Analysis of the influence of blade attachments on the hydrodynamic behavior and energy performance of the tubular pump based on GPM and CFD

The impellers of coastal tubular pumps have long been submerged in water and are easily attached to various aquatic organisms, which seriously affects the energy consumption and safe functioning of tubular pumps. The flow field and energy performance of the impeller blade surface under various blade attachment area ratios (BAARs) were analyzed based on the multi-dimensional flow field dynamic analysis (MFFDA) method. The results show that changes in the flow rate and BAARs cause fluctuations in the circulation derivative along the relative position of the axial streamline, with the range of the circulation derivative decreasing from −50–80 m2 s−1 at 0.6Qbep to −10–30 m2 s−1 at 1.0Qbep and 1.2Qbep. As the BAARs gradually increased, the flow pattern became more disordered, and the flow pattern uniformity at the impeller outlet section improved; however, the velocity weighted average angle decreased. Blade attachments lead to a significant increase in the entropy generation rate (EGR) on the blade surface and a decrease in the efficiency of the pump device. As the flow rate and BAARs expand, the range of high EGR zones behind the blade attachments increases, and the EGR rises accordingly, from 2–7 W m−2 K−1 to more than 7 W m−2 K−1.