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INDIVIDUALLY ACTUATED VARIABLE STATOR SYSTEM

IP.com Disclosure Number: IPCOM000245859D
Publication Date: 2016-Apr-13
Document File: 9 page(s) / 6M

Publishing Venue

The IP.com Prior Art Database

Abstract

This paper discloses a gas turbine aircraft engine design having an axial compressor featuring variable stator geometry and multiple stages wherein the multiple stages are separately controlled and are not mechanically linked. The engine compressor includes the compressor casing, unison (actuating) rings mounted around the compressor casing, and variable vanes. Each unison ring is mechanically connected to variable vanes by lever arms such that movement of unison ring results in a predetermined movement of the variable vane. In the traditional art the stages are kinematically connected such that their unison rings (and thus the vanes) move in one sequence, whereas in the proposed art each stage is actuated independently. The traditional art features one or two hydraulic motors per the system, while the proposed art features multiple electric or hydraulic motors per stage.

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INDIVIDUALLY ACTUATED VARIABLE STATOR

SYSTEM

ABSTRACT


[0001] This paper discloses a gas turbine aircraft engine design having an axial compressor featuring variable stator geometry and multiple stages wherein the multiple stages are separately controlled and are not mechanically linked. The engine compressor includes the compressor casing, unison (actuating) rings mounted around the compressor casing, and variable vanes. Each unison ring is mechanically connected to variable vanes by lever arms such that movement of unison ring results in a predetermined movement of the variable vane. In the traditional art the stages are kinematically connected such that their unison rings (and thus the vanes) move in one sequence, whereas in the proposed art each stage is actuated independently. The traditional art features one or two hydraulic motors per the system, while the proposed art features multiple electric or hydraulic motors per stage.

BACKGROUND


[0002] The present disclosure relates to engines having variable geometry and more specifically to actuation of the variable geometry using multiple electric motors or actuators connected to unison rings such that stages are separately controlled.


[0003] Conventional control of multiple unison rings in a variable geometry engine is generally provided through mechanical linkages. In these engines, a single actuator (or two actuators working in the same schedule) is mechanically linked to multiple independent unison rings through a shaft or a master lever, which is mechanically linked to each unison ring. The main limitation of the traditional art is that all the stages have one schedule, which is determined by the kinematics of the system (one degree of freedom logic); moreover, the resultant vane schedule is fixed and predefined by kinematics - there is limited design space to include highly non-linear schedules. Another problem with this conventional arrangement is that tuning the relative movement and positions of each unison ring is complex. Such tuning must be

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done mechanically by adjusting the connection apparatus and linkages for each unison ring; this costs manpower and causes that the linkage assemblies must consist of multiple piece parts, which increases the risk of assembly error. Another problem with this conventional arrangement is that the hydraulic actuator(s), torque shaft (or master lever) and associated linkages and connectors can be bulky and heavy and require substantial amount of space. Finally, feedback in the traditional art is collected from the torque shaft (or master lever), so all the displacements beyond represent an "uncontrolled region".


[0004] The issues described above are addressed by providing linear (either electric or hydraulic) motors configured to move each unison ring independently relative to the compressor casing.

BRIEF DESCRIPTION OF THE DRAWINGS


[0005] The disclosure may be best understood by reference to the following description...