Innovative High-Temperature Compliant Surface Foil Face Seal Development

Heshmat, H. and Walton II, J.F.  “Innovative High-Temperature Compliant Surface Foil Face Seal Development,” AIAA/ASME/SAE/ASEE Joint Propulsion Conference, July 21-23, 2008 Hartford, Connecticut.

An innovative compliant surface foil face seal being developed for aerospace applications will be described and discussed in this paper.  Due to the requirements of gas turbine applications, this compliant surface face seal was designed to accommodate large system thermo-mechanical excursions in all three dimensions.  The systematic design methodology and key governing flow equations used to establish the design and predict performance will be presented and discussed.  Additionally, the experimental parametric evaluation that was conducted to verify feasibility of the design concept will be presented.  Test parameters varied included seal diameter, seal land length to radius ratio, axial preload and corresponding gap heights, surface velocity, and differential pressure.  A total of six different seal configurations were tested having outer diameters of 97, 112, and 229 mm. Projected surface area pre-load levels up to 145 kPa, surface velocities from 0 to 425 m/s and differential pressures up to and greater than 140 kPa were used.  Seal leakage was measured for each test condition, normalized to flow factor and compared to the developed theoretical/empirical model.  Results from the experimental program show that excellent sealing performance and correlation with the theory was achieved.  Based on the excellent correlations, flow factor projections to 690 kPa were made.  A review of the high temperature seal design and forthcoming testing at temperatures to 800ºC using Korolon® coating and a high temperature superalloy substrate will also be presented.

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