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Design and Optimization of bionic Janus Blade in Hydraulic Torque Converter for Drag Reduction

Journal of bionic engineering 2018年第1期15卷 160-172页

作者： Chunbao Liu Chuang Sheng Hualong Yang Zhe Yuan School of Mechanical Science and Engineering Jilin University Changchun 130022 China Key Laboratory of Bionic Engineering Ministry of Education Jilin University Changchun 130022 China State Key Laboratory of Automotive Simulation and Control Jilin University Changchun 130022 China

The chief aim of the present work was to achieve drag reduction in stator blades with liquid using boundary layer control. A stator blade of hydraulic torque converter with bionic grooves in suction side and hydrophobic surface in pressure side was designed. The hydrophobic surface was created using anodic oxidation method and irregular A1203 thin films were found on the surface. They formed hierarchical structure consisting of mini porous structures and microscopic pore spaces, resulting in the hydrophobicity. The bionic groove was designed by Computational Fluids Dynamics （CFD） method. Multi-Island Genetic Algorithm （MIGA） was adopted for groove multi-objective optimization. Through optimization, the maximum drag reduction was close to 12% in oil. In addition, the drag reduction calculation was verified by closed channel experiment and ＂Tire Vortex＂ was proposed to explain the drag reduction mechanism. The bionic Janus blade could maintain its initial profile without any additional device, which had lower risk and less cost. The results are encouraging and show great potential to apply in other flow machineries.

关键词： hydraulic torque converter bionic blade boundary layer control drag reduction

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Analysis of water surface effects during the water-exit process of the vector bi-rotor aerial-aquatic vehicle

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Aerospace Science and Technology 2025年 164卷

作者： Yi Sun Youzhi Xu Huan Shen Jingheng Liu Yadong Gao Qijun Zhao Aihong Ji Lab of Locomotion Bioinspiration and Intelligent Robots the College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Jiangsu Key Laboratory of Bionic Materials and Equipment Nanjing 210016 China State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

The water-exit motion, as a critical core capability of aerial-aquatic vehicles, is essential for maintaining their stable and reliable performance. For most aerial-aquatic vehicles, the water-exit motion relies primarily on the high thrust generated by rotors. However, during the transition between media, maintaining a stable water-exit attitude is crucial for ensuring the stability of subsequent aerial flight. This effect is especially pronounced in multi-rotor aerial-aquatic vehicles utilizing vector control. This paper addresses the issue of poor attitude stability during the water-exit motion of vector bi-rotor aerial-aquatic vehicles. Employing multiphase flow numerical simulation methods, the study examines the impact of water surface effects at different water-exit heights ( H ) on the flow field variation performance of the vehicle. The initial water-exit height ( H i n i t i a l ) is determined, and the flow field variation principles induced by water surface effects are derived. Based on the numerical simulation results, a prototype of a vector bi-rotor aerial-aquatic vehicle with a coupled vector power system was developed. Near-surface flight tests were conducted in an outdoor lake environment to validate the flow field variation principles obtained from the simulations. Additionally, based on the experimental results, the optimal water-exit height ( H o p t i m a l ) was identified, and both the flow field variation principles and height-climbing water-exit strategy were further optimized. The results of this study can provide stable water-exit conditions for vector multi-rotor aerial-aquatic vehicles, effectively reducing disturbances during the transition. This contributes to the optimization of a complete water-exit strategy and lays a foundation for the development of robust water-exit control methods in future applications.

关键词： Aerial-aquatic vehicle Transition stability Vector control Water surface effect Water-exit process

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Analysis and suppression of subsynchronous oscillation of Rudong wind power through MMC-HVDC system

Analysis and suppression of subsynchronous oscillation of Ru...

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2021 Annual Meeting of CSEE Study Committee of HVDC and Power Electronics (HVDC 2021)

作者： J. Li X. Xie J. Yang H. Li Z. Shi K. Wang C. Fu W. Yang Key Laboratory of Far-shore Wind Power Technology of Zhejiang Province Huadong Engineering Corporation Limited Power China Hangzhou Zhejiang Province 310014 China State Key lab of Control and Simulation of Power Systems and Generation Equipment (Dept. of Electrical Engineering Tsinghua University) Haidian District Beijing 100084 China

