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EP-4234891-B1 - ROTARY SERVO FOR FIXED FAIL ACTUATORS

EP4234891B1EP 4234891 B1EP4234891 B1EP 4234891B1EP-4234891-B1

Inventors

  • BICKLEY, DANIEL J

Dates

Publication Date
20260506
Application Date
20230124

Claims (13)

  1. A rotary actuation system (50) of a gas turbine engine (10) for the control of a compressor variable geometry comprising: a servo assembly (52) that includes: a cylindrical outer sleeve (74) including multiple ports (76, 78); a cylindrical outer spool (80) annularly disposed within the cylindrical outer sleeve (74), and a cylindrical inner spool (84) annularly disposed within the cylindrical outer spool (80), wherein: the cylindrical outer spool (80) includes multiple channels (82) configured to provide fluidic interconnection between the multiple ports (76, 78) and the cylindrical inner spool (84) includes grooves (86) configured to provide fluidic interconnection through the multiple channels (82) of the cylindrical outer spool (80); and a stepper motor (70) mechanically coupled to the cylindrical outer spool (80); and an actuator (54) mechanically coupled to the compressor variable geometry (30) that controls compression provided by a compressor (14) of the gas turbine engine (10), wherein the stepper motor (70) is configured to rotate the cylindrical outer spool (80) within the cylindrical outer sleeve (74) to deliver a fluid to and thereby actuate the actuator (54) to control the compressor variable geometry (30).
  2. The rotary actuation system (50) of claim 1, wherein the actuator (54) is coupled to a body (28) of the gas turbine engine (10) via a rotary mount (64) such that the actuator (54) rotates when actuated about a mechanical coupling (62) to the stepper motor (70).
  3. The rotary actuation system (50) of claim 2, wherein the mechanical coupling (62) between the actuator (54) and the stepper motor (70) rotates the cylindrical inner spool (84) to decouple fluidic interconnection between the grooves (86) and the multiple channels (76, 78) to prevent further actuation of the actuator (54).
  4. The rotary actuation system (50) of claims 2 or 3, further comprising a rotary variable differential transformer (100) configured to produce an electrical signal representative of rotational movement of the mechanical coupling (62) between the actuator (54) and the cylindrical inner spool (84).
  5. The rotary actuation system (50) of any combination of claims 1-4, wherein the stepper motor (70) includes a magnetic detent that locks the stepper motor (70) in event of electrical failure to the stepper motor (70).
  6. The rotary actuation system (50) of any combination of claims 1-5, wherein the actuator (54) comprises a linear actuator that is mechanically coupled to a crank shaft (32) of the compressor variable geometry (30).
  7. The rotary actuation system (50) of any combination of claims 1-6, wherein the compressor variable geometry (30) includes compressor vanes that are mechanically disposed to change pitch in response to actuation of the actuator (54) by the stepper motor (70).
  8. The rotary actuation system (50) of any combination of claims 1-7, wherein the fluid comprises fuel used by the gas turbine engine (10) for combustion.
  9. The rotary actuation system (50) of any combination of claims 1-8, wherein the servo assembly (52) comprises an electrohydraulic servo assembly that receives the fluid as a high pressure fluid and a low pressure fluid, wherein the grooves (86) of the cylindrical inner spool (84) are disposed around the cylindrical inner spool (84) at 90 degree intervals, wherein the actuator (54) comprises a hydraulic actuator that drives a piston (92) via varying fluid pressures, and wherein the stepper motor (70) is configured to rotate the cylindrical outer spool (80) to deliver either the high pressure fluid or the low pressure fluid via the channels (82) to the ports (76, 78) in order to actuate the hydraulic actuator to drive the piston (92) mechanically coupled to the compressor variable geometry (30).
  10. The rotary actuation system (50) of claim 9, wherein the servo assembly (52) is fluidically coupled to a fluid pump that delivers the high pressure fluid and the low pressure fluid to the servo assembly (52).
  11. A method of operating a rotary actuation system (50) of a gas turbine engine for the control of a compressor variable geometry comprising: receiving a control signal; and rotating, by a stepper motor (70) of a servo assembly (52) and based on the control signal, a cylindrical outer spool (80) within a cylindrical outer sleeve (74) in which the cylindrical outer spool (80) is annularly displaced within to deliver a fluid to and thereby actuate an actuator (54) to control compressor variable geometry (30) of a gas turbine engine (10), wherein the cylindrical outer sleeve (74) includes multiple ports (76, 78), wherein the stepper motor (70) is mechanically coupled to the cylindrical outer spool (80), wherein the cylindrical outer spool (80) includes multiple channels (82) configured to provide fluidic interconnection between the multiple ports (76, 78) and a cylindrical inner spool (84), wherein the cylindrical inner spool (84) is annularly displaced within the cylindrical outer spool (80), the cylindrical inner spool (84) including grooves (86) configured to provide fluidic interconnection through the multiple channels (82) of the cylindrical outer spool (80), and wherein the actuator (54) is mechanically coupled to the compressor variable geometry (30).
  12. A gas turbine engine (10) comprising: a combustor (18); a compressor (14) fluidically upstream of the combustor (18) that includes compressor variable geometry (30) configured to control compression by the compressor (14); and the rotary actuation system (50) of claim 1 mounted to a body (28) of the gas turbine engine (10).
  13. The gas turbine engine (10) of claim 12, wherein the rotary actuation system (50) further comprises the rotary actuation system (50) recited by any combination of claims 2-10.

