Hybrid Electric Engine Tip Clearance Control via Electromechanical Actuation
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Solution Overview
Problem
Current systems for controlling tip clearance in hybrid electric engines are either heavy and costly or slow, particularly during rapid throttle maneuvers, as they rely on pneumatic or thermal methods that do not efficiently manage the position of blade outer air seals relative to turbine blades.
Innovation Solution
A hybrid electric propulsion system with an electric motor and a clearance control system that uses an electromechanical actuator and sensors to adjust the position of blade outer air seals in real-time, powered by a battery, super capacitor, or ultra capacitor, allowing for precise control of tip clearance based on operational states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pneumatic models or engine bleed air systems are used to control thermal expansion and contraction of casing components, then tip clearance control is achieved, but extra weight and cost are added that offset the corresponding improvements to engine efficiency
Solution Approach 1:
The patent replaces traditional pneumatic and thermal clearance control systems with an electromechanical actuator system. The actuator uses electrical signals from the controller to mechanically adjust the position of the blade outer air seal, eliminating the need for heavy pneumatic components and bleed air infrastructure while achieving precise tip clearance control.
2Speed
If thermal systems are used to control tip clearance, then clearance adjustment is possible, but the response is slow particularly during rapid throttle maneuvers
Solution Approach 1:
The patent implements a dynamic clearance control system where the electromechanical actuator can rapidly adjust the blade outer air seal position in real-time based on changing operational conditions. The controller receives inputs about engine state and electric motor operation, then dynamically positions the air seal to maintain optimal tip clearance during rapid throttle maneuvers, preventing energy losses from excessive clearance or tip rubbing.
3Manufacturing precision
If an electromechanical actuator system is implemented for real-time clearance control, then response speed and precision are improved, but device complexity increases
Solution Approach 1:
The patent integrates the clearance control function into the existing hybrid electric engine architecture by utilizing the electric motor and controller that are already present for power assist operations. The same controller that manages electric motor operation also controls the electromechanical actuator for tip clearance adjustment, eliminating the need for separate dedicated clearance control electronics and reducing overall system complexity.
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 solution enables faster and more efficient control of tip clearance, reducing aerodynamic losses and increasing engine efficiency by minimizing tip leakage, while reducing the need for heavy and slow thermal or pneumatic systems.
Implementation Method 1
the clearance control system includes an electromechanical actuator operably coupled to the at least one blade outer air seal, the electromechanical actuator configured to vary a position of the at least one blade outer air seal
Implementation Method 2
a position sensor that senses changes in a distance between a tip of the plurality of blades the at least one blade outer air seal
Implementation Method 3
the clearance control system includes a maneuver sensor that senses changes in rotation and/or acceleration of the gas turbine engine
Implementation Method 4
the power source is at least one of the following: a battery; a super capacitor; and an ultra capacitor
Data Source
AI summary
A hybrid electric propulsion system including: a gas turbine engine comprising a low speed spool and a high speed spool, the low speed spool comprising a low pressure compressor and a low pressure turbine, and the high speed spool comprising a high pressure compressor and a high pressure turbine; an electric motor configured to augment rotational power of the high speed spool or the low speed spool; at least one blade outer air seal positioned between an outer case of the high pressure turbine and a plurality of blades of the high pressure turbine; a clearance control system operably coupled to the at least one blade outer air seal, the clearance control system configured to vary a position of the at least one blade outer air seal with respect to the plurality of blades of the high pressure turbine; and a controller operably coupled to the electric motor and the clearance control system, wherein the controller is configured to operate the clearance control system based upon an operational state of the electric motor.