Evolution of flow features during transient operation of a Kaplan turbine

Other conference contribution, 2022

Hydraulic turbines are generally designed to continuously work at the best efficiency condition. However, due to the rapidly growing intermittent energy resources, the turbines are operated in transient, variable load, conditions. This causes additional stresses on the turbines and reduces their lifetime. Therefore, it is crucially important to study the transient flow field during these new operations. The current article presents the numerical simulation of a Kaplan turbine during transient operation. Such simulations involve a challenging mesh deformation procedure due to simultaneous change of guide vanes angles, runner blades angles, and runner rotation. The current work addresses the challenges in the mesh motion of Kaplan turbines transient operation. A novel numerical framework is developed in OpenFOAM to conduct this complicated procedure. The current framework is an improved extension of the previous methodology proposed by Salehi et al. 2020.