Variable geometry nozzles for turbomachines

摘要

An exhaust nozzle for a gas turbine engine comprising a duct 17(c) extending along an axis and having at a dowstream end thereof a mechanism for varying the geometry and area of the nozzle. The mechanism 28 comprises an axially translatable member 28 which has a face 29 extending in a direction transverse to the axis of the duct 17(c) against which pressurized gases flowing through the duct acts to balance out the loads on the flaps. A plurality of flaps 38,43 are spaced circumferentially around the axis of the duct. The flaps 38 are pivotally attached to the axially translatable member 28 and are provided with a cam follower 40 that co-operates with a cam 37. The cams 37 are fixed relative to the duct 17(c) and thereby defines the attitude of each flap 38 relative to the member 28. Seal plates 41 and 45 cover the gaps between adjacent flaps 38 and 43 to the seal plates 45. A plurality of struts interconnect the member 28 and the second flaps of the pivotal attachment of the flaps 43 to the flap 38. A set of flaps 47 are provided to provide fairing between the downstream ends of the member 28 and the flaps 43. In operation axial movement of the member 28 moves the flaps 38 and 43 to different positions.