Session: 09-03-01 Tidal Energy: Design and Innovation

Paper Number: 128066

128066 - Vertical Axis Autorotation Current Turbine (Vaact) Analysis With Power Take-Off Systems 

This paper investigates the turbine total damping coefficient (Kt) on the performance of Vertical Axis Autorotation Current Turbine (VAACT) through simulations with two-dimensional Computational Fluid Dynamics (CFD) model. The verification and validation are performed using the recommended practices from the International Towing Tank Conference (ITTC). The verification of domain, grid and time-step are accomplished and the model results are compared to tests carried out at Laboratory of Waves and Currents (LOC-COPPE/UFRJ) to S-Shaped VAACT profile. The power take-off (PTO) system is modelled in the CFD environment adding an external torque due to PTO system and the damping coefficient  into a User-Defined Function (UDF). The validation is conducted to Reynolds number ranging from 70,000 to 135,000. The phase diagram of dimensionless angular acceleration versus tip speed ratio gives the turbine performs a limit cycle because of autorotation phenomenon at which  is not very sensitive to Reynolds number. However, both  and  do seem very sensitive to  because their phase diagram may become very irregular when the damping coefficient increases. The time series suggest both lift and drag forces have important role on turbine's performance. Although the instantaneous efficiency is in phase to drag force, lift is responsible to drive the device at smaller drag magnitudes. The analysis also shows the returning blade adds a resisting torque on the turbine which might affect its performance, being represented by a stagnation point at this blade.

Presenting Author: Rodrigo Batista Soares Federal University of Rio de Janeiro

Presenting Author Biography: Rodrigo Batista Soares is undergraduation at Naval Architecture and Ocean Engineering from Federal University of Rio de Janeiro (2021) and master degree by the same university (2022). He has been working on renewable energy devices such as vertical turbines and floating solar systems.

Authors:

Rodrigo Batista Soares Federal University of Rio de Janeiro
Antonio Carlos Fernandes Federal University of Rio de Janeiro
Joel Sena Sales Junior Federal University of Rio de Janeiro