Numerical investigation on the effect of blade sweep on the performance of Wells turbine

A Wells turbine is one of the simplest and promising self-rectifying air turbines which is basic to the needs of the near future and likely to be economically viable. With the recent development in computer hardware and software, it has now become practicable to conduct a reasonable computation of three-dimensional turbulent flows through complex geometry. To investigate the effect of blade sweep on the performance of the Wells turbine, the numerical investigation was carried out under steady flow condition with a fully 3-D Navier–Stokes code for two kinds of blades, NACA0020 and CA9. As a result, it was found that the performance of the Wells turbine is considerably influenced by the blade sweep. The optimum blade sweep ratio (f=0.35) for the NACA0020 was found. This value is just the same as one obtained experimentally by the authors in the past. It was also found that the overall turbine performance for the NACA0020 is better than that for the CA9. It was shown that the numerical method is able quite well to predict the effect of blade sweep of the Wells turbine. The detailed flow patterns for several blade sweeps were also shown and discussed in this paper.