检索结果-内蒙古大学图书馆

Corrosion Effect Analysis on Thermal-Hydraulics of Lbe/Water Spiral Tube Steam Generator Under Oxygen-Controlled Environment

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Lu, Dingsheng Yang, Yupeng Wang, Chenglong Zhang, Dalin Qiao, Pengrui Tian, Wenxi Qiu, Suizheng Su, Guanghui H. School of Nuclear Science and Technology Shanxi Key Laboratory of Advanced Nuclear Energy and Technology Xi'an Jiaotong University Xi'An710049 China China Institute of Atomic Energy Beijing102413 China State Key Laboratory of Multiphase Flow in Power Engineering China

In order to explore the flow and heat transfer characteristics of spiral tube steam generators under Lead-Bismuth Eutectic (LBE) corrosion, the accelerated removal effect of LBE corrosion flow was perfected, and a bidirectional coupling model of LBE corrosion and flow heat transfer was established. Computational fluid dynamics (CFD) method was used to simulate the corrosion and flow heat transfer of helical tube steam generator under saturated oxygen concentration and oxygen-controlled environment. The results indicate that the corrosion of liquid LBE forms an oxidation layer, which hinders the heat transfer in the spiral tube steam generator. This leads to a significant increase in the wall friction coefficient and a decrease in the surface Nusselt number. However, it does not have a significant effect on the water side evaporation process of the spiral tube steam generator. The implementation of an oxygen-controlled environment can effectively reduce the influence of LBE corrosion on the flow heat transfer of the spiral tube steam generator. Especially under high temperature conditions, it can reduce the near wall temperature of LBE change by up to 57.5% and the outlet temperature change by up to 61.5%. The oxygen-controlled environment results in prolonged local hypoxia time, with a more pronounced effect at higher temperatures. © 2023, The Authors. All rights reserved.

关键词： Oxygen

Thermal-Mechanical Influence Aspects and Evaluation of Helical Cruciform Single Rod in Fluoride-Salt-Cooled High-Temperature Advanced Reactor

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Chen, Yiwen Zhang, Dalin Jiang, Dianqiang Li, Wei Wu, Xiaoli Tian, Wenxi Qiu, Suizheng Su, Guanghui Lu, Qi State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Xi’an710049 China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi’an Jiaotong University Xi’an710049 China Science Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China China

Helical cruciform fuels are novel in nuclear reactors, potential to increase reactor’s power density. However, the geometry is complicated so influence of it on the fuel performance is not identified yet. In this paper, impact of power density, cross-section parameters, and twist pitch on thermal and mechanical characteristics of fuel used in Fluoride-Salt-cooled high-Temperature Advanced Reactor is discussed based on fluid-thermal-mechanical coupling. For thermal features, twist pitch is key while others have few effects. Increase in twist pitch leads to temperature uniformity and rise owing to weaker mixing effects. Fuel center temperature at middle plane of 300mm-pitch rod is 829.58℃, 54.66℃ higher than that of 100mm-pitch rod. Difference of maximum and minimum temperature at 45° cross section of 500mm-pitch rod is 153.62℃, while the figure is only 74.00℃ of 300mm-pitch rod. Besides, axial temperature of cladding outer surface increases wavelike due to complex geometry. For mechanical features, not geometry sizes but temperature affects stress distribution. Maximum Von-Mises stress appears at the elbow, where maximum temperature exists, 116.8MPa under normal conditions, lower than tensile strength of the material. After identifying the influence of these factors, five dimensionless parameters are proposed to evaluate and rate fuel performance based on Technique for Order Preference by Similarity to an Ideal Solution. As a result, an optimization comes up, scoring 0.310, twice more than the original design, owing to the thermal uniformity and mechanical safety. This study provides a reference for identifying and evaluating the performance of helical structure. © 2024, The Authors. All rights reserved.

