Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
Analysis of the impacts caused by the insertion of leading-edge tubercles over a Francis turbine runner
Submission Author:
Henrique Matos Campos , SP
Co-Authors:
Henrique Matos Campos, Leandro Salviano, ALUISIO PANTALEAO
Presenter: Henrique Matos Campos
doi://10.26678/ABCM.ENCIT2022.CIT22-0157
Abstract
Nowadays, hydroelectricity is the major source of electricity in Brazil, but due to the environmental impacts caused, the construction of new hydroelectric power plants became complex. To keep the development of this source of energy, one of the alternatives found in the literature is the modernization of the existing power plants, which can be done by the usage of passive devices. Among the alternatives of passive devices for turbomachinery verified in the literature, the insertion of leading-edge tubercles has stood out due to the positive results found for their application in tidal and wind turbines. But until now, the effects of the insertion of leading-edge tubercles in hydraulic turbines are unknown. With this study, we seek to solve this gap in the literature by verifying the impacts caused by the insertion of leading-edge tubercles over a hydraulic turbine. To do that, we developed a numerical methodology using the software Ansys CFX to verify and quantify the impacts of the insertion of leading-edge tubercles over the runner of the Francis-99 turbine. Also, during the study, we decided to test the effects of the main leading-edge tubercles parameters on the turbine performance. To accomplish our goals, first, we validated our methodology by comparing the results of the simulation of the Francis-99 original geometry with experimental data provided for the turbine operation and with other numerical studies done using this benchmarking geometry. After validating our methodology, we tested six different configurations of leading-edge tubercles considering variations in their amplitude and wavelength. As a result of our simulations, we obtained minor gains in torque generation without causing significant impacts on the equipment efficiency, especially for the turbine operating at its best efficiency point or high load conditions. Analyzing the effects of the leading-edge tubercles parameters on the turbine performance, we verified that the tubercles with higher values of amplitude and wavelength provided the highest gains in torque generation. For the final study, we pretend to detail our developed methodology, present our validation study, and the results obtained for the insertion of the tubercles over the Francis-99 turbine runner. Also, we want to test the impacts of the tubercles over the pressure and velocity fields to verify possible impacts in cavitation and in the flow separation and reattachment.
Keywords
Computational Fluid Dynamics, CFX, Francis Turbines, Leading-edge tubercles, Francis-99
