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Experimental research on the characteristics of steam-water counter-current flow in the Pressurizer Surge Line assembly

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Experimental Thermal and Fluid Science 2018年 96卷 180-191页

作者： Jiangtao Yu Dalin Zhang Leitai Shi Zhiwei Wang Wenxi Tian G.H. Su S.Z. Qiu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University 28 Xianning West Road Xi’an 710049 China Shaanxi Key Lab. of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University 28 Xianning West Road Xi’an 710049 China

To investigate Counter-Current flow (CCF) characteristics in the Pressurizer Surge Line (PZR SL) assembly of the large advanced passive nuclear reactors, steam-water CCF experiments are carried out on a stainless steel test section, which is a 1:4 scaled-down model of the AP1000 PZR SL assembly. The inner diameter of the test PZR SL pipe is 90 mm, which also belongs to the large-diameter pipes, as same as the prototype PZR SL pipe, in the field of Counter-Current flow Limitation (CCFL) researches. The present steam-water CCFL experiments are conducted under normal pressure and saturated temperature, with the PZR simulator collapse water level ranging from 350 to 900 mm. CCFL becomes severer at higher steam flow rate, and the most limiting CCFL effect locates between the PZR simulator bottom head and the vertical part of PZR SL pipe. The onset of CCFL and zero liquid penetration (ZP) are two critical conditions in the CCF development process, dividing the process into three stages: Before-CCFL, Partial-CCFL, and CCFL-ZP. According to the local CCFL conditions, the development of the CCFL process is also divided into four-regions since onset of CCFL. The present steam-water CCF data are well normalized in terms of dimensionless Kutateladze (Ku) numbers, and a Ku-type empirical partial CCFL correlation is developed. The comparisons of the present CCF data and partial CCFL correlation with the CCF data and correlations of former experiment researches validate that the present empirical partial CCFL correlation is conservative to predict steam-water partial CCFL in the prototype PZR SL assembly of the large advanced passive nuclear reactors.

关键词： Steam-water counter-current flow Partial CCFL correlation Pressurizer surge line assembly Advanced passive nuclear reactors ADS Automatic Depressurization System ADS1-3 First to Third Stages of ADS ADS4 Fourth Stage of ADS CCF Counter-Current flow CCFL Counter-Current flow Limitation CCFL-1 The 1st grade of CCFL region CCFL-2 The 2nd grade of CCFL region CCFL-3 The 3rd grade of CCFL region CCFL-L Local CCFL at the T-junction of HL pipe and PZR SL pipe CCFL-S Local CCFL along the PZR SL pipe CCFL-U Local CCFL at the location between the PZR simulator bottom head and vertical part of PZR SL pipe CCFL-ZP Zero liquid penetration region or stage CMT Core Makeup Tank COCF Co-Current flow HL Hot Leg IRWST In-containment Refueling Water Storage Tank Ku Kutateladze PRHR Passive Containment Cooling System PWRs Pressurized Water Reactors PZR SL Pressurizer Surge Line RC Reactor Core RCS Reactor Coolant System RPV Reactor Pressure Vessel SBLOCAs Small-Break Loss-of-Coolant Accidents ZP zero liquid penetration

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Thermodynamic Analysis on Supercritical Water Gasification of Oily Sludge Using a Continuous Two-Step Method

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SSRN 2024年

作者： Wang, Gaoyun Zhang, Chenghao Zhao, Qiuyang Gao, Yunbo Jin, Hui Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University No. 28 Xianning West Road Xi’an710049 China Technical Inspection Center Sinopec Shengli Oilfield Company Dongying257000 China

A large amount of oily sludge is produced every year around the world and the traditional treatment techniques for oily sludge have deficiencies of incomplete processing and high energy consumption. Supercritical water gasification (SCWG) technology can cleanly convert oily sludge into hydrogen-rich gas and does not require an energy-consuming drying process. This work constructed the desorption-gasification two-step SCWG system based on the previous experimental study and investigated the influences of feed concentration, gasification temperature and sludge compositions on the energy efficiency and exergy efficiency of the system. The results showed that the two-step system had higher energy efficiency and exergy efficiency, as well as better adaptability to various sludge compositions under maintaining high efficiency conditions. The energy efficiency and exergy efficiency of the two-step system were 61.2% and 45.3% respectively under the gasification temperature of 600 ℃ and the feed concentration of 100wt%, which were 91.95% and 93.67% higher than those of the single-step system. Additionally, the desorption unit of two-step system operated at lower temperature, resulting in decreased use of high-temperature resistant materials and reduced economic costs. This research provides valuable insights into the construction and optimization of two-step SCWG of oily sludge. © 2024, The Authors. All rights reserved.

