检索结果-内蒙古大学图书馆

Adsorption and Agglomeration Characteristics of Fly Ash Particles in Low Low-Temperature Flue Gas Treatment Systems

ENERGY & FUELS 2019年第7期33卷 6302-6312页

作者： Yan, Yu Sun, Ke Deng, Lei Che, Defu Xi An Jiao Tong Univ Sch Energy & Power Engn State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Huadian Elect Power Res Inst Hangzhou 310030 Zhejiang Peoples R China

In China, low-low-temperature flue gas treatment systems (LLTSs) have been widely applied in power plants because of their high efficiency and low cost. However, the improper parameter design for this system has caused the insufficient adsorption of H2SO4 mist and the excessive agglomeration of particles, which eventually lead to corrosion and ash deposition problems. This paper tried to study the adsorption and agglomeration characteristics of ash particles to optimize the parameter design of LLTSs and solve the above problems. The results showed that the adsorption process could be divided into a rapid adsorption stage and a saturation stage. The high adsorption rate in the first stage resulted from the interaction of physical and chemical adsorption. The adsorption limit and the ultimate adsorption ratio of particles (D-P/S-p) were proposed as characterization parameters to evaluate the adsorption capacity. For example, the adsorption limit and D-p/S-p were 10.6 mg g(-1) and 94.3, respectively, for sample particles <68 mu m. Temperature is the crucial factor for the adsorption. When the temperature was decreased from 120 to 90 degrees C, the adsorption rate increased from 0.261 to 0.413 mg g(-1) min(-1) for particles <68 mu m and from 0.364 to 0.528 mg g(-1) min(-1) for particles >68-75 mu m. The particle size distribution had a greater impact on chemical adsorption than physical adsorption and could change the adsorption rate and limit considerably. The agglomeration of particles occurred in stages. In the initial stage, agglomeration mainly occurred among particles <= 75 mu m. Both the particle surface morphology and the agglomeration form can be categorized into four types. With increasing particle size, the agglomeration degree decreased significantly. The adsorption and agglomeration characteristics obtained by analyzing the element content and the combustion method of coal may help improve parameter selection and solve corrosion and ash deposition problems.

关键词： agglomeration Surface morphology flue gas treatment parametric design combustion method Corrosion

来源：评论

学校读者我要写书评

暂无评论

Void fractions in a rod bundle geometry at high pressure-part I: Experimental study

引用

INTERNATIONAL JOURNAL OF multiphase flow 2020年 122卷 103146-000页

作者： Gui, Miao Wang, Teng Liu, Zhaohui Sui, Zhiqiang Bi, Qincheng Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn 28 Xianning West Rd Xian 710049 Shaanxi Peoples R China

An investigation of void fraction measurement and prediction in a triangular-array rod bundle geometry was carried out under high pressure conditions (P=5-9 MPa and G = 100-350 kg.m(-2).s(-1)). The aims of this work were to expand the existing database and assess and modify the predictive models. The present paper is the Part I of this study, where the experimental work was presented to measure local, chordal and area-average void fractions respectively by a comprehensive measuring system composed by optical probes and gamma-ray densitometry. Non-uniform distribution of void fraction was investigated by local-to-local and local-to-average comparisons of void fractions. The results indicated that non-uniform distribution was not only related to the geometry, but also affected by the transition of flow regimes in rod bundle. The effects of pressure and mass flux on void fractions were also analyzed in detail in consideration of variations of fluid properties and drift-flux parameters. Additionally, both void fraction and interface frequency were compared with the flow regime map in TRACE code. The variation of interface frequency indicated that the droplet entrainment would occur in annular flow at high mass flux. In the Part II of this study, an assessment of existing models for void fraction prediction in rod bundles was carried out according to the present data and a newly-developed drift-flux model was proposed. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Void fraction Rod bundle geometry Optical probe Gamma-ray densitometry Non-uniform distribution

来源：评论

学校读者我要写书评

暂无评论

Fatigue Lifetime Estimation of a Heater in Coal-Fired power Plants Under a Flexible Operational Framework-Regulating Extraction Steam of High-Pressure Heaters 10

Fatigue Lifetime Estimation of a Heater in Coal-Fired Power ...