There may be complex interaction between the converter control systems of wind power and MMC-HVDC, which will lead to sub-/super-synchronous oscillation and threaten the safe and stable operation of the system. The relevant events have been reported in Guangdong Nan'ao, Shanghai Nanhui and Zhangbei projects. Rudong offshore wind power project is the first offshore wind power transmission system in China, and it is still under construction. Therefore, it is of great significance to carry out the research on the risk analysis and suppression measures of sub-synchronous oscillation in Rudong wind power MMC-HVDC system. First, the time-domain simulation model of Rudong wind power MMC-HVDC system is built in the PSCAD/EMTDC simulation model. Then, the effects of the number of wind turbine generators, wind power output and the parameters of MMC-HVDC controller on the sub-/super-synchronous oscillation characteristics of the system are further analyzed. Finally, the suppression measures based on supplementary frequency dependent gain control are proposed, the application position of the controller is discussed, and the parameter optimization method of the controller is given. The research content provides a certain guiding significance for the operation and control of Rudong wind power MMC-HVDC.

关键词： turbogenerators HVDC power transmission wind turbines power transmission control risk analysis time-domain analysis offshore installations HVDC power convertors wind power plants wind power

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Selective Separation of Volatile Fatty Acids, Nitrogen and Phosphorus from Anaerobic Acidogenic Fermentation Via Forward Osmosis Membrane Process

SSRN

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SSRN 2022年

作者： Zhu, Xian-Zheng Wang, Long-Fei Pan, Xin-Rong Zhang, Feng Huang, Min-Sheng Li, Wen-Wei Liu, Hou-Qi National and Local Joint Engineering Laboratory for Municipal Sewage Resource Utilization Technology Suzhou University of Science and Technology Suzhou215009 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration School of Ecological and Environmental Sciences East China Normal University Shanghai200062 China Suzhou Advanced Research Institute University of Science and Technology of China Suzhou215123 China

Selective separation and recovery of volatile fatty acids (VFA) and other valuable resources promotes a sustainable wastewater treatment system, but its cost-effective separation approaches are poorly understood. This study investigated the feasibility of applying a forward osmosis (FO) dewatering process for the selective separation of VFA, ammonium and phosphate from anaerobic acidogenic fermentation. Limited VFA rejection of fermentation broth, i.e., less than 20%, was observed under acidic conditions, while the rejection rate was significantly increased to ~90% at neutral pH. The transfer of ammonium across the membranes was remarkably impacted by the feed solution pH. Lower pH (~4) values resulted in higher rejection rates of ammonium (~96%), and the rate gradually declined as pH increased. The rejection of phosphate, which remained higher than 98%, was less sensitive to pH variations. The increase in water flux promoted the rejection of VFA, ammonium and phosphate, and the membrane orientation significantly impacted the transfer of nutrients in the FO process. The active layer facing the feed solution (AL-FS) mode exhibited higher rejection rates of VFA, ammonium and phosphate than the active layer facing the draw solution (AL-DS) mode, which was ascribed to the internal concentration polarization effect. Furthermore, approximately 80% of water could be effectively reduced from a real acidogenic fermentation liquor during the FO process;ammonium and phosphate were 3.72-fold and 4.10-fold concentrated in feed solution, respectively, and VFA was selectively separated in draw solution. The work confirmed the feasibility of utilizing FO processes in separating and enriching VFA, ammonium and phosphate from anaerobic fermentation liquors, providing meaningful information on promoting FO-based processes in treating wastewater. © 2022, The Authors. All rights reserved.

关键词： Nutrients

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A novel drone endoscope system for near-surface observation in fusion reactor vacuum chambers

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Measurement 2025年 256卷

作者： Youzhi Xu Yi Sun Huan Shen Lei Zheng Yong Cheng Shijie Liu Haibing Zhang Guodong Qin Aihong Ji Lab of Locomotion Bioinspiration and Intelligent Robots the College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Institute of Plasma Physics Chinese Academy of Science Hefei 230031 China Jiangsu Key Laboratory of Bionic Materials and Equipment Nanjing 210016 China State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

This paper presents a novel drone endoscope system (DES) for internal observation in fusion reactors. The system enables autonomous location and mapping in Global Navigation Satellite System (GNSS)-denied and dark environments in narrow, confined vacuum chambers. A computational fluid dynamics (CFD) simulation analysis was conducted to investigate the impact of nonlinear airflow interference introduced by internal chamber structural surfaces on the DES. Specifically, the influence of ceiling, ground, and wall surface effects is considered, and the nearest limiting safety distances for near-surface information acquisition are derived. Subsequently, the DES is employed to inspect the 1/8 vacuum chambers of the China Fusion engineering Test Reactor (CFETR). The system exhibits flight stability with ±0.03 m positional accuracy and ±3° angular error, enabling the acquisition of images of the internal chamber surfaces and three-dimensional reconstruction. This represents a novel approach to the internal observation mission of the fusion reactors.

