A Numerical Simulation of Horizontal Axis Hydrokinetic Turbine with and without Augmented Diffuser

Abstract

ABSTRACT: The hydrodynamic analysis of a horizontal axis hydrokinetic turbine is carried out, using a 3rd-generation diffuser. The turbine constituted of three blades and a radius of 0.75 m, using the hydrodynamic profile NREL S822 for the design of both the blades and the housing of the 3rd generation diffuser. Two horizontal axis hydrokinetic turbine with and without diffuser were meshed and subsequently hydrodynamically simulated using the ANSYS CFX 18.2® program in a transient state. As a result, the power coefficient ( ) CP of the turbine was obtained with and without a diffuser, in addition to the velocity profile of each model. The maximum power coefficient , . ( ) CP máx reached by the turbine with and without diffuser is 0.487 at a TSR of 9.948, and 0.285 at a TSR of 10.472, respectively, equivalent to an increase of 71% of CP with respect to the turbine without diffuser, and 82.1% with relation to the Betz limit. Speeds are reached between 1.5 to 2.1 m/s and 1.5 to 1.8 m/s, upstream of the turbine with and without diffuser, respectively, and from 2.3 to 2.6 m/s and 1.8 to 2.1 m/s downstream of it, in the same order.