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A numerical model of thermal analysis for woven wire screen matrix heat exchanger

Cryogenics 2009年第9期49卷 482-489页

作者： Shuangtao, Chen Yu, Hou Hongli, Zhao Lan, Xi State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Woven wire screen matrix heat exchanger (WSMHE) is a kind of compact, light-weight and high-efficiency matrix heat exchanger (MHE) for cryogenic applications. This paper presented a numerical model for the design and thermal analysis of WSMHE. The influence of wall thermal resistance, axial conduction, parasitic heat load and properties variation was taken into account, which is neglected in the traditional effectiveness-NTU method but important for compact cryogenic heat exchangers. The proposed numerical method is verified by effectiveness-NTU method under specific conditions, then it is tested according to experiment data, and a well agreement was obtained. Based on this model, a detailed analysis was performed on WSMHEs. The analysis results show that the axial conduction might result in evident decrease of effectiveness at low flow rate region;the effectiveness of WSMHEs with large flow rate could be remarkably enhanced by increasing its length;the influence of parasitic heat load varied little throughout of the flow rate region. Furthermore, the numerical model presented in this paper can be developed to the design and thermal analysis of small partition wall type heat exchangers. © 2009 Elsevier Ltd. All rights reserved.

关键词： Thermoanalysis

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Flame instability analysis of diethyl ether-air premixed mixtures at elevated pressures

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Chinese Science Bulletin 2010年第3期55卷 314-320页

作者： ZHANG Ni DI YaGe HUANG ZuoHua ZHANG ZhiYuan State Key Laboratory of Multiphase Flow in Power Engineering Xi 'an Jiaotong University Xi 'an 710049 China

Combustion characteristics of premixed diethyl ether-air mixtures were studied at different equivalence ratios and elevated initial pressures using schlieren photography and spherically propagating flame. Laminar burning velocities, Markstein number and critical radii at onset of cellular structure were obtained. The results show that an increase in initial pressure leads to a decrease in the unstretched laminar burning velocities. Laminar burning velocities give their peak values at the equivalence ratio of 1.1. Markstein number decrease with the increase of initial pressure and equivalence ratio, indicating that the instability of flame front is increased with the increase of initial pressure and equivalence ratio. The critical radii at onset of cellular flame structure are decreased with the increase of initial pressure.

关键词：不稳定性分析空气混合物火焰结构压力升高乙醚层流燃烧速度初始压力预混

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Simulation and experimental study of phase isolation induced by a static cyclone device in a vertical upward pipe

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International Journal of Energy for a Clean Environment 2015年第1-4期16卷 139-156页

作者： Wang, Shuai Wang, Dong Niu, Pengman Zhang, Xingkai State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

The study puts forward a forced way to realize phase isolation by using a static cyclone device and provides a basis for a systematic study of the phase-isolation phenomenon for an oil-water two-phase flow in a vertical upward pipe. An optimized style of the static cyclone device was chosen to simulate the phase-isolation characteristics that are influenced by various flow parameters (density, viscosity, velocity, oil diameter, etc.). It is observed that the phase-isolation characteristics are well approaching the ideal condition with the oil superficial velocity below 0.20 m/s and water superficial velocity between 0.25 and 0.8 m/s. The experimental results, which agree well with the simulation, also show that the static cyclone device can successfully be used to realize phase isolation. The phase-isolation method may provide an innovative approach to the measurement of phase holdup, the process of water reinjection, and the heat and mass transfer rates of a multiphase flow. © 2015 by Begell House, Inc.

