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Optimization of Single-Hole Fender Design for Offshore Wind Turbine Foundation Under Ship Collision

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SSRN 2023年

作者： Wang, Yujin Li, Chun Yue, Minnan Liu, Qingsong Sun, Kang Yue, Xinzhi Han, Zhiwei School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai China Shanghai Electric Wind Power Group Co. Ltd. Shanghai200233 China

This paper proposes a new design of protective fender for offshore wind turbine foundations based on nonlinear dynamics theory. The traditional anti-collision design for marine engineering platforms is not well-suited to wind turbine foundations, so the study uses the internal dynamics method and LS-DYNA to simulate the collision between a tripod foundation fender and a ship. The study analyzes impact force, energy absorption, stress, strain, and acceleration of the wind turbine tower top using finite element simulations under 19 relative hole angles. Results indicate that the optimal anti-collision protection is achieved with a hole angle of 20°. The study also examines the dynamic response and acceleration of the fender under different hole outer diameters of 0.5 m, 0.6 m, and 0.7 m and finds that the fender with a 0.7 m outer diameter exhibits the best anti-collision characteristics. The study utilizes a Kriging approximation model and a multi-objective genetic optimization algorithm to optimize the single-hole fender's design for minimum collision force and maximum energy absorption. The optimal parameter configuration has an inner hole diameter size of 0.658 m and a relative angle of 0.22°, achieving the best fender collision resistance ability. © 2023, The Authors. All rights reserved.

关键词： Offshore wind turbines

Clogging failure in microfilter for blood cell separation and its novel improvements

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Clogging failure in microfilter for blood cell separation an...

International Symposium on Physical & Failure Analysis of Integrated Circuits

作者： Tao Dong Zhaochu Yang Eirik Bentzen Egeland Frank Karlsen Henrik Jakobsen Norwegian Center of Expertise on Micro-and Nanotechnology I.M.S.T. /R. I Vestfold University College Norway State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China

Clogging failure is common for microfilter utilizing the flat membrane structure. To reduce clogging failure in microfilters, the turbine blade-like micropillar is introduced in microfilter design. Two improved cross-flow microfilter designs employing the blade-like micropillar barrier are presented, one with varied cross-section channels, and the other with Archimedes' spiral channels. Analogy experimental-data based simulations show that the two aforementioned novel microfilters have good filtrating efficiency and fantastic anti-clogging characteristics. And the commercial value of the turbine blade-like barriers is affirmed by the industry Partners.

关键词： Microfiltration Cells (biology) Filters Biomembranes Filtration Turbines White blood cells Nanotechnology Educational institutions power engineering

Inverse Analysis of Radiative Properties of Internal Medium and Surface for Cylindrical System Using Csm-Cgm Approach

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SSRN 2023年

作者： Zhang, Chao Li, Ben-Wen Zhou, Rui-Rui Li, Pan-Xin Huang, Ling-Yun Key Laboratory of Ocean Energy Utilization and Energy Conservation Ministry of Education School of Energy and Power Engineering Dalian University of Technology Dalian116024 China 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 State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Faculty of Land Resource Engineering Kunming University of Science and Technology Kunming650093 China

An inverse analysis is conducted to simultaneously estimate the radiative properties in a 2D cylindrical system including the extinction coefficient, scattering albedo, and the wall emissivity from the knowledge of the radiative heat flux over different boundaries. In which the collocation spectral method (CSM) is developed to solve the forward problem, the conjugate gradient method (CGM) is employed to solve the inverse problem, and the complex-variable-differentiation method is used to treat the sensitivity problem, separately. Meanwhile, the effects of measurement errors, initial values, and imaginary values of complex variables on the precision of the inverse analysis are investigated. Results show that the proposed inverse analysis can successfully retrieve the unknown radiative physical properties of 2D cylindrical system. Under the same physical properties, good inversion results can be obtained by using different wall (end walls and side wall) radiative heat fluxes, but the inversion efficiency from sidewall radiative heat flux is higher. Besides, it is found that, the inversion for the scattered participating medium is more efficient than that for the non-scattered participating medium;the true values and iterative convergence values have little effect on the inversion result;the influence of the initial values and the imaginary values of the complex variable on the inversion cannot be ignored. © 2023, The Authors. All rights reserved.