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Effects of temperature on creepage discharge characteristics in oil-impregnated pressboard insulation under combined AC–DC voltage

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Plasma Science and Technology 2019年第5期21卷 14-22页

作者： Fubao JIN Yuanxiang ZHOU Bin LIANG Zhongliu ZHOU Ling ZHANG Key Laboratory of Plateau Ecology and Agriculture College of Agriculture and Animal HusbandrySchool of Water Resources and Electric PowerQinghai UniversityXining 800016People's Republic of China State Key Lab of Control and Simulation of Power Systems and Generation Equipments Department of Electrical EngineeringTsinghua UniversityBeijing 100084People's Republic of China

Due to the complexity of the valve side winding voltage of the converter transformer, the insulation characteristics of the oil-impregnated pressboard(OIP) of the converter transformer are different from those of the traditional AC transformer. The study on effect of temperature on the creeping discharge characteristics of OIP under combined AC–DC voltage is seriously inadequate. Therefore, this paper investigates the characteristics of OIP creepage discharge under combined AC–DC voltage and discusses the influence of temperature on creepage discharge characteristics under different temperatures from 70 °C to 110 °C. The experimental results show that the partial discharge inception voltage and flashover voltage decrease with increasing temperature. The times of low amplitude discharge(LAD) decrease and amplitude of LAD increases. Simultaneously, the times of high amplitude discharge(HAD) gradually increase at each stage of creepage discharge with higher temperature. The analysis indicates that the charge carriers easily accumulate and quickly migrate directional movement along the electric field ahead of discharging. The residual charge carriers are more easily dissipated after *** ‘hump’ region of LAD moves to the direction of higher discharge magnitude. The interval time between two continuous discharges is shortened obviously. The concentration of HAD accelerates the development of OIP insulation creepage discharge. The temperature had an accelerating effect on the development of discharge in the OIP under applying voltage.

关键词： oil-impregnated pressboard insulation combined AC-DC voltage inception voltage creepage discharge temperature flashover voltage

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Multimodal Biometric Recognition System Based on bionic Crack Sensor

Multimodal Biometric Recognition System Based on Bionic Crac...

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第六届国际仿生工程学术大会暨2019年自然启迪科技国际研讨会

作者： Fu Liu Shoukun Jiang Ke Wang Zhiwu Han Tao Hou State Key Laboratory of Automotive Simulation and Control Jilin University College of Communication Engineering Jilin University Key Laboratory of Bionic Engineering(Ministry of Education China) Jilin University

bionic flexible crack-based sensor has received lots of attention because of its advantages of high sensitivity, flexibility and durability. However, there are few practical applications in real-world. In the paper, we have established a multimodal biometric recognition system, in which the finger bending force and hand vein image are applied for identification. Particularly, high-performance flexible strain sensors bioinspired by scorpion are first used to collect signals of finger bending force because of their excellent characteristics of high sensitivity, flexibility and durability. Experimental results show that the multimodal biometric recognition system is superior for personal recognition to independent hand vein system in terms of accuracy which is improved about 1.5%. Most importantly, this paper explores the application of bionic flexible crack-based sensors as biometric identification system.

关键词： crack-based sensor signals of finger bending force multimodal biometric recognition system hand vein

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Effect of UV radiation aging on creepage discharge characteristics of high temperature vulcanized silicon rubber at high altitude

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Plasma Science and Technology 2019年第5期21卷 23-33页

作者： Fubao JIN Yuanxiang ZHOU Bin LIANG Xidong LIANG Zhongliu ZHOU Ling ZHANG Key Laboratory of Plateau Ecology and Agriculture College of Agriculture and Animal HusbandrySchool of Water Resources and Electric PowerQinghai UniversityXining 800016People's Republic of China State Key Lab of Control and Simulation of Power Systems and Gen eration Equipments Departme nl of Electrical EngineeringTsinghua UniversityBeijing 100084People's Republic of China

The physicochemical properties and creepage discharge characteristics of aged high temperature Vulca nized(HTV)silicone rubber materials were investigated by ultraviolet radiati on(UV)aging method in this *** experimental results show that as the aging time increases,the creepage discharge flashover voltage increases first and then *** the aging time has little effect on the creepage discharge inception *** the aging time prolonged,the discharge endurance time of HTV silicone rubber is shortened,and the creepage discharge development velocity is *** the short time of applying voltage to aging material,the magnitude of discharge in creases *** to the partial discharge characteristic parameters of creepage discharge,the whole creepage discharge process is partitioned into four *** with unaged HTV silicone rubber,the aged HTV silicone rubber has less fluctuation in performance parameters and a clear *** study found that UV aging not only affects the physicochemical and hydrophobic properties of the HTV silicone rubber,but also accelerates the development of creepage discharge under AC voltage.