引用

10th International Conference on Applied Energy (ICAE)

作者： Zhao, Yongliang Fan, Peipei Liu, Ming Chong, Daotong Yan, Junjie Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

Although rapid load variation of coal-fired power plants has become a prior objective for improving the operational flexibility, it will cause a lifetime reduction of heaters due to alternating stresses during transient processes. In the paper, among four flexible regulating measures, the dynamic characteristics of thermal parameters were obtained by GSE software, and thermo-mechanical stresses of 1# high-pressure (HP) heater were calculated by Finite Element Analysis, then the fatigue lifetimes of 1# HP heater were estimated and compared. It turns out that the most stressed position is at water chamber baffle, the allowable numbers of cycles at four measures are 5913-9419, and fatigue damage ratios for per cycle are 0.0106-0.0169%. The study can provide a detailed reference for operators to ensure the operational security of coal-fired power plants within flexibility frameworks. (C) 2019 The Authors. Published by Elsevier Ltd.

关键词： Fatigue lifetime estimation thermo-mechanical stress dynamic simulation coal-fired power plant

来源：评论

学校读者我要写书评

暂无评论

An intensity-modulated photocurrent spectroscopy study of the charge carrier dynamics of WO3/BiVO4 heterojunction systems

引用

SOLAR ENERGY MATERIALS AND SOLAR CELLS 2020年第0期208卷 110378-000页

作者： Rodriguez-Gutierrez, Ingrid Djatoubai, Essossimna Su, Jinzhan Vega-Poot, Alberto Rodriguez-Gattorno, Geonel Souza, Flavio L. Oskam, Gerko Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian Shaanxi Peoples R China CINVESTAV IPN Dept Appl Phys Antigua Carretera Progreso Km 6 Merida 97310 Yucatan Mexico Fed Univ ABC UFABC Lab Alternat Energy & Nanomat Humanities & Nat Sci Ctr CCNH Santo Andre SP Brazil

Synergistic effects as a result of combining different photoactive materials provide a promising pathway to improve the photoelectrochemical performance in heterojunction devices for solar water splitting. The photoelectrochemical characteristics of tungsten trioxide (WO3) and bismuth vanadate (BiVO4) have been studied, comparing the single-phase materials with two heterojunction systems based on a WO3 underlayer and a thin, spin-coated BiVO4 top layer, using two types of underlayer: (i) a nanorod-based WO3 substrate prepared by hydrothermal methods (nr-WO3/BiVO4);and (ii) a spin-coated thin, compact WO3 substrate (pl-WO3/BiVO4). Intensity-modulated photocurrent spectroscopy (IMPS) was used to determine the charge separation efficiency, internal and external quantum efficiencies, and process time constants for the four systems in a phosphate buffer at pH 7, both without and with an added hole scavenger, Na2SO3. The heterojunction systems show excellent performance, which is ascribed to the superior capability of WO3 to extract photogenerated electrons from the BiVO4 film that acts as the main absorber. IMPS convincingly shows that the heterojunction configuration prevents surface recombination at the BiVO4/electrolyte interface, as well as the detrimental surface modification generally observed for WO3 photoelectrodes. The improved electron transport properties of the nr-WO3 substrate and the large area of the heterojunction interface result in better performance for nr-WO3/BiVO4, where at 455 nm water photo-oxidation is quantitative. For the single-phase BiVO4 photoelectrodes, an interesting photocurrent switching phenomenon is observed in the presence of the hole scavenger, indicating the intricate interplay between electron trapping and hole charge transfer;this phenomenon is prevented by the heterojunction structure because of the rapid electron extraction by WO3. These results show that IMPS gives detailed information on the reasons for the excellent performanc

关键词： WO3/BiVO4 heterojunctions Nanorod-based WO3 Intensity-modulated photocurrent spectroscopy (IMPS) Surface recombination Solar water splitting

来源：评论

学校读者我要写书评

暂无评论

Irreversibility Analysis of a Recuperative Heater during Undergoing the flowrate Impulsive Disturbance Transient Processes 10

Irreversibility Analysis of a Recuperative Heater during Und...

引用

10th International Conference on Applied Energy (ICAE)

作者： Wang, Chaoyang Zhao, Yongliang Wang, Zhu Liu, Ming Yan, Junjie Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

The recuperative heater is widely used in the industrial production processes, and the irreversibility analysis on the heater during transients is scarce but necessary. Numerical method was adopted to model the recuperative heat exchanger to exhibit its dynamic behaviors during transient processes. The difference between the transient and stationary irreversibility can be called additional irreversibility. In this paper, the dynamic behaviors of the recuperative heater during transients are presented. With these thermal parameters, the irreversibility of a recuperative heater during hot and cold fluid flow rates impulsive disturbance transient processes was calculated and analyzed in detail. The calculation results show that: compared with steady-state corresponding value, the real-time irreversibility rate of the heater during transients is different. The total additional irreversibility values with impulsive disturbance in hot and cold fluid flow rates are obtained separately. (C) 2019 The Authors. Published by Elsevier Ltd.

