Numerical Analysis of Heat Transfer and Flow of Stator Duct Models

This paper describes the analysis of the fluid flow in the stator ducts of a hydrogenerator using computational fluid dynamics. The main objective is to define permissible simplifications of the model in order to speed up the simulation. Therefore, the rotor-stator interaction is significant and needs to be taken under consideration. The software package ANSYS CFX supports two possibilities to connect these two reference models for steady-state simulations, the Frozen Rotor and the Stage model. Their differences are shown on a couple of parameters comparing these completely different reference models. Another important aspect pointed out in this paper is a comparison of the fluid flow and the heat transfer along one of the stator ducts. Last but not least, a quality and sensitivity study has been accomplished. The dependence of the computed wall heat transfer coefficient on the quality of the mesh near the wall is illustrated. Furthermore, the differences obtained lead to two particular turbulence models with different near-wall treatments, both of which have been applied.