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Optimizing Interfacial Environment of Triphasic Zno-Cu-Zro2 Confined Inside Mesoporous Silica Spheres for Enhancing Co2 Hydrogenation to Methanol

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SSRN 2022年

作者： Chen, Changwei Kosari, Mohammadreza Xi, Shibo Lim, Alvin M.H. He, Chi Zeng, Hua Chun Department of Chemical and Biomolecular Engineering Faculty of Engineering National University of Singapore 10 Kent Ridge Crescent 119260 Singapore State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Shaanxi Xi'An710049 China 1 Pesek Road Jurong Island 627833 Singapore

Herein, the well-known ternary Cu 0 -ZnO-ZrO 2 (CZZ) was spatially sequestered as fine, uniformly-dispersed optimized active interfaces onto an engineered mesoporous silica sphere (MSS), giving rise to Cu 0 -ZnO-ZrO 2 /MSS (CZZ-MSS) with confined binary Cu 0 -ZnO/Cu 0 -ZrO 2 and ternary interfaces that fostered methanol production under moderate conditions. By systematically investigating the CZZ-MSS performance. Besides, the strong metal-support interaction arising from interacting metallic Cu and metal oxides (ZnO and ZrO 2 ) within the confined, ultrasmall nanoparticles ( © 2022, The Authors. All rights reserved.

关键词： Zinc oxide

Thermally induced non-coalescence of compound droplets

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Applied Thermal engineering 2025年 276卷

作者： Jianmei Zhao Xing Li Bofeng Bai State Key Laboratory of Multiphase Flow in Power Engineering School of Chemical Engineering and Technology Xi’an Jiaotong University Xi'an 710049 China

Compound droplets surrounded by a gaseous phase with different temperatures widely exist in industrial applications. Previous research has focused on thermally induced non-coalescence or delayed coalescence between two single-phase droplets or a droplet and a liquid bath. The primary mechanism is the levitated intervening pressure in the lubricating air layer between droplets, which is caused by the thermocapillary convection. In this study, the non-coalescence of two compound droplets in a cold ambient air environment is experimentally investigated. The thermocapillary mechanism manifests three distinct features. First, as the two compound droplets approach each other, the temperature of the contact side of each droplet increases because of reduced heat loss, a phenomenon termed as the contact-side heating effect. This creates a surface temperature gradient, inducing Marangoni stress and subsequent surface convection. Second, owing to the immiscibility of the two phases within each compound droplet, the thermocapillary convection develops independently in each phase, forming independent convection which cannot be observed in single-phase droplets . It was observed that the directions of the thermocapillary convection within the two droplets were correlated and always planar symmetric, which is different from the uncorrelated and opposite convection of two single-phase droplets. Third and most importantly, the thermocapillary convection in the oil phase entrains the air into the lubricating film between droplets, inhibiting their coalescence only when the oil/water interface is adjacent to the contact zone.

关键词： Compound droplet Non-coalescence Thermocapillary convection

Solar-Wind Energy Complementary Coupling Realizes Magnetic-Field Assisted Efficient Photocatalytic Co2 Reduction

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SSRN 2023年

作者： Kong, Biao Ren, Yuqi Liu, Maochang Zhou, Jiancheng Wang, Ke Wang, Nan Li, Naixu School of Chemistry and Chemical Engineering Southeast University No.2 Dongnandaxue Road Jiangsu Nanjing211189 China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University No.28 Xianning West Road Shaanxi Xi'An710049 China

We report the synthesis of a Z-scheme monolithic photocatalyst in the form of copper foam supported TiO2 combining Cu2O and Ag nanoparticles (CF@TiO2/Cu2O-Ag). The designed catalysts with efficient charge separation show superior photocatalytic activity toward CO2 reduction, with a maximum CO yielding rate of 25.58 μmol‧g-1‧h-1. More importantly, we develop a solar-wind energy complementary device, which enables the strong coupling of the magnetic field into the photocatalytic reaction. Specifically, the in-situ space electric field generated from the wind-driven induced electromotive force further enhances the separation and transportation of photogenerated charge carriers in the Z-scheme system. The productivity of CO in the proof-of-concept device based on the use of CF@TiO2/Cu2O-Ag catalyst reaches 71.66 μmol‧g-1‧h-1. This study provides an ideal approach for reinforcing photocatalytic CO2 reduction through muti-field coupling and highlights the prospect of solar-wind energy coupled photocatalysis. © 2023, The Authors. All rights reserved.

关键词： Titanium dioxide

Research on the Performance Enhancement of Accident Tolerant Fuel for Eliminating Core Melting Based on Isaa

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SSRN 2022年

作者： Tang, Shaowei Zhang, Bin Shan, Jianqiang School of Nuclear Science and Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China

Based on the Integrated Severe Accident Analysis (ISAA) code, this paper studies the influence of thermo-physical properties of Accident Tolerant Fuel (ATF) materials on the plant responses to severe accidents. By selecting ATF with IMDP as the core material and SiC as the cladding material and changing different physical parameters, it is found that fuel density and cladding density have the greatest influence on the fuel temperature rise. In addition, to eliminate core melting, the ATF parameters in ISAA are modified step by step to improve the thermodynamic properties of the fuel, and the core is finally made to reach thermal equilibrium. According to the calculation results, the supporting capacity of the cladding, the supporting capacity of the core supporting plate, and the melting point of the fuel are the main factors limiting the core melting, which can be eliminated by appropriately improving these properties. © 2022, The Authors. All rights reserved.

