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Research on MDO of ship propulsion shafting dynamics considering the coupling effect of a propeller-shafting-hull system

Liu Jinlin, Gu Zheng, Liu Shuyong

Polish Maritime Research

2023

nr 1

86--97

Dynamic designs for ship propulsion shafting can be categorised as complex multi-disciplinary coupling systems. The traditional single disciplinary optimisation design method has become a bottleneck, restricting the further improvement of shafting design. In this paper, taking a complex propulsion shafting as the object, a dynamic analysis model of the propeller-shafting-hull system was established. In order to analyse the coupling effect of propeller hydrodynamics on shafting dynamics, the propeller’s hydrodynamic force in the wake flow field was calculated as the input for shafting alignment and vibration analysis. On this basis, the discipline decomposition and analysis of the subdisciplines in design of shafting dynamics were carried out. The coupling relationships between design variables in the subdisciplines were studied and the Multi-disciplinary Design Optimisation (MDO) framework of shafting dynamics was established. Finally, taking the hollowness of the shaft segments and the vertical displacement of bearings as design variables, combined with the optimal algorithm, the MDO of shafting dynamics, considering the coupling effect of the propellershafting-hull system, was realised. The results presented in this paper can provide a beneficial reference for improving the design quality of ship shafting.

The effect of various surfactants on fatty acid for apatite flotation and their adsorption mechanizm

Liu Shuyong, Han Baisui, Zhao Tonglin

Physicochemical Problems of Mineral Processing

2021

Vol. 57, iss. 5

46--56

The synergistic effect of surfactants, i.e., Tween-80 (polyethylene glycol sorbitan monooleate), Span-80 (sorbitanoleate), and MES (fatty acid methyl ester sulfonates), on fatty acid collectors were investigated using single mineral flotation experiments, surface tension measurement, Fourier transform infrared spectrum, and contact angle measurements. The single mineral flotation experiments showed that it was possible to efficiently separate apatite from magnetite, quartz, and biotite by mixing fatty acids with surfactants. The surface tension measurement showed that the surfactants could significantly reduce the surface tension and Critical Micelle Concentration (CMC) of fatty acids. Fourier transform infrared spectroscopy analysis indicated that all of the surfactants did not react with the fatty acids, but only physically adsorbed on the surface of apatite, thus promoting the chemical adsorption of fatty acids on apatite. However, the surfactant chemisorbed on magnetite and competing with a fatty acid, which led to a decrease in the flotation recovery. The results for contact angle measurement showed that the contact angle difference between apatite and magnetite increased with the addition of surfactant, and resulted in an efficient separation.