Dynamics of two-phase face seals

The effect of phase change on load support is studied analytically for parallel and tapered face seals. An adiabatic model for low Reynolds number flow is considered. The descriptive fluid equations are integrated numerically to give opening force due to fluid film pressure. Loci of steady-state solutions are plotted for water to give curves of load support as a function of film thickness. A quasi-steady transient analysis is made for axial excursions of the seal rings. The general conclusions are: 1. The load support generated by fluid pressure can be multivalued for a given film thickness. 2. Axial disturbances of the seal rings may lead to sudden drops in load support with three possible results. a. Sufficient damping may allow the seal to return to the previous equilibrium operating position. b. The seal may collapse to an equilibrium position of smaller film thickness where face contact is more likely and a significantly higher operating temperature is assured. c. A limit cycle of self sustained osci...