关键词： Two phase flow

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Syngas production by photoreforming of formic acid with 2D V_(x)W_(1-x)N_(1.5) solid solution as an efficient cocatalyst

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Frontiers in Energy 2024年第5期18卷 640-649页

作者： Xiaoyuan Ye Yuchen Dong Ziying Zhang Wengao Zeng Bin Zhu Tuo Zhang Ze Gao Anna Dai Xiangjiu Guan International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

Formic acid(FA)is a potential biomass resource of syngas with contents of carbon monoxide(CO,60 wt.%)and hydrogen(H_(2),4.4 wt.%).Among the technologies for FA conversion,the photoreforming of FA has received widespread attention due to its use of green solar energy conversion technology and mild reaction ***,a V-W bimetallic solid solution,V_(x)W_(1-x)N_(1.5) with efficient co-catalytic properties was first and facilely *** CdS was used as a photocatalyst,the activity performance of the V_(0.1)W_(0.9)N_(1.5) system was over 60%higher than that of the W_(2)N_(3) *** computational simulations and experiments showed the V_(0.1)W_(0.9)N_(1.5) had great metallic features and large work functions,contributing a faster photo-generated carrier transfer and less recombination,finally facilitating a great performance in cocatalyst for syngas production in photoreforming *** work provides an approach to synthesizing novel transition metal nitrides for photocatalysis.

关键词： photocatalysis syngas formic acid cocatalyst solid solution

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Steady state investigation on neutronics of a molten salt reactor considering the flow effect of fuel salt

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Chinese Physics C 2008年第8期32卷 624-628页

作者：张大林秋穗正刘长亮苏光辉 State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University School of Nuclear Science and Technology Xi'an Jiaotong University

The Molten Salt Reactor （MSR）, one of the ‘Generation Ⅳ＇ concepts, is a liquid-fuel reactor, which is different from the conventional reactors using solid fissile materials due to the flow effect of fuel salt. The study on its neutronics considering the fuel salt flow, which is the base of the thermal-hydraulic calculation and safety analysis, must be done. In this paper, the theoretical model on neutronics under steady condition for a single-liquid-fueled MSR is conducted and calculated by numerical method. The neutronics model consists of two group neutron diffusion equations for fast and thermal neutron fluxes, and balance equations for six-group delayed neutron precursors considering the flow effect of fuel salt. The spatial discretization of the above models is based on the finite volume method, and the discretization equations are computed by the source iteration method. The distributions of neutron fluxes and the distributions of the delayed neutron precursors in the core are obtained. The numerical calculated results show that, the fuel salt flow has little effect on the distribution of fast and thermal neutron fluxes and the effective multiplication factor; however, it affects the distribution of the delayed neutron precursors significantly, especially the long-lived one. In addition, it could be found that the delayed neutron precursors influence the neutronics slightly under the steady condition.

关键词： MSR steady state neutronics flow effect delayed neutron precursors

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Advanced encapsulation strategies for high-temperature molten salt: Synthesis methods and performance enhancement

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Renewable and Sustainable Energy Reviews 2025年 218卷

作者： Xiao, Tong Xu, Jinliang Xie, Jian Dong, Xinyu Liu, Chao Wang, Yan Yu, Xiongjiang Zhang, Liang Department of Energy Engineering Zhejiang University Zhejiang Province Hangzhou310027 China Beijing Huairou Laboratory Huairou District Beijing101400 China Beijing Key Laboratory of Multiphase Flow and Heat Transfer North China Electric Power University Beijing102206 China Hebei Key Laboratory of Low Carbon and High Efficiency Power Generation Technology North China Electric Power University Baoding071003 China

