Performance Analysis of a Helical Savonius Rotor with Shaft at 45° Twist Angle Using CFD

Rajat Gupta, Bachu Deb, R. D. Misra

Abstract


Helical Savonius rotor is considered to be superior to conventional Savonius rotor in terms of higher power coefficient (Cp) and better starting characteristic. However studies related to helical Savonius rotors is few. In view of this, in this paper, the performance of a helical Savonius rotor with shaft at 45° bucket twist angle for one complete cycle of rotation was analyzed using Computational Fluid Dynamics. A two-bucket helical Savonius rotor with shaft was designed using GAMBIT, having a height of 60 cm and diameter of 17 cm with 45° bucket twist angle. A three dimensional Computational Fluid Dynamics analysis using Fluent package was done to predict the performance of the rotor. Standard k-? turbulence model with second order upwind discretization scheme and standard wall condition was used. Grid independence test was also conducted to have the best meshing accuracy. Power coefficients (Cp) of the rotor at different tip speed ratios were evaluated for rotor angle variation from 0° to 180°. Cp at each rotor angle increased with increase of tip speed ratio up to an optimum tip speed ratio, but then decreased even if tip speed ratio was further increased. Moreover, the effect of rotor angle on Cp in a complete cycle of rotation was analyzed. Cp was found to be positive at all rotor angles, and higher values of Cp were obtained at rotor angles namely 45°, 90°, 225° and 270°, which would contribute maximum power production by the rotor. In addition to these, flow physics of the rotor was studied using tangential velocity plots w.r.t. rotor angle and path lines across the rotor. It was found that at 45°, 90° and 135° rotor angles, maximum concentration of the path lines near the tip of the blades in the upstream and downstream side of the rotor had occurred, which would be responsible for generation of maximum power coefficient in its clockwise rotation.

Full Text: PDF DOI: 10.5539/mer.v3n1p118

Refbacks

  • There are currently no refbacks.


Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.

Mechanical Engineering Research   ISSN 1927-0607 (Print)   ISSN 1927-0615 (Online)

Copyright © Canadian Center of Science and Education

To make sure that you can receive messages from us, please add the 'ccsenet.org' domain to your e-mail 'safe list'. If you do not receive e-mail in your 'inbox', check your 'bulk mail' or 'junk mail' folders.

------------------------------------------------------------------------------------------------------------------------------

lockss_logo_2_120 images_120. proquest_logo_120

doaj_logo_new_120