Clocking effect on the internal flow field and pressure fluctuation of PAT based on entropy production theory

Abstract

The high-quality development of energy is closely related to the efficiency of energy utilization, and improving the hydraulic performance of the pump as turbine (PAT) has become increasingly important. To investigate the influence mechanism of the clocking effect on the hydraulic performance of the PAT, an energy loss analysis method based on entropy production theory is used to explore its hydraulic performance and internal flow characteristics. The results show that the clocking effect has an impact on the PAT at all flow rates. Compared to the initial scheme, the efficiency of the C6 scheme is improved by 1.60 % and 1.93 % at the 1.0QBEP and 1.43 QBEP conditions respectively. From C1 to C6, as the guide vane clocking angle increases, the flow field near the tongue and guide vane improves, and the loss of the vortices in the volute weakens, consequently improving the hydraulic performance of the PAT. The clocking effect's influence on pressure pulsation is more significant at low flow rates, with the C6 scheme exhibiting the best pressure pulsation characteristics. The research presented in this paper reveals the cause of the clocking effect and provides a theoretical basis for the hydraulic optimization of the PAT.