In the pursuit of a global paradigm shift in energy structure and carbon neutrality objectives, high-temperature thermal energy storage technologies have garnered significant attention due to their high efficiency and cost advantages. Latent heat storage utilizing molten salts demonstrates notable advantages including high energy density and isothermal phase change characteristics, playing crucial roles in industrial waste heat recovery, renewable energy utilization, and energy supply-demand balance regulation. Nevertheless, practical implementation is hindered by critical limitations, primarily molten salt leakage and equipment corrosion. Encapsulation technology has emerged as an effective mitigation strategy, enhancing system safety and longevity. This review systematically examines the latest advancements in molten salt encapsulation technology, focusing on three primary methods: melt infiltration, capsule method, and mixed sintering. Moreover, this review summarizes the impact of encapsulation strategies on molten salt phase change materials (PCMs) performance, including thermophysical properties, mechanical characteristics, cycling stability, and economic viability. Additionally, emerging research directions such as biomimetic design, multifunctional composite materials, and industrial waste utilization are extensively explored, highlighting their applications and potential advantages in molten salt encapsulation. Finally, the technical characteristics and advantages of encapsulated molten salts were analyzed across various configurations, including heat exchangers, finned systems, and cascaded phase change material (PCM) systems. The work aspires to inspire more innovative research, thereby driving technological breakthroughs in high-temperature energy storage applications of molten salt composite PCMs. © 2025 Elsevier Ltd

关键词： Waste heat utilization

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Insight into the interaction between water and surfactant aerosol particles based on molecular dynamics simulations

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Particuology 2023年第6期77卷 128-135页

作者： Chao Zhang Zhichao Zhang Longxiang Bu Yang Yang Wei Xiong Yueshe Wang School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai200093China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and TechnologyShanghai200093China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710049China

The ubiquitous surfactant significantly influences the hygroscopic growth of atmospheric aerosol ***,knowledge on the morphology of surfactant particles after the adsorption of water is *** this study,the interaction between water and particles composed of surface active malonic acid(MA)or adipic acid(AA)are simulated based on the molecular dynamics *** key point is the combined effect of temperature and water content on the structural properties of particles and the surface propensity of surfactants at the equilibrium *** show that demixed structure 1 with the adsorption of water clusters on acid grain,mixed structure and demixed structure 2 with acids coating on water droplet can be *** temperature increasing from 160 K to 330 K the surface propensity of MA and AA increases first and then *** the standard atmospheric temperature(280-330 K),the surface propensity of MA and AA increases with increasing water content and alkyl group,and its sensitivity to temperature and water content varies ***,all surfactants at the particle surface orient their hydrophobic groups toward the *** findings improve our insight into the surfactant partitioning and further assist in more accurate prediction of the particle hygroscopic growth.

关键词： Aerosol particles Surfactant Surface propensity Hygroscopic growth Molecular dynamics

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Study on the self-diffusion coefficients of binary mixtures of supercritical water and H 2 , CO, CO 2 , CH 4 confined in carbon nanotubes

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Water Research 2025年 283卷 123856页

作者： Bowei Zhang Xiaoyu Li Jie Zhang Junying Wang Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering (SKLMF) Xi’an Jiaotong University 28 Xianning West Road Xi’an 710049 Shaanxi PR China

Nano-confined binary mixtures are prevalent in the chemical industry, geology, and energy sectors. Investigating their mass transfer behavior can enhance process intensification. This study examines the confined self-diffusion coefficients of binary mixtures of supercritical water (SCW) with H 2 , CO, CO 2 and CH 4 in carbon nanotubes (CNT) using molecular dynamics (MD) simulations at temperatures of 673-973 K, a pressure of 25-28 MPa, solute molar concentrations of 0.01-0.3, and CNT diameters of 9.49-29.83 Å. We developed a novel machine learning (ML) clustering method to optimize abnormal MSD- t data, effectively extracting information and providing algorithmic enhancements for calculating the diffusion coefficient. We analyzed the effects of temperature, solute molar concentration, and CNT diameter on the confined self-diffusion coefficient and energy input. Results indicate that over 60 % of the solute energy input derives from the Lennard-Jones effect of the CNT wall. The confined self-diffusion coefficient of solutes increases linearly with temperature, saturates with increasing CNT diameter, and remains relatively constant with varying concentration. Finally, based on the unique relationship between CNTs and the confined self-diffusion coefficient, we developed a new mathematical model for prediction. The regression line exhibits an R 2 value of 0.9789, offering a new method for predicting the properties of nano-confined fluids.

