ROTOR BLADE GEOMETRY OPTIMIZATION IN KAPLAN TURBINE

Abstract

This paper presents a description of the method and results of rotor blade shape optimization. The rotor blading constitutes a part of a turbine’s flow path.

The optimization consists in selecting a shape that minimizes the polytrophic loss ratio [1]. The shape of the blade is defined by the mean camber line and thickness of the airfoil. The thickness is distributed around the camber line based on the ratio of distribution. A global optimization was done by means of Genetic Algorithms (GA) with the help of Artificial Neural Networks (ANN) for approximations. For the numerical simulation of a flow through the model Kaplan turbine, the geometry employed in the model was based on the actual geometry of the existing test stage. The fluid parameters and the boundary conditions for the model were based on experimental measurements which were carried out at the test stand at the Department of Turbomachinery and Fluid Mechanics at the Gdansk University of Technology. The shape of the blading was optimized for the operational point with a maximum efficiency.