Performance Enhancement of Fluidic Diode for a Wave Energy System through Genetic Algorithm

Abstract

The oscillating water column (OWC) is an extensively studied wave energy converter that produces pneumatic power from the motion of the sea waves, which can be harvested using a pair of turbines without additional devices. However, its efficiency is hampered by poor flow blockage. Researchers have proposed a fluidic diode (FD) to improve flow blockage. Its performance is given by diodicity, which is the ratio of pressure drop in reverse to forward flow. A higher resistance in the reverse path signifies enhanced flow blockage, while a lower resistance in the forward flow minimises power loss at the turbine entry. In the present study, the numerical investigation was performed by solving three-dimensional unsteady Reynolds-Averaged Navier Stokes equations using ANSYS-Fluent 16.1 to simulate the flow behaviour inside the FD. Five geometrical parameters for FD were varied to obtain its optimal shape leading to a lower pressure drop in the forward direction and higher in reverse. The optimal shape was obtained through the genetic algorithm, showing a 12% improvement in performance compared to the base model. Detailed fluid flow and performance analysis of both base and optimum models are presented in this article.