关键词： Chemical industry

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A systematic improvement of the high-quality temperature field reconstruction for acoustic pyrometry

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Case Studies in Thermal engineering 2025年 72卷

作者： Jingkao Tan Na Li Qulan Zhou Yanyuan Hu Lehang Chen Zhongquan Gao Jie Zhou State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Xi'an Aerospace Propulsion Institute Xi'an 710100 China

Obtaining an accurate temperature distribution in furnaces for industrial combustion devices is critical. Acoustic pyrometry (AP) is a promising methodology for high-quality temperature field reconstruction, which is widely used in the monitoring of atmosphere, room, and furnace. However, due to the harsh working environment and the engineering limitations, the number of installed acoustic transducers is restricted, which in turn results in sparse valid data and an ill-posed AP problem. We used multiple means of improvement to improve the reconstruction performance of AP in a gradual and systematic manner. The fast finite-difference shooting method, the adaptive grid evolution strategy (AGES) and the radial basis function approximation with polynomial reproduction (RBFPR) were proposed and integrated into the sequential process optimization approach we concluded to systematically improve the reconstruction performance over the initial algorithm. In this approach, we optimized the parameters used for the reconstruction sequentially, analyzed the effectiveness of various means of improvement, finalized and validated an algorithm that takes into account universality and precision. Qualitative and quantitative analyses of the simulation and experimental results show the validity of the finalized algorithm and the sequential process optimization approach, demonstrating its significance for furnace temperature field measurement, combustion control, and environmental protection.

关键词： Inverse problem Acoustic pyrometry Acoustic tomography Acoustic refraction Algorithm improvement Domain discretization Temperature field reconstruction

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MXene-derived Ni/TiO2-x/Ti3C2 catalyst for enhanced photothermal CO2 methanation: Unraveling the roles of photoexcited carriers

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Chemical engineering Journal 2025年 515卷

作者： Sun, Fan Xin, Yu Xing, Xueli Lou, Jiahui Wang, Qiliang Hong, Hui International Research Center for Renewable Energy & State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China School of Aeronautics and Astronautics University of Chinese Academy of Sciences Beijing100049 China Huaneng Clean Energy Research Institute Beijing102209 China Shandong Institute of Advanced Technology Jinan250100 China Department of Architecture and Built Environment University of Nottingham NottinghamNG7 2RD United Kingdom

Photothermal catalysis has emerged as a promising approach for CO2 conversion, which combines photo and thermal energy to drive catalytic reactions efficiently. While light can lower activation barriers and enhance reaction rates, the interplay between light and heat within the catalytic framework remains largely unexplored. In this study, we investigate the critical role of photogenerated carriers in enhancing catalytic performance under solar irradiation, unraveling their contribution to the CO2-to-CH4 conversion process. A multilayer accordion-like Ni/TiO2-x/Ti3C2 catalyst, which exhibits excellent photothermal and photoelectric response characteristics was fabricated for efficient photothermal CO2 methanation. Experimental results demonstrated that introduction of light during thermal catalysis markedly enhanced the CO2 conversion rate, with a 55 % increase achieved at 548 K. Furthermore, the required temperature for maximum CO2 conversion rate was reduced by 50 K compared to the thermal-driven process. Meanwhile, the effects of concentrated ratio and incident wavelength on CO2 conversion were also examined, revealing a synergistic effect between photogenerated carriers and thermal energy. Further characterizations, including steady-state and transient photoluminescence spectroscopy, in-situ XPS, in-situ EPR, in-situ DRITFs, were employed to elucidate the enhancement mechanisms of photogenerated carriers in the catalytic reaction. At the same time, an outdoor experimental prototype was developed to verify the feasibility of photogenerated carrier-thermal synergistically driven CO2 methanation. Our findings provide valuable insights into the role of photo-generated carriers in photothermal CO2 methanation, offering new perspectives for the design of efficient photothermal catalysts and advancing solar catalytic CO2 conversion technologies. © 2025

关键词： Activation energy

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