Writing Resources
As the speed of hydraulic machines increases these machines are more prone to cavitation erosion that reduces the machine performance and the lifetime Cavitation erosion is defined as the formation and subsequent collapse of cavities or bubbles that contain vapor or mixture of vapor and gas within a liquid 1 The collapsing of the bubble will produce highly localized large amplitude shock waves and or microjets that hit the solid surface in contact with the liquid Accumulation of this loading due to repeated collapses causes local surface damage The early features of the damage are pit formation and surface deformation These features rapidly develop and lead to a loss in the surface material This process of development is still controversial or ambiguous A vibratory cavitation erosion test is widely used in studying the erosion mechanisms 2 and factors influencing the erosion damage such as liquid properties test conditions It is well recognized that the rate of erosion is time dependent where this rate increases from trivial values reaches a maximum then decreases and levels off to a steady value 3 Therefore cavitation erosion rate of a material can be divided into four stages according to ASTM standards G 32 1 an incubation period an acceleration period a steady state period and attenuation period
