Abstract:
This document analyzes and improves the efficiency of a Pelton turbine located at the test bench in the laboratory of the Universidad Autónoma del Caribe. The study focuses on the variables associated with the injector, mainly the nozzle diameter and the inlet and outlet angles of the jet impacting the buckets, with the aim of ensuring that the turbine reaches the angular velocity (RPM) required to properly operate the Prony brake. This device is used to apply a controlled mechanical load and measure the power developed by the turbine.
Based on the above, the power and efficiency of the system are evaluated under different injector openings. Experimental tests were carried out using 6 mm and 12 mm nozzles, both with and without the brake. The results indicate that the performance of the Pelton turbine depends directly on the nozzle diameter, pressure, and flow rate. Variations in the injector diameter significantly modify the flow behavior, affecting the jet velocity, the available hydraulic power, and consequently, the mechanical efficiency of the system.
It was determined that increasing the nozzle diameter leads to an increase in flow rate and hydraulic power; however, the latter tends to stabilize beyond a certain opening, generating losses of useful energy that should be transmitted to the rotor. Specifically, with the 6 mm nozzle, flow restriction losses occur during the tests with the brake, negatively affecting efficiency; unlike the test without the brake, in which the efficiency remains stable.
In general, smaller-diameter injectors show better results in terms of flow rate, pressure, and jet velocity, achieving higher hydraulic and mechanical efficiency values. This behavior is reinforced by the specific speed, which is directly related to efficiency and reflects a better use of the energy transmitted from the jet to the runner.
