The effect of basin geometry on gravitational vortex hydropower

Abstract

This study aims to determine the shape of the conical basin that is suitable to be applied to the gravitational vortex hydropower (GVHP) by observing the shifting location of the core of water vortex. Three types of basin that will be observed are: a basin with cylindrical height of 20 mm (type A); a basin with conical height of 20 mm and cone angle of 60° (type B); and a basin with conical diameter of 50 mm, conical height of 20 mm, and cone angle of 45° (type C). There are two methods which were used, the analytical method was used to determine geometric parameters which affect water vortex formation, and then the numerical method was performed using computational fluid dynamics (CFD) with multiphase, transient-SST, and steady-state condition. Highest velocity was achieved with conical basin type B which will form a strong water vortex formation. If the velocity gets higher, the pressure will also drop. Velocity gets higher gradually until it reaches the outlet, which in turn causing pressure to drop gradually as well. This will create pressure differences which will cause a suction effect and form a strong water vortex. Thus, the conical basin (type B) was concluded to be a basin which creates a good water vortex formation.