SIMULATION STUDY WITH ARBITRARY PROFILE LIQUID ANNULAR SEALS

This paper presents an improved dynamic analysis for liquid annular se als with arbitrary profile based on a method first proposed by Nelson and Nguyen. An improved first-order solution that incorporates a conti nuous interpolation of perturbed quantities in the circumferential dir ection is presented. The original method uses an approximation scheme for circumferential gradients of zeroth order solution based on Fast F ourier Transforms (FFT). A simpler scheme based on cubic splines is fo und to be computationally more efficient, with better convergence at h igher eccentricities. Arbitrarily varying seal profiles in both axial and circumferential directions are considered. A procedure for computi ng dynamic coefficients based on external specific load is discussed. An example case of an elliptical seal with varying degrees of axial cu rvature is analyzed. A case study based on actual operating clearances (6 axial planes with 68 clearances/plane) of an interstage seal of th e Space Shuttle Main Engine High Pressure Oxygen Turbopump (SSME-ATD-H POTP) is presented.