Experimental study on 3D vortex gravitational turbine runner

Abstract

Vortex turbine is one of the solutions to utilize the low head hydro energy resources. In recent studies, researchers employ four main runner types, namely: flat radial, paddle, centrifugal, and modified form. The turbine performance can be increased by improving the turbine runner from these types into three dimensions (30) type. In this present work, the performance of a 30 type runner was designed and examined experimentally. The experiment showed that the maximum efficiency was around 24%, at rotational speeds about 90 to 120 rpm. The maximum efficiency was reached at the design condition. The turbine has demonstrated its capability to run from low rotational speed around 40 rpm to relatively high rotational speed 194 rpm. Compared with the previous runner profile, the 30 runner profile can produce a higher rotational speed and showed its stability to run in a wider range of rotational speed. At low rotational speed, power and efficiency decrease because water leaves the runner blade too fast before transferring its energy to the blade. Whereas at high rotational speed the water tends to be pushed out. The turbine performance and efficiency still can be increased by improving the runner profile.