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Efficient Charge Transfer at the Donor-Bridge-Acceptor Interface for Excellent Supercapacitors

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SSRN 2023年

作者： Yin, Baoyi Hao, Liang Li, Xiaogan Yang, Qi-Guo 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 Microelectronics Dalian University of Technology Dalian116024 China

The intrinsic electrochemical activity and active sites of the battery-like electrode in supercapacitors originate from efficient charge transfer at the interface. A seamless all-carbon graphdiyne layer on CoNi2S4 yolk-shell spheres (CoNi2S4/GDY YSSs) provides a unique structure of a flawless "donor–bridge–acceptor" interface, where Ni atoms and Co atoms serve as electron donors and acceptors, respectively, connected by the sp-C–Ni and sp-C–Co bonds as bridges. Importantly, this particular can facilitate effective electron transfer from the Ni atoms to the Co atoms, resulting in more interfacial Co2+ active sites. Additionally, the seamless all-carbon graphdiyne layer greatly enhances the structural and interfacial stabilities of CoNi2S4 yolk-shell spheres, effectively avoiding structural deterioration. Profiting from its structural merits, the CoNi2S4/GDY YSSs electrode delivers a considerable capacitance of 856 C/g at 1 A/g, along with exceptional rate capability (61.9% for 50-fold current density increase). Furthermore, an asymmetric supercapacitor with the CoNi2S4/GDY YSSs electrode cathode achieves a remarkable maximum energy density of 91.7 Wh/kg at a power density of 793 W/kg. Furthermore, the strategy proposed in this study has the potential to open up new pathways for the battery-like electrode design with realistic supercapacitor applications. © 2023, The Authors. All rights reserved.

关键词： Charge transfer

Adsorption and Agglomeration Characteristics of Ash Particles after Reducing Flue Gas Temperature below the Acid Dew Point

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Energy Procedia 2017年 142卷 3301-3306页

作者： Yu Yan Ke Sun Yun Sun Yubo Zhang Junwen Guo Lei Deng Defu Che State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China Huadian Electric Power Research Institute Hangzhou 310030 China Ningxia Electric Power Research Institute Ningxia 750002 China Xi’an Thermal Power Research Institute Co. Ltd. Xi’an 710054 China

In order to develop suitable low-low temperature flue gas system for China and determine its operation parameters, the adsorption characteristics of ash particles for sulfuric acid mist need to be investigated, as well as the adhesion characteristics of ash particles after the adsorption. In this paper, experiments were conducted on a laboratory-scale fixed bed adsorption reaction system. The adsorption characteristic curves of different particle sizes and adsorption temperature were obtained. The results show that adsorption temperature has a larger influence on the adsorption process compared with particle size. And there exists an adsorption limit in the adsorption process. In addition, the ultimate D/S (D p /S p ) of ash particle is defined, which means the ratio of ash particle weight (mg) to adsorbed H 2 SO 4 weight (mg) when ash particle reaches the adsorption limit. It is an inherent attribute of ash particle, only influenced by the particle constituents and sizes, representing the ultimate adsorption capacity of ash particle for sulfuric acid. The experiment results show that the chemical constituents of ash are the main determinate factors of adsorption limit and the D p /S p . And the D p /S p could be used cooperatively with D/S when people design the parameters of low-low temperature flue gas system for different types of coal. Furthermore, there was a significant agglomeration phenomenon between ash particles after the adsorption reaction, and it can increase the average size of particles which is conducive to the removal of PM.

关键词： Low-low temperature flue gas system sulfuric acid mist adsorption characteristics agglomeration Characteristics

Digital twin modeling and fault diagnosis on the feedwater pump system of thermal power plant

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Digital twin modeling and fault diagnosis on the feedwater p...

Digital Twins and Parallel Intelligence (DTPI), IEEE International Conference on

作者： Yugang Liu Chi Luo Chen Chen Zhu Wang Ming Liu Clean Combustion and Flue Gas Purification Key Laboratory of Sichuan Province Dongfang Boiler Co. Ltd Chengdu China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

ISBN: (数字)9798350349252

ISBN: (纸本)9798350349269

The high penetration of renewable energy introduces increased volatility into the power system, presenting more challenging peak shaving and frequency modulation missions for thermal power plants that serve as schedulable power sources within the system. Frequent load cycling place higher demands on the operation stability of core power plant equipment and introduce additional safety risks. As the core system of the power cycle, the operational reliability and energy efficiency of the feedwater pump system (FPS) are crucial. Therefore, this paper focuses on the core equipment and parameters of the FPS, developing a digital twin model based on mechanism modeling method and neural network data-driven modeling method. By comparing the mean absolute error, root mean square error, and coefficient of determination of simulation parameters of different modeling methods, digital twin parameters with higher simulation accuracy were obtained. Utilizing these predicted parameters, an FPS fault diagnosis model (FFDM) for the FPS was developed. By calculating comprehensive deviation degree and the contribution of each parameter, fault early warning and source tracing were achieved, providing guidance for the closed-loop control.

