Table of Content

28 March 2024, Volume 58 Issue 3 Previous Issue   

New Type Power System and the Integrated Energy

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Operation Parameters of Air-Cooled Fuel Cell Based on In-Situ Testing of Reaction State CHEN Minxue, QIU Diankai, PENG Linfa 2024, 58 (3):  253-262.  doi: 10.16183/j.cnki.jsjtu.2022.318 Abstract ( 205 )   HTML ( 22 )   PDF (25048KB) ( 206 )   Save The internal reaction state of air-cooled proton exchange membrane fuel cell (PEMFC) is the key factor affecting the output performance and stability of the cell. By developing an in-situ testing device for the reaction state of air-cooled fuel cell, the real-time measurement of cell temperature and current density is realized, and the influence mechanism of hydrogen outlet pulse interval, hydrogen inlet pressure and cathode wind speed on the performance of the cell is revealed. The results show that the distribution of temperature and current density in air-cooled cells is uneven. The temperature difference can reach 20 °C, and the current density difference reaches 400 mA/cm2 when the average current density is 500 mA/cm2. As the interval between pulses decreases and the inlet pressure increases, the performance of the hydrogen outlet area and the uniformity of the distribution increase, which can reduce the fluctuation of current density in the cells and improve output stability. If the cathode wind speed is too low, the temperature in central areas is high, and the temperature distribution uniformity is reduced. However, excessive wind speed causes the generating water to be blown away. The water content of the proton exchange membrane thus decreases, and the uniformity of the current density distribution deteriorates. Figures and Tables | References | Related Articles | Metrics

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SOH Online Estimation of Lithium-Ion Batteries Based on Fusion Health Factor and Integrated Extreme Learning Machine QU Keqing, DONG Hao, MAO Ling, ZHAO Jinbin, YANG Jianlin, LI Fen 2024, 58 (3):  263-272.  doi: 10.16183/j.cnki.jsjtu.2022.306 Abstract ( 46 )   HTML ( 8 )   PDF (3259KB) ( 28 )   Save Online estimation of the state of health (SOH) of lithium-ion batteries (LIB) is crucial for the security and stability operation of battery management systems. In order to overcome the problem such as long training time, large amount of computation, and complex debugging process of the LIB SOH estimation methods based on traditional data-driven, an LIB SOH estimation method based on fusion health factor (HF) and integrated extreme learning machine is proposed. The interval data with a high correlation with the SOH was found by analyzing the dQ/dV and dT/dV curves of the battery. Multi-dimensional HFs are extracted from the interval data, and the indirect HF are obtained by principal component analysis. The stochastic learning algorithm of extreme learning machine is used to establish the nonlinear mapping relationship between indirect HF and SOH. Considering the unstable output of a single model, an integrated extreme learning machine model is proposed. The unreliable output is eliminated by setting credibility evaluation rules for the estimation results, and the estimation accuracy of the model is improved. Finally, the method proposed in this paper is validated using the NASA LIB aging dataset and the LIB aging dataset of Oxford University. The results show that the average absolute percentage error of SOH estimation method proposed is less than 1%, and it has a high accuracy and reliability. Figures and Tables | References | Related Articles | Metrics