关键词： Desorption

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3d Printing Cup Evaporator with Open Architecture for Seawater Desalination

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SSRN 2024年

作者： Liu, Xinzhe Liu, Qingyuan Liu, Zheng Liu, Guohua Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power University Beijing102206 China Key Laboratory of Power Station Energy Transfer Conversion and System North China Electric Power University Ministry of Education Beijing102206 China

Solar interfacial evaporation exhibits great potential for alleviating the global freshwater crisis, but the salt crystallization on the photothermic surface during steam generation limits its practical application. Here, we propose a cup evaporator featuring vertically aligned mass transfer grooves for water transport and salt backflow. The cup design allows for efficient collection of diffuse energy reflections from the bottom that would otherwise be lost, with an energy efficiency of more than 95% upon one sun. The open capillary grooves enable the evaporator to form a stable liquid film around the cup surface, which significantly improves the steam generation without compromising on salt rejection, achieving a evaporation rate of 2.249kg/m2/h. The temperature difference between the liquid film and the inner wall of evaporator promotes heat convection induced salt drainage, leading to accurate salt crystallization around the lip of the cup. In a long-term test, the evaporator can continuously work with a stable evaporation rate by spatially isolating the crystallization sites from the open architecture. Moreover, the outdoor test of evaporator demonstrates a daily freshwater generation more than 9.8 kg/m2, which is sufficient to satisfy individual drinking water requirements. As an example of functional integration, this device was also tested for wastewater purification of various kinds of common pollutants, meeting the World Health Organization’s drinking water standards. This evaporator featuring high energy efficiency, strong salt-rejection, and excellent water purification capabilities, holds great promise for supplying freshwater to water-stressed communities. © 2024, The Authors. All rights reserved.

关键词： Desalination

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Effect of Noble Metal in CdS/M/TiO ₂ for Photocatalytic Degradation of Methylene Blue under Visible Light

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International Journal of Green Nanotechnology: Materials Science and engineering 2010年第2期1卷 M94-M104页

作者： Shen, Shaohua Guo, Liejin Chen, Xiaobo Ren, Feng Kronawitter, Coleman X. Mao, Samuel S. State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049 China Lawrence Berkeley National Laboratory University of California at Berkeley Berkeley CA 94720 United States

The CdS/M/TiO 2 (M = Ag, Ru, Au, Pd, and Pt) three-component nanojunction systems were constructed using a two-step photodeposition method, and evaluated for their photocatalytic activities through the degradation of ... 详细信息

The CdS/M/TiO ₂ (M = Ag, Ru, Au, Pd, and Pt) three-component nanojunction systems were constructed using a two-step photodeposition method, and evaluated for their photocatalytic activities through the degradation of methylene blue in aqueous solution under visible light irradiation. The authors found that the photocatalytic activity of CdS/M/TiO ₂ (M=Ag, Ru, Au, Pd, Pt) three-component nanojunctions was superior to that of CdS/TiO ₂ two-component system. Moreover, the photocatalytic activity of the three-component nanojunction system was found to be dependent significantly on the type of the noble metals. The results can be explained by the influence of charge transfer on the basis of the work functions of different noble metals. © 2010 Copyright Taylor and Francis Group, LLC.

关键词： CdS/M/TiO 2 heterojunction noble metal photocatalysis Z-scheme

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Opto-Thermoplasmonic Pneumatic Pistons Actuator

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SSRN 2024年

作者： Wang, Hongbiao Xu, Jinliang Zhang, Yuqian Yan, Xin Liu, Guohua Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power University Beijing102206 China Key Laboratory of Power Station Energy Transfer Conversion and System North China Electric Power University Ministry of Education Beijing102206 China

