Numerical Calculation Of Heat Transfer Performance Of Self-lubricating Polyoxymethylene-based Composites Filled By Molybdenum Disulfide

As a general sliding bearing material, the steel-copper-plastics self-lubricating layered multi-phase materials are composed of low carbon steel, copper powder and polymer. It has better anti-oxidation, anti-corrosion and excellent running-in friction. It is widely used as self-lubricating bearing materials in case of few or no lubricating oil. However, heat transfer has an important influence on the tribological performance of the self-lubricating materials because the rubbing surface material is from polymer-based composites with lower heat transfer ability and lower melting point.In this thesis, it was selected polyoxymethylene (POM) composites filled by molybdenum disulfide (MoS₂) particles. A numerical method was used to establish a numerical model to predict the effective thermal conductivity. Based on this model two methods including finite element and effective heat resistance are proposed to calculate the effective thermal conductivity of the composites. It was found that their calculation results were similar.The thermal conductivity was not only affected by the filler content but also by the filler's shape and array in the composites. On the basis of studying the effect of M0S2 content on the effective thermal conductivity of composite, using the finite element method it was calculated the composites' effective thermal conductivity in which the filler shapes were sphere, square, rectangle and cylinder respectively. The calculation results showed that the filler shape played an important role in the aspect of effective thermal conductivity. As the filler was placed in transverse and lengthways in the composites, it gained obvious different results.The friction and wear experiments were carried out with the self-lubricating surface materials of pure POM or POM filled by M0S2 under end-face rubbing conditions. It was found that the friction coefficient and surface temperature of POM filled by M0S2 were lower than those of pure POM. According to the structure analyzing of each layer of self-lubricating composites filled by M0S2, the heat transfer model of the self-lubricating composites was established based on heat transfer theory, tribological principle, instant temperature distributions analyzed by using ANSYS software. The results showed that the simulation data were in good agreement with the experimental results.