关键词： Geometry

Numerical Study on the Local Heat Transfer Characteristic of Supercritical Co2 in Semicircular/Circular Channel Under Cooling Condition

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Zhong, Shao-Geng Ren, Yan Wu, Weidong Yang, Ying-Ying Yang, Qi-Guo School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai200093 China

A mathematic-physical model was established to explore the local heat transfer characteristics of supercritical CO2 in semicircular and circular channels under cooling condition, which was applied in the field of supercritical CO2 Brayton cycle. The numerical method was validated by the experimental data with the average error of 3.79%, meeting the accuracy requirement. And the operation pressure, cooling heat flux, inlet velocity and hydraulic diameter were 8~9 MPa, 10~14 kW·m-2, 1.2~5 m·s-1 and 1~2 mm, respectively. The results showed that the local heat transfer coefficient of supercritical CO2 would increase at first and then decrease along the flow direction regardless of the semicircular channel and circular channel, and the peak value gradually decreased with increasing operation pressure and disappeared when the inlet velocity exceeded 3 m·s-1. Meanwhile, the heat transfer performance of the semicircular channel was weaker than that of the circular channel due to the influence of the corner area and the buoyant effect, and the latter played a dominant role. For the horizontal flow, the buoyant effect was increased, while the heat transfer was decreased with increasing hydraulic diameter of the semicircular channel. Besides, the influence of different flow directions on the heat transfer performance of the semicircular channel (about 6.2%) was greater than that of the circular channel (about 0.48%, and could be ignored). Finally, the heat transfer correlation of the supercritical CO2 cooling process in the horizontal semicircular channel was modified by considering the influence of the dimensionless buoyancy effect and hydraulic diameter, and the prediction errors of 90% correlation calculation results were within ±14% after the modification. These results will provide some theoretical guidance on the design and optimization of the cooler for the supercritical CO2 Brayton cycle system. © 2022, The Authors. All rights reserved.

关键词： Heat flux

High-Entropy (Cocrfemnni)3o4 Catalysts for Propane Catalytic Destruction: Effect of the Precipitation Agent

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Ma, Yue Zhang, Yun Jian, Yanfei Jiang, Zeyu Chai, Shouning Li, Lu Xia, Lianghui He, Chi State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Department of Physics and Information Technology Baoji University of Arts and Sciences Shaanxi Baoji721016 China National Engineering Laboratory for VOCs Pollution Control Material & Technology University of Chinese Academy of Sciences Beijing101408 China

Efficient catalytic destruction of light alkane with ultra-stable and highly symmetric structure is still an intractable issue. High entropy oxides (HEOs) with high chemical disorder and lattice distortion and superior stability have shown great potential in heterogeneous thermocatalysis. Herein, spinel-type HEOs are synthesized via a scalable co-precipitation method with different precipitants (NaOH, Na2CO3, and NaHCO3) and firstly adopted in catalytic destruction of propane. Results demonstrate that the HEO-NaOH possesses the best activity, achieving 90% of propane conversion at 325 °C with an apparent activation energy of 56 kJ·mol-1. Compared with other two HEOs, HEO-NaOH system has larger quantities of surface oxygen vacancies and easily forming several reactive oxygen species (OOH-, O2-, and OH-, etc.), which significantly contribute to the catalytic performance. Moreover, the excellent water resistance of HEOs is verified due to their high conformational entropy and structural stability. Reaction mechanism reveals that OOH- and O2- are the key species in the oxidation of C3H8, which break C-H and C-C bonds in sequence, and are then converted to oxygenated compounds via oxygen oxidation before the final mineralization. The present work provides new insights into the fabrication of efficient catalysts for light alkane destruction as well as other thermocatalytic applications. © 2023, The Authors. All rights reserved.

关键词： Sodium hydroxide

Transient Cooling Performance of R134a Flash-Evaporation Spray Enhanced by Cold Air Jet: A Novel Heat Transfer Enhancement Method in Laser Dermatology

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Li, Bufa Wang, Junfeng Tian, Jiameng Chen, Bin Xu, Haojie School of Energy and Power Engineering Jiangsu University Zhenjiang212013 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China

Nevus of Ota is a dermal hyperplastic pigmented disease with a morbidity rate of 0.1%–0.6% in the Asian population. Laser surgery with the assistance of cryogen spray cooling (CSC) is a potential clinical treatment for nevus of Ota. However, for Asians with high melanin content, it is necessary to enhance cooling capability without the increment of refrigerant amount. In this study, a R134a flash-evaporation cryogen spray cooling coupled with cold air jet (CSC-CAJ) was developed to improve the cooling capacity. Epoxy resin was employed as a skin phantom to investigate the heat transfer characteristics of CSC-CAJ with different air jet parameters. Air jet parameters of CSC-CAJ are recommended to be T a = -7 °C, V a = 3 m 3 /h Z a = 10 mm and Φ a = 30°. Compared to CSC, CSC-CAJ could reduce the minimum surface temperature from -39 °C to -42.1 °C, and the average value of convection heat transfer coefficient ( h ) of CSC-CAJ could increase from 8 W/(m 2 ·k) to 12.9 W/(m 2 ·k) or 61.3% for the recommended parameters. The liquid film residence time ( τ ) decreases from 301 ms to 234 ms or 23.3%. In addition, based on the visualization observation and surface heat transfer measurement, the frost formation phenomenon on the surface and the heat transfer enhancement mechanisms are well understood. Four modes, including Leidonfrost mode, no runoff mode, runoff mode and evaporation mode, are proposed to describe the four stages of CSC-CAJ. A non-dimensional correlation of normalized Nusselt number ( Nu *) and time ( t *) is summarized. The primary heat transfer enhancement mechanism of CSC-CAJ is found to be the increase in cryogen evaporation rate and the ratio of heat removal from the phantom surface to phase change latent heat. © 2022, The Authors. All rights reserved.

