波力発電用流体ダイオードに関する研究

（性能に及ぼすバイパスの影響）

抄録

A twin-impulse turbine for bi-directional flow has been developed for wave energy converter. However, the previous studies described that the mean efficiency of the twin turbine would be much lower than that of impulse turbine for a unidirectional flow, since a portion of airflow gets through the turbine under reverse flow whose efficiency is very low. For that reason, a fluidic diode was adopted in the twin impulse turbine in order to reduce the air flow through the turbine under reverse flow. In this study, we investigated the rectification effect of the fluidic diode when a blunt body was provided with a bypass. Computational fluid dynamics (CFD) analysis were conducted to investigate the effect of fluidic diodes on the turbine performance. In the CFD analysis, RANS equations are used as governing equations and the standard k-ε model is used as the turbulence model. The computational domain is composed of a circular tube and fluidic diode and meshed with an approximately 1.5 million mesh elements. As a result, it was found that the rectification effect of the fluidic diode was enhanced by installing a conical bypass with a bypass width ratio of d/D=0.088 and an angle of 44 degrees of a blunt body.