Optical manipulation of liquids has extensive applications, ranging from biological research to information technology. However, existing technologies struggle with a fundamental limitation, as the pinning force of the contact line significantly resists liquid motion. In this study, a novel strategy is introduced to govern fluid motion and overcome this barrier. Our approach involves positioning a nanofluid slug within a sealed capillary tube and directing irradiation to one side of the slug. Intensive local vaporization is generated due to the thermo-plasmonic effect of nanoparticles, leading to a considerable driving force and rapid motion of the slug. Based on this principle, the opto-thermoplasmonic pneumatic piston was proposed. The direction of motion is controlled by modulating the irradiation direction. Furthermore, the laser beam parameters enable adjustable piston oscillation frequency and speed. To better understand the characteristics of the opto-thermoplasmonic pneumatic piston, theoretical studies were conducted to analyze the kinetic characteristics of the piston, revealing an expression consistent with the Kelvin-Voigt model. Various factors affecting the performance of the pneumatic pistons were also studied. Based on the experimental results and motion model, we found and explained that the oscillation amplitude presents an exponential relationship with the working frequency [[EQUATION]], where the coefficient a is related to the laser power, slug length, and nanofluid concentration, while the coefficient b is solely dependent on the nanofluid concentration. These opto-thermoplasmonic pneumatic pistons epitomize a new paradigm for manipulating aqueous mesoscopic systems, thus forging new paths for light-propelled soft motors with precise motion control. © 2024, The Authors. All rights reserved.

关键词： Irradiation

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Numerical Simulation for Non-Uniform Ptco Catalyst Degradation Under Constant Voltage Condition and its Impact on Pemfc Performance

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SSRN 2023年

作者： Yang, Yunjie Bai, Minli Zhou, Zhifu Wu, Wei-Tao Hu, Chengzhi Gao, Linsong Li, Yang Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116023 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'An710049 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China

PtCo alloys are commonly utilized as catalysts in proton exchange membrane fuel cell (PEMFC) to reduce Pt loading and to achieve higher oxygen reduction reaction (ORR) activity. However, long-time operation can result in a reduction in electrochemical surface area (ECSA) in PEMFC. Meanwhile, the dissolved Co2+ may also contribute to additional local oxygen transport resistance. In this study, catalyst aging model and Co2+ transport and its effect on oxygen transport model have been integrated with the 3D single phase PEMFC performance model to develop a long-term performance model for investigating the impact of non-uniform catalyst degradation and Co2+ contamination on PEMFC performance during constant voltage operation. The results show that Co2+ contamination causes additional mass transfer losses and reduces the peak power of PEMFC. And it is found that the non-uniform degradation of catalyst and Co2+ contamination eventually affects the current density distribution in aged PEMFCs. In addition, the model is also applied to study a 50 cm2 PEMFC under long time constant voltage operation. The predicted ECSA loss is 73.1% and 62.0%, and output power reduction is 55.9% and 43.0% after 80,000 hours at a constant voltage of 0.75 V and 0.65 V, respectively. © 2023, The Authors. All rights reserved.

关键词： Numerical models

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Influence of Bi3+ Doping on the Electrochemical Properties of Ti/Sb-Sno2/Pbo2 Electrode for Zinc Electrowinning

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SSRN 2024年

作者： Wu, Jia Kang, Xuanqi Xu, Shuangwen Wei, Zhen Xu, Shangyuan Liu, Kang Feng, Qing Jia, Bo Wang, Yunhai Xían Taijin New Energy & Materials Sci-Tech CO. Ltd Xi’an710016 China Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiao tong University Xi’an710049 China

Bi3+ doped Ti/Sb-SnO2/PbO2 electrode materials were fabricated by electrodeposition to improve its electrochemical performance in zinc electrowinning. The surface morphology, chemical composition and hydrophilicity of the as-prepared electrodes are characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and contact angle. The electrochemical measurement and the accelerate lifetime experiment are also conduct to investigate the electrocatalytic performance and stability of the electrodes. The results showed that Bi3+ modification electrode has an important effect on the coating morphology, crystal structure, surface hydrophilicity, electrocatalytic activity and stability. The electrode prepared from the solution containing 2 mmol·L-1 Bi(NO3)3 (marked as the Ti/Sb-SnO2/2Bi-PbO2 electrode) exhibits the best hydrophilicity performance (θ=21.6°) and the longest service life (1196 h). During the electrochemical characterization analysis, the Ti/Sb-SnO2/2Bi-PbO2 electrode showed the highest oxygen evolution activity, which can be attributed to the highest electroactive surface (qT*=21.20 C·cm-2) and the best charge transfer efficiency. DFT calculation demonstrate that the doping of Bi lead to the decrease in the OER reaction barrier and increase the DOS of the electrode, which further enhanced the catalytic activity and conductivity of the electrode. Moreover, the simulated zinc electrowinning experiment demonstrate that the Ti/Sb-SnO2/2Bi-PbO2 electrode consume less energy than other electrodes. Therefore, it is expected that the Bi modified electrodes may become a very promising electrode material for zinc electrowinning in the future. © 2024, The Authors. All rights reserved.

