The authors presented hydraulic characteristics of a newly developed cross-flow turbine for a wave power plant. This turbine could be rotated in a fixed direction in the oscillating flow and could take off the power continuously from the wave. The performance tests were carried out on the turbine and the relation between the take-off power and the applied load was investigated. In addition, the behavior of a vortex formed in the runner was visualized.
The large energy resource available in waves has long been recognized and after twice oil crisis, a number of concepts for wave energy conversion systems have been developed (Lewis, 1985). The pneumatic system for primary power conversions has the advantage it acts as a speed mu1typ1ying devise. The most successful system is the Wells Turbine which has a self rectfying characteristic and a large number of tests have been carried out on the turbine (Lewis, 1985). However, the turbine has some problems such as the small starting torque or the noise with high speed rotation. In this paper, we propose the use of a cross-flow turbine for a wave power plant. This system introduce directly a oscillating flow of wave into the turbine. The turbine has two symmetrical nozzles around about a cross-flow runner and they function as a nozzle or diffuser with the change of flow direction. It is shown that this turbine is rotated in a fixed direction in the oscillating flow produced by wave and can take off the power continuously from wave.
Figure 1 shows the outline of a turbine for a wave power plant. The turbine was composed of runner, casing and guidevanes, and was axisymmetry about a runner axis. We used the guidevane which indicated the highest efficiency in the steady flow experiment.