关键词： Conjugate gradient method

Numerical Simulation for Non-Uniform Ptco Catalyst Degradation Under Constant Voltage Condition and its Impact on Pemfc Performance

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SSRN 2023年

作者： Yang, Yunjie Bai, Minli Zhou, Zhifu Wu, Wei-Tao Hu, Chengzhi Gao, Linsong Li, Yang Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116023 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'An710049 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China

PtCo alloys are commonly utilized as catalysts in proton exchange membrane fuel cell (PEMFC) to reduce Pt loading and to achieve higher oxygen reduction reaction (ORR) activity. However, long-time operation can result in a reduction in electrochemical surface area (ECSA) in PEMFC. Meanwhile, the dissolved Co2+ may also contribute to additional local oxygen transport resistance. In this study, catalyst aging model and Co2+ transport and its effect on oxygen transport model have been integrated with the 3D single phase PEMFC performance model to develop a long-term performance model for investigating the impact of non-uniform catalyst degradation and Co2+ contamination on PEMFC performance during constant voltage operation. The results show that Co2+ contamination causes additional mass transfer losses and reduces the peak power of PEMFC. And it is found that the non-uniform degradation of catalyst and Co2+ contamination eventually affects the current density distribution in aged PEMFCs. In addition, the model is also applied to study a 50 cm2 PEMFC under long time constant voltage operation. The predicted ECSA loss is 73.1% and 62.0%, and output power reduction is 55.9% and 43.0% after 80,000 hours at a constant voltage of 0.75 V and 0.65 V, respectively. © 2023, The Authors. All rights reserved.

关键词： Numerical models

Understanding Copper Corrosion in Bentonite-Enriched Environments: Insights from the Point Defect Model

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SSRN 2024年

作者： Ning, Zhiyuan Zhou, Qulan Li, Na Macdonald, Digby D. Zhou, Jie State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Departments of Nuclear Engineering and Materials Science and Engineering University of California at Berkeley BerkeleyCA94720 United States Xi’an Aerospace Propulsion Institution Xi’an China

The laboratory simulated copper corrosion in a bentonite/groundwater solution, analyzing the kinetics of metal passivation through potentiodynamic polarization, potentiostatic polarization, and electrochemical impedance spectroscopy experiments. Corrosion development patterns were inferred from morphological characterization, and the mechanisms by which bentonite affects copper corrosion were comprehensively elucidated based on the point defect model. The research revealed that bentonite affects copper corrosion resistance through Donnan exclusion, cation adsorption, and hydrolysis of salts. Based on the point defect model, the study elucidated the microscopic mechanism of pitting corrosion induced by bentonite hydrolysis salts, calculating the polarizability of the passive layer/outer layer interface as α = 0.1. The reliability of the cation adsorption and adsorption-desorption mechanisms was confirmed through experimental data fitting, point defect model fitting, and theoretical analysis. © 2024, The Authors. All rights reserved.

关键词： Hydrolysis

Novel doped barium cerate-carbonate composite electrolyte material for low temperature solid oxide fuel cells

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Novel doped barium cerate-carbonate composite electrolyte ma...

第五届世界氢能技术大会(WHTC2013)

作者： Yuanfei Hei Cheng Wang Jianbing Huang Zongqiang Mao Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084P.R. China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049P.R. China

Experimental Studies of Liquid Immersion Cooling for 18650 Lithium-Ion Battery Under Different Discharging Conditions

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SSRN 2022年

作者： Li, Yang Zhou, Zhifu Hu, Leiming Bai, Minli Gao, Linsong Li, Yulong Liu, Xuanyu Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116023 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China Department of Mechanical Engineering Carnegie Mellon University Pittsburgh15213 United States

