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Theoretical Analysis on the Lifetime of Sessile Droplet Evaporation

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Theoretical Analysis on the Lifetime of Sessile Droplet Evap...

作者： Shen, Yang Cheng, Yongpan Xu, Jinliang Zhang, Kai Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy North China Electric Power University Beijing102206 China School of Energy Power & Mechanical Engineering North China Electric Power University Beijing102206 China

There are two stages for a sessile droplet evaporation on the solid substrate, one is the "constant contact radius" (CR) mode, the other is the "constant contact angle" (CA) mode. In this paper, the theoretical model is built up for sessile droplet evaporation for the two modes, the lifetime of evaporating droplet is obtained under different initial contact radius, initial contact angle and critical contact angle for mode transition. It is found that in the CR mode, the variation of initial contact angle is nonlinear with the time. For both CR and CA modes the lifetime is proportional to R02 (R0 is the initial contact radius of droplet) for two modes. When the critical contact angle for mode transition from CR to CA is increased, the lifetime for CR mode is decreased while the lifetime for CA mode is increased, and the overall lifetime is also increased. This result may be of great significance for sessile droplet evaporation. © Springer Nature Switzerland AG 2020.

关键词： Evaporation

Fluoride-Salt-Cooled High-Temperature Reactor: An Integrated Nuclear-Based Energy Production and Conversion System

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SSRN 2023年

作者： Zhang, Dalin Li, Xinyu Jiang, Dianqiang Zhou, Xingguang Lv, Xindi Yun, Shichang Wu, Wenqiang He, Xuanang Li, Haoyang Min, Xin Chen, Kailong Tian, Wenxi Qiu, Suizheng Su, G.H. Zhao, Quanbin Fu, Yao Tang, Chuntao Zhuo, Wenbin Li, Jinggang Zuo, Jiaxu 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 Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai201800 China Shanghai Nuclear Engineering Research & Design Institute CO. LTD. Shanghai200233 China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Nuclear Power Institute of China Chengdu610213 China China Nuclear Power Technology Research Institute Guangdong Shenzhen518000 China Nuclear and Radiation Safety Center Ministry of Ecology and Environment People's Republic of China Beijing100082 China

Based on the analysis of energy structure and the development trends of advanced nuclear energy technology, combining the complementary advantages of nuclear energy and other energy sources in China, the Fluoride-salt-cooled High-temperature Reactor(FuSTAR) system has been proposed. FuSTAR system is designed to address production capacity issues in areas with energy shortages or resource concentration and can be combined with high-temperature process heat to achieve high-value-added processes such as hydrogen production. In this paper, the Tri-structural isotropic fuel combined with helical cruciform elements has been studied in detail on the neutron physics and thermal-hydraulic properties, and the flow and heat transfer experiment is carried out for the first time. The multilayer nonlinear programming method has been applied to the design of thermal transport systems. Then the optimal parameters and configuration of the thermoelectric conversion system are obtained by the superstructure optimization method. The inherent safety of FuSTAR is demonstrated through deterministic safety analysis. In addition, the iodine-sulfur cycle technology and the characteristics of tritium production are also analyzed. This study highlights the significant potential of integrating nuclear energy with other energy sources in an optimized energy-production system. © 2023, The Authors. All rights reserved.

关键词： Nonlinear programming

Comparison of Gelatinous and Calcined Magnesia Supported Ni or/And Co-Based Catalysts for Aqueous Bioglycerol Phase Reforming

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SSRN 2021年

作者： Liu, Dashuai Dou, Binlin Zhang, Hua Wu, Kai Zhao, Longfei Zeng, Pingchao Chen, Haisheng Xu, Yujie School of Energy and Power Engineering Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing100190 China

In this study, glycerol aqueous phase reforming was carried out in a batch reactor. The gases produced were H2, CO, CH4, and CO2 during the experiment. The catalysts used included Ni or/and Co catalysts supported by MgO. Meanwhile, two different MgO supporters were prepared by the sol-gel method and calcining method, and the active metal was added by an initial wet impregnation (IWI) method. The catalysts were characterized by BET, BJH, TEM, and XRD. In order to achieve the purpose of comparison, the activity of different types of catalysts was tested under similar conditions. It was found that the amount of hydrogen produced by the catalyst containing gelatinous MgO supporter is more than 1.5 times that of other catalysts, and the Ni-Co-MgO had the best catalytic effect among the same types of catalysts. The activity of the Ni-Co-MgO catalyst was tested under different temperatures, concentrations, and CaO conditions. We found that Ni-Co bimetallic catalyst supported on gelatinous MgO has the best highest gas production, while the catalyst containing calcined MgO support usually has a better hydrogen selectivity. Through the stability study of the Ni-Co-MgO catalyst, we found that the bimetallic catalyst supported by gelatinous MgO support has better catalytic stability. © 2021, The Authors. All rights reserved.