关键词： high temperature vulcanized silicone rubber creepage discharge UV aging inception voltage flashover voltage high altitude characteristic parameters

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Effect of bionic Unit Shapes on Solid Particle Erosion Resistance of ZrO2-7wt%Y2O3 Thermal Barrier Coatings Processed by Laser

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Journal of bionic engineering 2018年第3期15卷 545-557页

作者： Panpan Zhang Fuhai Li Xiaofeng Zhang Zhihui Zhang Chaolin Tan Luquan Ren Yueliang Wang Wenyou Ma Min Liu The Key Laboratory of Bionic Engineering (Ministry of Education China) Jilin University 5988 Renmin Street Changchun 130022 China Guangdong Institute of New Materials National Engineering Laboratory for Modern Materials Surface Engineering Technology the Key Lab of Guangdong for Modern Surface Engineering Technology Guangzhou 510651 China The State Key Laboratory of Automotive Simulation and Control Jilin University 5988 Renmin Street Changchun 130022 China

Inspired by the coupling phenomena in biological systems, to improve the solid particle erosion resistance of Thermal Barrier Coatings （TBCs）, different kinds of bionic units were made on the coating surfaces using bionic Coupled Laser Remelting （BCLR） process. The NiCoCrAlYTa/ZrO2-7wt%Y2O3 double-layer structured TBCs were prepared by air plasma spraying. The microstructure, microhardness and phase composition of the as-sprayed and bionic specimens were examined. The solid particle erosion behaviors of bionic specimens as function of bionic unit shape were investigated. The results indicated that the bionic specimens had better erosion resistance than the as-sprayed specimen. The specimen with striation and grid bionic units had the better erosion resistance, while the dot showed the worse. The bionic units were characterized by the dense columnar crystal structure and the high hardness, which are the main reasons for improving the erosion resistance. Under the synergistic action of the shear stress and normal stress on the protrusive coating surface, the erosion failure of the as-sprayed TBCs was proved to be the fracture and spallation of the splats. By contrast, the spallation of segmented bionic unit occurred in the overlapping area between the adjacent laser irradiation, and the erosive unit surface presented the clear and deep furrows, which revealed that the erosion failure mechanism of bionic TBCs was dominated by brittle and some ductile erosion. These results showed more opportunities for bionic application in improving the solid particle erosion resistance of components in the windy and sandy environment.

关键词： bionic thermal barrier coatings erosion resistance laser

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Dynamics of nitrogen oxides emissions in the pilot wastewater treatment plant: Characteristics and mechanisms

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Journal of Environmental Sciences 2025年

作者： Xinyi Xu Ke Han Zhen Liu Huiqi Jiang Yanhui Zhao Jinhe Wang Jian Zhang Yangang Ren Zhen Hu School of Environmental Science & Engineering Shandong University Qingdao 266237 China Resources and Environment Research Institute School of Municipal and Environmental Engineering Shandong Jianzhu University Ji’nan 250101 China. State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China State Key Lab Microbial Technol Shandong University Qingdao 266237 China

Nitrogen oxides (NO x ), consisting of nitric oxide (NO) and nitrogen dioxide (NO 2 ), pose significant risks to human health and the environment, potentially causing respiratory and cardiovascular diseases. In contrast to extensive research on industrial NO x emissions, there has been a paucity of attention on the dynamics of NO x in wastewater treatment plants (WWTPs). This study investigated NO x emission patterns in a pilot-scale WWTP, revealing that NO dominated NO x emissions (0.013 % of the nitrogen load), peaking nocturnally (4 a.m.- 6 a.m.) and primarily originating from the oxic zone due to ammonia-oxidizing bacteria activity and aeration stripping synergistically increasing NO x emission. NO 2 emissions were minimal (0.003 % of the nitrogen load), with limited conversion from NO. Pearson correlation analysis identified ammonium removal efficiency and nitrate accumulation efficiency as key drivers of NO x production. The microbial community composition was closely linked to NO x emissions, with nitrifying bacteria such as Nitrosomonas contributing to NO x generation in the oxic zone, while denitrifying bacteria like Methylotenera contributed to NO x emissions under oxygen-limited conditions in the anoxic zone. This study enhanced the comprehension of the intricate processes of the nitrogen cycle during wastewater treatment and provided theoretical guidance for further optimization of WWTPs.

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