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Variable Speed Leakage Characteristics of Scroll Compressors for Miniature Compressed Energy Storage

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SSRN 2024年

作者： Qi, Shijia Liu, Zhen Li, Zheng Zhang, Zhichao Huang, Tengjun Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle Hubei University of Arts and Science Hubei Xiangyang441053 China School of Automotive and Traffic Engineering Hubei University of Arts and Science Hubei Xiangyang441053 China Department of Mechanical and Construction Engineering Northumbria University Newcastle upon TyneNE1 8ST United Kingdom

Scroll compressor is especially suitable for miniature compressed air energy storage systems. This paper analyzes the influence of rotational speed on the radial leakage characteristics of a scroll compressor by developing a three-dimensional transient numerical model with radial clearance. In this model, the fluid flow in the chamber of the scroll compressor at different rotating speeds is simulated using the dynamic grid technology. The method of monitoring points is used to obtain a lot of flow field information in the chamber during the working process, thus revealing the change in the transient flow field in the chamber and the influence of rotational speed on compression performance. The results show that within a certain speed range, when the power consumption increases, the deviation between the theoretical volume flow rate and the actual volume flow rate increases with the increase in speed, but the leakage loss gradually decreases. The leakage flow disturbs the uniformity of flow field distribution in the corresponding chamber but does not change the evolution trend of the flow field. The air flow rate in each chamber is gradually increasing. Still, the upstream diffusion of the leakage air flow temperature in the same compression chamber is blocked, which leads to a gradual decrease in the air temperature in the corresponding chamber. As a result, the temperature in the chamber gradually becomes evenly distributed, and the high-temperature region is increasingly concentrated in the downstream region of the compression chamber. The results of this study provide a theoretical basis for the prototype's improvement and optimization by analyzing the scroll compressor's performance parameters in practical work. © 2024, The Authors. All rights reserved.

关键词： Numerical models

Distribution Pattern and Differentiation Thresholds of Gas Content in Large Oil-Filled Equipment

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Distribution Pattern and Differentiation Thresholds of Gas C...

IEEE Conference on Energy Internet and Energy system Integration (EI2)

作者： Rui Liu Shilong Niu Li Chen Qing He Tianhe Yang Meng Huang State Grid On-site Test and Evaluation Technology Laboratory for High Voltage Electrical Equipment (Hubei Electrical Power Research Institute) Wuhan China State Key Laboratory of New Energy Power System North China Electric Power University Beijing China State Grid Hubei Power Co. Wuhan China

In the existing threshold calculation methods, there are problems such as establishing distribution models based on large group data of different types of oil-filled equipment, or specifying the threshold using normal dissolved gases analysis (DGA) data of some individuals while fault data of others, etc. In order to address these problems, this paper proposes a differentiation gas content threshold calculation method applicable to large oil-filled equipment individuals. The method is based on the gas content normal data and fault data of individuals of oil-filled equipment, establishes parameter model based on the Weibull distribution to fit the data, and uses the inverse cumulative distribution function and the P-R curve to calculate and select the reasonable thresholds as the attention value and warning value. The differentiated thresholds are obtained for five kinds of large oil-filled equipment individuals, and compared with the traditional threshold calculation method, the thresholds obtained by this method are more effective in identifying defects and faults, and can significantly reduce the occurrence of false alarms and omissions.

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Measurement of 3d Pavement Morphology Using Improved Binocular Reconstruction Under Structured Light Constraint Mechanism

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SSRN 2024年

作者： Wang, Yuanyuan Zhang, Hengtong Shu, Haicheng Wang, Zhongren Xue, Jinshun Yang, Jianhua Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle Hubei University of Arts and Science No.296 Longzhong Road Xiangyang441053 China School of Mechanical Engineering Hubei University of Arts and Science No.296 Longzhong Road Xiangyang441053 China Enterprise Technical Center Bridge Construction Group Co.Ltd Xiangyang Road Xiangyang441023 China School of Civil Engineering and Architecture Hubei University of Arts and Science No.296 Longzhong Road Xiangyang441053 China

For the special object of asphalt pavement, due to dark surface color, weak regional texture, and inconspicuous features points, traditional binocular vision is not ideal for measuring the three-dimensional (3D) morphology. To achieve accurate measurement of 3D pavement morphology, this paper introduced sine-encoded stripe structured light and explores a matching strategy that combines image spatial domain information with frequency domain phase information. The phase shift iterative matching algorithm under structured light constraint mechanism was proposed. A binocular reconstruction measurement system was subsequently constructed to evaluate the measurement accuracy of the proposed algorithm and the measurement effect in real scenarios. The results show that the constraint effect of structured light enhances the effective matching between pixels and improves the measurement accuracy. The maximum absolute deviation measured by the proposed algorithm is only 0.4 mm, which can meet the precision requirements of 3D pavement morphology measurement. © 2024, The Authors. All rights reserved.