关键词： Fault diagnosis Data-driven modeling Neural networks Predictive models power system stability Energy efficiency Digital twins Safety power system reliability power generation

Preliminary Conceptual Design with Neutronics and Thermal-Hydraulics Assessments of Fustar

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SSRN 2023年

作者： Zhou, Xingguang Zhang, Dalin Li, Xinyu Lv, Xindi Jiang, Dianqiang Tian, Wenxi Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Lab. of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi'an Jiaotong University Xi'An710049 China

The fluoride-salt-cooled high-temperature advanced reactor (FuSTAR) is an advanced small modular reactor, which aims to the electric supplement and clean heat production to western China. In this study, neutronics and thermal-hydraulics analysis are also carried out, and established the core layout and material ratio under the near-critical condition. The parameters of the designed core are evaluated quantitatively from various aspects. The results show that FuSTAR has sufficient shutdown depth, the equilibrium cycle is 3.24 years, and the discharge burnup depth is 106 GWd/MtU. The analysis of 1/6 core porous media shows that the peak fuel temperature under normal operating condition is 1009.3 K, which is far below the limit of 1573 K. Relevant design and analysis results can provide the reference for the subsequent small modular FHR design and construction. © 2023, The Authors. All rights reserved.

关键词： Computational fluid dynamics

Analysis of Gas-Cooled Micro Modular Reactor (MMR) Fuel

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SSRN 2024年

作者： Deng, Chaoqun Zhu, Siyang He, Yanan Wu, Yingwei He, Kai Zhang, Jing Su, Guanghui School of Nuclear Science and Technology Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China China Nuclear Power Engineering Co. Ltd. Beijing100840 China

The gas-cooled micro modular reactor (MMR) is a novel concept with compact fuel form consists of thousands of tri-isotropic fuel (TRISO) particles dispersed in silicon carbide matrix. The MMR fuel is high volume packing fraction and horizontally placed within graphite channels. Due to the complexity of the fuel structure and the challenges involved in simulation, a multi-scale and multi-physics coupled analyses method of MMR fuel was realized in this work by implementing physical models into the open-source finite element platform MOOSE. Though the simulation of the typical design MMR fuel during normal operation, the thermal-mechanical analysis and the failure analysis were conducted. The results show that the arrangement of MMR fuel horizontally within graphite channels resulted in non-uniform gap between the fuel and graphite brick, leading to an "off-center" temperature distribution within the fuel, the peak temperature is about 1314 K. Higher-temperature sub-zones exhibit greater internal pressure within TRISO and show greater tensile stress in the Chemical Vapor Deposited Silicon Carbide (CVD-SiC) layer. Regarding fuel failure analysis, this work found limited impact from Pd penetration and kernel migration. Pressure-induced particle failure, closely linked with stress in CVD-SiC, emerges as the primary failure criterion. The overall probability of fuel failure remains relatively low, with a maximum probability of 4.1×10-5. Statistical data reveals that a significant majority (71%) of TRISO particles exhibit a failure probability below 2×10-5, while only 8.8% reach 4×10-5 © 2024, The Authors. All rights reserved.

关键词： Graphite

Fully resolved simulations of a stationary finite-sized particle in wall turbulence over a rough bed

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Physical Review Fluids 2019年第9期4卷 094302-094302页

作者： Xing Li S. Balachandar Hyungoo Lee Bofeng Bai State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China Mechanical & Aerospace Engineering University of Florida Gainesville Florida 32608 USA Power Reactor Development Division Korea Atomic Energy Research Institute Daedeok-daero 989 Yuseong-gu Daejeon 305–353 Republic of Korea

Understanding the force on a finite-sized particle immersed in a turbulent boundary layer close to a rough wall is of fundamental importance in predicting particle motion in a variety of industrial and environmental applications. Here we perform fully resolved direct numerical simulations with an immersed boundary method to investigate the forces on a stationary finite-sized particle in wall turbulence over a rough bed. Results show that for the particle sitting on the rough bed, lift is the main contributor to wall-normal force and can be well predicted with proper application of existing force models. The higher lift force is mainly due to the sweep events which temporarily increase the relative velocity as well as local shear magnitude. In contrast, for a particle located slightly away from the rough bed, the wall-normal force is mainly due to the wall-normal component of drag, so ejections and outward interactions are responsible for the increase in the wall-normal force. The standard drag law with near-wall correction can reasonably predict this wall-normal force on the particle, except for the large fluctuations due to self-induced vortex shedding.

