TITLE:
Wells Turbine for Wave Energy Conversion —Improvement of the Performance by Means of Impulse Turbine for Bi-Directional Flow
AUTHORS:
Shinya Okuhara, Manabu Takao, Akiyasu Takami, Toshiaki Setoguchi
KEYWORDS:
Fluid Machinery; Wells Turbine; Impulse Turbine; Wave Energy Conversion; Ocean Engineering
JOURNAL NAME:
Open Journal of Fluid Dynamics,
Vol.3 No.2A,
July
24,
2013
ABSTRACT:
Wells turbine has inherent disadvantages in comparison with conventional turbines: relative low efficiency at high flow coefficient and poor starting characteristics. To solve these problems, the authors propose Wells turbine with booster turbine for wave energy conversion, in order to improve the performance in this study. This turbine consists of three parts: a large Wells turbine, a small impulse turbine with fixed guide vanes for oscillating airflow, and a generator. It was conjectured that, by coupling the two axial flow turbines together, pneumatic energy from oscillating airflow is captured by Wells turbine at low flow coefficient and that the impulse turbine gets the energy at high flow coefficient. As the first step of this study on the proposed turbine topology, the performance of turbines under steady flow conditions has been investigated experimentally by model testings. Furthermore, we estimate mean efficiency of the turbine by quasi-steady analysis.