Variable stator cascades for axial-flow turbines of gas turbine engines

Abstract

This invention relates to a variable stator cascade for axial-flow turbines of gas turbine engines, especially for high-pressure turbines, where the turbine nozzle vanes are each pivotally arranged about an axis of rotation and are cooled when in operation. The inner and outer rings of the variable stator cascade are formed of interlocking inner and outer ring segments which provide circumferential sealing action where each turbine nozzle vane is pivotally arranged and disconnectably connected by respective root and tip side pivot pins in association with each respective inner and outer ring segments. A continuous inner stator ring, is centrally located at inner ring segments of the stator cascade by means of teeth and a slot-and-key arrangement whereby each outer ring segment arranged at the turbine casing cooperates with the vane attachment assembly to radially guide the nozzle vane and associated inner ring segment. A variable stator cascade is secured in radial, axial and circumferential position by means of the respective outer ring segments. The turbine nozzle vanes have at their respective root and tip sides, vane plates arranged in the area of the inner and outer walls of a turbine duct attached to which are the pivot pins arranged outside the turbine duct and which take the shape of tubular cylindrical cooling air ducts which communicate with the interior of the vane.