A numerical investigation into the effect of diffusers on the performance of hydro kinetic turbines using a validated momentum source turbine model

Effect of shroud on the performance of horizontal axis hydrokinetic turbines

“…Comparing a few shroud models he later stated a cylindrical inlet degrades the turbine performance. Gaden and Bibeau (2010) using the commercial code ANSYS CFX simulated the turbine rotor blade as a momentum source region and found an enhancement factor of 3.1 for the same shroud used in the previous study. The inconsistency of the enhancement factors obtained in the two studies is stated to be due to the different methods used to simulate the rotor blade.…”

“…The theoretical analysis was done for an infinitely long circular cylinder as the shroud. In contrast to what Iwasaki obtained, Gaden and Bibeau (2010) and Isensee and Abdul-Razzak (2012) more than five decades later showed that a purely cylindrical shroud degrades the turbine performance. Lilley and Rainbird (1956) used the one-dimensional momentum theory and vortex theory to study diffuser augmented wind turbines.…”

Computational study of diffuser augmented wind turbine using actuator disc force method

“…It has been proved experimentally by several manufacturers that this practice increases the wind turbine performances when compared with the bare configuration [7,8]. Some independent studies, using primarily computational fluid dynamics (CFD), suggest a substantial rise in power production up to three times more than the bare turbine [9]. Nevertheless, details of these studies are not made available on public domain.…”

Numerical investigation of the power generation of a ducted composite material marine current turbine

“…Due to the limited space and manufacturing cost, it is important to know the relationship between the diffuser size and its performance benefits. Gaden and Bibeau (2010) found that increasing the area ratio gave increases in power initially but at higher ratios had only minimal benefits. This is expected intuitively due to separation and drag behavior.…”

“…The use of a diffuser as an option to increase the extracted power has been studied numerically and experimentally. Results have shown that the extracted power is larger than that of wind or water turbines without a duct (Gilbert and Foreman, 1983;Lawn, 2003;Setoguchi et al, 2004;Kirke, 2006;Ponta and Jacovkis, 2008;Gaden and Bibeau, 2010).…”