CFD investigation to quantify the effect of layered multiple miniature blades on the performance of Savonius rotor

Present study is focussed on improvement of the coefficient of performance (COP) of a Savonius rotor using numerical simulation software. Quantification of the improvement is based on the comparison of the coefficient of performance (COP) of a basic configuration constituting a conventional Savonius rotor to that of a modified configuration developed by adding concentric multiple miniature blades inside the rotor blades of the basic configuration. Validation and grid convergence studies are carried out using k-ε and Shear Stress Transport (SST) turbulence models. Validation study suggested Shear Stress Transport (SST) model as more accurate and better option in present study. Shear Stress Transport (SST) turbulence model is used in the numerical simulations of the modified configuration. Optimum level of grid refinement is achieved through grid convergence study. Boundary layer mesh is created on the rotor blades, by estimating distance of first mesh node from the wall using desired values of y+ for both k-ε and Shear Stress Transport (SST) turbulence models. An improvement in COP spanning between 8.1% and 11.34% is achieved with the modified configuration.