ANALYSIS FOR ROTORDYNAMIC COEFFICIENTS OF HELICALLY-GROOVED TURBULENT ANNULAR SEALS.
An analysis for helically-grooved turbulent annular seals is developed to predict leakage and dynamic coefficients, as related to rotordynamics. The grooved surface pattern is formulated as an inhomogeneous directivity in surface shear stress. The governing equations, based on both Hirs' turbulent lubrication theory and 'fine-groove' theory, are expanded in the eccentricity ratio to yield zeroth and first-order perturbation solutions. Numerical results are presented for proposed grooved seals in the High Pressure Oxygen Turbopump (HPOTP) of the Space Shuttle Main Engine (SSME) and for a water-pump application. The results show that an optimum helix angle exists from a rotordynamic stability viewpoint. Further, a properly designed helically-grooved stator is predicted to have pronounced stability advantages over other currently used seals.
author list (cited authors)
Kim, C. H., & Childs, D. W.