Stator Vane Radial Displacement for Tip Clearance Control
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Solution Overview
Problem
In gas turbine engines, the minimal stator vane tip clearance between stator vanes and rotor is compromised due to thermal expansion and centrifugal force, leading to potential tip strikes and excessive loading, which can be detrimental to engine operation and efficiency.
Innovation Solution
A system allowing radial displacement of stator vanes within the engine, utilizing a coil spring to maintain minimal tip clearance by compressing and biasing the stator vane against the outer shroud, enabling the vane to translate radially and adjust to temperature changes, thereby preventing excessive loading and maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If stator vane tip clearance is minimized for maximum efficiency, then compressor efficiency is improved, but thermal expansion and centrifugal force cause the clearance to vary undesirably during operation
Solution Approach 1:
The stator vane assembly is designed with dynamic characteristics, allowing the stator vanes to move radially in response to thermal expansion and centrifugal forces during operation. The spring-loaded mechanism enables the assembly to adapt its clearance dynamically, maintaining optimal performance while accommodating operational variations.
Solution Approach 2:
The invention utilizes changes in physical parameters (thermal expansion and centrifugal force) during engine operation to naturally adjust the clearance. By designing the stator vane assembly with compliant characteristics, the system allows parameters like radial position to change in response to operational conditions, maintaining stable clearance despite parameter variations.
2Productivity
If stator vane tip clearance is minimized, then compressor efficiency is improved, but tip strikes and excessive loading occur during operation
Solution Approach 1:
A spring-loaded mechanism is incorporated into the stator vane assembly to provide beforehand cushioning. The spring acts as a cushioning element that absorbs excessive forces and prevents tip strikes by allowing controlled movement of the stator vanes away from the rotor during conditions that would otherwise cause contact or excessive loading.
Solution Approach 2:
The spring-loaded mechanism serves as an intermediary between the stator vanes and the compressor case. This intermediary element absorbs and mitigates the harmful effects of thermal expansion and centrifugal forces, preventing direct contact between stator vane tips and the rotor, thereby protecting the system from tip strikes and excessive loading.
3Productivity
If stator vane assembly is made fixed to maintain minimal clearance, then compressor efficiency is maximized, but the assembly cannot adapt to temperature changes
Solution Approach 1:
The stator vane assembly transitions from a fixed design to a dynamic one, where the stator vanes can move radially in response to temperature changes. The spring-loaded mechanism enables this dynamic adaptation, allowing the assembly to maintain optimal clearance across varying temperature conditions while preserving compressor efficiency.
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 effectively minimizes stator vane tip clearance, preventing tip strikes and maintaining compressor section efficiency by allowing radial displacement of stator vanes, thus enhancing the operational stability and performance of the gas turbine engine.
Implementation Method 1
utilizing a coil spring to maintain minimal tip clearance by compressing and biasing the stator vane against the outer shroud
Implementation Method 2
Due to thermal expansion and centrifugal force, clearance between the stator vane array and the rotor may undesirably vary during operation
Implementation Method 3
Due to thermal expansion and centrifugal force, clearance between the stator vane array and the rotor may undesirably vary during operation
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A stator vane assembly (500) may comprise a stator vane (210), an outer shroud (240), and a spring (550). A first end of the stator vane (210) may be fixed to an inner diameter (ID) surface (324) of a vane platform (220). A slot (444) may be disposed in a surface of the outer shroud (240), wherein a portion of the stator vane (210) is configured to be located within the slot (444). In various embodiments, the stator vane (210) may be configured to translate in a radial direction in response to a force between the stator vane (210) and a rotor (530). In various embodiments, the spring (550) may be configured to be coupled to an outer diameter (OD) surface (446) of the vane platform (220), wherein the spring (550) is configured to bias the ID surface (324) of the vane platform (220) toward the outer shroud (240).