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 grooved" theory, are expanded in the eccentricity ratio to yield zeroth and first order perturbation solutions. The zeroth order equations define the steady state leakage and the cirumferential velocity development due to wall shear for a centered rotor position. The first order equations define perturbations in the pressure and axial and circumferential velocity fields due to small motion of the rotor about the centered position. Numerical results are presented for proposed grooved seals in the High Pressure Oxygen Turbopump of the Space Shuttle Main Engine and for a water pump application.
author list (cited authors)
Childs, D. W., & Kim, C. H.