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Anticipating the lifespan: Predicting the durability of an anode-supported solid oxide fuel cell short stack over 50,000 h

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Progress in Natural Science:Materials International 2024年第3期34卷 606-613页

作者： Muhammad Zubair Khan Amjad Hussain Seung-Bok Lee Tak-Hyoung Lim Rak-Hyun Song department of Materials Science & engineering Pak-Austria Fachhochschule: Institute of Applied Sciences and Technology Mang Haripur Hydrogen energy Research Division Korea Institute of Energy Research department of Advanced energy and System engineering Korea University of Science and Technology (UST)

In the present study, the operational lifetime of a solid oxide fuel(SOFC) short stack is predicted by investigating the performance degradation of both the short stack and its cells throughout 1000 h at 800°C. The short stack and integral cell voltages are continuously measured during the long-term test, with electrochemical impedance spectroscopy(EIS) conducted every 200 h. The short stack voltage decreased rapidly for the initial 200–300 h and afterwards, it decreased at a slow rate due to the increase in the Ohmic and polarization resistances in the same manner. Scanning electron microscopy results show that there is no delamination or cracking among constituent layers of the short-stack cells. The single degradation effects of the Ni coarsening in the anode, cation migration and surface segregation in cathode and oxide scale growth in metallic interconnect mesh are successfully integrated into a comprehensive lifetime prediction model. The experimentally measured voltage degradation data of the short stack fits well with the developed mathematical model and allows the successful prediction of the lifetime up to 50,000 h.

关键词： Degradation Impedance Lifetime SOFC Stack

New approach for particle size and shape analysis of iron-based oxygen carriers at multiple oxidation states

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Particuology 2024年第7期90卷 493-503页

作者： Victor Purnomo Marcelo Dal Belo Takehara Robin Faust Lidiya Abdisa Ejjeta Henrik Leion Division of energy and Materials Department of Chemistry and Chemical EngineeringChalmers University of TechnologyGöteborg 41258Sweden Division of energy Science Department of Engineering Sciences and MathematicsLuleåUniversity of TechnologyLuleå97187Sweden

One of the crucial issues in the chemical looping technology lies in its bed material:the oxygen carrier.Particle size analysis of an oxygen carrier is important since in a fluidized bed the material can only work well within a specific size range.While the favorable size ranges for oxygen carrier materials have already been reported,none of the published studies has analyzed the particle size and shape of oxygen carriers in detail.Furthermore,the effect of oxygen carriers'oxidation degree on such properties has not been considered either.This study aimed to report the particle size and shape analysis of five iron-based oxygen carriers,one natural ore,one synthetic material,and three residue products,at different oxidation degrees using dynamic image analysis(DIA).The oxygen carriers were prepared at different mass conversion degrees in a fluidized bed batch reactor.The size distribution,sphericity,and aspect ratio of the oxygen carrier particles were examined experimentally using a Camsizer instrument.Our results show that the DIA method was successfully able to analyze the particle size and shape of our oxygen carriers with satisfying accuracy for comparison.The oxidation state of the investigated materials seems to only affect the particle size and shape of oxygen carriers to a minor extent.However,exposures to redox cycles in a fluidized bed reactor may alter the particle size and shape of most oxygen carriers.

关键词： Oxygen carrier Size and shape analysis Dynamic image analysis Oxidation state Fluidized bed Chemical looping

Detection of onset of agglomeration in a bubbling fluidized bed biomass combustor using reactive Eulerian computational fluid dynamics

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Particuology 2024年第7期90卷 504-515页

作者： Abdullah Tasleem Atta Ullah Fei Li Qun Yi William Nimmo Syed Sheraz Daood department of Chemical engineering Pakistan Institute of Engineering and Applied Sciences(PIEAS)Lehtrar RoadP.O.Nilore45650IslamabadPakistan Institute of Process engineering Chinese Academy of SciencesBeijing100190China School of Chemical engineering and Pharmacy Wuhan Institute of TechnologyWuhan430205China energy engineering Group Energy 2050Department of Mechanical EngineeringUniversity of SheffieldSheffieldS37RDUnited Kingdom Institute of energy and Environmental engineering Faculty of ElectricalEnergy&Environmental EngineeringUniversity of the PunjabQuaid-e-Azam CampusLahorePakistan energy engineering Research and Development Centre Faculty of ElectricalEnergy&Environmental EngineeringUniversity of the PunjabQuaid-e-Azam CampusLahorePakistan

