Computational analysis of the effect of diffuser and swirl inducers on the performance of ocean current turbine

The increased need for power generation has led to exploration of the untapped naturally available, renewable energy sources. The researchers worldwide focus on the application of green engineering principles with the motive to create lesser or zero pollution of the environment. Ocean currents possess remarkable potential capability to generate power, worldwide. The average global tidal current velocity is 1.4 m/sec and the power generated by the horizontal axis ocean current turbine is influenced by the velocity of the marine currents. In the current study, a CFD analysis is performed using Ansys Workbench Fluent® to decide the shape of the diffuser to be added to the turbine and swirl inducers to increase the turbulence, which creates the increase in velocity of the fluid flow. The effect of shroud parameters (dimension, inclination, attachments) on the flow velocity and performance is studied. The study enables to decide the shape of the shroud to be added to the turbine. In addition, a performance analysis of the turbine is carried by varying the configuration of the swirl inducers. The swirl inducers influence the further enhancement of the tidal current velocity. In the current study, two swirl model configurations explored in the study, the second model extracted more power output in comparison to the first model. However, the results show that diffuser with swirl around the turbine can further accelerate the water at the entrance and a velocity coefficient up to 1.995. The turbine shall be located at a distance approx. 0.4 m to 0.7 m from the swirl inducer. Hence, the introduction of the shroud and the swirl inducers in the horizontal axis turbine is an effective way to improve its performance.