检索结果-内蒙古大学图书馆

Experimental Study on the Two-Phase flow Structure in a Supercritical Water-Fluidized Bed

INDUSTRIAL & engineering CHEMISTRY RESEARCH 2019年第43期58卷 20099-20108页

作者： Huang, Jikai Lu, Youjun Jia, Lei Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Qilu Univ Technol Shandong Acad Sci Energy Res Inst Jinan 250014 Shandong Peoples R China

A supercritical water-fluidized bed (SCWFB) is a very promising reactor for the clean utilization of biomass. In the present article, the flow structure in SCWFB is analyzed from a microscopic point of view via a special measurement system based on a capacitance probe. Five groups of particles are fluidized under a supercritical condition in a wide range of operating parameters: 20-27 MPa and 410-570 degrees C. Fluctuations and distributions of local voidage are analyzed in detail to shed some light on the special flow structure. The results show that bubbles tend to move toward the axial line of SCWFB and slugging fluidization is formed at a higher superficial velocity. In particular, a Core-Annulus flow in SCWFB is found, which is enhanced by the increase of superficial velocity or decrease of the particle diameter. The results may be useful for the development of the SCWFB technique.

关键词： Bubbles Electrical properties Supercritical fluids Probes Water

来源：评论

学校读者我要写书评

暂无评论

Exploring Geometric Chirality in Nanocrystals for Boosting Solar-to-Hydrogen Conversion

引用

Angewandte Chemie 2024年第45期136卷

作者： Wenlong Fu Qi Gao Chunyang Zhang Lili Tan Biao Jiang Chengyu Xiao Prof. Maochang Liu Prof. Peng-peng Wang State Key Laboratory for Mechanical Behavior of Materials Shaanxi International Research Center for Soft Matter School of Materials Science and Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 PR China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 PR China

Advancing catalyst design is pivotal for the enhancement of photocatalytic processes in renewable energy conversion. The incorporation of structural chirality into conventional inorganic solar hydrogen nanocatalysts promises a significant transformation in catalysis, a feature absent in this field. Here we unveil the unexplored potential of geometric chirality by creating a chiral composite that integrates geometric chiral Au nanoparticles (NPs) with two-dimensional C 3 N 4 nanosheets, significantly boosting photocatalytic H 2 evolution beyond the achiral counterparts. The superior performance is driven by the geometric chirality of Au NPs, which facilitates efficient charge carrier separation through the favorable C 3 N 4 -chiral Au NP interface and chiral induced spin polarization, and exploits high-activity facets within the concave surfaces of chiral Au NPs. The resulting synergistic effect leads to a remarkable increase in photocatalytic H 2 evolution, with an apparent quantum yield of 44.64 % at 400 nm. Furthermore, we explore the selective polarized photo-induced carrier separation behavior, revealing a distinct chiral-dependent photocatalytic HER performance. Our work advances the design and utilization of chiral inorganic nanostructures for superior performance in energy conversion processes.

关键词： Geometric chirality Nanoparticles Photocatalytic hydrogen evolution reaction Chiral effect

来源：评论

学校读者我要写书评

暂无评论

Constructing built-in electric fields in bimetallic selenide heterojunctions to bidirectional catalyze polysulfide conversion for flexible lithium-sulfur batteries

引用

Chemical engineering Journal 2025年 516卷

作者： Fangchao Han Shichao Zhang Dezhi Yan Yalan Xing Jun Xia Xianggang Guan Qiang Lu Puheng Yang Xiaomeng Wu Qianfan Zhang School of Materials Science and Engineering Beihang University Beijing 100191 PR China Chinese Acad Sci Inst Proc Engn State Key Lab Multiphase Complex Syst POB 353 Beijing 100190 PR China Shanghai Institute of Space Power Sources/State Key Laboratory of Space Power Sources PR China

Parasitic shuttle effects and sluggish kinetics severely limit the practical applications of lithium-sulfur (Li–S) batteries. Developing conducting catalysts with high catalytic activity is effective strategy to address such issues. Electronic engineering as tuning strategy can optimize the electronic structure and enhance the redox reaction kinetics. Herein, NiSe 2 -CoSe 2 hollow microspheres with abundant heterogeneous interfaces were synthesized as sulfur cathode catalysts. DFT calculations show that heterostructure can promote electron redistribution and form built-in electric field (BIEF), which causes the directional transfer of electrons. Additionally, NiSe 2 -CoSe 2 has optimized adsorption energy, which can effectively suppress shuttle effect. Meanwhile, electrochemical tests further confirmed bidirectional catalytic ability. Benefiting the merits, S/NiSe 2 -CoSe 2 -GO-CNF (S/NiCo-GN) achieved an initial discharge specific capacity of 1353.35 mAh g −1 at 0.2C and stable 1000 cycles at 1C with a capacity decay rate of only 0.044 % per cycle. Moreover, S/NiCo-GN also achieved high areal capacity of 1.688 mAh cm −2 at 0.5C under high loading (∼2.5 mg cm −2 ) and lean electrolyte (∼10 μL mg −1 ) conditions. The flexible pouch cell further demonstrated its high safety, good thermal stability, and robust mechanical stability. This work provides guiding methods for the design of efficient catalysts, which can contribute to the realisation of high-performance Li–S batteries.

