Geared Cam Blade Track Assembly for Precise Tip Clearance
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Solution Overview
Problem
Existing blade tip clearance systems in rotating machines, such as gas turbine engines, are complex, expensive, and lack precision and speed in adjusting the radial position of blade tracks across varying operating conditions, leading to inefficiencies due to either blade rub or leakage.
Innovation Solution
A mechanical actuator system comprising a static turbine casing, blade track carriers, and cam-shaped portions with an actuator that allows for rapid and precise radial movement of blade tracks, using an annular gear ring and pinion gears for adjustment, reducing the need for pneumatic systems and enabling uniform articulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing blade tip clearance systems are used, then blade tip clearance can be maintained, but the system becomes complex and expensive with insufficient precision and speed in adjusting radial position
Solution Approach 1:
The system divides the blade track adjustment mechanism into multiple independent blade track carriers, each capable of individual radial positioning. Each carrier is a separate segment that can be adjusted independently, allowing precise control of blade tip clearance at multiple locations around the turbine stage without requiring a complex monolithic system.
Solution Approach 2:
The patent replaces complex pneumatic or hydraulic adjustment systems with a purely mechanical cam-based mechanism. The cam-shaped portions translate rotational motion into precise radial displacement of blade tracks through geometric conversion, eliminating the need for complex fluid power systems while achieving superior positioning precision and speed.
2Speed
If existing blade tip clearance systems are used, then blade tip clearance can be maintained, but the adjustment speed is insufficient across varying operating conditions
Solution Approach 1:
The blade track carriers and cam mechanisms are designed to be dynamically adjustable during turbine operation. The cam-shaped portions can rapidly rotate to reposition blade tracks in response to changing operating conditions, enabling the system to adapt quickly to different speeds, temperatures, and loads while maintaining optimal blade tip clearance.
Solution Approach 2:
The system enables rapid change of the radial position parameter of blade tracks through cam rotation. By varying the cam rotation angle, the radial position of blade tracks is directly adjusted, allowing the system to adapt to different operating conditions by simply changing this geometric parameter without complex control systems.
3Loss of energy
If blade tip clearance is reduced to minimize leakage, then engine efficiency improves, but the risk of blade impingement against the shroud increases
Solution Approach 1:
The system provides precise control over blade tip clearance through the cam mechanism, enabling maintenance of an optimal gap size that prevents both excessive leakage and blade impingement. The ability to accurately position blade tracks at the correct radial distance ensures the clearance remains within the safe operating window under all conditions.
Solution Approach 2:
By precisely controlling the radial position parameter of blade tracks through cam rotation, the system maintains blade tip clearance within the optimal range. This prevents gas leakage losses when clearance is small, while avoiding blade impingement when clearance is large, thus simultaneously improving efficiency and reliability through parameter optimization.
4Ease of operation
If pneumatic systems are used for blade track adjustment, then radial position can be controlled, but the system becomes more complex and costly
Solution Approach 1:
The patent substitutes pneumatic or hydraulic control systems with a purely mechanical cam-based adjustment mechanism. The cam-shaped portions convert simple rotational motion into precise radial positioning of blade tracks through geometric conversion, providing ease of operation while eliminating the complexity and cost of pneumatic systems.
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 provides a simpler, cost-effective, and rapid adjustment of blade tip clearance, enhancing engine efficiency by minimizing blade rub and leakage, and allowing for precise control of radial position across a range of operating conditions.
Implementation Method 1
one or more cam-shaped portions rotatable about the axis of rotation... rotation of the one or more cam-shaped portion effects radial movement of the blade track
Implementation Method 2
the actuator may include an annular gear ring carried by the turbine casing, and wherein each of the plurality of blade track support assemblies may include a geared head engaged with the gear ring
Implementation Method 3
the actuator further may include a pinion gear carried by the turbine casing and engaged with the annular gear ring
Data Source
AI summary
An assembly is disclosed for adjusting the radial position of a blade track relative to a blade of a turbine stage in a gas turbine engine. The assembly comprises a static turbine casing, a blade track carrier, a blade track support assembly, an actuator, and a blade track. The blade track carrier comprises a pair of radially extending flanges each defining at least one bore in radial and axial alignment with each other forming a pair of bores. The blade track support assembly comprises a portion extending through each bore in a pair of bores, and one or more cam-shaped portions rotatable about an axis of rotation. The blade track has an arcuate flange and a support flange, the support flange being carried by the cam-shaped portion of the blade track support assembly such that rotation of the cam-shaped portion effects radial movement of the blade track.