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

作者： Liu, Yang Shan, Jianqiang Zhang, Bo Liu, Wei State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University No. 28 Xianning West Road Xi'an Shaanxi Province710049 China Nuclear Power Institute of China State Key Laboratory of System Desgin Technology Chengdu Sichuan Province610213 China

A bundle mechanistic model to predict critical heat flux (CHF) over a pressurized water reactor (PWR) operating range in flow boiling has been proposed based on a concept of the bubble crowding in the wall bubbly layer. The new bundle mechanistic model has the following differences with the original tube model proposed by Weisman & Pei. Firstly,the radial velocity distribution within the bundle was used to derive the radial turbulence intensity factor ib instead of the velocity distribution inside the tube. Secondly, a grid enhancement factor was introduced to quantify the effect of grid on CHF enhancement, based on the measurement experiment of the turbulence intensity factor ib with grid. Thirdly, for the turbulence intensity factor ib, the new model considers the influence of pressure and mass flow rate under two phases, and the original ib only considers the influence of mass flow rate. Finally, the new established bundle CHF mechanism model was verified by comparing with the typical PWR CHF data. © 2019 American Nuclear Society. All rights reserved.

关键词： Heat flux

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Encapsulation of Co/Co3o4 Hetero-Nanoparticles within the Inner Tips of N-Doped Carbon Nanotubes: engineering Mott-Schottky Nanoreactors for Efficient Bifunctional Oxygen Electrocalysis Toward Flexible Zinc-Air Batteries

SSRN

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SSRN 2022年

作者： Zhang, Binbin Lu, Tingyu Ren, Yiping Huang, Longzhen Pang, Huan Zhao, Qun Tian, Shu Yang, Jun Xu, Lin Tang, Yawen Tian, Xinlong School of Chemistry and Materials Science Jiangsu Key Laboratory of New Power Batteries Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials Nanjing Normal University Nanjing210023 China School of Chemistry and Chemical Engineering Yangzhou University Yangzhou225009 China College of Chemistry and Chemical Engineering Nantong University Nantong226019 China Nanjing IPE Institute of Green Manufacturing Industry Nanjing211100 China State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China State Key Laboratory of Marine Resource Utilization in South China Sea Hainan Provincial Key Lab of Fine Chemistry School of Chemical Engineering and Technology Hainan University Haikou570228 China

We demonstrate a typical Mott-Schottky electrocatalyst by ingeniously encasing Co/Co3O4 hetero-nanoparticles within the inner tips of N-doped carbon nanotubes (abbreviated as Co/Co3O4@N-CNTs hereafter) through a facile and scalable hydrogel-bridged pyrolysis strategy. Experimental and theoretical findings collectively manifest that the spontaneous charge redistribution at the Co/Co3O4 heterointerfaces is essential to promote the charge transfer capability, lower down the reaction barriers for oxygen electrocatalysis, and ultimately boost the intrinsic activities. Accordingly, the well-designed Co/Co3O4@N-CNTs exhibit admirable ORR and OER activities and long-term robustness in KOH medium, exceeding the commercial Pt/C and RuO2 benchmarks, respectively. Furthermore, the Co/Co3O4@N-CNTs-assembled flexible all-solid-state zinc-air battery displays a high power density, remarkable rate capability, excellent rechargeablity and outstanding mechanical flexibility even under severe deformations, predicting the great potentials in diverse next-generation wearable electronic devices. The rationale of the construction of Mott-Schottky heterojunctions may provide an innovative and instructive avenue to design diversified energy nanomaterials. © 2022, The Authors. All rights reserved.

关键词： Doping (additives)

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Thermodynamic and safety analysis for hydrogen production in a supercritical water gasification system of coal by multi-oxidizers distribution

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Energy 2025年 331卷

作者： Kui Luo Runqiu Dong Xujun Li Zhiyong Peng Libo Lu Jialing Xu Hui Jin Liejin Guo State Key Laboratory of Multiphase Flow in Power Engineering (SKLMF) Xi'an Jiaotong University NO.28 Xianning West Road Xi'an 710049 Shaanxi Province China Dongfang Steam Turbine Co. Ltd. Deyang 618000 China Jiangxi Provincial Key Laboratory of Particle Technology Jiangxi University of Science and Technology Ganzhou 341000 China School of Smart Energy Shanghai Jiao Tong University Shanghai 201100 China

Coal supercritical water gasification (SCWG) for hydrogen production technology is highly prospective due to the clean and efficient treatment process. A single oxidation reactor heating method is usually used in existing work limiting the efficient and stable operation of the system due to high component temperatures. This paper proposed the heat supply strategy of multi-oxidation reactor and heat exchanger layout to improve the system performance for the realization of reasonable matching of material flow and energy flow in each stage of the system. The improved system reduced the maximum temperature of the oxidation reactor from 1550 °C to 850 °C, and the system exergy efficiency and H 2 yield reached 49.30 % and 101 kg/h (at the mass ratio of coal to water of 1:10), respectively. The exergy flow results showed that the improved system exergy loss was concentrated in the oxidation reactor (34.00 %) heat exchanger (28.86 %), cooler (19.07 %), and gasification reactor (9.70 %). Exergy efficiency increased as the mass ratio of coal to water increased to the maximum exergy efficiency of 53.50 %. As the temperature increased from 600 °C to 675 °C, the exergy efficiency decreased from 53.10 % to 48.70 %. System adjustability analysis showed that the system can be stabilized over a 40 %–100 % range of feed fluctuations. This work may provide an optimization strategy for efficient operation and dynamic safety regulation of H 2 production by SCWG technology.

