Design and Testing Methodology for Motion & Vibration Characterization of Advanced Seals

Advanced seals like brush seals, retractable labyrinth seals, leaf seals and film-riding seals are flexible seals capable of accommodating radial and axial motions of the rotor relative to the stator in turbomachinery applications like gas turbines, steam turbines and aircraft engines. In addition to determining the leakage performance of these advanced seals, it is important from a seal-rotor interaction perspective to characterize the seal radial motion relative to the rotor and from a seal reliability perspective to characterize seal vibrations caused by the surrounding air flow. In this paper, we present the development of a high-pressure non-rotating test fixture to study aerostatic performance of a film-riding seal. We present test data for airflow actuated seal radial motion relative to a stationary rotor, flow-induced seal vibrations, and pressure fields around the seal and compare these test data with simple predictive models. We demonstrate the utility of this test fixture as a design tool for characterizing aerostatic performance of advanced seals and as a method for validating mathematical models for predicting seal performance.