Gas Turbine Rotor Tip Clearance Control via Tunable Vibration Isolators
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Solution Overview
Problem
Gas turbine engines face inefficiencies and increased costs due to rotor tip clearance and shaft dynamics issues, including non-linear stiffness and damping in squeeze film dampers, which result in reduced efficiency and higher manufacturing costs.
Innovation Solution
The implementation of a gas turbine engine rotor tip clearance and shaft dynamics system that includes vibration isolators with linear and independently tunable stiffness and damping, coupled with actuators and control systems to actively manage rotor position and dynamics, allowing precise control of rotor tip clearance and shaft behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If squeeze film dampers are used to control rotor dynamics, then damping and stiffness are provided, but the stiffness and damping coefficients are highly non-linear and inexorably linked, making precise control impossible
Solution Approach 1:
The invention divides the rotor support system into separate functional elements: vibration isolators mounted on the engine case provide linear stiffness, while squeeze film dampers are positioned at bearing locations to provide damping. This segmentation allows independent control of stiffness and damping parameters, resolving the contradiction where traditional coupled systems cannot precisely control both parameters simultaneously.
Solution Approach 2:
The vibration isolators act as intermediary elements between the engine case and rotor bearing assembly. These isolators provide the necessary linear stiffness support while allowing the squeeze film dampers to independently provide damping control, thereby mediating between the conflicting requirements of stiffness and damping control.
2Manufacturing precision
If complex design features and high precision manufacturing tolerances are used to reduce blade tip clearance, then operational clearance is improved, but manufacturing costs increase markedly
Solution Approach 1:
The invention changes the fundamental parameters of rotor support by introducing vibration isolators with adjustable stiffness characteristics. This allows the rotor bearing assembly to be positioned with precise control over clearance parameters without requiring complex design features or excessively tight manufacturing tolerances on other components.
Solution Approach 2:
The vibration isolators introduce dynamic adjustability to the rotor support system, allowing the stiffness and positioning characteristics to be tuned to achieve optimal blade tip clearance. This dynamic approach replaces static, high-precision manufacturing requirements with adjustable, controllable parameters.
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 enhances efficiency and reduces operational and manufacturing costs by enabling precise control of rotor tip clearance and shaft dynamics, improving engine performance and reducing the need for complex designs and high-precision manufacturing.
Implementation Method 1
Each of the vibration isolators is mounted on the engine case and is coupled to the rotor bearing assembly, and each vibration isolator is configured to provide linear and independently tunable stiffness and damping
Data Source
AI summary
A gas turbine engine rotor tip clearance and shaft dynamics system and method are provided. The system includes a gas turbine engine that is disposed within an engine case and includes a rotor. A rotor bearing assembly disposed within the engine case rotationally mounts the gas turbine engine rotor. Vibration isolators mounted on the engine case are coupled to the rotor bearing assembly, and are configured to provide linear and independently tunable stiffness and damping. A method includes determining the location of a gas turbine engine rotor rotational axis, disposing the gas turbine engine rotor in an engine case at the rotational axis location, mounting a plurality of vibration isolators that include a plurality of adjustment devices on the engine case, coupling each vibration isolator to the gas turbine engine rotor, and locking the gas turbine engine rotor at the rotational axis location using the plurality of adjustment devices.