Movable Pulley VSV Actuation Arrangement for Gas Turbine Engines
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Solution Overview
Problem
High actuation loads in variable stator vane systems of gas turbine engines require high fuel pressure, leading to undesirable demands on the fuel system architecture and can result in immovable vanes, causing aborted take-offs and service interruptions.
Innovation Solution
An actuation arrangement with a movable pulley connected to the actuator connector and a belt that loops around the pulley, increasing the pulling length and reducing frictional resistance, allowing for reduced actuation loads and efficient movement of variable stator vanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional actuation arrangement with direct belt connection is used, then the structure is simple, but the actuation load is high requiring high fuel pressure
Solution Approach 1:
A movable pulley is introduced as an intermediary component between the belt and the actuator connector. The belt loops around this movable pulley, creating a mechanical advantage that reduces the actuation load by approximately half compared to a direct connection, while maintaining structural simplicity
Solution Approach 2:
The belt is configured to loop around the movable pulley in a circumferential direction, utilizing the third dimension (depth/height) to create the force distribution path. This dimensional approach allows the belt to engage the pulley from multiple directions, effectively distributing the actuation force
2Force
If high fuel pressure is used to overcome frictional resistance, then the actuation load is sufficient, but the demands on the fuel system architecture increase
Solution Approach 1:
The movable pulley acts as a force amplifier intermediary, reducing the required actuation load by creating multiple belt segments that share the load. This mechanical advantage allows the fuel system to operate at lower pressures, simplifying the overall fuel system architecture
3Force
If the actuation load is high, then the belt can overcome frictional resistance, but the VSVs may become immovable causing aborted take-offs
Solution Approach 1:
The movable pulley serves as a reliable intermediary that consistently reduces the actuation load required to move the VSVs. By distributing the force through multiple belt segments, it ensures sufficient force is always available to overcome frictional resistance, preventing immovable VSV conditions and aborted take-offs
Solution Approach 2:
The circumferential looping of the belt around the movable pulley creates redundant force paths in multiple dimensions, ensuring that the actuation force is reliably distributed and cannot be compromised by single-point failures or excessive friction at any single location
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces the actuation load required to move variable stator vanes, minimizing the risk of immovable vanes and associated service interruptions by distributing the force more efficiently, thus enhancing the reliability of gas turbine engine operations.
Implementation Method 1
an actuation arrangement further comprises a movable pulley movable relative to said tubular casing and connected to the actuator connector and wherein the belt has a loop portion provided between the proximal and distal ends which loops around the movable pulley
Implementation Method 2
the loop portion for transferring forces generated in the belt by the actuator to the movable pulley to effect movement of the movable pulley and thereby the actuator connector towards the anchor
Data Source
AI summary
An actuation arrangement for effecting actuation of a variable stator vane pivotally mounted on a tubular casing. The actuation arrangement includes: an actuator connector connected to the variable stator vane via an actuating lever; an anchor fixedly mounted relative to the circumference of the tubular casing; an actuator; and a belt extending from the actuator to the fixed pulley. The actuation arrangement further includes a movable pulley movable relative to the tubular casing and connected to the actuator connector. The belt has a loop portion provided between the proximal and distal ends which loops around the movable pulley, the loop portion for transferring forces generated in the belt by the actuator to the movable pulley to effect movement of the movable pulley and actuator connector towards the anchor to effect actuation of the variable stator vane via the actuating lever.