Ryszard Szwaba

Leakage flow reduction in different configuration of labyrinth seal on a turbine blade tip

This paper contains experimental and numerical investigation of the leakage flow over the blade tip in turbine stage. Experiments were conducted in non-rotating linear channel. Test rig was intended to model the geometry of the labyrinth seal of the blades of the lower pressure turbine stage. Investigated model contained two different geometries of labyrinth fins. Moreover smooth and honeycomb stator landing were tested. Experimental measurements have been supported by CFD simulation which gives valuable information of flow structure in labyrinth seal and show complex flow physics in the investigated model.

Transition Effect on Shock Wave Boundary Layer Interaction on Compressor Blade

Intensive research on the laminar flow is carried out nowadays. The main objective is to keep the laminar boundary layer as long as possible for the drag or losses reduction, depending on the application. Nevertheless, in some applications, the laminar layer interaction with the shock wave may lead to a strong flow separation. The process of separation usually becomes unsteady and causes buffeting at airfoils and shock oscillations in the internal flows. Shock oscillation causes pulsation of pressure, and consequently a change of the blade load. The main objective of this research is to study the effect of transition on the flow structure of the shock wave boundary layer interaction. This paper focuses on the influence of boundary layer transition on the flow pattern in the blade passage of a compressor cascade. The main question is whether the induced transition upstream of the shock can improve the pressure unsteadiness and the flow downstream of the interaction. The results presented here concern experimental investigations and the used combination of various methods allowed gaining an insightful analysis of the application of transition control devices into a complex flow structure in a compressor cascade passage.