Variable Vane Positioning via Torque Tube Cam Mechanism
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Solution Overview
Problem
Existing turbine engine compressor systems lack the ability to independently and variably control the pitch of vanes across different stages, leading to suboptimal performance due to synchronized and constant velocity rotation of unison rings, which restricts adaptability to changing rotational speeds.
Innovation Solution
A variable vane positioning system utilizing a torque tube, cam follower, and cam mechanism, where the torque tube rotates to move the cam, which in turn moves the cam follower and unison ring, allowing for independent and variable positioning of vanes relative to airflow, enabling customized vane pitch adjustments based on rotational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a torque tube is used to rotate unison rings in synchronous compressor systems, then all unison rings move in synchrony for uniform distance and at constant velocity, but the vanes of different stator stages cannot be independently positioned and cannot adapt to changing rotational speeds
Solution Approach 1:
The patent divides the previously unified unison ring into multiple independent unison rings (first unison ring and second unison ring). Each unison ring can be independently controlled to rotate by different amounts and at different velocities, enabling independent vane positioning for each stator stage while maintaining the benefit of a distributed control architecture
Solution Approach 2:
The patent introduces variable velocity control for each unison ring, allowing the first unison ring and second unison ring to rotate at different velocities according to the rotational speed of the compressor. This dynamic adjustment capability enables the vanes to adapt to changing operating conditions while using a mechanical control system
2Adaptability or versatility
If separate actuators are used for each unison ring to enable independent positioning, then vane adaptability improves, but device complexity and cost increase
Solution Approach 1:
The patent uses a single torque tube to perform multiple functions: it controls both the first unison ring and the second unison ring independently. By providing variable velocity control capability within the same actuator, the torque tube achieves independent positioning of multiple unison rings without requiring separate actuators for each ring
Solution Approach 2:
The patent introduces variable velocity control mechanisms as intermediaries between the torque tube and each unison ring. These intermediaries allow the single torque tube to translate its rotation into different rotational velocities for each unison ring, enabling independent control without direct separate actuation
3Productivity
If constant velocity rotation is used for unison rings, then the control system is simple, but compressor performance is suboptimal under varying rotational speeds
Solution Approach 1:
The patent implements variable velocity control for the unison rings, where the rotational velocity of each unison ring can be adjusted according to the operational rotational speed of the compressor. This dynamic control allows the vane positioning to optimize compressor efficiency across different operating conditions while maintaining a relatively simple mechanical control architecture
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
This system allows for optimized compressor performance by enabling independent vane positioning across stages, reducing off-schedule behavior, and eliminating the need for separate actuators, thereby reducing weight, cost, and maintenance while improving efficiency and aircraft range.
Implementation Method 1
Rotation of the torque tube causes movement of the cam, and movement of the cam moves the cam follower, and movement of the cam follower moves the unison ring and the variable vane coupled thereto
Data Source
AI summary
An apparatus and method of controlling the position of a variable vane in a compressor and a kit for adding such apparatus to the compressor are disclosed. The vane is coupled to a unison ring, a cam is secured to a torque tube, a cam follower is secured to the unison ring. The cam follower is secured such that a wall of the cam follower is in contact with the cam. Rotation of the torque tube causes movement of the cam, and movement of the cam moves the cam follower, thereby moving the unison ring and the variable vane coupled thereto.