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Interval Estimation of State of Health for Lithium Batteries Considering Different Charging Strategies ZHANG Xiaoyuan, ZHANG Jinhao, YANG Lixin 2024, 58 (3):  273-284.  doi: 10.16183/j.cnki.jsjtu.2022.347 Abstract ( 120 )   HTML ( 5 )   PDF (3204KB) ( 131 )   Save State of health (SOH) estimation of lithium-ion (Li-ion) batteries is of great importance for battery use, maintenance, management, and economic evaluation. However, the current SOH estimation methods for Li-ion batteries are mainly targeted at specific charging strategies by using deterministic estimation models, which cannot reflect uncertain information such as randomness and fuzziness in the battery degradation process. To this end, a method for estimating the SOH interval of Li-ion batteries applicable to different charging strategies is proposed, which extracts multiple feature parameters from the cyclic charging and discharging data of batteries with different charging strategies, and automatically selects the optimal combination of feature parameters for a specific charging strategy by using the cross-validation method. In addition, considering the limited number of cycles in the whole life cycle of Li-ion batteries as a small sample, support vector quantile regression (SVQR), which integrates the advantages of support vector regression and quantile regression, is proposed for the estimation of SOH interval of lithium-ion batteries. Li-ion battery charge/discharge cycle data with deep discharge degree is selected as the training set for offline training of the SVQR model, and the trained model is used for online estimation of the SOH of Li-ion batteries of different charging strategies. The proposed method is validated using three datasets with different charging strategies. The experimental results show that the proposed method is applicable to different charging strategies and the estimation results are better than those of quantile regression, quantile regression neural network and Gaussian process regression. Figures and Tables | References | Related Articles | Metrics

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Interval Prediction Technology of Photovoltaic Power Based on Parameter Optimization of Extreme Learning Machine HE Zhizhuo, ZHANG Ying, ZHENG Gang, ZHENG Fang, HUANG Wandi, ZHANG Shenxi, CHENG Haozhong 2024, 58 (3):  285-294.  doi: 10.16183/j.cnki.jsjtu.2022.338 Abstract ( 215 )   HTML ( 6 )   PDF (1907KB) ( 337 )   Save This paper proposes an interval prediction technology of photovoltaic (PV) power based on parameter optimization of extreme learning machine (ELM) model. First, the weighted Euclidean distance is proposed as the evaluation index of PV power prediction interval. The historical sample units are screened and the ELM training set is optimized. Then, a hybrid optimization algorithm for ELM parameters is proposed. The hidden layer input and output weights and biases parameters of the ELM model are optimized by using the elitist strategy genetic algorithm and quantile regression, and the trained model is used to predict the PV power range. Finally, an actual calculation example is constructed based on the historical data of PV power plants and weather stations. The PV power interval is predicted, and the results are compared with those obtained by other methods. The results of the calculation example show that the method proposed can greatly improve the accuracy of interval prediction while increasing the reliability of interval prediction. Figures and Tables | References | Related Articles | Metrics

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Fault Detection in Power Distribution Systems Based on Gated Recurrent Attention Network CHEN Haolan, JIN Bingying, LIU Yadong, QIAN Qinglin, WANG Peng, CHEN Yanxia, YU Xijuan, YAN Yingjie 2024, 58 (3):  295-303.  doi: 10.16183/j.cnki.jsjtu.2022.091 Abstract ( 113 )   HTML ( 5 )   PDF (2938KB) ( 93 )   Save To improve fault identification accuracy in power distribution systems, a model named gated recurrent attention network is proposed. First, a higher weight is put on the key cycles of fault phase based on the attention mechanism, making the model focus more on these key messages by weight assignment. Then, the gated recurrent network is adopted, which controls the memory transmission with gate signal and constructs the relationship between input waveform and probability of events at different stages to process the waveform sequence, thereby improving recognition accuracy. Experiments based on both simulation and field data show that the proposed method, under the small-sample-learning condition, is much better than other commonly-used classification models, such as support vector machine, gradient boosting decision tree, and convolutional neural network, providing new insights into fault identification technology in power distribution systems. Figures and Tables | References | Related Articles | Metrics

