Numerical investigation of the sealing capacity of centrifugal instabilities in shaft seals

VIONNET CA

INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW

Elsevier

Lugar: Amsterdam, The Netherlands; Año: 1995 vol. 16 p. 254 - 262

0142-727X

The study of a thin, incompressible Newtonian fluid layer trapped between two almost parallel, sliding surfaces has been actively pursued in the last four decades. This subject includes lubrication applications such as slider bearings or the sealing of nonpressurized fluids with shaft seals. In the present work, the flow of lubricant fluid through a microgap formed beween a synthetic seal and a rotary shaft is first analyzed using scaling arguments and then numerically. The study is initially carried out assuming that a "small-gap" parameter “delta” attains an extreme value in the Navier-Stokes equations. The precise meaning of small gap is achieved by the particular limit “delta” = 0, which, within the bounds of the hypotheses, predicts transport of lubricant through the sealed area by centrifugal instabilities. The incidence of temperature variations attributable to viscous dissipation of mechanical energy in the fluid properties is also investigated. Numerical results obtained with the finite element method are presented. In particular, the influence of inflow and outflow boundary conditions and their impact in the simulated flow are discussed.