Session: 14-03 Turbine Cavities 1

Paper Number: 128735

128735 - Comparison of Rim Sealing Effectiveness in Different Geometrical Configurations 

Rim seals are employed to control the quantity of hot gas ingested inside the stator-rotor cavities of gas turbines in order to protect them from overheating. The determination of the correct quantity of sealing flow to be injected inside the wheel-space still represents a demanding task for engine designers who need to find a compromise between efficient protection of the components and minimization of the mixing losses arising from the use of an excessive quantity of purge. Moreover, the flow field developing inside the wheel-space is characterized by a complex unsteady behavior which still require expensive and time consuming CFD simulations to be accurately modeled.

The experimental characterization of the rim sealing effectiveness by means of scaled down geometries that replicate the rim seals found in actual engines still represent a widely used approach in literature. Most of the time, the effectiveness is experimentally measured by seeding the purge flow with a foreign gas, for example CO2, and then sampling the concentration at different radial positions on the stator surface. However, the obtained results can greatly depend on the specific geometry of the tested rim seal and different geometrical parameters may have an impact on the resulting effectiveness values.

This paper presents the application of the CO2 gas sampling technique to compare the performance in terms of sealing effectiveness of seven different geometrical configurations of radial rim seals. In particular, the tested geometries differ in terms of axial overlap, radial gap, and distance between the TE of the vanes and the LE of the blades. This approach allowed to obtain a comprehensive dataset that was then correlated by using the Orifice Model in order to investigate the relationship between the geometrical parameters and the performance of the different configurations.

Presenting Author: Lorenzo Orsini University of Florence

Presenting Author Biography: Ph.D. student at DIEF of University of Florence. The Ph.D. research is focused on the development and integration of experimental multidisciplinary methodologies for the study of secondary air systems and stator/rotor cavities in industrial and aeronautical gas turbines.

Authors:

Lorenzo Orsini University of Florence
Alessio Picchi University of Florence
Bruno Facchini University of Florence
Alessio Bonini Baker Hughes
Luca Innocenti Baker Hughes