Papers by Author: Chun Li

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Authors: Qian Feng Fang, T. Liu, Chun Li, X.P. Wang, G.G. Zhang
Abstract: In this paper, we review the damping mechanisms in oxide materials, such as the short-range jump of oxygen vacancies and cation vacancies, movement of domain walls, and grain boundary sliding. Some examples in doped ZrO2, La2CuO4+δ, La2Mo2O9 and other oxide materials are briefly discussed, in which the damping capacity can reach as high as 30%. These oxides could be possibly applied as high damping materials either in the form of bulk components, or as additives in composites, or as hard damping coatings. In the last two potential applications, the high hardness and strength as well as high damping capacity of the oxides are simultaneously exploited, which cannot be realized by the usual high-damping metals and alloys.
Authors: Chun Li, Jia Xuan Wang, Hua Qing Miao
Abstract: In this paper, based on the liquid forging part flange LY12, the influence of heat treatment on the organization and performance of the liquid forging part was studied through microstructure, mechanical properties and tensile fracture surface analysis methods, this article also has some guiding significance to the formulation of the best liquid forging process parameters. The results show that the sample after natural aging which mechanics performance is best, and grain is relatively small; the latter two that after artificial aging are relatively poor. With the extension of artificial aging time, the mechanical properties and the organization has a descending trend.
Authors: Zhou Ye, Hai Yang Zhao, Yang Yang, Chun Li, Wei Gao
Abstract: The flow in a single-stage fan is analyzed through numerical simulation. The results indicate that there exists a best prewhirl angle which can make flow loss minimal at a given flow rate. So we can improve the internal flow field structure by changing the prewhirl angle, thus the fan efficiency can be raised. In addition, the flow separation on the suction surface is sensitive to the variation of the prewhirl angle. The range of the separation on suction surface increases with the decrease of the prewhirl angle, and expands to the central area of the blades.
Authors: Jia Xuan Wang, Chun Li, Li Hong Jiang, Min Fang
Abstract: In this paper, semi-solid slurry was prepared by power ultrasonic on flowing A356 melts. A simple device of ultrasonic treatment was made and the method of applying power ultrasound from the top of ingot was adopted. we investigated the influence of the experimental parameters impact on the size and morphology of the primary phase α-Al in A356 slurry, which included the power of the power ultrasound, treatment temperature and the distance between ultrasonic source and the melts ( here refer to from vibration head to the bottom of melt channel in this paper). The regularity of ultrasonic influence on grain refinement and morphology spheroidizing of primary phase α-Al in A356 alloy were obtained. The results show that when the loading power range from 800W to 1000W, the grain refinement effect goes more obviously with the increasing power of ultrasonic, howerer, when the power is up to 1500W, the effect goes worse; and the best primary phase is obtained at 615 oC among the four treatment temperature (645 °C, 630 °C, 615 °C, 600 °C); with the increase of the distance, among the four groups data (7mm, 9mm, 12mm, 15mm), the microstructure of A356 alloy goes more coarse and the segregation is more serious, the average grain size and form factor of the best primary phase α-Al was 29.47um and 0.78, respectively in this study.
Authors: Zhou Ye, Hai Yang Zhao, Lu Zhang, Chun Li, Wei Gao
Abstract: Taking the relative tip clearance as the variable, we numerically simulated the effect of tip clearance size on the performance of a straight-blade axial flow fan using the 3-D viscous flow solver. The tip clearance is referenced in the relative value. By comparing the flow field corresponding to five different values of the tip clearance 0, 0.5%, 1.0%, 1.5% and 2.0% with other parameters kept constant, we concluded that the changing of the tip clearance has a great influence on the performance of the axial flow fan. Both the efficiency and the total pressure decrease with the increase of the tip clearance.
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