关键词： Recuperative heaters Irreversibility analysis Dynamic modeling Transisent processes

来源：评论

学校读者我要写书评

暂无评论

Experimental Research on Water Droplet Erosion Resistance Characteristics of Turbine Blade Substrate and Strengthened Layers Materials

引用

MATERIALS 2020年第19期13卷 4286页

作者： Di, Juan Wang, Shunsen Yan, Xiaojiang Jiang, Xihang Lian, Jinyi Zhang, Zheyuan Xie, Yonghui Taiyuan Univ Sci & Technol Coll Mech Engn 66 Waliu Rd Taiyuan 030024 Peoples R China Xi An Jiao Tong Univ Inst Turbomachinery State Key Lab Multiphase Flow Power Engn 28 Xianning West Rd Xian 710049 Peoples R China SUNY Stony Brook Dept Mech Engn Stony Brook NY 11794 USA

In this paper, the water droplet erosion (WDE) performance of typical martensitic precipitation substrate 0Cr17Ni4Cu4Nb in steam turbine final stage, laser solid solution strengthened sample, laser cladding sample and brazed stellite alloy samples have been studied based on a high-speed rotating waterjet test system. The WDE resistance of several materials from strong to weak is in sequence: Brazed stellite alloy > laser cladding sample > laser solid solution sample > martensitic substrate. Furthermore, the WDE resistance mechanism and the failure mode of brazed stellite alloy have been revealed. It is found that the hard carbide in the stellite alloy is the starting point of crack formation and propagation. Under the continuous droplet impact, cracks grow and connect into networks, resulting in the removal of carbide precipitates and WDE damage. It is proved that the properties of the Co-based material itself is the reason for its excellent WDE resistance. And the carbides have almost no positive contribution to its anti-erodibility. These new findings are of great significance to process methods and parameter selection of steam turbine blade materials and surface strengthened layers.

关键词： water droplet erosion surface strengthening 0Cr17Ni4Cu4Nb stellite alloy steam turbine

来源：评论

学校读者我要写书评

暂无评论

Modified Stainless Steel as Anode Materials in Bioelectrochemical Systems

引用

ACS Symposium Series 2020年 1342卷 165-184页

作者： Pu, Kai-Bo Bai, Ji-Rui Chen, Qing-Yun Wang, Yun-Hai Department of Environmental Science and Engineering Xi'an Jiaotong University Xi'an710049 China State Key Lab of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

As a promising anode material in bioelectrochemical systems (BESs), stainless steel-based bioanodes were reviewed. The anode material must have good biocompatibility, excellent electrical conductivity, large specific surface area, high corrosion resistance, and a low cost. The design of stainless steel-based bioanodes has been the focus of numerous research studies over the past decade. The present chapter summarizes and discusses the recent advances in stainless steel-based bioanodes and their configurations. The stainless steel-based bioanodes will be discussed in terms of optimization of stainless steel structures, carbon modification, metal oxide modification, conductive polymer modification, and others. © 2019 American Chemical Society. All rights reserved.

关键词： Corrosion resistance

来源：评论

学校读者我要写书评

暂无评论

Chloride ions as an electrolyte additive for high performance vanadium redox flow batteries

引用

APPLIED ENERGY 2021年 289卷 116690-116690页

作者： Zhang, Z. H. Wei, L. Wu, M. C. Bai, B. F. Zhao, T. S. Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Hong Kong Univ Sci & Technol HKUST Energy Inst Dept Mech & Aerosp Engn Kowloon Clear Water Bay Hong Kong Peoples R China

Employing chloride ions as additive in electrolytes is proposed for all vanadium redox flow batteries. The influences of different concentrations of chloride ions in the electrolyte on the battery performance are investigated. It is found that the chloride ions improve the reaction activity of VO2+/VO2+ redox couples. At a current density of 200 mA cm(-2), the battery with an optimum chloride ion concentration of 0.04 M attains an energy efficiency and vanadium utilization ratio of 82.5% and 86.3%, which are 2% and 4.1% higher than those without the additives. Further, at 400 mA cm(-2), the battery with 0.04 M chloride ions shows a high rate capability by delivering the specific discharge capacity of 5.95 Ah L-1. Moreover, the battery with 0.04 M chloride ions exhibits the capacity retention rate of 83.1% after one hundred cycle test, which is nearly 12% higher than that of pristine battery. The results suggest that chloride ions, as low-cost additives in electrolytes, offer great promise for high-performance vanadium redox flow battery application.

