| 摘要 |
<p>Preferably a turbofan engine includes a fan blade (22), rotatably mounted within a generally cylindrical casing (18) for rotation about a lengthwise extending central axis. An annular lining (24, 26) is mounted within the casing between a tip of the fan blade (22) and the casing (18). The lining (24, 26) seals the tip of the fan blade (22) within the casing (18). The lining (24, 26) includes a brush seal (34) that extends around an inner circumference of the casing (18), and has a plurality of bristles (38) that extend radially inward from the seal (34). A retaining membrane (36) extends around the brush seal (34), preventing the bristles (38) from extending substantially in a radial direction from the brush seal (34). The retaining membrane (36) is adapted to release the bristles to extend radially inward to occupy a region between the tip of the fan blade (22) and the casing (18) upon a radial excursion of the fan blade (22). The bristles (38), once released, at least partially seal the tip of the fan blade (22) and the casing (18) reducing air recirculation at the blade tip.</p> |
