CFD Research on a Nozzle Inlet for a Hydrokinetic Power Generator*

Hydrokinetic power generation is directly correlated with water flow velocity. Existing turbine designs primarily focus on deployment in high-velocity water currents. To enhance turbine performance, this research investigates the use of a nozzle or concentrator to increase inlet flow velocity. The nozzle design aims to maximize flow acceleration while minimizing downstream flow recirculation, which can negatively impact turbine wake development.

A 1/64th scale model was constructed to experimentally evaluate nozzle performance. Results indicate a 20-30% increase in turbine inlet velocity with the nozzle. Performance comparisons between triplex and helical blade designs are underway, with measurements of turbine speed, power output, and efficiency. Additionally, the nozzle's impact is being assessed relative to commercial benchmarks like the MeyGen tidal turbine.

To complement experimental efforts, a transient computational fluid dynamics (CFD) model incorporating a rotating mesh is being developed. Accurate CFD simulations require meticulous geometry setup, mesh generation around inlet walls, and appropriate simulation parameters. Post-processing of CFD results will validate the model and provide further insights into nozzle performance.