关键词：

来源：评论

学校读者我要写书评

暂无评论

The effect of interstitial carbon atoms on defect evolution in high entropy alloys under helium irradiation

引用

ACTA MATERIALIA 2022年 233卷

作者： Su, Zhengxiong Shi, Tan Yang, Jinxue Shen, Huahai Li, Zhiming Wang, Sheng Ran, Guang Lu, Chenyang Xi An Jiao Tong Univ Dept Nucl Sci & Technol Xian 710049 Peoples R China China Acad Engn Phys Inst Nucl Phys & Chem Mianyang 621900 Sichuan Peoples R China Cent South Univ Sch Mat Sci & Engn Changsha 410083 Peoples R China Xiamen Univ Coll Energy Xiamen 361102 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China

In this work, a design strategy based on a typical multi-principal element alloy (Fe50Mn30Co10Cr10, at. %) was proposed to tune the irradiation behavior by adding interstitial carbon atoms (Fe49.5Mn30Co10Cr10C0.5, at. %). Advanced scanning transmission electron microscopy was employed to study the evolution of dislocation loops and helium bubbles in alloys after 400 keV He+ ion irradiation at three different temperatures ranging from 350 degrees C to 450 degrees C. The results showed that the interstitial carbon atoms inhibited the growth of He bubbles and irradiation hardening. The high-resolution energy dispersive spectroscopy mapping revealed that the segregation at the dislocation loops in Fe49.5Mn30Co10Cr10C0.5 was efficiently lessened compared to that in Fe50Mn30Co10Cr10, which shows an even superior performance than the equiatomic FeMnCoCrNi Cantor alloy. Radiation-induced "W-shaped" elemental oscillation patterns with a width of about 1 nm around dislocation loops, were observed for the first time in high-entropy alloys. Such nanoscale local elemental fluctuations are suggested to modify the lattice friction and thus have an impact on the mechanical properties of the material. First-principles calculations suggest that the interstitial carbon atoms can effectively enhance the site-to-site local lattice distortion and modify vacancy migration energy near carbon atoms. Our systematic experiments demonstrate that adding interstitial carbon atoms into multi-principal element or high-entropy alloy is beneficial for the reduction in irradiation hardening and volumetric swelling, as well as radiation-induced segregation. (C) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

关键词： High-entropy alloys Helium bubbles Interstitial carbon atoms Radiation-induced segregation Irradiation hardening

来源：评论

学校读者我要写书评

暂无评论

Experimental Study on the Boiling Heat Transfer Characteristics of R134a in a Helically Coiled Tube

引用

Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2019年第3期40卷 587-593页

作者： Niu, Xiao-Juan Yuan, Huai-Jie Quan, Chen Bai, Bo-Feng Zhao, Liang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The characteristics of R134a boiling heat transfer in a vertically helically coiled tube are studied. The experimental parameters are as follows: the heat flux is 10∼60 kW•m-2, the mass flux is 195∼400 kg•m-2 •s-1, the pressure is 0.8∼1.1 MPa, and the outlet vapor quality is 0.1∼0.9. The experimental data are compared with the existing correlations of boiling heat transfer coefficient. Based on the analysis of boiling heat transfer mechanism, a new correlation for boiling heat transfer in coiled tube is proposed. The circumferential distribution characteristics of wall temperature and heat transfer coefficient are analyzed. The wall temperatures at inner and top side are relatively higher, and the heat transfer coefficients at the bottom and the outer side are relatively higher. The local heat transfer coefficients are compared with the new correlation proposed in this paper. The results show that the heat transfer coefficients at top and bottom sides can be predicted by the new correlation. However, the new correlation underestimates the heat transfer coefficient at the outer side and overestimates that at the inner side, the deviations are 16.6% and -11.9% respectively. © 2019, Science Press. All right reserved.