关键词： Fluid-particle interactions Sediment transport

Research on the Combustion Effect and Mechanism of Aluminum Droplets in Ap/Htpb Composite Propellant

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SSRN 2023年

作者： Yang, Bin Wang, Jiahao Lou, Yongchun Zhao, Yu Wang, Ji Wang, Ying 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 Shanghai Space Propulsion Technology Research Institute Shanghai201109 China

To investigate the combustion phenomenon of aluminum droplets within propellants, this study amalgamates the evaporation combustion process of aluminum droplets with the AP/HTPB (Ammonium perchlorate/Hydroxyl-terminated polybutadiene) multi-flame structure model. Consequently, a numerical simulation approach is established to depict the combustion behavior of aluminum droplets in a high-temperature gas environment. The paper scrutinizes the dynamics, deformations, combustion characteristics, and their influence on the propellant flow field under diverse conditions. The findings of this research affirm that the non-uniform flow velocity at the AP and HTPB inlets imparts distinct pressures on the droplets' surface, thereby precluding their spherical morphology. As the droplet diameter diminishes, the effect of deformation gradually abates, leading the droplets to gravitate towards the AP region. The addition of aluminum droplets disrupts and enhances heat transfer within the external flow field of propellant combustion, while their own combustion engenders a substantial amount of heat, thus elevating the overall combustion temperature of the propellant. Moreover, aluminum droplets perturb the distribution of different components in the flow field, affording more opportunities for intermolecular encounters, and consequently augmenting the efficiency of the overall reaction compared to scenarios without aluminum droplets. Remarkably, the combustion efficiency of aluminum droplets is amplified in high-pressure environments. © 2023, The Authors. All rights reserved.

关键词： flow fields

Experimental Study of Liquid Immersion Cooling for Different Cylindrical Lithium-Ion Batteries Under Rapid Charging Conditions

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SSRN 2022年

作者： Li, Yang Bai, Minli Zhou, Zhifu Lv, Jizu Hu, Chengzhi Gao, Linsong Peng, Chunyang Li, Yulong Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116024 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

In this study, the fluorinated liquid immersion cooling scheme has been proposed and tested for cooling the six different types of cylindrical lithium-ion batteries (LIBs) under fast charging conditions. SF33, with the boiling point of 33.4 °C, is chosen as the fluorinated liquid for the immersion cooling. Firstly, the voltage and temperature responses of LIBs under fast charging conditions with natural convection and SF33 immersion cooling were explored. It is found that the SF33 immersion cooling has a significant advantage over natural convection on controlling the battery temperature, thus ensuring the stability and safety of LIBs in the fast charging process. Subsequently, the high-speed photography was used to observe the bubble behaviors in the cooling process of SF33, and the heat transfer mechanism in the two-phase heat transfer process corresponding to immersion cooling of LIB was preliminary analyzed and discussed. It can be concluded that when the charging current is higher, the phenomenon of subcooled boiling as well as saturation boiling is generated in the SF33. The transition from single-phase convective heat transfer to boiling heat transfer greatly increases the heat transfer coefficient. © 2022, The Authors. All rights reserved.

关键词： Liquids

Simulation of the PHEBUS FPT-1 experiment using MELCOR and exploration of the primary core degradation mechanism

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Annals of Nuclear Energy 2015年 85卷 193-204页

作者： Jun Wang Michael L. Corradini Wen Fu Troy Haskin Yapei Zhang Wenxi Tian Guanghui Su Suizheng Qiu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an 710049 China College of Engineering The University of Wisconsin-Madison Madison 53706 United States Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China

Core degradation evaluation of probability, progression and consequences of a core degradation accident is critical for evaluation of risk as well as its mitigation. However, research and modeling of severe accidents to date are limited, and their accuracy in predicting severe accident consequences is still insufficient. It is therefore important to explore the mechanisms of core degradation and to develop mitigation measures for severe accidents. PHEBUS FPT1 is a typical and classic core degradation experiment. MELCOR is a world famous severe accident analysis code developed by Sandia National Lab that has seen wide application, a broad user base, and a number of supporting experiments. The PHEBUS experiment was simulated using MELCOR in this paper. Experimental data on, thermal power and steam mass flow rates are used to determine average pressure, energy distribution, molten mass, temperature of the fuel, and hydrogen generation. Data from the PHEBUS experiment and Cho’s calculations are used to compare the average pressure, several fuel temperatures and the hydrogen generation rate. The results confirm the validity of MELCOR’s simulation of the PHEBUS experiment. The temperature distribution of the core is provided. These results are used to determine the mode and behavior of core degradation with the intent of building a foundation for further research.

关键词： PHEBUS FPT1 MELCOR Core degradation