Mainshaft Seals for Small Gas Turbine Engines

Abstract

An experimental evaluation of mainshaft seals for small gas turbine engines was conducted with shaft speeds to 213 m/s (700 ft/sec), air pressures to 148 N/cm2 abs. (215 psia), and air temperatures to 412 K (282 F). A radial face seal incorporating self-acting geometry for lift augmentation was evaluated. In addition, three conventional carbon seal types (face, circumferential segmented, and rotating ring) were run for comparison. Test results indicated that the conventional seals used in this evaluation may not be satisfactory in future advanced engines because of excessive air leakage. On the other hand, the self-acting face seal was shown to have the potential capability of limiting leakages to one-half that of the conventional face seals and one-fifth that of conventional ring seals. A 150 hour endurance test of the self-acting face seal was conducted at speeds to 145 m/s (475 ft/sec), air pressures to 124 N/cm2 abs. (180 psia), and air temperatures to 408 K (275 F). The seal wear was not measurable. ...