Influence of Blade Number on the Hydrodynamic Performance of a Propeller-Type Axial Turbine for In-Pipe Installation

Abstract

In-pipe hydraulic turbines are a promising energy-harvesting technology. Recent studies have demonstrated a strong influence of the turbine blade number on the performance of an axial propeller-type turbine. However, limited research has been dedicated to turbine diameters less than 100 mm. Therefore, this research aimed to determine the effect of the number of blades on the hydrodynamic performance of a 75.3 mm diameter axial propeller turbine for in-pipe installation. A parametric numerical study was performed by varying the angular velocity from 1600 to 3800 rpm and the number of blades from 2 to 6. Results identified an inverse correlation between the hydraulic efficiency of the turbine and its blade number and a direct correlation between the pressure head and the turbine torque. Furthermore, the performance showed hydraulic behavior comparable to those found in literature, confirming a similar hydraulic behavior as turbines with diameters exceeding 100 mm. Additionally, the turbine’s internal flow behavior was analyzed by visualizing the vortex structure using the Q-criterion. Lastly, this study provides a deeper understanding of the effect of the number of blades on the hydrodynamic performance of an axial turbine for in-pipe installation.