关键词： Evaporation

Dynamic simulation of coal-fired power plant integrated with trough solar collector operating in parallel with high pressure heaters

学校读者我要写书评

暂无评论

Dynamic simulation of coal-fired power plant integrated with...

2019 Canadian Society for Civil engineering Annual Conference, CSCE 2019

作者： Yan, Hui Li, Xin Liu, Ming Chong, Daotong Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China

ISBN: (纸本)9780791883747

Solar-aided coal-fired power plant (SACFPP) is a costeffective approach to overcome solar energy intermittency. SACFPPs frequently operate in dynamic processes due to power load and solar energy fluctuations. This study investigated the dynamic characteristics of SACFPPs;such characteristics are important for flexibility evaluation and control system design. The SACFPP used in this study was based on a 660 MW coalfired power plant, and a trough collector system (TCS) operates in parallel with high pressure (HP) heaters. After model development and validation, the dynamic performance of the SACFPP was analyzed under four load ratios of power plant, with disturbances of two parameters: direct normal irradiance (DNI) and mass flowrate ratio to TCS. The performance was also compared with three parallel TCS connection modes. Results showed that the magnitude and response time for power variation under DNI disturbance increased with load ratio. With 500 W/m2 DNI step increments, power increased by approximately 18.4, 21.2, 24.7, and 29.8 MW in 2200, 2330, 2550 and 2620 s at 70%, 80%, 90%, and 100% load ratios, respectively, when all the HP heaters were replaced. The serial number and the number of HP heaters replaced also increased the power variation and response time. Under mass flowrate ratio to TCS increase disturbance, the power rapidly changed to its maximum and then slowly decreased, but the variation value depended on the load ratio. Copyright © 2020 ASME.

关键词： Coal fired power plant

Atomic Nickel on Graphitic Carbon Nitride as a Visible Light-Driven Hydrogen Production Photocatalyst Studied by X-ray Spectromicroscopy

学校读者我要写书评

暂无评论

ACS Sustainable Chemistry and engineering 2023年第14期11卷 5390-5399页

作者： Huang, Yu-Cheng Li, Yanrui Arul, K. Thanigai Ohigashi, Takuji Nga, Ta Thi Thuy Lu, Ying-Rui Chen, Chi-Liang Chen, Jeng-Lung Shen, Shaohua Pong, Way-Faung Dong, Chung-Li Chou, Wu-Ching Department of Electrophysics National Yang Ming Chiao Tung University Hsinchu30010 Taiwan Research Center for X-ray Science & Department of Physics Tamkang University New Taipei City25137 Taiwan International Research Center for Renewable Energy State Key laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Photon Factory Institute of Materials Structure Science High Energy Accelerator Research Organization Tsukabu305-0801 Japan UVSOR Synchrotron Facility Institute for Molecular Science Okazaki444-8585 Japan National Synchrotron Radiation Research Center Hsinchu30010 Taiwan

