Optimization of impeller parameters for hydrodynamic turbine based on multi-objective orthogonal test design

Abstract The inherent instabilities within the structure of turbine-type energy recovery integrated machine (TT-ERIM) can compromise its smoothness and longevity, potentially leading to malfunctions. The dynamics of the dual-side impeller of TT-ERIM is research using computational fluid dynamics software CFX and manipulating the inlet flow rate. The 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 hydraulic turbine impeller is suboptimal at low flow rates, escalating at conditions below the rated flow. Conversely, the pressure fluctuations of the turbine impeller remain consistent and are slightly reduced with excessively high flow rates. Generating a negative pressure zone in the turbine impeller indicates an uneven overall pressure distribution. This research provides a theoretical platform for enhancing the TT-ERIM operational stability.