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Your search keyword '"Zheng, Jianxiao"' showing total 19 results
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19 results on '"Zheng, Jianxiao"'

2. Vibration Characteristics and Finite Element Analysis of Circular Flexure in Harmonic Gear Using Carbon Fiber Composites

Author

Zheng, Jianxiao, Zhang, Xiaokang, Guo, Baoliang, Chen, Zhuo, Chaari, Fakher, Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Haddar, Mohamed, Series Editor, Cavas-Martínez, Francisco, Editorial Board Member, di Mare, Francesca, Editorial Board Member, Kwon, Young W., Editorial Board Member, Trojanowska, Justyna, Editorial Board Member, Xu, Jinyang, Editorial Board Member, Rui, Xiaoting, editor, and Liu, Caishan, editor

Published
2024
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9. Analysis of motion characteristics of rail car under high-speed impact.

Author

WANG Fazhan, LI Wenxuan, YU Wenbo, ZHANG Jianyong, and ZHENG Jianxiao

Subjects
MOTION analysis, SPACE trajectories, LEGAL motions, SPEED limits, MATHEMATICAL models
Abstract

Aiming at the complex running state and instability state of rail car body under high-speed impact, a mathematical model of the collision force and overturning force of the car body is established by using the state space trajectory method of modern control theory. The program is written by Matlab language to solve the motion state of the rail car under high-speed impact, and then the change law of the motion state of the car body under different working conditions is obtained. The results show that the maximum nodding angle is related to the impact speed and the length-height ratio of the car body. The nodding angle increases with the increase of impact speed while decreases with the increase of length-height ratio. The turning radius of the rail is related to the turning angle. The limit instability state of the car body is affected by side-impact angle and varies with speed. The larger the speed, the smaller the allowable value. The stability of the car body motion state and the limit instability speed decrease with the decrease of the impact slope. With the increase of the impact slope, the stability of the car body motion state increases, and the limit instability speed increases. [ABSTRACT FROM AUTHOR]

Published
2023
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15. An improved semi-empirical model for thermal analysis of lithium-ion batteries

Author

Chang Yang, Juan Wang, Zheng Jianxiao, Yang Naixing, Hongya Yue, Xuefeng Zhang, and Fu Yonghong

Subjects
Materials science, General Chemical Engineering, Nuclear engineering, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Battery pack, 0104 chemical sciences, Ion, Diffusion process, Heat generation, Thermal, Electrochemistry, Entropy (information theory), Heat of combustion, 0210 nano-technology, Thermal analysis
Abstract

The key to accurate simulation the thermal characteristics of lithium-ion batteries is to develop a reliable estimation model of the battery calorific value, which is very useful to design the thermal management system of the battery pack. This paper proposes a semi-empirical thermal model with virtues of high computational efficiency and precision for thermal analysis of the lithium-ion battery. In this model, a generalized and simple equation is developed to calculate the heat generation rate of the battery on the basis of its thermogenesis mechanisms. Two experimental fitting equations are acquired to estimate the battery ohmic resistance and entropy change coefficient, and a general formula is derived for the polarization resistance based on an approximate model of lithium diffusion process. Then, the semi-empirical thermal model is established for the battery by using the proposed computational method of the heat generation rate. The galvanostatic discharging and charging processes of a prismatic lithium-ion battery are separately simulated at the different currents and temperatures, and the corresponding experiments are conducted for the model validation. The results show that the battery temperatures simulated by the proposed model are good agreement with the experimental data. According to the calculation, the mean absolute deviations of the simulated battery temperatures are 0.27 °C for the discharging processes and 0.17 °C for the charging process under the orthogonal conditions of the operation currents (0.3C, 1.0C and 2.0C) and the ambient temperatures (10 °C，25 °C and 35 °C). Compared with the theoretically based model, the proposed model exhibits a higher computational accuracy in the most operating regions and improves calculation speed by more than 4.0 times at the same grid density and time step setups. Consequently, the semi-empirical model proposed in this work is well-suited to pre-assess thermal characteristics and thermal management system schemes of the large-scale battery pack due to its superiorities of easy implementation, high computational efficiency and high precision.

Published
2019

17. A comparative assessment of the battery liquid‐cooling system employing two coolants: Phase change material emulsion and water.

Author

Yang, Naixing, Wang, Juan, Xu, Shiwei, Zheng, Jianxiao, Wang, Liangliang, and Yu, Juan

Subjects
ELECTRIC vehicle batteries, PHASE change materials, COOLANTS, EMULSIONS, ENERGY consumption, COOLING systems, HEAT capacity
Abstract

Summary: This work proposes a novel liquid‐cooling system that employs the phase change material (PCM) emulsion as the coolant for the battery pack. To compare the proposed scheme with the traditional water cooling system, a thermal model is developed for the battery pack with cooling systems, where the system start‐stop control and time hysteresis phenomenon are considered in simulations. The results show that either increasing the inlet velocity or temperature improves the battery temperature uniformity for the two schemes, but it enlarges the pumping energy consumption during the whole discharging process. Compared with the water cooling system, the proposed PCM emulsion cooling scheme can not only significantly decrease the battery temperature difference but also effectively shorten the system operating time. According to the calculation, the pumping energy consumption with using the PCM emulsions as the coolant decreases 18.9% in minimum and 66.6% in maximum than that with using the water as the coolant. Consequently, the proposed PCM emulsion cooling system is superior to the water cooling system in terms of the heat dissipation capacity, the temperature uniformity, the pump power requirement, and the pumping energy consumption, which is well‐suited for the cooling system of the battery pack in electric vehicles. In addition, the proposed thermal model can be used well to simulate the thermal characteristics of the vehicle‐mounted battery liquid‐cooling system under actual operating conditions. [ABSTRACT FROM AUTHOR]

Published
2022
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