothermal synthesis and applications

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Nano Research 2017年第2期10卷 381-396页

作者： Yongjun Ji Zheying Jin Jing Li Yu Zhang Hezhi Liu Laishun Shi Ziyi Zhong Fabing Su State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing I O0190 China University of Chinese Academy of Sciences Beijing 100049 China School of Chemistry and Chemical Engineering Shandong University Jinan 250100 China Institute of Chemical Engineering and Sciences 1 Pesek Road Jurong Island Singapore 627833 Singapore School of Chemical & Biomedical Engineering Nanyang Technological University (NTU) 62 Nanyang Drive Singapore 637459 Singapore

Hierarchically heterostructured hollow spheres are of great interest for a wide range of applications owing to their unique structural features and properties. However, the fabrication of well-defined hollow spheres with highly specific morphology for mixed transition metal oxides on a large scale remains challenging. In this work, uniform rambutan-like heterostructured CeO2~CuO hollow microspheres with numerous copper-ceria interfacial sites and nanorods and nanoparticles as building blocks are prepared via a facile hydrothermal method followed by calcination. Importantly, this approach can be readily scaled up and is applicable to the synthesis of various CuO-based mixed metal oxide complex hollow spheres. The as-prepared CeO2-CuO hollow rambutans exhibit superior performance both as electrode materials for supercapacitors and as Cu-based catalysts for the Rochow reaction, mainly due to the small primary nanoparticle constituents, high surface area, and formation of numerous interior heterostructures.

关键词： heterostructure hollow sphere rambutan supercapacitors Rochow reaction

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The code development and thermo-hydrodynamic analysis of the reflood during severe accident in PWR

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Annals of Nuclear Energy 2017年 99卷 9-18页

作者： S.P. Niu Y.P. Zhang W.X. Tian S.Z. Qiu G.H. Su State Key Laboratory on Power Engineering and Multi-Phase Flow Xi’an Jiaotong University Xi’an 710049 China

The reflooding, i.e. injecting water to the uncovered degraded core, is the most important accident management measure to terminate a severe accident and to stop the core from being melt in LWR. The reflooding of LWR core during severe accident may lead to the core cooling and cessation or to the temperature escalation and further development of the accident. That will depend on several important parameters, characterizing the core state and the way of the reflooding. Appropriate understanding of the complex core reflooding phenomena is necessary for the prediction of the system evolution. Based on the reflood flow and heat transfer characteristics, a thermo-hydraulic analysis model for the reflood phase was developed and presented in this paper. Based on this model, a code module was developed for the thermo-hydraulic analysis of reflood. The calculation results for the different conditions are compared with the FLECHT data and the QUENCH data, respectively. The results showed that the calculation results and the experiment data are in substantial agreement. Then the influences of the system pressure, the subcooling of coolant and the wall temperature on reflood characteristics were studied, too. The quench velocity falls when the wall temperature went up. The quench velocity increases when the system pressure increases. The quench velocity drops with the increasing of water temperature. The paper also provides a theoretical basis for safety analysis of fuel element cladding during reflood phase.

关键词： Severe accident Reflood Thermo-hydraulic analysis Code development

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A depth estimation algorithm of plenoptic camera for the measurement of particles

A depth estimation algorithm of plenoptic camera for the mea...

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IEEE International Workshop on Imaging Systems and Techniques (IST)

作者： Yuanchi Ma Wu Zhou Tianlei Qian Xiaoshu Cai Institute of Particle and Two-phase Flow Measurement / Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology shanghai China

Plenoptic camera has been widely studied in many areas such as circuit analysis, microbiological detection and remote sensing. But the application of plenoptic camera was rarely get attention in three-dimensional measuring for particles and fluid. The applicability and accuracy of existing algorithm for depth estimation and three-dimensional measuring is acceptable [8]. However, the traditional algorithm for depth estimation is not suitable for measuring of particles and fluid in the result of some differences between particles and other kinds of objects in three-dimensional measuring with plenoptic cameras especially in the case of low density of particles system. This paper presents an improved depth estimation algorithm of plenoptic camera for the measurement of particles. This improved algorithm can effectively restrain miscalculation of depth by pretreatment and searching for the area of maximum gradient. The improvement of accuracy and precision of this depth estimation algorithm compared with the traditional algorithm was proved by a series of experiments.

关键词： Cameras Particle measurements Atmospheric measurements Estimation Lenses Calibration Area measurement

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Correction: Epoxide ring-opening reaction promoted by ionic liquid reactivity: interplay of experimental and theoretical studies

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Catalysis Science & Technology 2019年第22期9卷 6532-6532页

作者： Shengxin Chen Guixiang Zeng Yingwei Li Bin He Ruixia Liu Suojiang Zhang Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and Engineering State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Beijing 100190 P. R. China Kuang Yaming Honors School Nanjing University Nanjing 210023 P. R. China University of Chinese Academy of Sciences Beijing 100049 P.R. China

Correction for ‘Epoxide ring-opening reaction promoted by ionic liquid reactivity: interplay of experimental and theoretical studies’ by Shengxin Chen et al., Catal. Sci. Technol., 2019, DOI: 10.1039/c9cy00953a.

Correction for ‘Epoxide ring-opening reaction promoted by ionic liquid reactivity: interplay of experimental and theoretical studies’ by Shengxin Chen et al., Catal. Sci. Technol., 2019, DOI: 10.1039/c9cy00953a.

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Correction to: Glucose in Conjunction with Multiple Laser Pulses on Laser Treatment of Port-wine Stain: An in vivo Study

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Lasers in medical science 2018年第9期33卷 2015页

作者： Jun Ma Bin Chen Dong Li Yue Zhang Zhaoxia Ying State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China. State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China. chenbin@***. Department of Dermatology Second Affiliated Hospital Xi'an Jiaotong University Xi'an 710049 Shaanxi China. yzx1919@***.

In the originally published article, the title was incorrectly copied from another article. The correct title is "Glucose in Conjunction with Multiple Laser Pulses on Laser Treatment of Port-wine Stain: An in viv...

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Chain structure of head-on collisions in boundary driven granular gases

arXiv

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arXiv 2018年

作者： Chen, Yanpei Wang, Wei Hou, Meiying State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Soft Matter Physics Beijing National Laboratory for Condense Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China College of Physics University of Chinese Academic of Sciences Beijing100049 China

We report a peculiar dynamic phenomenon in granular gases, chain structures of head-on collisions caused by the boundary heated mechanism form a network in an Airbus micro-gravity experiment and horizontal vibrated one in the laboratory, which differ markedly from the grazing-collision-dominant in randomly driven granular fluid. This new order property is an orientation correlation between the relative position and the relative velocity of any particle pair, which weakens the collision frequency and leads a long range boundary effect. By the histogram of the relative position and the relative velocity, we find this position-velocity correlation is not only at limits of very small relative velocities but also large ones, which means the breakdown of molecular chaos assumption is not limited to a small portion of the phase space[1]. Through a simple anisotropic angular distribution model of the relative position and the relative velocity, we could modify classical uniform angular integration results of mean field values taking the effect of the observed collision chain structure explicitly into account. Copyright © 2018, The Authors. All rights reserved.

关键词： Granular materials

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