Mechanical Engineering

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Forced Oscillation Characteristics of Natural Gas Mixed with Hydrogen Combustion in Gas Turbine Central Staged Burner SHI Ting, JIN Ming, GE Bing, ZANG Shusheng 2024, 58 (3):  304-311.  doi: 10.16183/j.cnki.jsjtu.2022.454 Abstract ( 150 )   HTML ( 4 )   PDF (12811KB) ( 178 )   Save Natural gas mixed with hydrogen combustion is one of the important measures to reduce carbon emissions of gas turbine. However, the composition change of fuel will lead to changes in the flame structure and combustion stability of the combustor. In order to analyze the combustion instability of natural gas mixed with hydrogen combustion in the central staged burner, the effects of different hydrogen doping ratios on the transient flame structure, pressure and heat release response of the central staged combustion are experimentally studied. The proper orthogonal decomposition (POD) method is used to extract the characteristic modes of flame pulsation. It is found that the flame pulsation mainly includes two modes: a strong pulsation in the interference zone of flame and an axial disturbance. The experimental results show that as the volume ratio of hydrogen doped increases from 0% to 30%, the flame front moves upstream, the spacing between two staged flames is shortened, the energy proportion of pulsation mode corresponding to the flame interference increases, and the coupling of pressure and heat release is strengthened, which ultimately results in a 9% increase in pressure response and a 37% increase in heat release response in the combustor. Figures and Tables | References | Related Articles | Metrics

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Influence of Quenching Height and Air Distribution Ratio on Combustion Characteristics of RQL Combustor HUI Lei, LIU Aiguo, WU Xiaoqu, ZHANG Yunjie, ZENG Wen 2024, 58 (3):  312-323.  doi: 10.16183/j.cnki.jsjtu.2022.197 Abstract ( 72 )   HTML ( 5 )   PDF (23391KB) ( 42 )   Save Based on the principle of the rich-burn/quench/lean-burn (RQL) technology, a low emission combustion chamber for gas turbine was designed. The effects of different heights of quenching structure and distribution ratios of the air flow on the flow field, temperature field, and pollutant formation characteristics of combustion chamber were studied under the premise of keeping the inlet parameters of combustion chamber unchanged. The results show that the height of quenching structure and the proportion of air distribution are important parameters affecting the combustion performance of the combustion chamber. With the decrease of the height of quenching structure, the NOx emission increases at the exit of the combustion chamber. The NOx emission from combustion chamber outlet first decreases and then increases with the decrease of the proportion of air mass flow from the main combustion hole to the fired air mass flow in oil-rich areas, and an optimal proportion of air mass flow makes the NOx minimum. The production of thermal NOx is directly related to the size of the region with a temperature higher than 1 900 K and the maximum gas temperature. The designed combustion chamber has a minimum NOx emission of less than 35 mg/m3 under the studied working conditions, which achieves the emission standard of a low pollution combustion chamber. Figures and Tables | References | Related Articles | Metrics

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Coupling Characteristics of Lubrication and Flexible Multibody Dynamics of Piston-Liner Pairs in Diesel Engines ZHAI Xumao, TIAN Xinwei, ZHANG Chuanbin, LI Yujuan, LIU Shuo, CUI Yi 2024, 58 (3):  324-332.  doi: 10.16183/j.cnki.jsjtu.2022.357 Abstract ( 113 )   HTML ( 5 )   PDF (11548KB) ( 98 )   Save In this paper, a new piston-liner tribo-dynamic coupling model is proposed to study the dynamics and lubrication characteristics of the piston-liner friction pair of four-stroke vehicle diesel engines. In the model, the piston-rod-crankshaft flexible multibody dynamic system is described by absolute nodal coordinate formulation (ANCF), and the lubrication behavior is described by the averaged Reynolds equation and the Greenwood-Tripp asperity contact theory. The simulation is realized based on commercial software combined with self-developed codes. The results show that the liner has a maximum transient deformation of 23.6 μm due to cylinder pressure and piston knocking behavior. Compared with the rigid model, the proposed model considering the elastic deformation increases lateral displacement of piston by 40% with oil film pressure concentration in lubrication domain. In addition, the friction power loss of flexible model in one cycle is smaller and 17.7% lower than that of rigid model. Figures and Tables | References | Related Articles | Metrics

