Predicted Geometry Effects on Oil Vapor Flow Through Buffer-Gas Labyrinth Seals

Abstract

Mass transport characteristics of buffer-gas labyrinth seals operating in the flooded, nonmist regime were studied using numerical simulations. Discussion is given of the extension, to account for oil vapor mass transport, of a finite volume computer code that was previously validated using nonoil labyrinth hot-film anemometer as well as leakage measurements. A parametric study was conducted to obtain a first understanding of oil vapor transport from the liquid film on the stator wall and to assist oil seal designers. Various geometry effects with various oil film lengths were investigated. It was found in the present investigation that increasing the buffer gas pressure can increase the oil vapor mass flow to the process gas due to increased evaporation from the liquid oil film. In addition, it was found that buffer-gas mass flow is mainly affected by the clearance and the total flow area of the buffer-gas injection.