The choice of a type of combustion technology to be used for heat or power generation depends on economic,technical,operational and fuel availability constraints.The benefits associated with the evolving market driven by the fluidised bed combustion(FBC)technology cannot be overlooked especially when gauged at 65 GWth of worldwide installed capacity alongside added benefits of handling fuel variation,low pollutant emissions and high combustion efficiency.Biomass or biomass waste will continue to have a vital role to play in the future FBC technology-based power generation.Biomass often contains high levels of inorganic species that can form sticky agglomerates posing a significant risk to boiler operation resulting in unscheduled outages.This added complexity of the behaviour of the fuel and bed material mix highlights the requirement for simulation models to identify agglomeration to help improve the overall performance and reliability of FBC technology.To resolve this problem,this research devised a simulation strategy for the detection of agglomeration using the Eulerian–Eulerian approach.The developed modelling strategy is validated with the experimental data available in literature for two-dimensional simplified geometry of a pilot-scale fluidised bed combustor.The model results were found promising and robust to predict bed defluidisation times and other parameters consistent with the experimental data.

关键词： Fluidized bed combustion Eulerian Models Biomass Agglomeration Defluidisation

Mathematical modeling and simulations of stress mitigation by coating polycrystalline particles in lithium-ion batteries

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 947-962页

作者： N.IQBAL J.CHOI S.F.SHAH C.LEE S.LEE department of Mechanical Roboticsand Energy EngineeringDongguk University-SeoulSeoul 04620Republic of Korea

A chemo-mechanical model is developed to investigate the effects on the stress development of the coating of polycrystalline Ni-rich LiNixMnyCo_(z)O_(2)(x≥0.8)(NMC)particles with poly(3,4-ethylenedioxythiophene)(PEDOT).The simulation results show that the coating of primary NMC particles significantly reduces the stress generation by efficiently accommodating the volume change associated with the lithium diffusion,and the coating layer plays roles both as a cushion against the volume change and a channel for the lithium transport,promoting the lithium distribution across the secondary particles more homogeneously.Besides,the lower stiffness,higher ionic conductivity,and larger thickness of the coating layer improve the stress mitigation.This paper provides a mathematical framework for calculating the chemo-mechanical responses of anisotropic electrode materials and fundamental insights into how the coating of NMC active particles mitigates stress levels.

关键词： lithium-ion battery(LIB) polycrystalline particle coating finite element simulation Ni-rich LiNixMnyCo_(z)O_(2)(x>0.8)(NMC)

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Smart electrochemical sensing of amyloid-beta to manage total Alzheimer's diseases

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Neural Regeneration Research 2024年第6期19卷 1185-1186页

作者： Ajeet Kaushik School of engineering University of Petroleum and Energy Studies (UPES) NanoBioTech Laboratory Department of Environmental Engineering Florida Polytechnic University

Need for Alzheimer ’s disease progression monitoring: Alzheimer ’s disease(AD) is an irreversible progressive brain disorder that causes severe and incurable neuro-impairment. The World Health Organization estimates that 55 million people are affected by AD dementia by 2020 which may exceed 78 million by 2030 and 139 in 2050. The estimated cost to manage AD is above US$ 1.3 trillion, which will further increase to US$ 2.8 trillion by 2030.

关键词： IMMUNOSENSOR

Effects of the inlet particle spatial distribution on the performance of a gas-solid cyclone separator

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Particuology 2024年第2期85卷 133-145页

作者： Yuge Yao Manxia Shang Xiwei Ke Zhong Huang Tuo Zhou Junfu Lyu Key Laboratory for Thermal Science and Power engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing100084China

The present study was aimed at the inlet particle spatial distribution of a gas-solid separator with high solid loading and investigated its effects on cyclone performance and the inner flow pattern.The flow fields of a cyclone with different rectangular particle flow areas on the inlet surface were numerically simulated using a four-way coupling method.The simulated results indicate that reducing the inlet particle flow area and lowing the inlet particle position can effectively reduce the scattered particles inside the cyclone separator and enhance the separation performance.Vertically gathering the particles to the centerline can also weaken the particle back-mixing.The particles near the roof account for the swirling particle ceiling phenomenon.The inlet particle spatial distribution affects the pressure drop mainly by affecting the gas tangential velocity in the cylinder body.Moreover,compared to the hori-zontal particle distribution on the inlet surface,the vertical particle distribution has greater effects on cyclone performance.

