THE ROTOR DYNAMIC COEFFICIENTS OF ECCENTRIC MECHANICAL FACE SEALS

The Reynolds equation is extended to include the effects of radial def lection in a seal with two flexibly mounted rotors. The resulting pres sures are used to obtain the forces and moments introduced in the axia l and angular modes by the inclusion of eccentricity in the analysis. The rotor dynamic coefficients: relating the forces and moments in the se modes to the axial and angular deflection are shown to be the same as those presented in the literature for the concentric case. Addition al coefficients ave obtained to express the dependence of these forces and moments upon the radial deflections and velocities. The axial for ce is shown to be decoupled from both the angular and radial modes, bu r the angular and radial modes are coupled to one another by the depen dence of the tilting moments upon the radial deflections. The shear st resses acting upon the element faces are derived and used to obtain th e radial forces acting upon the rotors. These forces are used to obtai n rotor dynamic coefficients for the two radial degrees of freedom of each rotor. The additional rotor dynamic coefficients call be used to obtain the additional equations of motion necessary to include the rad ial degrees of freedom in the dynamic analysis. These coefficients int roduce additional coupling between the angular and radial degrees of f reedom, but the axial degrees of freedom remain decoupled.