Analysis of eccentric annular pressure seals : a new solution procedure for determing reactive force and rotordynamic coefficients

Typescript (photocopy).A new analysis procedure which solves for leakage, reactive force, and rotordynamic coefficients of eccentric annular liquid and gas pressure seals is presented in this dissertation. This analysis procedure is based on a perturbation technique and utilizes a turbulent bulk-flow model with Moody's friction factor. A set of zeroth-order equations and a set of first-order equations are derived from a perturbation of the flow variables. Solution to the zeroth-order equations yields leakage and reactive force: whereas solution to the first-order equations yields the rotordynamic coefficients. The solution for the zeroth-order equations are obtained by means of a new and efficient integration technique. Comparisons to existing experimental data indicate that predictions for liquid annular seals are very good. However, predictions for annular gas seals can not be verified due to lack of test data. The results of this study also indicate that in systems of relatively low rotor stiffnesses, a rotor eccentricity below 0.40 in annular seals has essentially no effect on the vibration characteristics of the rotor