关键词： Heat transfer coefficients

来源：评论

学校读者我要写书评

暂无评论

Stabilizing platinum atoms on CeO2 oxygen vacancies by metal-support interaction induced interface distortion: Mechanism and application

引用

APPLIED CATALYSIS B-ENVIRONMENTAL 2020年 278卷 119304-119304页

作者： Jiang, Zeyu Jing, Meizan Feng, Xiangbo Xiong, Jingchao He, Chi Douthwaite, Mark Zheng, Lirong Song, Weiyu Liu, Jian Qu, Zhiguo Xi An Jiao Tong Univ Sch Energy & Power Engn State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China China Univ Petr State Key Lab Heavy Oil Proc Beijing 102249 Peoples R China WISDRI City Environm Protect Engn Ltd Co Wuhan 430205 Hubei Peoples R China Univ Chinese Acad Sci Natl Engn Lab VOCs Pollut Control Mat & Technol Beijing 101408 Peoples R China Cardiff Univ Sch Chem Cardiff Catalysis Inst Main BldgPk Pl Cardiff CF10 3AT Wales Chinese Acad Sci Inst High Energy Phys Beijing Synchrotron Radiat Facil Beijing 100049 Peoples R China Xi An Jiao Tong Univ Sch Energy & Power Engn MOE Key Lab Thermofluid Sci & Engn Xian 710049 Shaanxi Peoples R China

Exploring thermally robust single atom catalysts (SACs) is of great significance. Here, we develop a universal strategy for stabilizing Pt atoms on the mono-oxygen vacancies of CeO2 with diverse exposed facets. The stabilization mechanism was proposed that the formed Pt-O-Ce interface will be taken into distortion spontaneously to keep thermodynamics stable through strong metal-support interactions. The highest degree of Pt-O-Ce distortion is achieved over Pt1-CeO2{100} material, which exhibits exceptional efficiency and thermal stability for oxygenated hydrocarbon removal. The enhanced adsorption capacity of O-2 and methanol confirmed in the distortion interface is seen as another crucial reason for improving the stability of SACs. Methanol oxidation on Pt1-CeO2{100} obeys the L-H mechanism under relatively low temperature and then goes through to the MVK mechanism with temperature increasing. We believe that these results would bring new opportunities in the fabrication of SACs and applications of them in thermal reactions.

关键词： Single-atom catalyst Metal-support interaction Electronic structure Interface distortion VOC oxidation Intrinsic mechanism

来源：评论

学校读者我要写书评

暂无评论

Effects of diluents on laminar burning characteristics of bio-syngas at elevated pressure

引用

FUEL 2019年 248卷 8-15页

作者： Zhou, Quan Cheung, C. S. Leung, C. W. Li, Xiaotian Huang, Zuohua Hong Kong Polytech Univ Dept Mech Engn Hung Hom Kowloon Hong Kong Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

A study on the effect of diluents (N-2/CO2) on laminar flame speed and flame instability of H-2 /CO/CH4/air premixed flame was conducted using outwardly propagating spherical flame and CHEMKIN package. Experiments and numerical computation were conducted at an initial temperature of 303 +/- 3 K, pressures of 0.1-0.5 MPa, equivalence ratios of 0.6-1.5 with N-2 or CO2 dilution ratios from 0% to 45%, at an interval of 15%. The measured laminar flame speed was compared with values predicted using the Li mechanism. The thermal and chemical kinetic analyses were also presented. The results show that the Li mechanism can give a good predication on laminar flame speed of H-2/CO/CH4/air premixed flames. But with N-2/CO2 dilution, the Li mechanism gives slight underestimations at fuel-rich conditions. Laminar flame speed decreases with the increase of N-2/CO(2 )dilution ratios. Results indicate that CO(2 )dilution has a stronger dilution effect, thermal effect, and chemical effect than those of N(2 )dilution, and thereby it can substantially decrease the laminar flame speed of H-2/CO/CH4/air mixture. On the other hand, flame instability is slightly promoted with N-2/CO2 dilution at atmospheric pressure, while at elevated pressure, it is suppressed with N-2/CO2 dilution due to the significant decrease of thermal expansion ratio and increase of flame thickness. Compared with N(2 )dilution, CO(2 )dilution has a stronger inhibiting effect on hydrodynamic instability.

