Experimental Study on the Effect of Nozzle Angle and Blade Number on Hydro Turbine Performance

Abstract

This study investigates the effect of nozzle angle and blade number on the performance of a small-scale hydro turbine. Three nozzle angles, namely 15°, 30°, and 45°, were tested using three runner configurations consisting of 11 blades, 13 blades, and 15 blades. The turbine performance was evaluated under three flow rate conditions of 3.5 L/s, 4.5 L/s, and 5.6 L/s, and four electrical load levels of 0 W, 5 W, 10 W, and 15 W. The main performance parameters measured were generator rotational speed, voltage, and current. The results showed that both nozzle angle and blade number significantly affected turbine performance. Among the tested configurations, the 30° nozzle angle consistently produced the highest generator speed and voltage output, while the 11-bladed runner demonstrated the best overall performance compared with the 13-bladed and 15-bladed runners. In addition, turbine performance increased with increasing flow rate and decreased with increasing electrical load, whereas the output current showed a slight increase as the load increased. The highest performance was obtained at a flow rate of 5.6 L/s using the combination of a 30° nozzle angle and an 11-bladed runner. These findings indicate that proper optimization of nozzle angle and blade number is essential for improving the efficiency and output of small-scale hydro turbine systems.