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Quantifying the interaction between a single kerogen molecule and shale fluids from the perspective of elements and chemical groups

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Separation and Purification Technology 2025年 362卷

作者： Huaisen Song Yongfei Yang Jinlei Wang Lei Zhang Hai Sun Junjie Zhong Kai Zhang Jun Yao State Key Laboratory of Deep Oil and Gas China University of Petroleum (East China) Qingdao 266580 Shandong PR China Center of Multiphase Flow in Porous Media School of Petroleum Engineering China University of Petroleum (East China) Qingdao 266580 Shandong PR China

During the implementation of underground H 2 storage (UHS), geological CO 2 sequestration (GCS), and CO 2 -enhanced oil recovery (CO 2 -EOR) measures in shale reservoirs, kerogen will interact with typical shale fluids (H 2 , CO 2 , shale oil and gas). These interactions will thereby affect the implementation effects of the above industrial measures. Kerogen at various maturity degrees exhibits complex interactions with shale fluids due to its different molecular structures, which are shaped by factors such as reservoir type, maturation time, and geological environment. Despite this complexity, the types of elements (C, H, O, N, and S) and chemical groups that constitute kerogen molecules are limited. In this study, we utilized molecular dynamic (MD) simulations to reveal the interaction mechanism between a single kerogen molecule and typical shale fluid (H 2 , CH 4 , Neopentane, and CO 2 ) from the perspective of component elements and chemical groups. In addition, we developed an interaction energy fitting formula to quantify these interactions without relying on MD simulations, thereby facilitating the rapid assessment of the difficulty in separating shale fluids from shale organic matter. Lastly, we proposed two simplification strategies to reduce the experimental procedures involved in constructing kerogen molecules, while allowing for a certain degree of evaluation of the interaction between kerogen and shale fluids.

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Flocculation of suspended cohesive particles in homogeneous isotropic turbulence

arXiv

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arXiv 2021年

作者： Zhao, K. Pomes, F. Vowinckel, Bernhard Hsu, T.-J. Bai, B. Meiburg, E. Department of Mechanical Engineering UC Santa Barbara Santa BarbaraCA93106 United States State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Leichtweiß-Institute for Hydraulic Engineering and Water Resources Technische Universität Braunschweig Braunschweig38106 Germany Center for Applied Coastal Research Department of Civil & Environmental Engineering University of Delaware NewarkDE19716 United States

We investigate the dynamics of cohesive particles in homogeneous isotropic turbulence, based on one-way coupled simulations that include Stokes drag, lubrication, cohesive and direct contact forces. We observe a transient flocculation phase characterized by a growing average floc size, followed by a statistically steady equilibrium phase. We analyze the temporal evolution of floc size and shape due to aggregation, breakage, and deformation. Larger turbulent shear and weaker cohesive forces yield elongated flocs that are smaller in size. Flocculation proceeds most rapidly when the fluid and particle time scales are balanced and a suitably defined Stokes number is O(1). During the transient stage, cohesive forces of intermediate strength produce flocs of the largest size, as they are strong enough to cause aggregation, but not so strong as to pull the floc into a compact shape. Small Stokes numbers and weak turbulence delay the onset of the equilibrium stage. During equilibrium, stronger cohesive forces yield flocs of larger size. The equilibrium floc size distribution exhibits a preferred size that depends on the cohesive number. We observe that flocs are generally elongated by turbulent stresses before breakage. Flocs of size close to the Kolmogorov length scale preferentially align themselves with the intermediate strain direction and the vorticity vector. Flocs of smaller size tend to align themselves with the extensional strain direction. More generally, flocs are aligned with the strongest Lagrangian stretching direction. The Kolmogorov scale is seen to limit floc growth. We propose a new flocculation model with a variable fractal dimension that predicts the temporal evolution of the floc size and shape. © 2021, CC BY.

关键词： Flocculation

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Effect of particle size on the thermal performance of NaNO3/SiC)2/C composite phase-change materials

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Particuology 2019年第3期17卷 169-175页

作者： Liang Liu Liqiong Wang Weichun Ge Yanfeng Ge Yun Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China State Grid Liaoning Electric Power Supply Co. Ltd. Shenyang 110004 China

Storage of thermal energy is a key technology for energy conservation and application of renewable energy sources. In this paper, the thermal performance of inorganic composite phase-change materials (PCMs;NaNO3/SiO2/C) is studied under extreme thermal conditions and the effect of raw particle size is examined. We designed a thermal shock test platform with a diffusive combustion system and in-situ infrared thermal imaging. The influences of the heat flux magnitude and exposure time on the performance of the PCMs were examined under vertical thermal shock conditions. Leakage of molten salt in the composite PCMs was observed as the heat flux reached a threshold point. The morphology and thermal properties were characterized by ex-situ SEM, XRD, DSC, and BET. Raw particles with sizes in the range of 105-500 μm were used to synthesize the composite material and examine its role in thermal shock behavior. Our experiments showed that deterioration of the thermal storage density was slowed as the particle size was increased. This work provides useful guidance for improving the anti-thermal shock ability of future material designs.

