Numerical and experimental evaluation of the performance of a gravitational vortex turbine rotor

In this study, the evaluation of the rotor performance of a gravitational vortex turbine (TVG) for its application in distributed power generation is presented. A numerical analysis was carried out on a specific configuration of a TVG, characterized by its spiral inlet and conical discharge. The dimensions of the discharge chamber and the inlet channel, such as the inlet channel width (w), length (L), and height (h), the discharge cone height (H) and diameter (d), and the envelope angle (γ) were determined through previous optimization studies documented in the literature. These dimensions are related to the basin diameter (D), which was set at 500 mm for this study. The ratios used, such as L/D, h/D, H/D, γ w/D and d/D were 1.518, 0.565, 1.572, 92.41°, 0.362, and 0.108, respectively. The rotor has a curvature and a helical pitch angle of 68.8°, has 6 blades, a rotor height of 200 mm and the middle section of the rotor is 314.4 mm (0.4H) from the top of the discharge cone, with an lower and upper diameter of 151.60 mm and 284.44 mm. Using a three-dimensional computational domain and unsteady flow simulations, efficiency curves as a function of angular velocity were obtained. In addition, the TVG was manufactured and experimental tests were carried out on a laboratory-scale test bench to validate its performance. These tests allowed us to compare the experimental results (33.84% at 88 RPM) with the numerical results (32.67% at 106,667 RPM), revealing a difference of 3.37% between the maximum efficiency values. It is essential to continue the turbine optimization process to ensure that the designed TVG plays a role in fostering sustainability and facilitating the shift towards cleaner and sustainable energy alternatives. Key words. Gravitational vortex turbines, distributed generation, renewable energy, hydraulic efficiency.