Tribological Performances Of Representative Diatom Shell Structure And Its Application In Water-lubricated Bearing

Coscinodiscus sp. is a kind of typical diatom living in the hash marine environment.It is found that the multilevel porous structures of Coscinodiscus sp. have mechanicalperformances, such as elasticity and toughness et al. However, few research has beenmade focused on the tribological performances of these structures in the past years. Thetribological performances for the porous structures are first studied in present study.Based on this, tribological performances for the water-lubricated bearing with the abovestructure are simulated further. The associated conclusions obtained are desired to givehelpful references to control the lubrication faults of the water-lubricated bearing andimprove its transmission efficiency.The present study is sponsored by the National Natural Science Foundation ofChina (No:51375509), which is named as “Investigation of tribological performancesfor water-lubricated bearing using representative shell structures of diatoms”. The mainresearch contents are listed as below:Firstly, the cultural method for the diatom was introduced first, and then a set ofdiatom culturing device was invented and designed by the author and his advisor et al.Based on this equipment, the diatom was cultivated. Taking the coscinodiscus sp as theresearch object, its images, especially the surface topography, were observed andcaptured through ZEISS AURIGA double beam system equipment (Scanning ElectronMicroscope). The author’s observation reveals that the coscinodiscus sp shell ischaracterized by elaborate multistage porous structures.Secondly, a basic unit of Coscinodiscus sp. is chosen and its tribologicalperformances are studied with the fluid-structure interaction method (FSI) in the CFXmodel from ANSYS14.5version. The tribological performances, such as theload-carrying capacity (pressure-resistance ability), frictional force and frictioncoefficient of the diatom shell, are analyzed at different pore diameters, pore depths andspaces between the pores and compared those without the pore structures. Thenumerical results show that the single-layer pore structures of the Coscinodiscus sp.shell can increase its load-carrying capacity, and reduce the frictional force and frictioncoefficient. The result is verified through the similar experiments, which provide acertain reference for diatom shell tribology research.Based on the above research, the tribological performances for the double-layer pore structures of the Coscinodiscus sp. are analyzed at different pore sizes andcompared with the corresponding values of the single-layer pore structures and theimporous structures. It is found that the double-layer pore structure has the largestload-carrying capacity, followed by the single-layer pore structure and imporousstructure. The opposite trend holds for the friction coefficient of the above threestructures.Lastly, the surface texturing similar with the Coscinodiscus sp. porous structureabove is applied to the inner surface of the water-lubricated bearing. The acoustic powerlevel and relevant tribological performances are analyzed using the FLUENT fromANSYS14.5version. The simulation shows that the noise of the bearing, expressed inthe form of the acoustic power level, decreases due to the effect of the bionic structureabove. Within the range of a certain size, the noise declines with increasing dimpledepth. And a reduction in the noise depends on the dimple position. Moreover, theappropriate size and position of the dimple can improve the load-carrying capacity andreduce the friction of the bearing.