CFD analysis of the performance of a novel impeller for a double suction centrifugal pump working as a turbine

A novel impeller, designed for double suction centrifugal pumps, has been recently proposed, showing higher performance than the baseline with a back-to-back configuration. The impeller is characterized by a new arrangement of its vanes, which come up alternately on the same circumferential exit actually, doubling the number of blades at the outlet. These characteristics may be helpful to effectively harness energy when the pump is used as a turbine, since the higher number of blades improves the flow guidance at the inlet of the runner and the new shape of the vanes reduces the losses inside the channels. This work aims to quantify the improvement in terms of performance as a PaT of the new design with respect to the baseline. Both configurations have been investigated by means of 3D U-RANS simulations. Furthermore, the rotary stagnation pressure inside the vanes at their best efficiency points and their characteristic curves have been calculated and compared. Eventually, advantages in terms of power coefficient and space saving have been pointed out by scaling the novel geometry.