Pressure pulsation and radial force characteristics of dual-side impellers for the turbine energy recovery integrated machine

Abstract The inherent instabilities within the structure of the turbine-type energy recovery integrated machine (TT-ERIM) have the potential to compromise its smoothness and longevity, which could result in malfunctions. The dynamics of the dual-side impeller of TT-ERIM have been investigated through the use of computational fluid dynamics software (CFX) and the manipulation of the inlet flow rate. Pressure pulsation and radial force on each side under different flow conditions, and their impact on the hydraulic performance of the impeller and volute, are compared and evaluated through unsteady numerical calculations. The results show that the pressure fluctuation pattern of a centrifugal pump impeller is suboptimal at low flow rates, with fluctuations increasing as the flow rate falls below the rated value. Conversely, the pressure fluctuations of the turbine impeller remain consistent and are slightly reduced with excessively high flow rates. The generation of a negative pressure zone in the turbine impeller is indicative of an uneven overall pressure distribution. This research provides a theoretical framework for enhancing the TT-ERIM operational stability.