SSME seal test program: test results for saw-tooth pattern damper seal.
Direct and transverse force coefficients for 11, saw tooth pattern, and damper seal configurations were examined. The damper seal uses a deliberately roughened stator and smooth rotor to increase the net damping force developed by a seal. The designation sawtooth pattern refers to a stator roughness pattern. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or dams. All seals use the same smooth rotor and have the same constant, minimum clearance. The stators examined the consequences of changes in design parameters axial groove depth, number of teeth, number of sawtooth sections, number of spacer elements, dam width, axially aligned sawtooth section versus axially staggered sawtooth sections and groove geometry. It was found that none of the sawtooth pattern seals perform as well as the best round hole pattern seal. Maximum damping configurations for the sawtooth and round hole pattern stators have comparable stiffness performance. Several of the sawtooth pattern stators outperformed the best round hole pattern seal. (A)
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