Deviation of Flow Pattern in Pelton Turbine Bucket Due to Angular Eccentricity of the Jet

Abstract

One of the primary operating issues for the hydropower sector is the severe degradation of the hydro-mechanical components of hydropower projects (apart from storage-type plants). The eroded pieces are regularly replaced with fresh ones (or repaired ones) and are fixed by welding. The templates created from sheets and utilized for bucket profile control during repair and maintenance have the drawback of not being able to record the angular deviation of the bucket profile. Additionally, secondary flows and bucket warping may be brought on by unequal loading, an eccentric jet, and changes in mechanical qualities. A relative angular eccentricity between the jet and bucket results from both of the aforementioned cases. This study aims to investigate how the angular eccentricity between the jet and bucket affects the flow behavior. Numerical flow analysis is done in this work to examine the impact of eccentricity on the Pelton turbine's bucket using the commercial Computational Fluid Dynamics (CFD) Fluent code ANSYS. To mesh, ANSYS ICEM was utilized, and the Volume of Fluid (VOF) method's implicit scheme formulation was employed to represent the transient state of the jet until a steady state was reached. For focal situations of jet-bucket interaction, the results of theoretical calculations, experimental observations, and numerical modeling were compared.