Computational performance analysis of a two-slotted bucket Savonius rotor

Abstract

The objective of the current computational study is to predict the performance output of a modified two-bucket Savonius rotor. Each bucket consists of three arc-type blades of different radius which is determined by the slot width ratio, in the range of 0.05 to 0.15 and the slot central angle, in the range of 0 to 20 deg. Nine configurations are designed with a fixed rotor diameter and a variable slot width and slot central angle, aiming to resolve the performance output and investigate the effect of the two previous parameters on the power and the static torque coefficients. The commercial CFD package Fluent® is used to solve the unsteady Reynolds-Averaged Navier-Stokes equations, along with Spalart-Allmaras turbulence model. Initially, a standard Savonius rotor, was used to validate the computational procedure using experimental results available in literature. Next, the same validated model is used to resolve the designed slotted bucket configurations. The performance of the examined slotted bucket configurations indicates improved self-starting characteristics, but a lower power coefficient compared with the solid bucket Savonius rotor. Lower values of slot width ratio have improved output performance while the slot central angle, does not greatly affect the overall performance of slotted bucket rotor.