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Topology Optimization of Infill Structures for Additive Manufacturing Considering Structural Strength WANG Chen, LIU Yichang, LU Yufan, LAI Zhanglong, ZHOU Mingdong 2024, 58 (3):  333-341.  doi: 10.16183/j.cnki.jsjtu.2022.333 Abstract ( 34 )   HTML ( 7 )   PDF (6354KB) ( 27 )   Save A topology optimization approach is proposed to design lightweight and high-strength porous infill structures for additive manufacturing. The maximum stress approximated by the p-norm function is minimized to enhance the structural strength. A local volume constraint is utilized to generate porous infill pattern. A continuation strategy on the upper bound of the local volume fraction is proposed to improve the stability of the optimization process and avoid the sharp rising of stress. An overhang constraint is utilized to make sure that the optimized infill structures are self-supporting and can support the given shell. Besides, two-field-based topology optimization formulations are used to ensure that the optimized infill structures satisfy the minimum length scale for additive manufacturing. The numerical results show that the optimized infill structures can significantly improve the structural strength compared with the optimized design of compliance minimization problem at the same weight. A compliance constraint is further imposed in the optimization model and the relation between stiffness and strength of the infill structures is also discussed. Figures and Tables | References | Related Articles | Metrics

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Influence of Countersink Fillet Radius on Mechanical Performance of CFRP/Al Bolted Joints WANG Xianfeng, ZOU Fan, LIU Chang, AN Qinglong, CHEN Ming 2024, 58 (3):  342-351.  doi: 10.16183/j.cnki.jsjtu.2022.288 Abstract ( 59 )   HTML ( 3 )   PDF (16690KB) ( 69 )   Save Carbon fiber reinforced polymer (CFRP) and aluminum alloys (Al) are widely used in the new generation of commercial aircraft due to their excellent mechanical/physical properties. CFRP/Al countersink bolted structures are important connection forms, where the radius of the countersink fillet affects the mechanical connection performance. The countersink fillet radius is an important factor affecting the mechanical performance of bolted joints. In this paper, the countersink fillet radius is controlled by specially-designed drill-countersink tools with different countersink fillet radii. Meanwhile, the finite element model based on the progressive damage method of composite material is established and utilized to simulate the mechanical performance of different composite/metal bolted joints. The failure mechanism of CFRP/Al bolted joints is analyzed. The results show that the countersink fillet radius can be effectively controlled by specially-designed drill-counterbore tools. The ultimate strength of bolted joints with dimple in the CFRP layer is higher than that in the aluminum alloy layer. In terms of the countersink fillet radius, both CFRP and aluminum alloy materials have the maximum strength when the countersink fillet radius is 1.0 mm. That is, the countersink fillet radius should be slightly larger than the bolt fillet radius, which is conducive to a better mechanical performance. Figures and Tables | References | Related Articles | Metrics

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RUL Prediction Method for Quay Crane Hoisting Gearbox Bearing Based on LSTM-CAPF Framework SUN Zhiwei, HU Xiong, DONG Kai, SUN Dejian, LIU Yang 2024, 58 (3):  352-360.  doi: 10.16183/j.cnki.jsjtu.2022.440 Abstract ( 96 )   HTML ( 4 )   PDF (5678KB) ( 252 )   Save The health condition of hoisting gearbox bearings of quay cranes is of great importance for the safety of port production. A remaining useful life (RUL) predicting framework for lifting gearbox bearings of quay crane under time-varying operating conditions is proposed. First, the working load is discretized and the condition boundaries are determined. Then, the long short-term memory (LSTM) network model is adopted to predict the load and the corresponding operating conditions. Afterwards, considering the degradation rates and jump coefficients under different operating conditions, the state degradation function is established based on the Wiener process. Finally, the condition-activated particle filter (CAPF) is used to predict the degradation state and RUL of bearings. The proposed prediction framework is verified by the full-life data of the hoisting gearbox bearings in a port in Shanghai collected by the NetCMAS system. A comparison with the other three prediction methods shows that the proposed framework is able to obtain more accurate degradation states and RUL predictions under time-varying operating conditions. Figures and Tables | References | Related Articles | Metrics

