Study on Cavitation Erosion Mechanism of Ultra-High Molecular Weight Polyethylene (UHMWPE) and Polytetrafluoroethylene (PTFE)

Abstract

Polymer materials possess low density, high strength, corrosion resistance, and excellent cavitation erosion resistance. As a result, they are widely used in marine, water conservancy, and other engineering equipment as replacements for metal materials. However, polymer friction pairs working in a water environment for an extended period are easily damaged by cavitation erosion. In this work, the cavitation behavior of polytetrafluoroethylene (PTFE) and ultra-high molecular weight polyethylene (UHMWPE) in deionized water and seawater is investigated through experiments and computational fluid dynamics (CFD) simulations. The results indicate that the cavitation erosion resistance of UHMWPE is significantly better than that of PTFE, and the UHMWPE has four cavitation process stages, while the PTFE has only three cavitation stages. 316 L counterparts in the seawater corrosion and cavitation coupling effect of a large number of metal particles off and wash polymer material surface, so that the cavitation erosion of PTFE and UHMWPE is more serious in seawater environment. CFD simulation demonstrates that the cavitation erosion zone under the radiator shows a semicircular distribution. Meanwhile, the formation of ring-shaped cavitation pit is related to the distribution of bubbles on the surface of the radiator. The cavitation rate of PTFE and UHMWPE is slowed down by the “water cushion effect.”