A comparison between entropy generation analysis and effrst law effciency in a monoplane Wells turbine

Abstract

Wells turbine is a promising self-rectifying device in the field of ocean wave energy conversion. This study presents an Entropy Generation Analysis (EGA) of isothermal ow through a monoplane Wells turbine. The numerical computation has performed by solving the steady, incompressible, and three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations with RNG k " turbulence model in a noninertial reference frame rotating with the turbine rotor. Then, local entropy generation rates, related to viscous dissipation around rotor blades, were calculated from the velocity fields. The results indicate that separation and boundary-layer interaction have a direct effect on the entropy generation. The blade entropy generation decreases from hub to tip and from leading edge to trailing edge in suction surface. Also, the result of comparison shows that the point of minimum entropy generation coincides with the point of maximum first law effciency of thermodynamics. The results prove that viscous entropy generation distribution provides designers with useful information about the causes of ow irreversibilities. Future monoplane Wells turbine designs should concentrate essentially on optimizing the blade geometry.