Turbomachine Blade Clearance Control via Electromagnetic Sensing
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Solution Overview
Problem
Conventional turbomachine blade clearance systems face inefficiencies due to relative differential thermal expansion, leading to gaps or excessive contact, which reduces engine cycle efficiency, and existing methods for measuring and adjusting clearance are cumbersome and weight-additive.
Innovation Solution
A turbomachine blade clearance system featuring an actuator with a shaft and waveguide, an antenna for electromagnetic communication, and a sensing system using different electromagnetic frequencies to determine and adjust gap clearance between blades and seals, allowing precise control of blade clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If clearance between blades and casing is reduced to improve aerodynamic efficiency, then engine efficiency is improved, but risk of rubbing under extreme conditions increases
Solution Approach 1:
The patent implements dynamic clearance control by making the seal movable relative to the housing via an actuator system. The seal position is continuously adjusted based on real-time gap measurements and operational conditions, transitioning from a static oversized clearance to a dynamically optimized clearance that maintains efficiency during normal operation while preventing rubbing during extreme conditions.
Solution Approach 2:
The system incorporates a feedback mechanism where the gap distance is continuously measured using electromagnetic sensing (antenna and waveguide), processed by a controller, and used to actuate the seal position. This closed-loop control enables the system to respond to changing thermal expansion and operational conditions, automatically adjusting clearance to maintain optimal values.
2Measurement precision
If separate waveguides, wires, and complex circuitry are used to measure clearance distance, then measurement capability is achieved, but system weight increases
Solution Approach 1:
The patent combines multiple functions into integrated components. The waveguide serves both as a structural element of the actuator assembly and as the measurement sensor housing. The antenna is integrated into the actuator structure, eliminating the need for separate wiring harnesses and external circuitry, thereby reducing overall system weight while maintaining measurement precision.
Solution Approach 2:
The actuator shaft structure serves multiple purposes: it provides mechanical actuation for seal positioning, houses the waveguide for electromagnetic signal transmission, and supports the antenna for gap measurement. This multi-functional design eliminates redundant components and reduces system weight.
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 enables precise adjustment and measurement of blade clearance, enhancing sealing efficiency and reducing weight-related issues, thereby improving overall engine performance.
Implementation Method 1
at least one antenna disposed in electromagnetic communication with the waveguide such that a signal from the antenna can be directed by the waveguide
Implementation Method 2
The turbomachine blade seal can be configured to reflect the first electromagnetic wave back into the waveguide and pass the second electromagnetic wave therethrough to a reflection point
Implementation Method 3
The sensing system can be configured to determine a gap distance based on the determined difference in distance traveled by the first and second electromagnetic waves
Implementation Method 4
The actuating portion of the actuator can include any suitable actuator such as a linear mechanical actuator and/or a piezo-electric actuator
Data Source
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AI summary
A turbomachine blade clearance system includes an actuator (101) including an actuating portion (103) that can be fixed to an interior surface of a turbomachine housing (50) and a shaft (105) for actuating movement relative to the turbomachine housing, a turbomachine blade seal (107) operatively connected to the shaft of the actuator and configured to move relative to the turbomachine housing to adjust a distance from a turbomachine blade (60) of a turbomachine to maintain a predetermined gap clearance (70) between the blade seal and the blade, a waveguide (108) disposed within the shaft, and at least one antenna (106) disposed in electromagnetic communication with the waveguide such that a signal from the antenna can be directed by the waveguide.