Analysis of the leakage path in an air-lubricated seal

An experimental methodology is described, conceived to support the design of an air-lubricated lip seal for pneumatic actuators. The aim of the work was to measure the very narrow gap occurring between a new radial sealing device and the counterpart during working conditions, when compressed air in the sealed volume detaches the mating surfaces, causing a small and controlled leakage flow. A spring-energized lip seal, suitably assembled, was chosen as case on study, and a Fizeau interferometer was employed to measure the leakage path thickness. In order to compare leakage data, numerical simulations were carried out by means of a commercial CFD code on the gap geometries defined during experiments. The achieved results are presented.