A gas turbine engine comprising an upstream zone 3 and a downstream zone 7. The downstream zone is a fire critical zone that requires a predetermined flow rate of ventilation fluid during use. A convergent-divergent nozzle conveys fluid from the upstream zone to the downstream zone via a throat aperture 5, wherein the nozzle includes an assembly 9 movable to vary the size of the throat aperture of the nozzle, thereby regulating the flow of fluid to the downstream zone. The movable assembly may include a shape memory alloy (SMA) member. The shape memory alloy member may be actuated through application of heat, by passing an electric current through the member. There may be one or more heater elements controllable to heat the member. A spring member (11, figure 5) may be provided to urge the movable assembly. The shape memory alloy member may be a sheet member. The sheet member and spring member may be provided as a laminate sub-assembly. The shape memory alloy may be provided as a wire (13).
Convergent-divergent nozzle
2016-10-26
Patent
Electronic Resource
English
Convergent-divergent nozzle flows.
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