Description

TECHNICAL FIELD The disclosure relates to gas turbine engines in general and in particular to a rotary actuation system of a gas turbine engine for the control of a compressor variable geometry. BACKGROUND Gas turbine engines may include an axial compressor that provides compression (e.g., of air) prior to combustion. The axial compressor may include multiple compression stages, each stage including a row of rotating blades (referred to as a rotor) and a row of stationary blades (referred to as a stator). In each adjacent compressor stage, the rotors and stators become smaller to accommodate the increase in pressure across each stage and thereby maintain near constant axial velocity of the air. To improve fuel efficiency and responsiveness of the compressor in achieving targeted levels of compression during variable conditions (e.g., accelerating, decelerating, etc.), the compressor may include variable geometry, such as in the form of variable stators. Actuators may control the variable geometry, where such actuators are controlled via an electrohydraulic servo assembly that operates with respect to a control signal and a fluid (such as fuel). The actuators may receive, via the electrohydraulic servo assembly, the fuel as a way by which to adjust linear movement of the actuator that then adjusts the position of the variable geometry. The electrohydraulic servo assembly may include a rotary stepper motor that is electrically controlled via a control signal. The rotary stepper motor is further coupled via a mechanical mechanism (e.g., a rotary to linear translation mechanism coupled to a lever) that is mechanically coupled to a variable geometry feedback link that indicates mechanical movement of the variable geometry. This feedback link adjusts the delivery of the fuel (via the lever) and accompanying activation of the actuator to balance movement of the variable geometry with fuel delivery to the combustor to potentially achieve the improved fuel efficiency and responsiveness of the gas turbine engine. US 2018/320715 A1 discloses a fail-fixed hydraulic actuator system of the prior art. SUMMARY In one aspect, the invention is directed to a rotary actuation system of a gas turbine engine for the control of a compressor variable geometry as in claim 1. In another aspect, the invention is directed to a method of operating a rotary actuation system of a gas turbine engine for the control of a compressor variable geometry as in claim 11. In another aspect, the invention is directed to a gas turbine engine comprising: a combustor; a compressor fluidically upstream of the combustor that includes compressor variable geometry configured to control compression by the compressor; and the rotary actuation system of claim 1 mounted to a body of the gas turbine engine. The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a conceptual diagram illustrating an example gas turbine engine that includes a rotatory actuator assembly for control of compressor variable geometry in accordance with various aspects of the techniques described in this disclosure.FIG. 2 is a conceptual diagram illustrating the rotatory actuator assembly of FIG. 1 in more detail.FIGS. 3A-3C are diagrams illustrating cross-sectional views of the cylindrical outer spool and the cylindrical inner spool at different positions along an axis of the servo valve shown in the example of FIG. 2.FIG. 4 is a flowchart illustrating example operation of the rotary actuator assembly of FIG. 2 for control of compressor variable geometry in accordance with various aspects of the techniques described in this disclosure. DETAILED DESCRIPTION The disclosure describes a gas turbine engine in which a compressor of the gas turbine engine includes a rotary actuator assembly. The rotary actuator assembly may operate rotationally in order to potentially avoid complicated mechanical mechanisms required to translate rotational motion of the stepper motor into linear operation for configuring the servo valve to deliver a fluid (e.g., fuel) to drive the linear motion of the actuator. The rotary actuator assembly may include a rotary servo valve in which a cylindrical outer spool annularly disposed within a cylindrical outer sleeve is mechanically coupled to the rotary stepper motor. Responsive to receiving a control signal, the rotary stepper motor may rotate the cylindrical outer spool to deliver the fuel to the actuator and thereby actuate the actuator to deliver linear force to control the compressor variable geometry (e.g., stators). In this way, the rotary actuator assembly may reduce the complexity of the complicated mechanical mechanisms to translate rotational motion of the stepper motor into linear operation for configuring the servo valve to deliver the