关键词： Thermodynamic properties

Multi-parameter optimization to improve the erosion resistance of coating by FE simulation

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Multi-parameter optimization to improve the erosion resistan...

ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition, GT 2021

作者： Li, Fang Wang, Shunsen Cai, Liuxi Feng, Zhenping State Key Laboratory of Multiphase Flow in Power Engineering Institute of Turbomachinery Xi'an Jiaotong University No. 28 Xianning West Road Xi'an710049 China School of Chemical Engineering and Technology Xi'an Jiaotong University No. 28 Xianning West Road Xi'an710049 China

ISBN: (纸本)9780791885000

Finite element method (FEM) was used to study the stress peak of stress S11 (Radial stress component in X-axis) on the steam turbine blade surface of four typical erosion-resistant coatings (Fe2B, CrN, Cr3C2-NiCr and Al2O3-13%TiO2). The effect of four parameters, such as impact velocity, coating thickness, Young's modulus and Poisson's ratio on the stress peak of stress S11 were analyzed. Results show that: the position of tensile stress peak and compressive stress peak of stress S11 are far away from the impact center point with the increase of impact velocity. When coating thickness is equal to or greater than 10μm, the magnitude of tensile stress peak of stress S11 on the four coating surfaces does not change with the coating thickness at different impact velocities. When coating thickness is equal to or greater than 2μm, the magnitude of tensile stress peak of stress S11 of four coatings show a trend of increasing first and then decreasing with the increase of Young's modulus. Meanwhile, the larger the Poisson's ratio, the smaller the tensile stress peak of stress S11. After optimization, When coating thickness is 2μm, Poisson's ratio is 0.35 and Young's modulus is 800 GPa, the Fe2B coating has the strongest erosion resistance under the same impact conditions, followed by Cr3C2-NiCr, CrN, and the Al2O3-13%TiO2 coating, Al2O3-13%TiO2 coating has the worst erosion resistance. Copyright © 2021 by ASME.

关键词： Finite element method

Effects of Imposing Contact Angle Schemes and Constructing a Special Ghost Fluid Layer on the Heated Substrate in Pseudopotential Lattice Boltzmann Simulation of Sessile Droplet Evaporation

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SSRN 2022年

作者： Wang, Dongmin Cheng, Ping Key Laboratory of Multiphase Flow and Heat Transfer in Shanghai Power Engineering School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China School of Mechanical Engineering Shanghai Jiao Tong University Shanghai200240 China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application Suzhou University of Science and Technology Suzhou215009 China

The primitive pseudopotential-based scheme (PP scheme), the modified pseudopotential-based scheme (MP scheme) and the improved virtual-density scheme (IVD scheme) are the three most widely used contact angle schemes to simulate wall wetting characteristics in the pseudopotential lattice Boltzmann (LB) model under isothermal conditions. In this paper, these three widely used contact angle schemes are applied to simulate the problem of sessile droplet evaporation on a heated substrate, which is a non-isothermal phase-change process where temperature varies spatially and temporally. It is found that (i) using the PP scheme (primitive pseudopotential-based scheme) and the MP scheme (modified pseudopotential-based scheme) may lead to algorithmic instability problems in certain ranges of contact angles, deformation of droplet interface shape or Marangoni vortices shape, generation of unphysical vortices near the heated substrate, or result in erroneous temperature distributions near droplet triple-phase line. (ii) The IVD scheme (improved virtual-density scheme) has better algorithmic stability than the PP scheme and MP scheme (primitive pseudopotential-based scheme and the modified pseudopotential-based scheme), where the droplet interface shape and Marangoni vortices shape are correct, the unphysical vortices and the erroneous temperature distribution near droplet triple-phase line disappear. (iii) If a special ghost fluid layer (as proposed in this paper) is constructed on the wall when the PP scheme or the MP scheme (primitive pseudopotential-based scheme or the modified pseudopotential-based scheme) is implemented, the instability of the numerical solution is improved, the deformation of droplet interface shape and the Marangoni vortices shape are corrected, and the unphysical vortices near the heated substrate and the erroneous temperature distribution near droplet triple-phase line disappear. The addition of such a special kind of ghost fluid layer at the heated wa

关键词： Vortex flow

Numerical Study on the Impact Characteristics of a Single Molten Lead Bismuth Droplet on Water

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SSRN 2024年

作者： Lin, Yue Zhang, Dalin Chen, Yutong Zhang, Xisi Deng, Jian Du, Peng Tian, Wenxi Qiu, Suizheng Su, Guanghui Department of Nuclear Science and Technology State Key Lab. of Multiphase Flow in Power Engineering Shaanxi Key Lab. of Advanced Nuclear Energy and Technology Xi’an Jiaotong University No.28 Xianningxilu Beilinqu Shaanxi Xi’an710049 China Institute of Reactor Engineering Technology China Institute of Atomic Energy Beijing102413 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu610213 China