In this study, the fluorinated liquid immersion cooling as a new cooling scheme has been tested and discussed for cooling the 18650 lithium-ion battery. OpteonTM SF33, with boiling point of 33.4oC, is chosen as the fluid for the immersion cooling. Comparison of the liquid immersion cooling and convective air cooling for a 18650 lithium-ion battery under 2C, 4C and dynamic load conditions are made. It is found that the immersion cooling better cools the battery cell under all these conditions. Under 4C discharging, the maximum cell temperature rise is 14.06°C for the forced air cooling, while is 4.97°C for the liquid immersion cooling. As the cooling fluid’s temperature basically governs the battery cell temperature, the cooling fluid’s temperature should not be too low. This study demonstrates that the lithium-ion battery has non-negligible power losses under cooling liquid temperature of 10oC and 15oC, compared with temperature above 20oC. Lastly, the two-phase boiling heat transfer mechanisms associated with immersion cooling of lithium-ion battery are discussed with bubble dynamics analysis. It is found under higher C rate, more aggressive boiling heat transfer is induced. The battery temperature is controlled to be below 34.5oC even under 7C discharging condition. © 2022, The Authors. All rights reserved.

关键词： Lithium-ion batteries

Propagation and Burning Velocity of Iron-Methane-Oxygen-Nitrogen Turbulent Expanding Flames

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SSRN 2023年

作者： Cai, Xiao Su, Limin Su, Shouguo Wang, Jinhua Alden, Marcus Li, Zhongshan Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Division of Combustion Physics Lund University P.O. Box 118 LundS221 00 Sweden

The propagation and burning velocity of iron-methane-oxygen-nitrogen turbulent expanding flames were experimentally studied by employing a newly optimized spark-ignition, fan-stirred combustion chamber, in which micron-sized iron particles can be dispersed homogeneously. Fine iron particles with averaged diameter of 1.9 μm was used in the present study. The flame trajectory of iron-methane mixture at different turbulence intensities and iron concentrations was recorded using a high-speed camera. It was found that the flame propagation speed increases as iron-methane turbulent flame expands. The acceleration process is mainly caused by the extension of flame surface dissipation spectrum by increasing the largest flame scales (flame radius). The turbulent burning velocity, ST increases significantly with the turbulence intensity, which is well known feature in gaseous flames. However, the iron concentration does not have an obvious effect on the ST, which is unique to iron flame in turbulence environment. Because the turbulent flame propagation is dominated by turbulent heat transfer, which is characterized by turbulence intensity. In addition, the formation of iron flame front is controlled by the couple effects of iron concentration and turbulence intensity in turbulent environment. Furthermore, the laminar burning velocity, SL was accurately determined using a nonlinear extraction method. A correlation of turbulent burning velocity was obtained based on the experimental iron-methane data. The measured ST and its correlation would be used to develop practical iron burners and to validate turbulent combustion models of iron flames. © 2023, The Authors. All rights reserved.

关键词： Iron

Thermal Management for the 18650 Lithium-Ion Battery Pack by Immersion Cooling with Fluorinated Liquid

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SSRN 2023年

作者： Li, Yang Bai, Minli Zhou, Zhifu Wu, Wei-Tao Hu, Chengzhi Gao, Linsong Liu, Xinyu Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116023 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'An710049 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China

In this work, a new battery thermal management system (BTMS) utilizing a SF33-based liquid immersion cooling (LIC) scheme has been proposed. Firstly, the comparative investigation focuses on the temperature response of the LIC and forced air cooling (FAC) modules in different scenarios. The results demonstrate that LIC module effectively mitigates heat accumulation, thereby presenting notable advantages in terms of temperature control and equalization, even though the LIC module works under the stage without phase change occurrence. During 2C and 3C charging, the highest temperatures of the LIC module are observed to be 10 °C and 19.1 °C only lower than those of the FAC module, respectively. Furthermore, the highest temperature differences of the LIC module are only 12.89% and 8.57% of the corresponding values exhibited by the FAC module. Moreover, the associated cooling energy consumption for the LIC module is greatly reduced, amounting to only 16.47% and 43.76% of that required by the FAC module. Subsequently, an active control scheme for the LIC is initially proposed, and the phase change process of the LIC under various discharging rates is recorded and analyzed using a high-speed camera. This study serves as a preliminary proof of concept for the feasibility of SF33-based LIC scheme in BTMS. © 2023, The Authors. All rights reserved.

关键词： Lithium-ion batteries