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Joint Policy Optimization of Quality Control, Condition-Based Maintenance and Spare Ordering for a Degradation System HAN Mengying, MA Shugang, YANG Jianhua, LI Wei, MA Zhichao 2024, 58 (3):  361-370.  doi: 10.16183/j.cnki.jsjtu.2022.356 Abstract ( 92 )   HTML ( 3 )   PDF (5697KB) ( 95 )   Save A joint policy of quality control, condition-based maintenance and spare ordering is proposed for a degradation system subject to the delay time concept. First, considering the fact that product quality is largely dependent on system state, a two-stage inspection policy is proposed, in which the system state is detected during the initial deterioration process, but the product quality is checked after the defective state is found by an inspection. Then, based on the condition inspection information, quality information and failure information, the corresponding maintenance activity is chosen. Combining the state of the spare part when the system replacement is required, all possible events during an inspection interval are discussed and then a mathematical model of average cost rate is established. Afterwards, a simulation-based optimization approach coupling discrete event simulation and response surface methodology is devised to obtain a near optimal joint policy. Finally, a numerical example is provided to demonstrate the effectiveness and applicability of the proposed policy by comparing it with the comparative policy. Figures and Tables | References | Related Articles | Metrics

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Comprehensive Analysis of Performance of Air Cooled Multistage Thermoelectric Cooler SUN Yuetong, MENG Fankai, ZHOU Lin, XU Chenxin 2024, 58 (3):  371-381.  doi: 10.16183/j.cnki.jsjtu.2022.451 Abstract ( 114 )   HTML ( 7 )   PDF (2314KB) ( 154 )   Save The multistage thermoelectric cooler can provide a larger temperature difference, but its refrigeration and economic performance decreases rapidly with the increase of stages. Considering all kinds of internal effects of thermoelectric materials and the irreversibility of external heat transfer, a finite time thermodynamic model of air cooling multistage thermoelectric cooler is established. The calculation method for cooling capacity and coefficient of performance are given. In order to describe and analyze the performance of multistage thermoelectric cooler comprehensively, the index thermodynamic perfectibility is introduced, and the performance evaluation index of coordinated performance coefficient is proposed. The effects of working current, cross-sectional area of thermoelectric leg and temperature difference on cooling capacity, coefficient of performance, thermodynamic perfectibility and coordination performance coefficient are analyzed. With the cooling temperature difference of 87 ℃, when the current is 2.55 A and 1.30 A respectively, and the cross-sectional area of the thermoelectric arm is 2.2 mm2 and 3.0 mm2 respectively, the cooling capacity and coefficient of performance reach the maximum respectively. Considering the refrigeration and economic performance, when the current is 1.75 A, the best coordination performance of cooling capacity, power consumption, and refrigeration coefficient can be obtained. Figures and Tables | References | Related Articles | Metrics

Materials Science and Engineering

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Effect of Adding Tantalum on Microstructure and Properties of NiTi Shape Memory Alloy Manufactured by Wire Arc Additive Manufacturing ZUO Xinde, CHEN Yi, LI Yang, LUO Zhen, AO Sansan 2024, 58 (3):  382-390.  doi: 10.16183/j.cnki.jsjtu.2022.254 Abstract ( 125 )   HTML ( 3 )   PDF (23304KB) ( 94 )   Save NiTiTa ternary shape memory alloy is a potential biomedical material, and wire arc additive manufacturing (WAAM) technology has been widely used in the research of NiTi alloys. It is of great significance to study the effect of Ta addition on the microstructure and properties of WAAM NiTi alloys. In this paper, 5-layer NiTi and NiTiTa alloy walls were fabricated by WAAM technology, and the effects of Ta addition on the microstructure, phase transformation behavior, mechanical properties and corrosion resistance of NiTi alloys were systematically studied. The results show that the grains of the NiTiTa alloy are remarkably refined compared with NiTi alloys, and the precipitation phase of NiTiTa alloy changes from Ni3Ti of NiTi alloy to Ni(Ti, Ta)2. In addition, the phase transition temperature of the NiTiTa alloy is significantly increased, which makes the phase at room temperature change from the complete austenite phase (B2) to a mixed phase of austenite (B2) and martensite (B19'). Tensile tests show that the tensile strength of NiTiTa samples is increased by 9.5% compared with NiTi samples, but the elongation is decreased by 6.8%. The polarization curve results show that the NiTiTa alloy has a higher corrosion potential and a lower corrosion current density, which means a significantly improved corrosion resistance. This paper lays a theoretical foundation for promoting the application of NiTiTa alloys fabricated by WAAM technology in the biomedical field. Figures and Tables | References | Related Articles | Metrics

