An impulse turbine with self-pitch-controlled guide vanes was proposed by the authors in the previous paper. The unsteady characteristics of this turbine have been investigated experimentally by the use of turbine test equipment in which the sinusoidally reciprocating flow conditions are simulated. The results have been compared with those of a Wells turbine. Furthermore, in I order to clarify the usefulness of quasi-steady analysis of this turbine, they have been also compared with the analytical results that are calculated on the basis of the experimental data obtained by the model testing of a turbine rotor with fixed guide vanes under steady unidirectional flow conditions. As a result, it has been clarified that the impulse turbine presented I here is superior to the Wells turbine both in I starting characteristics and design speed of rotor. The quasisteady analysis is available for this turbine.
In 1976, Dr.A.A. Wells proposed a form of selfrectifying axial flow air turbine, the so-called Wells turbine, as a device suitable for energy conversion in an oscillating water column. There are several reports which investigate the performance of the Wells turbine focusing in both the starting and running characteristics (Inoue, etl aI., 1985, 1986a, 1986b, 1986c, 1986d,1988, 1988, Kaneko, et aI., 1986, 1987, Raghunathan, et aI., 1982, 19~7a, 1987d, 1987c, 1989b, 1989c, Setoguchi, et aI., 1986). According to these results, the Wells turbine has inherent disadvantages lower efficiency, poorer starting and a high axial thrust in comparison with conventional turbine. So far, some new versions have been tried to overcome these points (Gato, et al.,1990, Hamakawa, et al.,1988, Inoue, et al.,1986b,1989, Kaneko, et al.,1990, Raghunathan, et al, 1987d, 1989a, Sarmento, et al,1987, Setoguchi, et aI, 1990, 1991). On the other hand, the authors have proposed an impulse turbine with self-pitch-controlled guide vanes, which is designed to develop a practical wave power generator system (Kim, et al., 1988,1990).