As an important link in the possible occurrence of steam explosions, the interaction between molten materials and coolant is of great significance for safety analysis in severe accidents of nuclear reactors. This study is based on the two-dimensional multiphase and multi-component fluid dynamics code ACENA to model the process of single molten lead bismuth droplet impacting a water tank and obtain the velocity changes of the molten droplet as it moves through the water tank. Furthermore, a sensitivity analysis of relevant factors such as the heat transfer area fraction and drag coefficient of the droplet is carried out. To verify models in ACENA, the computation results are compared to experimental data. It is demonstrated that the overall trend of the velocity curve acquired by the ACENA code during the interaction between a molten lead bismuth droplet and water is consistent with the experimental results. The droplet falling velocity increases with the increase in droplet temperature when the temperature of water is the same, and the droplet falling velocity increases with the increase of water temperature at the same droplet temperature. The simulation results by ACENA code for MFCI are in good agreement with experiments which verifies the accuracy of relevant models in ACENA. It can provide an effective means for safety analysis of nuclear reactors in China. © 2024, The Authors. All rights reserved.

关键词： Drops

Experimental and Kinetic Modeling Study on the Oxidation and Laminar Combustion Characteristics of Natural Gas

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SSRN 2023年

作者： Chen, Xiaoxiao Zeng, Wen Zheng, Weilin Hu, Erjiang Ma, Hongyu Liaoning Key Lab of Advanced Test Technology for Aerospace Propulsion System Shenyang Aerospace University Liaoning Shenyang110136 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shanxi Xi'An710049 China AECC Shenyang Engine Research Institute Shenyang110015 China

The oxidation process in the flow tube reactor at the conditions of P=0.1 MPa, T=500-1850 K, f=0.5, 1.0, 3.5, and the laminar combustion process in the constant volume combustion bomb at the conditions of P=0.1, 0.2, 0.3 MPa, T=300, 350, 400 K, f= 0.7-1.4, the O2 contents of 15%, 18% and 21%, the CO2 and H2O contents of 0%, 10%, and 20% of natural gas (0.9 methane/0.07 ethane/0.03 propane, mole fraction) were experimental tested. In the oxidation process of natural gas, with the equivalence ratio increasing, the starting and ending temperatures for oxidation reaction of natural gas are increased, the reaction temperatures corresponding to CO generation and consumption are higher, and the amount of NO production is decreased. In the the laminar combustion process of natural gas, at the conditions of higher pressure, equivalence ratio, CO2 and H2O contents, the flame front is not smooth as a large number of cracks and cell structures appear, and the flame is unstable. Moreover, with the initial temperature and oxygen content increasing or the initial pressure, CO2 and H2O contents decreasing, the laminar flame speed is increased. Furthermore, combined the path sensitivity analysis, rate of production analysis, reaction path analysis and the decoupling method, a reduced reaction mechanism (including 40 species and 189 reactions) of natural gas was developed. Through comparing with the calculated results by the Aramco 2.0 mechanism and the corresponding test data, the reduced reaction mechanism can well predict the oxidation, ignition delay and laminar combustion characteristics of natural gas under various conditions. © 2023, The Authors. All rights reserved.

关键词： Sensitivity analysis

Energy and exergy analyses of a novel recirculated regenerative rotary desiccant wheelassisted dehumidification system 33

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Energy and exergy analyses of a novel recirculated regenerat...

33rd International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS 2020

作者： Han, Xiaoqu Wu, Wenxiang Chong, Daotong Su, Minqi Zhang, Dan Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an China MOE Key Laboratory of Thermal Fluid Science and Engineering Xi'An Jiaotong University Xi'an China

The indoor air humidity and temperature in the marine cabins could be as high as 80% and 40 °C - 50 °C, respectively, which may cause security risks to crews and devices. The incorporation of solid desiccant wheel for improved dehumidification and air quality control would contribute to energy saving in air conditioning system through waste heat recovery for regeneration. In the present work, a novel recirculated regenerative rotary desiccant wheel-assisted dehumidification system was proposed. The energy and exergy performances of the system under variable working conditions were quantitatively studied based on experimental tests. The dehumidification effectiveness, dehumidification performance coefficient (DCOP), sensible energy ratio and coefficient of performance (COP) were introduced as key energetic indicators. The effects of air bypass ratio (50% - 85%), process air temperature (28 °C - 40 °C), relative humidity of process air (60%RH - 80%RH) and regeneration air temperature (130 °C - 150 °C) on the system performances were obtained. It was found the COP of the system ranged between 0.4 and 1.8, while the exergy efficiency was only 4% - 11%. An optimal bypass ratio existed which was determined 55%-60%. Overall, the energy saving and exergy consumption characteristics of the proposed system at various working conditions were explored to prompt its practical application. © ECOS *** right reserved.

关键词： Waste heat