Abstract:

The objective of this present numerical work is to evaluate and compare the performance of the proposed outer overlap Bach type rotor with conventional simple Savonius rotor and modified Bach type rotor. In order to improve the performance of the modified Bach type rotor at low wind speed regimes, the outer overlap Bach rotor is proposed. Modeling and discretization of the computational domain with mesh is carried out using GAMBIT 2.4 and the analysis is performed using ANSYS FLUENT 14.5. SST k-ω turbulence model is used to achieve the closure for the governing equations. All the different blade shapes of the rotors are tested at same free stream conditions and the performance characteristics curves are plotted along with contours to visualize the flow physics over the rotor. The proposed outer overlap Bach type rotor showed an improved performance by 15% in terms of coefficient of power over the existing modified Bach type rotor. A Cp(max) of about 0.48 is obtained at a tip speed ratio of 0.60 by the proposed outer overlap Bach rotor.

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