APPLICATION OF FLUIDIC CURTAINS TO TURBINE ROTOR TIP SEAL GEOMETRIES

摘要

Fluidic curtain sealing has recently been shown to offer strong potential especially when a combination of fluidic curtain and a conventional labyrinth seal is used. A series of fundamental dimensionless ratios have been proposed and the design space created by these parameters explored and validated experimentally using a simple annular test rig. The advance described in this paper is to use these design parameters to develop a set of engine realistic designs to demonstrate how a fluidic curtain seal may be realized in a high pressure steam turbine stage. Design tools of increasing fidelity are used to support this exploration; firstly basic ratios in the geometry and their known influence on performance are used to identify candidate geometries. CFD is used to demonstrate that previous performance predictions can be transferred to a realistic tip seal, and that candidate fluidic curtain seal designs are able to provide significant leakage reduction over the baseline seal design.