关键词： Sol-gel process

RECENT ADVANCES OF SURFACE WETTABILITY EFFECT ON flow BOILING HEAT TRANSFER PERFORMANCE

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Frontiers in Heat and Mass Transfer 2021年 17卷

作者： Cao, Shuang Yang, Hui Zhao, Luxing Wang, Tao Xie, Jian School of Energy and Power Engineering Zhengzhou University of Light Industry Zhengzhou450002 China Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power University Beijing102206 China

flow boiling heat transfer is an effective way to fulfill the energy transfer. The wettability of boiling surface influences the liquid spreading ability and the growth, departure, and release frequency of bubbles, which determines the heat transfer performance. According to the wettability and combination forms, boiling surface are classified into weak wetting surface, strong wetting surface, and heterogeneous wetting surface. Fabricating by physical, chemical method or coating the original surface with a layer of low surface energy, the weak wetting surface has more effective activation point and nucleation center density to improve heat transfer performance at low heat flux. The strong wetting surface always formed by physical or chemical treatment to enhance the rapid rewetting of the wall surface. It has a smaller bubble separation diameter, higher separation frequency and higher CHF. The heterogeneous wetting surface, having the synthetic effects of the strong and weak surface wettabilities, is a hot issue of recent study. But its composition and heat transfer enhancement mechanism are very complicated which need to study thoroughly. Furthermore, the intelligent wetting surface, having the dynamics wettability function, is also briefly analyzed in this paper. Despite the advances in this aspect, the boiling surfaces can be further optimized by fabricate effective wettability to achieve a strong stability, high heat transfer performance and realize the synergistic effect of flow pattern and heat transfer. © 2021, Global Digital Central. All rights reserved.

关键词： Wetting

Physics-Based Probabilistic Assessment of Creep-Fatigue Failure for Pressurized Components by Extended Direct Steady Cycle Analysis-Driven Neural Network

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SSRN 2022年

作者： Wang, Xiaoxiao Ma, Zhiyuan Yang, Jie Chen, Haofeng Xuan, Fuzhen Department of Mechanical & Aerospace Engineering University of Strathclyde James Weir Building 75 Montrose Street GlasgowG1 1XJ United Kingdom Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China School of Mechanical and Power Engineering East China University of Science and Technology Shanghai200237 China

To achieve a high-reliability design with a feasible balance between accuracy and efficiency, the physics-based probabilistic assessment for creep-fatigue failure is proposed under the probabilistic Linear Matching Method (pLMM) framework. At the physical level, the structural failure mechanism is reflected in the prepared training database, which is generated by the direct method, extended Direct Steady Cycle Analysis (eDSCA) procedures. And to efficiently express the relationship between design parameters and structural responses implicitly, the extended DSCA-driven neural network (EDDNN) is built with the superior fitting quality of damage and lifetime. With the benchmarks of pressurized structures provided, the applicability of the proposed probabilistic analysis approach in solving practical problems is demonstrated, where the reliability-based evaluation diagram is established according to different requirements. Furthermore, a novel data classification scheme is proposed to deal with the randomness in creep damage-dominated probabilistic assessment. © 2022, The Authors. All rights reserved.

关键词： Failure (mechanical)

Electromagnetic-conductance measurement method for the flow rate and void fraction of gas-liquid two-phase flows

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Measurement: Sensors 2020年 10-12卷

作者： Chang, Fucheng Hu, Zitu Li, Xi Feng, Zongrui Ni, Shiyao Li, Huixiong State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Xi'an710049 China

Gas-liquid two-phase flow systems are widely existed in many engineering systems and industrial processes, and measurement techniques for two-phase flows are crucial in a diverse range of engineering applications. Most of the existing measurement techniques usually brought extra resistance to the flow in the branch pipes and, to some extent, influenced the original distribution of the gas-liquid two-phase flows in the parallel T-junction system. In order to study the distribution characteristics of two-phase flow in vertically parallel T-junctions, the electromagnetic-conductance measurement method was developed to measure the void fraction and liquid flow rate of the gas-liquid two-phase flow in the branch pipes. Electromagnetic-conductance measurement technique has the advantages of high response rate, satisfactory accuracy and low disturbance on the flow field of gas-liquid two-phase flows. In order to calibrate the conductance measurement method, experiments were carried out with the liquid velocity range of 0.2–2 m·s-1, the gas velocity range of 0–50 m·s-1 and the volume void fraction range of 0–0.99. Through the calibration experiments, the relationship between the resistance value of each conductivity sensor and the volume void fraction of two-phase fluid was decided to be established as a logistic function. By the error analysis of the calibration results, 75.9% of experimental results of the void fraction in the gas-liquid two-phase flow fell within the ±20% error bands. The electromagnetic-conductance measurement method proposed in this paper could provide a reference for accurate and non-interference measurement of two-phase flow in parallel T-junctions. © 2020 The Authors

关键词： Two phase flow

Unveiling the Unexpected C-C Dissociation Capacity and Intrinsic Mechanism of Undercoordinated Pd Cluster/Ceo2 for the Efficient and Stable Catalytic Mineralization of Propane