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Inorganic Acid Doped Polyaniline/Carbon Fiber Composite Electrode as a Marine Electric Field Sensor HOU Xiaofan, SUN Jiuzhe, XU Jiawei, HU Chengru, FU Yubin 2024, 58 (3):  391-399.  doi: 10.16183/j.cnki.jsjtu.2022.156 Abstract ( 78 )   HTML ( 4 )   PDF (38540KB) ( 49 )   Save Carbon fiber electrode has the advantages of low cost, good chemical stability, and tunable performance, which can be utilized to develop high performance marine electric field sensors. Polyaniline/carbon fiber (PANI/CF) composite electrode doped with hydrochloric acid, sulfuric acid, and phosphoric acid are respectively fabricated by electrochemical in-situ polymerization, and their electrochemical performance and electric field response of the composite electrodes are studied respectively. The results show that conductive polyaniline film is uniformly formed on the surface of carbon fiber, and the characteristic redox peak occurs in the cyclic voltammetry test. Electrochemical impedance analysis shows that the low frequency (0.01 Hz) impedance of PANI/CF composite electrode decreases to at most 1/118 of that of the blank electrode, which is conducive to the quick response to weak underwater electric field signal. In the electric field response performance test, the potential drift of hydrochloric acid doped PANI/CF composite electrode is as low as 1.77 mV/d and it can better respond to 1 mV/10 mHz low-frequency and low-intensity electric field signal. It also has the minimum linearity error (0.111%), indicating the best response sensitivity among these modified electrodes. The preparation method of the composite electrode is simple and low-cost. Therefore, it is expected to be developed into a new generation of marine electric field sensor with low cost and high performance. Figures and Tables | References | Related Articles | Metrics

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A Fatigue Life Prediction Method for Fiber-Reinforced Composite Laminates XU Rongxia, GAO Jianxiong, ZHU Pengnian, WU Zhifeng 2024, 58 (3):  400-410.  doi: 10.16183/j.cnki.jsjtu.2022.312 Abstract ( 34 )   HTML ( 5 )   PDF (2766KB) ( 12 )   Save To address the fatigue life prediction problem of fiber-reinforced composite laminates, a method for predicting fatigue life was proposed by closely combining theory and simulation, unidirectional board and multi-directional laminate. Based on the fatigue test data of several sets of carbon fiber/resin-based T300/QY8911 unidirectional plates under cyclic stress, the fatigue life model and damage function of unidirectional plates were established by using the GM(1, 1) model of the gray system. Compared with the traditional least squares method fitting, this method improves the prediction accuracy. Stress analysis, failure analysis and material degradation of laminates were performed by finite element methods. The results of the failure analysis were combined with the established fatigue life model and damage function of the unidirectional laminate to calculate the fatigue life and damage of the multidirectional laminate. A comparison of the experimental data and those of other prediction methods indicates the prediction method established reduces the relative error of fatigue life prediction and the results predicted is in good agreement with the experimental results. Figures and Tables | References | Related Articles | Metrics