Interactive wear of abrasion and cavitation erosion and its influencing factors

Computational fluid dynamics(CFD) method was used to simulate the vapor,liquid and solid phase flow fields of a hydraulic turbine in working condition and to compare the flow behaviors near the turntable surface for the two cases of single cavitation erosion and cavitation-abrasion interactive wears.Influences of cavitation hole diameter and hole spacing on interactive wears were analyzed.Experimental tests of interactive wears in three-phase flow were conducted by using a rotating wearing device.Results show that pressure and vapor distributions on the turntable surface are significantly different in the two cases,and in a region around the cavitation hole,interactive wears are more severe than single cavitation erosion while abrasion often appears in the regions of greater volume fractions of vapor phase and greater pressure gradients.In the region around a certain cavitation hole,under interactive effects abrasion takes a fish-tail shape that expands in a certain angle along the hole edge in the rotational direction.This abrasion is intensified as the hole diameter or the hole spacing is decreased.In the latter case,cavitation erosion is superimposed on abrasion.Numerical calculations agree with the experimental results in terms of wear region shapes and wearing intensity on the turntable surface.