Experimental study on an OWC radial-flow impulse turbine in steady and reciprocating airflows.

Self-rectifying air turbines, acting as a power take-off facility, can convert the incident pneumatic power to the shaft torque in the oscillating water column devices. The radial-flow impulse turbine (RFIT) is becoming popular because of its excellent operating performance. A generic RFIT model was designed and tested in constant and reciprocating airflows. The incident and torque coefficients are reported with the scatter diagrams of the turbine efficiencies. The steady-state efficiency in the constant airflow and the average efficiency in the reciprocating airflows peak at 0.48 and 0.49, respectively. The RFIT model has a significant difference in operation performance under the centrifugal and centripetal modes, and the varying frequency of the sinusoidal reciprocating airflows has a more obvious influence on the centripetal mode. In the comparison between two types of airflows with the same pneumatic power, the RFIT model is found to obtain a better performance in the reciprocating airflows. • A radial-flow turbine model was tested in reciprocating airflows experimentally. • Significant differences were observed under centrifugal and centripetal modes. • The varying frequency of airflow has a greater influence on the centripetal mode. • The turbine model can obtain a larger average efficiency in reciprocating airflows. [ABSTRACT FROM AUTHOR]