| 摘要 |
1,111,195. Jet propulsion nozzles. GENERAL ELECTRIC CO. July 15, 1966 [Dec.8, 1965], No.31827/66. Heading F1J. The invention relates to an annular convergentdivergent nozzle for a jet engine comprising a duct within which is disposed a central plug so as to define a convergent-divergent gas flow duct. Flap means are pivotally mounted radially outwardly of the throat so as to form the divergent nozzle portion, the flap members being freely mounted so that they take up a position in dependence on the pressure difference thereacross. In a first embodiment as applied to a gas turbine jet engine comprising an exhaust gas flow duct 14 and an air flow duct 17, the nozzle comprises a central plug member 20 having a double conical surface 36. A series of adjustable flap members 22 are mounted at the downstream end of the jet pipe and define with the plug member an annular convergent duct and an annular throat 28, the flap members 22 being movable by means of an actuator 26. The annular divergent portion is provided by a series of flap members 32 which are pivotally mounted at their downstream ends 34 to a further series of flap members 30 which are pivotally mounted at their upstream ends 31 to the outer wall 18 of the air flow duct 17. The flap members 32 and 30 are freely mounted although the flaps 32 are connected by links 44 to the flaps 22 so as to maintain an annular air flow passage 42 therebetween. The flap members 30, 32 are thus free to take up positions dependent on the pressures prevailing within the nozzle and externally thereof, Fig. 2 being the position taken up during non-reheat or subsonic operation while Fig. 3 is that taken up during reheat, supersonic operation. In Fig. 4 the central plug member may be adjusted so as to vary the diameter thereof, as indicated at 50. The outer wall 48 comprises a frusto-conical portion 54 which together with the plug member defines the nozzle throat. At the downstream end of the frusto-conical portion 54 a series of flap members 56 are freely mounted at 58 and take up position dependent on the pressure difference thereacross.
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