Effects of Relative Position between a Stator and a Rotor on Steam Condensing Flow in Rotating Machinery

Abstract

Flow of steam is different from other gas flows and involves droplet generation in the flow field. This phase-transition affects not only flow aspects, but also machine performance in a negative way. These days, CFD is widely used in machine design and optimization processes, so phase-transition phenomena in steam flows should be considered in CFD to predict the internal flows precisely. In the past, non-equilibrium wet-steam model was implemented on in house code T-Flow and it was applied to steady calculations of a steam turbine model with changing stator/rotor interface. The results showed that mixing plane method is not appropriate to simulate steam condensing flow and frozen rotor method can be affected by relative position between a stator and a rotor. Therefore, steady wet-steam flows with non-equilibrium phase-transition were simulated for a steam turbine model in this study with 4 different stator-rotor positions and their effects on the wet-steam flow fields were investigated in detail.