关键词： Thermal storage Phase change material Particle size Thermal shock Decomposition temperature

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Correction to: Modification of a first‑generation solid oxide fuel cell cathode with Co3O4 nanocubes having selectively exposed crystal planes

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Materials for Renewable and Sustainable Energy 2022年第3期11卷 299-299页

作者： Xu, Xi Wang, Chao Fronzi, Marco Liu, Xuehua Bi, Lei Institute of Materials for Energy and Environment College of Materials Science and Engineering Qingdao University Qingdao China State Key Laboratory of Multiphase Flow in Power Engineering International Research Centre for Renewable Energy Xi’an Jiaotong University Xi’an China

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

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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： Built-in electric field Heterojunction Hollow microspheres Shuttle effect

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flow prediction of heterogeneous nanoporous media based on physical information neural network

Gas Science and Engineering

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Gas Science and engineering 2024年 125卷

作者： Liang Zhou Hai Sun Dongyan Fan Lei Zhang Gloire Imani Shuaishi Fu Yongfei Yang Kai Zhang Jun Yao National Key Laboratory of Deep Oil and Gas China University of Petroleum (East China) Qingdao 266580 PR China Research Center of Multiphase Flow in Porous Media School of Petroleum Engineering China University of Petroleum (East China) Qingdao 266580 PR China

The simulation and prediction of fluid flow in porous media play a profoundly significant role in today's scientific and engineering domains, particularly in gaining a deeper understanding of phenomena such as the migration and fluid flow in underground rock formations and the enhancement of oil recovery rates. The flow of fluids in nanoscale porous media requires consideration of the effects of microscale phenomena, which are challenging to accurately describe using traditional physical models. Currently, research in deep learning for porous media predominantly focuses on conventional porous media, and there is an urgent need for investigations into heterogeneous nanoporous media. Simultaneously, there is a necessity to overcome the limitations of traditional data-driven models lacking physical prior knowledge. Therefore, the integration of physics-informed neural networks, which combine deep learning with physical principles, becomes essential for inferring relatively accurate results from sparse data. In this work, based on the heterogeneity of porous media in shale, we have introduced a deep learning model that couples physical information to predict the flow in heterogeneous nanoscale porous media. In the Physical Information Neural Network model, we utilize point clouds and couple them with deep residual networks. Discrete sampling points are used as inputs, and a multi-level residual connection, along with dimension concatenation, is employed to fuse feature information. The network, through backpropagation, takes into account the Navier-Stokes equations and wall conditions in heterogeneous nanoscale porous media. The results indicate that the apparent permeability and pressure field accuracy are over 90% and 95%, respectively. The Physical Information Neural Network demonstrates promising prospects for predicting flow in nanoscale porous media. Future work will extend to the multiphase complex flow in three-dimensional porous media.

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Two-dimensional self-adapting fast Fourier transform algorithm for nanoparticle sizing by ultrafast image-based dynamic light scattering

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Particuology 2018年第6期16卷 74-84页

作者： Dechuan Zhang Xiaoshu Cai Wu Zhou Institute of Particle and Two-Phase Flow Measurement University of Shanghai for Sdence and TechnologyShanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering (University of Shanghai for Sdence and Technology)Shanghai 200093China

In nanoparticle sizing using the ultrafast image-based dynamic light scattering (UIDLS)method,larger impurities and dark noise from the complementary metal-oxide-semiconductor (CMOS)detector affect measurement *** solve this problem,a two-dimensional self-adapting fast Fourier transform (2D-SAFFT)algorithm is proposed for *** light scattering images of nanoparticles are processed using 2D fast Fourier transforms,and a high-frequency threshold and a low-frequency threshold are then set using the self-adapting algorithm to eliminate the effects of the dark noise of the CMOS detector and the *** signals caused by the dark noise of the CMOS detector and the impurities are cut off using the high-frequency threshold and the low-frequency *** signals without the high- and low-frequency components are then processed again using an inverse Fourier transform to obtain new images without the dark noise and impurities *** mean diameters of the measured nanoparticles can be obtained from images obtained using *** standard latex nanoparticles (46,100, 203,508,994nm)and commercial nanoparticles (antimony-doped tin oxide,indium tin oxide,TWEEN- 80,nano-Fe,and nano-Al2O3)were measured using this new *** show that 2D-SAFFT can effectively eliminate the effects of dark noise from the CMOS detector and the impurities.

关键词： Dynamic light scattering Nanoparticle size Fast Fourier transform algorithm Spectrum segmentation

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