Study of operating mode of axial and centrifugal pumps with hydroabrasive wear of parts in flow section of pumping units

Abstract

To date, a significant amount of work has been done to study the processes of cavitation and hydroabrasive wear in laboratory conditions. Using existing equations for assessing hydroabrasive or cavitation wear leads to certain inaccuracies since the action mechanism underlying them does not correspond to the actual operating conditions of hydraulic machines. Very little has been studied about the issues associated with joint and intense cavitation-abrasive wear, which always occur in fullscale hydraulic machines operating on natural watercourses with high turbidity. So far, the wear of the working bodies of centrifugal and axial pumps has been poorly studied, depending on the mode of their operation, and a methodology has not been developed for selecting operating modes, taking into account the wear of their parts. In this paper, the wear of parts of axial and centrifugal pumps in laboratory conditions is studied, and the dependences of wear on the characteristic dimensions and duration of their operation are given. The results of micrometering of the working parts of the pumps showed that the blades of the impellers along the length and width wear out unevenly both in size and shape. In axial and centrifugal pumps, the most intense wear occurs at the outlet sections of the impeller blades and their sealing elements. When pumping muddy water for 2000 hours, the sealing gaps of type D pumps with a head of 75–80 m are 2.8– 3.1 mm. With an increase in the end clearance of the impeller of an axial pump from the impact of a slotted cavitation-abrasive flow, the pressure value and the local concentration of solid particles in the flow play a leading role.