Session: 23-14: Seal Turbomachinery Applications II

Submission Number: 178946

Innovative Eye Seal Geometry With Annular Fins Featuring Backward End Projections for Shrouded Centrifugal Compressors 

In centrifugal compressors, secondary losses significantly influence stage efficiency and, consequently, the overall performance of the machine. Among these losses, leakage through the impeller eye is particularly critical. Labyrinth seals, installed between the impeller shroud and the casing, are widely employed to mitigate this leakage due to their non-contact design. Their effectiveness is primarily based on the ability to limit the leakage mass flow from high- to low-pressure regions by dissipating kinetic energy through successive cavities and annular fins. The performance of labyrinth seals is strongly affected by both geometric and operational parameters, including clearance, annular fins number, and cavity depth. A new design of labyrinth seal was developed to reduce leakage and improve compressor efficiency. This innovative design includes a backward end projection at the tip of each annular fin, extending in a direction parallel to the impeller’s rotation axis. CFD simulations were firstly conducted to evaluate several shape ratio of this end projection, examining their influence on leakage flow. From these analyses, the configuration offering the optimal balance between performance, leakage reduction, and manufacturability was selected for experimental validation. The chosen design was tested on a single-stage centrifugal compressor test rig, and the results closely matched the CFD predictions, confirming the reliability of the design methodology and the effectiveness of the new seal configuration in reducing secondary losses.

Presenting Author: Marco Tarchiani University of Florence

Presenting Author Biography: Marco Tarchiani graduated in Mechanical Engineering at the University of Florence in 2024, where he is currently a Ph.D. student. His work involves the development and use of an experimental test rig for analyzing the performance of centrifugal compressors.

Authors:

Marco Tarchiani University of Florence
Luca Romani University of Florence
Stefano Rago University of Florence
Alberto Baroni Baker Hughes
Andrea Agnolucci Baker Hughes
Elisabetta Belardini Baker Hughes
Angelo Grimaldi Baker Hughes
Alessandro Bianchini University of Florence
Francesco Balduzzi University of Florence
Giovanni Ferrara University of Florence