Engineering evaluation and reflection on the operation stability of large-scale tubular pump

Abstract Large-scale tubular pumps are widely used in the fields such as low-head agricultural irrigation, water diversion project and urban drainage. For this pump type, the rotation axis is perpendicular to the gravity direction, resulting in the operation instability risks induced by the constant static pressure difference. However, due to the large size of prototype pumps and the difficulty of field tests, there is currently a lack of on-site monitoring data, which makes it difficult to truly understand the actual operation of large-scale tubular pumps and to provide engineering experience with direct guidance for similar projects. To fill this research gap, this paper takes the largest shaft-well tubular pump in China as an example, and the on-site monitoring of the prototype is carried out. On the one hand, the distribution characteristics of stability indexes such as pressure fluctuations, vibrations and shaft swings are quantified, and it is proved that the performance of large-scale tubular pumps cannot be estimated only by the hydraulic model experiments. On the other hand, the potential risks to be addressed such as the phenomenon of pressure polarization oscillation, low-speed-induced dry friction of bearing shells, and the cantilever-induced bending deformation of pump shaft are reflected, which should be paid more attention to in the future development. These research results can provide valuable engineering experience for the safe and stable operation of large-scale tubulars.