EXPERIMENTAL AND NUMERICAL INVESTIGATION OF A THREE DIMENSIONAL BOUNDARY LAYER IN THE REGION BETWEEN A CASING AND A BLADE TIP

摘要

The present paper deals with the influence of three dimensional boundary layer flows in turbomachines on the stall behaviour and flow loss generation. For example, it is of interest to understand the flow phenomens of rotating stall or the separation in the region of the hub of the stator blades. The flow is very complex in this regions, because the mainly 2D-boundary layers of the blades interact with the boundary layer of the casing or hub, respectively. In the present paper a short review of two- and three dimensional boundary layer flows is given. It is explained, which role three dimensional boundary layer flows play in turbomachinery aerodynamics and how it is possible to investigate these flows by experimental and numerical methods in order to understand the major flow phenomens. The emphasis lies on a comparison between experimential and numerical investigations. It is described, which kind of separated flows can be treated by CFD.