The photocatalytic production of solar hydrogen through water splitting by graphitic carbon nitride (g-C3N4) has gained substantial interest due to its advantageous characteristics, such as eco-friendliness, wealth on the earth, favorable bandgap, and easy preparation. Nevertheless, the performance for photocatalytic overall water splitting has been significantly restricted owing to the rapid recombination of charge carriers and slow catalytic kinetics. This investigation demonstrates the utilization of a single-atom Ni-terminating agent to coordinate with the heptazine moieties of g-C3N4, resulting in the formation of a new electronic orbital. g-C3N4 with single-atom Ni-termination can achieve highly efficient photocatalytic overall water splitting into H2 and H2O2 upon visible light irradiation, without requiring the use of any additional cocatalysts. The underlying cause of the enhanced photocatalytic performance of single-atom Ni-incorporated g-C3N4 in hydrogen evolution reaction is identified using synchrotron X-ray spectroscopy and microscopy. The X-ray spectro-microscopic results discover that the new hybrid orbital that is critical for optimizing photocatalysis is associated with carbon defects. The atomic and electronic structures and the band gap of g-C3N4 are adjusted by the new hybrid orbital. Moreover, it synergistically enhances visible light absorption, thereby promoting the separation and transfer of photogenerated charge carriers. The single-atom Ni and the adjacent C atom are recognized as the active sites for water oxidation and reduction, respectively, supporting the efficient photocatalytic splitting of water via a two-electron transfer pathway. This study demonstrated a promising material design for promoting photocatalytic activity in solar energy conversion applications. © 2023 American Chemical Society

关键词： Electronic structure

Conducting Polymers Meet Lithium-Sulfur Batteries:Progress,Challenges,and Perspectives

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2023年第5期6卷 159-182页

作者： Xin Chen Chengcheng Zhao Kai Yang Shiyi Sun Jinxin Bi Ningrui Zhu Qiong Cai Jianan Wang Wei Yan Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery Department of Environmental EngineeringXi'an Jiaotong UniversityXi'an 710049China Advanced Technology Institute University of SurreyGuildfordSurrey GU27XHUK College of Arts College of Landscape Architecture Fujian Agriculture and Forestry UniversityFuzhou 350108China Department of Chemical&Process Engineering Faculty of Engineering and Physical Sciences University of SurreyGuildford GU27XHUK

Lithium-sulfur(Li-S)batteries have attracted increased interest because of the high theoretical energy density,low cost,and environmental *** polymers(CPs),as one of the most promising materials used in Li-S batteries,can not only facilitate electron transfer and buffer the large volumetric change of sulfur benefiting from their porous structure and excellent flexibility,but also enable stronger physical/chemical adsorption capacity toward polysulfides(LiPSs)when doped with abundant heteroatoms to promote the sulfur redox kinetics and achieve the high sulfur *** review firstly introduces the properties of various CPs including structural CPs(polypyrrole(PPy),polyaniline(PANi),polyethylene dioxothiophene[PEDOT])and compound CPs(polyethylene oxide(PEO),polyvinyl alcohol(PVA)and poly(acrylic acid)[PAA]),and their application potential in Li-S ***,the research progress of various CPs in different components(cathode,separator,and interlayer)of Li-S batteries is systematically ***,the application perspective of the CPs in Li-S batteries as a potential guidance is comprehensively discussed.

关键词： conducting polymers Li-S batteries modified materials polysulfides

Characteristics of Bubble Dynamic Behavior on the Surface of Photoelectrode Under the Influence of a Vertical Magnetic Field

学校读者我要写书评

暂无评论

SSRN 2023年

作者： Feng, Yuyang Wang, Yechun Zhang, Bo Cao, Zhenshan Liu, Miaomiao Zhen, Canghao Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Xinjin Weihua Institute of Clean Energy Research Nanhai District Guangdong Province Foshan City China

The magnetohydrodynamic (MHD) flow around the bubble induced by the Lorentz force owing to the applied magnetic field significantly affects the behavioral characteristics of the bubble on the electrode surface. However, the mechanism of the impact of a magnetic field perpendicular to the electrode on the dynamic behavior of bubbles remains unclear. In this study, the evolution law of a single oxygen bubble on the surface of a TiO2 photoelectrode under the influence of a vertical magnetic field with different magnetic induction intensities was investigated. The vertical magnetic field effectively promoted the rapid detachment of bubbles from the electrode surface, and greatly improved the gas evolution efficiency. The mass transfer was dominated by single-phase free convection during bubble evolution. Under the influence of the vertical magnetic field, the mass transfer coefficient near the electrode was enhanced, and the adverse effects of bubbles on mass transfer were counteracted when they entered the reaction-controlled growth phase. The further multiphysics simulation found that the MHD convection decreased the local supersaturation of reaction product oxygen molecules near the electrode, thereby reducing concentration overpotential and increasing the reaction rate. This study provides an experimental and theoretical basis for promoting the bubble detachment and the reaction rate on the gas evolving electrode surface during photoelectrochemical water splitting. © 2023, The Authors. All rights reserved.

关键词： Efficiency