关键词： Gas-solid cyclone Inlet particle spatial distribution Four-way coupling Separation efficiency Scattered particle

Data-driven Reactive Power Optimization of Distribution Networks via Graph Attention Networks

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Journal of Modern Power Systems and Clean energy 2024年第3期12卷 874-885页

作者： Wenlong Liao Dechang Yang Qi Liu Yixiong Jia Chenxi Wang Zhe Yang Wind engineering and Renewable energy Laboratory Ecole Polytechnique Federale de Lausanne (EPFL) the College of Information and Electrical engineering China Agricultural University the College of Electrical engineering and Automation Shandong University of Science and Technology the department of Electrical and Electronic engineering (energy Digitalization Laboratory) The University of Hong Kong the department of Electrical engineering The Hong Kong Polytechnic University

Reactive power optimization of distribution networks is traditionally addressed by physical model based methods, which often lead to locally optimal solutions and require heavy online inference time consumption. To improve the quality of the solution and reduce the inference time burden, this paper proposes a new graph attention networks based method to directly map the complex nonlinear relationship between graphs(topology and power loads) and reactive power scheduling schemes of distribution networks, from a data-driven perspective. The graph attention network is tailored specifically to this problem and incorporates several innovative features such as a self-loop in the adjacency matrix, a customized loss function, and the use of max-pooling layers. Additionally, a rulebased strategy is proposed to adjust infeasible solutions that violate constraints. Simulation results on multiple distribution networks demonstrate that the proposed method outperforms other machine learning based methods in terms of the solution quality and robustness to varying load conditions. Moreover, its online inference time is significantly faster than traditional physical model based methods, particularly for large-scale distribution networks.

关键词： Distribution networks Reactive power Load modeling Transformers Machine learning algorithms Inference algorithms Static VAr compensators

Review on heat-to-power conversion technologies for hypersonic vehicles

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Chinese Journal of Aeronautics 2024年第5期37卷 148-179页

作者： Yinke QI Xiaofeng MA Peixue JIANG Yinhai ZHU Key Laboratory for Thermal Science and Power engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Beijing Key Laboratory of CO_(2)Utilization and Reduction Technology Department of Energy and Power EngineeringTsinghua UniversityBeijing 100084China

Hypersonic vehicles have enormous military and economic value,while their power and thermal protection demands will increase substantially with the rise in Mach number and duration.Converting the tremendous high-quality heat on the vehicle surface and engine wall into electrical energy through heat-to-power technologies will not only play a role in thermal protection,but also supply power for the vehicle.This paper provides a comprehensive review of heat-to-power conversion technologies on hypersonic vehicles,including the indirect conversion of Brayton and Rankine cycles,direct conversion of thermoelectric materials,and combined conversion.For the open Brayton cycle with hydrocarbon fuel as the working fluid,the Power-to-Weight Ratio(PWR)can achieve the highest,at around 1.8,due to the high PWR of the hydrocarbon fuel turbine and the few components of the system.However,its work capacity is limited by the flow rate of the supplied fuel.The closed Brayton cycle can maintain a relatively high PWR,ranging from 0.2 to 0.8,while achieving relatively high output power and conversion efficiency.The Rankine cycle has a higher PWR,its range is close to that of the closed Brayton cycle,peaking at about 0.88.The thermoelectric materials technology has a small power generation level,making it more suitable for scenarios with low power demand.This review provides a basis for selecting and developing heat-to-power conversion technologies on hypersonic vehicles.

关键词： Hypersonic vehicles Heat-to-power conversion Brayton cycle Rankine cycle Thermoelectric materials

Characterization and Analysis of Inconel 718 Alloy Ground at Different Speeds

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Chinese Journal of Mechanical engineering 2024年第2期37卷 137-149页

作者： Hao Liu Huili Han Qinghong Jiang Minglin He Bi Zhang department of Mechanical and energy engineering Southern University of Science and TechnologyShenzhen 518055China department of Mechanical engineering Hong Kong Polytechnic UniversityHong KongChina

Inconel 718(IN718)alloy is widely applied to fabricate high temperature resistant or corrosion resistant parts due to its excellent mechanical performance.However,the machining of IN718 alloy is difficult as it may cause serious tool wear and poor surface quality(SQ)of the workpiece.In this work,grinding experiments on IN718 alloy at different speeds were conducted by using a CBN grinding wheel.The relationship between grinding speed,SQ and subsurface damage(SSD)was well studied.With increasing grinding speed,surface roughness decreased,and SQ was greatly improved.Meanwhile,the microhardness of the grinding surface declined as the grinding speed increased.The SSD depth was almost unchanged when the grinding speed was lower than 15 m/s,then it decreased with higher grinding speeds.It was attributed to the mechanical-thermal synergistic effect in the grinding process.The results indicated that increasing grinding speed can effectively improve the SQ and reduce the SSD of IN718 alloy.The conclusion in the work may also provide insight into processing other hard-to-machining materials.

关键词： Surface integrity Grinding speed IN718 alloy Precision machining CBN grinding wheel