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SSRN 2022年

作者： Xia, Lianghui Jian, Yanfei Wang, Jingjing Wang, Yao Chai, Shouning Liu, Yujie Li, Lu Yu, Yanke Albilali, Reem 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 Chemistry College of Science Imam Abdulrahman Bin Faisal University P.O. Box 1982 Dammam31441 Saudi Arabia National Engineering Laboratory for VOCs Pollution Control Material & Technology University of Chinese Academy of Sciences Beijing101408 China

Light alkanes extensively presented in industrial exhausts have led tremendous harm to the atmospheric environment and human health. However, their stable molecule structure and inferior adsorption and activation efficiency make them as one category of the most intractable pollutants to be efficient controlled. Herein, we developed a Pd single cluster/CeO2 catalyst (Pd/CeO2-SCC-R) by a scalable deposition precipitation strategy, which demonstrates unexpected activity (propane total destructed below 300 oC) and thermal stability (even dramatically treated at 800 oC for multiple cycles) attributed to the strong metal-support interaction (SMSI) and unsaturated Pd metal sites caused by the shorter Pd-O distance. Mechanism studies determine that the Pd/CeO2-SCC-R possesses highly-efficient C-C cleavage ability owing to the persistent formation of large amounts of oxygen vacancies and low-coordinated Pd species, and the addition of H2O intrinsically accelerates propane activation and intermediate mineralization attributed to suppression of by-products by OH species. In comparison, the Pd single atom/CeO2 catalyst is preferentially for C-H bonds cleavage and inactive for C-C bonds cracking due to the saturated Pd sites anchored to the oxygen of supports directly, which generates more non-oxidation by-products as propyne and propylene, inhibiting the continuous decomposition of propane due to the retardatory oxidation of pyruvate species. The present work sheds critical insight to the production of fulfilling products through the directional cleavage of C-C/C-H bonds in the activation of light alkane molecules. © 2022, The Authors. All rights reserved.

关键词： Oxygen vacancies

Numerical Simulation of Acoustic Propagation in Gas Ultrasonic flowmeter

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SSRN 2022年

作者： Xiao, Yongqing Zhang, Meng Li, Dong Yang, Yueming Ma, Bingkun Qi, Jianhui School of Energy and Power Engineering Shandong University Jinan250061 China Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power University Beijing102206 China Suzhou Research Institute Shandong University Suzhou215123 China Shandon Academy of Sciences China

Ultrasonic flowmeter has been widely used in chemical smelting, industrial production and other fields. Through the COMSOL Multiphysics software, the non-linear trajectory of the rays in the non-invasive and intrusive UFW is first simulated by the ray tracing method. Then, the transient ultrasonic propagation process is simulated to analyze the reasons for the error of ultrasonic propagation. Finally, the cause of the error of the transducer is analyzed by the sound pressure signal at the receiving end. It was found that it is precisely because of the high-speed flow that the ultrasonic propagation is distorted, which is manifested as the non-linear trajectory and downstream drift of the sound beam. The signal at the receiving end also fails to hit the correct position due to beam drift, resulting in sound pressure falling below the detected value. © 2022, The Authors. All rights reserved.

关键词： flow measurement

Bowl-Shaped Carbon Loaded Co9s8 Nanoparticles Connected by Carbon Nanotubes with Excellent Rate Performance for Sodium-Ion Batteries

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SSRN 2022年

作者： Yang, Guorui Zhou, Ziyi Liu, Xiaofeng Zhang, Yue Wang, Silan Yan, Wei Ding, Shujiang School of Chemistry Engineering Research Center of Energy Storage Materials and Devices Ministry of Education "Four Joint Subjects One Union" School Enterprise Joint Research Center for Power Battery Recycling & Circulation Utilization Technology Xi’an Jiaotong University Xi’an710049 China Xi'an Key Laboratory of Solid Waste Recycling and Resource Recovery State Key Laboratory of Multiphase Flow in Power Engineering Department of Environmental Science and Engineering Xi'an Jiaotong University Xi'An710049 China

Sodium-ion batteries (SIBs) are expected to replace lithium-ion batteries in the energy storage sector owing to their low cost and abundant resources. However, developing suitable anode materials to meet the high energy density requirements of SIBs remains an ongoing challenge. Herein, we design a hollow nitrogen-doped bowl-like carbon decorated with Co9S8 nanoparticles linked by carbon nanotubes (HNBC@Co9S8@CNTs) as an anode material for SIBs. The HNBC@Co9S8@CNTs electrode exhibits impressive rate performance (280.9 mAh g-1 at 5 A g-1) and cycling stability (426.5 mAh g-1 after 500 cycles at high current density of 1 A g-1) due to the advantages of highly conductive three-dimensional (3D) interconnected structures. In addition, its pseudo-capacitance and sodium storage diffusion kinetics are analyzed in depth using Cyclic Voltammetry (CV) and galvanostatic intermittent titration technique (GITT). The results elucidate that the partially surface-induced capacitive sodium storage, highly conductive 3D interconnected structures, and fast reaction kinetics synergistically contribute to the high-rate performance. This work may provide new insights for the fabrication of various metal sulﬁde or sulﬁde composites with high sodium storage capacity. © 2022, The Authors. All rights reserved.

关键词： Sodium-ion batteries