关键词： Vanadium redox flow battery Electrolyte Chloride ion Efficiency Vanadium utilization

来源：评论

学校读者我要写书评

暂无评论

Theoretical Insights into the Limitation of Photocatalytic Overall Water Splitting Performance of VIA Group Elements Doped Polymeric Carbon Nitride: A Density Functional Theory Calculation Predicting Solar-to-Hydrogen Efficiency

引用

SOLAR RRL 2021年第6期5卷

作者： Wang, Yiqing Zhao, Daming Deng, Hao Li, Mingtao Chen, Jie Shen, Shaohua Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Int Res Ctr Renewable Energy Xian 710049 Peoples R China King Abdullah Univ Sci & Technol Div Phys Sci & Engn KAUST Catalysis Ctr Thuwal 239556900 Saudi Arabia

Polymeric carbon nitride (p-C3N4) is thermodynamically feasible for photocatalytic overall water splitting. Element doping is proved effective in enhancing the photocatalytic performance of p-C3N4. The effect of doping is usually interpreted from the angle of electronic structures by first-principles density functional theory (DFT) calculations. However, the information on electronic structures is insufficient for understanding and predicting the ultimate criterion of solar-tohydrogen (STH) efficiency. Herein, a DFT calculation method is provided to investigate and predict the STH of VIA group elements doped p-C3N4 by calculating the efficiencies of both light absorption and carrier utilization. Particularly, significant efforts are made to calculate the energy barriers for the surface hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to determine the carrier utilization efficiency. Moreover, the chemisorption energies of the reactant intermediates are calculated to quantify the intermediates affinity for HER and OER on the surface. Among the VIA elements, oxygen is discovered as the most effective dopant in promoting the STH because oxygen-doped p-C3N4 has the lowest energy barriers for OER and the largest chemisorption energy for intermediates absorption. The calculation results highlight the importance of the surface reaction properties for efficient photocatalytic overall water splitting.

关键词： density functional theory calculations overall water splitting polymeric carbon nitride solar-to-hydrogen efficiency VIA group elements doping

来源：评论

学校读者我要写书评

暂无评论

Non-Hermitian delocalization in a 2D photonic quasicrystal

arXiv

引用

arXiv 2023年

作者： Zhang, Zhaoyang Liang, Shun Septembre, Ismaël Yu, Jiawei Huang, Yongping Liu, Maochang Zhang, Yanpeng Xiao, Min Malpuech, Guillaume Solnyshkov, Dmitry Key Laboratory for Physical Electronics and Devices The Ministry of Education Shaanxi Key Lab of Information Photonic Technique School of Electronic Science and Engineering Faculty of Electronics and Information Xi’an Jiaotong University Xi’an710049 China Institut Pascal PHOTON-N2 Université Clermont Auvergne CNRS Clermont INP Clermont-FerrandF-63000 France International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Department of Physics University of Arkansas FayettevilleAR72701 United States National Laboratory of Solid State Microstructures School of Physics Nanjing University Nanjing210093 China Paris75231 France

Quasicrystals show long-range order, but lack translational symmetry. So far, theoretical and experimental studies suggest that both Hermitian and non-Hermitian quasicrystals show localized eigenstates. This localization is due to the fractal structure of the spectrum in the Hermitian case and to the transition to diffusive bands via exceptional points in the non-Hermitian case. Here, we present an experimental study of a dodecagonal (12-fold) photonic quasicrystal based on electromagnetically-induced transparency in a Rb vapor cell. The transition to a quasicrystal is obtained by superposing two honeycomb lattices at 30◦ with a continuous tuning of their amplitudes. Non-Hermiticity is controlled independently. We study the spatial expansion of a probe wavepacket. In the Hermitian case, the wavepacket expansion is suppressed when the amplitude of the second lattice is increased (quasicrystal localization). We find a new regime, where increasing the non-Hermitian potential in the quasicrystal enhances spatial expansion, with the C12 symmetry becoming visible in the wavepacket structure. This real-space expansion is due to a k-space localization on specific quasicrystal modes. Our results show that the non-Hermitian quasicrystal behavior is richer than previously thought. The localization properties of the quasicrystals can be used for beam tailoring in photonics, but are also important in other fields. Copyright © 2023, The Authors. All rights reserved.

关键词： Quasicrystals

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：