关键词： Hydrophilicity

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Nuclear Thermal Coupling Optimization of Baffled Ntp Reactor

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SSRN 2022年

作者： Duan, Zimian Zhang, Jing Han, Zichao Wang, Mingjun Wu, Yingwei He, Yanan Tian, Wenxi Qiu, Siuzheng Su, Guanghui Shaanxi Key Lab. of Advanced Nuclear Energy and Technology Xi’an Jiaotong University Xi’an710049 China Department of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Nuclear thermal propulsion (NTP) technology has characteristics of high power and high specific impulse. In particular, CERMET fuel reactor has received a lot of research due to its simple form and structure. A general CERMET fuel reactor model is established by using three-dimensional Monte Carlo neutron dynamics program and commercial CFD program Fluent. After nuclear thermal coupling optimization, three partition schemes of baffled reactor were proposed to reduce the temperature difference between the wall and the coolant and lower the relative spike factor in the inner region. A feasible design of redundant control system was then proposed, with a cold clean excess reactivity greater than $3.44 and a minimum dry shutdown reactivity lower than -$5.95, where there was a high control accuracy of 6.7 pcm/mm. The reactor realized safety of the core temperature lower than 3000K under the conditions of total exit temperature of 2650K and thrust of 25000lb. © 2022, The Authors. All rights reserved.

关键词： Cermets

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Correlation Analysis for Online CO 2 Leakage Monitoring in Geological Sequestration

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Energy Procedia 2013年 37卷 4374-4382页

作者： Denglong Ma Jianqiang Deng Zaoxiao Zhang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University No.28 Xianning West Road Xi’an 710049 P.R. China School of Chemical Engineering and Technology Xi’an Jiaotong University No.28 Xianning West Road Xi’an 710049 P.R. China

The paper presents a method for monitoring CO 2 leakage in geological carbon dioxide sequestration. The unsteady state dispersion of leakage CO 2 from geosequestration simulation results showed that the ensemble trend of elevated concentration caused by CO 2 leakage can be viewed as a concentration step change perturbation to the background variation and the initial stage of dispersion process is an increasing variation. The correlation between O 2 and CO 2 variation is well linear if there is no leakage. The external linear perturbation decreases the correlation coefficient. Moreover, too large step change concentration will also reduce the average correlation coefficient. Therefore, online correlation analysis between O 2 and CO 2 in atmosphere is useful to distinguish the leakage CO 2 from complex background variation especially at the beginning of leakage occurring.

关键词： Geosequestration Carbon storage CO 2 leakage monitoring Correaltion analysis

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Thermal Stress in a Circular Nano-Inhomogeneity

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SSRN 2022年

作者： Huang, Haojie Xing, Shichao Song, Kun School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai China School of Energy and Power Engineering Shanghai Key Laboratory of Power Enegy in Multiphase Flow and Heat Transfer Shanghai China Key Laboratory of Construction Hydraulic Robots of Anhui Higher Education Institutes Tongling University Tongling244061 China School of Mechanical and Power Engineering Nanjing Tech University 30 Puzhu South Road Jiangsu Nanjing China

The thermal stress of nanocomposites is worth studying in that the extreme stress affects its reliability. In this paper, we propose a set of interfacial conditions to simulate the interfacial phonon scattering and interfacial elasticity in the nanocomposite, and obtain closed-form solutions for the thermal-elastic fields around the circular nano-inhomogeneity. The results show that the interfacial thermal stress within matrix is more sensitive to interfacial phonon scattering than that in the nano-inhomogeneity, while the size change of inhomogeneity has greater impact on the stress of the nano-inhomogeneity than that of the matrix. In view of the significant effects of thermal conductivities and thermal expansion coefficients on the thermal stress around inhomogeneity, the maximum von Mises stress is reduced up to three orders of magnitude by adjusting these parameters. More importantly, the thermal stresses within matrix and inhomogeneity can be respectively designed as "zero" even though the nanocomposite is subjected to a large thermal loading, which is viewed as an update mechanism of "neutral inhomogeneity". Our work provides guidance for the design of nanocomposites and has important potential applications. © 2022, The Authors. All rights reserved.

关键词： Thermal stress

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