Numerical analysis of heat transfer and flow of stator duct models

This paper describes the analysis of the fluid flow in stator ducts of a hydro generator using Computational Fluid Dynamics (CFD). The main object 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 the 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. Based on this research the conclusion can be drawn that the wall heat transfer coefficients are constrained by the quality of the mesh near the wall. Furthermore, the differences obtained lead to two particular turbulence models with different wall treatments, both of has been applied.