关键词： Bio-syngas N-2 dilution CO2 dilution Laminar flame speed Cellular instability

来源：评论

学校读者我要写书评

暂无评论

Promoting "adiabatic core" approximation in a rapid compression machine by an optimized creviced piston design

引用

FUEL 2019年 251卷 328-340页

作者： Wu, Yingtao Yang, Meng Tang, Chenglong Liu, Yang Zhang, Peng Huang, Zuohua Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Hong Kong Polytech Univ Dept Mech Engn Hung Hom Kowloon Hong Kong Peoples R China

Rapid compression machine (RCM) is a widely-used experimental instrument for measuring ignition delay time (IDT) in the low-to-intermediate temperature range. In this work, to enhance the validity of the "adiabatic core" approximation in RCM, a piston crevice for suppressing the piston-driven vortex and therefore promoting the temperature homogeneity in the combustion chamber was firstly optimized by numerical simulation with a dynamic mesh strategy. Results show that crevice volume should be large enough to contain most of the boundary layer cold gas during the compression so as to assure the temperature homogeneity in the reaction chamber. While the shape of the crevice (with sufficiently large volume) only weakly affects the temperature homogeneity. An optimized piston was tested across wider ranges of pressure, the chamber length, and inert gas under experimental conditions. Based on the optimized piston crevice, a RCM was established and tested. Test results have confirmed that the crevice shape does not affect the IDT measurements, provided the crevice volume fixed. In addition, the present IDTs show consistency with those using other RCMs, as well as with the numerical predictions obtained by using the well-recognized and validated kinetic mechanisms, which support the validity of the present RCM facility for ignition delay measurement.

关键词： Rapid compression machine (RCM) Creviced piston Adiabatic core Temperature homogeneity Ignition delay time

来源：评论

学校读者我要写书评

暂无评论

Numerical analysis of the axial lead-bismuth pump performace base on the different rotation speed 18

Numerical analysis of the axial lead-bismuth pump performace...

引用

18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019

作者： Wang, Kailin Li, Liangxing Xie, Wei Zhang, Shuangbao State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xianning West Road 28# Xi’an city710049 China

The hydraulic performance of lead-bismuth eutectic (LBE) pump is of great importance for the safety aspects concerning lead-alloy cooled fast reactors (LFRs). To investigate the effect of different rotation speed on the performance of axial LBE pump, different rotation speed axial LBE pumps are designed by planar cascade and streamline method with the same mass flow rate and hydraulic head. Ansys BladeGen is used to establish the three-dimensional model of the axial-flow pump. CFD software (Ansys CFX) carry out numerical calculation. Numerical studies are used to compared the performance between two pumps with different rotation speed. To improve the accuracy of CFD simulation, the numerical result is verified by grid independence method and compared with theoretical calculation result. The flow velocity of the liquid LBE have great impact on the design of LBE pump because of the requirement to avoid affect of corrosion. It is found that the maximum flow velocity of low rotation speed pump is about 7.8 m/s, which is lower than the maximum flow velocity of high rotation speed pump in the case of constant volume and performance. Performance of low rotation speed pump meets the requirements of the reactor operating under long-term high load. The research results could be a viable solution used as a reference for the development of LFRs. © 2019 American Nuclear Society. All rights reserved.

关键词： Pumps

来源：评论

学校读者我要写书评

暂无评论

Magnetic nanofluid behavior including an immersed rotating conductive cylinder: finite element analysis

引用

SCIENTIFIC REPORTS 2021年第1期11卷 1-21页

作者： Hamzah, Hameed K. Ali, Farooq H. Hatami, M. Jing, D. Jabbar, Mohammed Y. Univ Babylon Coll Engn Mech Engn Dept Babylon Hilla Iraq Xi An Jiao Tong Univ Int Res Ctr Renewable Energy State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Esfarayen Univ Technol Dept Mech Engn Esfarayen North Khorasan Iran

In this paper, numerical Galerkin Finite Element Method (GFEM) is applied for conjugate heat-transfer of a rotating cylinder immersed in Fe3O4-water nanofluid under the heat-flux and magnetic field. The outer boundaries of the cavity were maintained at low temperatures while beside the cylinder were insulated. It is assumed that the cylinder rotates in both clockwise and counter-clockwise directions. The dimensionless governing equations such as velocity, pressure, and temperature formulation were analyzed by the GFEM. The results were evaluated using the governing parameters such as nanoparticles (NPs) volume fraction, Hartmann and Rayleigh numbers, magnetic field angle and NPs shapes. As a main result, the average Nusselt number increases by increasing the NPs volume fraction, inclination angle and thermal conductivity ratios, while increasing the Hartmann number decreased the Nusselt number. Furthermore, platelet NPs had the maximum average Nusselt number and spherical NPs made the minimum values of Nusselt numbers among examined NPs shapes.

关键词：

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：