关键词： Morphology

Measurement of 3d Pavement Morphology Using Improved Binocular Reconstruction Under Structured Light Constraint Mechanism

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SSRN 2024年

关键词： Morphology

Research on visibility detection model optimization based on dark channel prior and image entropy and visibility development trend prediction

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IOP Conference Series: Earth and Environmental Science 2021年第1期826卷

作者： Hao Zhou Mingyu Dai Dapai Shi Yuchi Meng Boyang Peng Tingxuan Chen Vehicle Engineering Jilin University Changchun Jilin 130000 China Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle Hubei University of Arts and Science Xiangyang Hubei 441053 China

In this paper, a visibility detection model based on the dark channel prior and image entropy is established to improve the lane line detection algorithm. Our algorithm does not need to preset the target, nor is it affected by the camera calibration parameters and position. It transforms the visibility calculation problem into the atmosphere transmittance calculation problem and refines the required results through the guided filter, achieving more accurate and stable visibility estimation results. In addition, based on the changing regularity of the visibility over time obtained by the detection model, a mathematical model is established to predict the change of heavy fog. We use ADF to test the visibility obtained in the visibility detection model and calculate the autocorrelation and partial autocorrelation functions. Finding the original sequence non-stationary, we perform the difference on the data, remove all insignificant factors and then incorporate the data into ARIMA model for fitting, finally getting the fitting and prediction results. The results are found similar to the actual situation, indicating that the results obtained by the visibility prediction model are robust and reliable.

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Sub-Synchronous Oscillation Damping Controller design for Doubly-Fed Wind Turbines Considering Oscillation Frequency Detection

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SSRN 2024年

作者： Qin, Shiyao Wang, Zehui Li, Shaolin Chen, Renjie Jia, Lingjie Peng, Xiaotao China Electric Power Research Institute Haidian District Beijing China Hubei Key Laboratory of Power Equipment & System Security for Integrated Energy School of Electrical Engineering and Automation Wuhan University Wuhan China School of Electrical Engineering and Automation Wuhan University Wuhan China Wuhan Iron & Steel Design & Research Institute China

Doubly fed induction generators are widely used in wind power generation because of their efficient and low-cost power generation and active-reactive power decoupling control features. In this paper, we propose a parametric adaptive damping controller based on oscillation detection to address the problem of sub-synchronous oscillations in doubly fed induction generators connected to the grid by series compensation. This paper firstly constructs the impedance model of grid-connected doubly-fed wind turbine and analyzes the characteristics of the sub-synchronous oscillation based on impedance analysis and then concludes that the negative equivalent resistance at the resonance frequency is the reason for the sub-synchronous oscillation. Subsequently, a damping controller based on proportional resonance is designed, and a parameter design method is proposed by impedance analysis. Finally, the oscillation suppression effect of the controller is analyzed by time domain simulation and it is tested that the controller can suppress sub-synchronous oscillation and has adaptability in scenarios with different parameters. © 2024, The Authors. All rights reserved.

关键词： Wind turbines

Research on large equipment maintenance system in life cycle

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IOP Conference Series: Earth and Environmental Science 2017年第1期69卷

作者： Xiaowei Xu Hongxia Wang Zhenxing Liu Nan Zhang School of Automobile and Traffic Engineering Wuhan University of Science and Technology Wuhan 430081 China Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle Xiangyang 441053 China

In order to change the current disadvantages of traditional large equipment maintenance concept, this article plans to apply the technical method of prognostics and health management to optimize equipment maintenance strategy and develop large equipment maintenance system. Combined with the maintenance procedures of various phases in life cycle, it concluded the formulation methods of maintenance program and implement plans of maintenance work. In the meantime, it takes account into the example of the dredger power system of the Waterway Bureau to establish the auxiliary platform of ship maintenance system in life cycle.

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Field-Harmonic-Oriented design of Vernier Permanent Magnet Machine Towards High Torque Density and Low Torque Ripple

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Field-Harmonic-Oriented Design of Vernier Permanent Magnet M...

International Conference on electrical Machines and systems (ICEMS)

作者： Li Fang Dawei Li Yuanzhi Zhang Jiewen Wu School of Electrical and Electronics Engineering Huazhong University of Science and Technology Wuhan China School of Electricla Engineering and Automation (Hubei Key Laboratory of Power Equipment and System Security for Integrated Energy) Wuhan University Wuhan China College of Design and Engineering National University of Singapore Singapore

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