Variable Stator Vane Sealing Structure for Axial Compressor
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Solution Overview
Problem
The existing axial compressors in gas turbines face issues with fluid leakage and corrosion in the sliding portion between the variable stator vane and the casing, leading to degraded device reliability, especially when water or fluid droplets are sprayed for cooling, causing rust and unsteady fluid phenomena like rotating stall.
Innovation Solution
The implementation of a sealing structure with a counterbored groove and flange portion around the rotational shaft of the variable stator vane, combined with a sealing member like an O-ring, to prevent fluid leakage and corrosion, ensuring reliable operation during varying flow conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If water or fluid droplets are sprayed for cooling in the axial compressor, then the inlet air density increases and gas turbine output improves, but fluid leakage and corrosion occur in the sliding portion between the variable stator vane and casing
Solution Approach 1:
A sealing member (O-ring) is introduced as an intermediary element between the variable stator vane and casing to prevent fluid leakage. The sealing member intercepts the harmful fluid before it can reach the sliding portion, thus protecting the mechanical components from corrosion while maintaining the cooling function.
Solution Approach 2:
The sealing structure is extracted as a separate, dedicated component from the variable stator vane assembly. By isolating the sealing function into a distinct O-ring element, the design allows the cooling system to operate without compromising the integrity of the sliding mechanism.
2Measurement precision
If the variable stator vane is rotated to vary angle of attack during starting or partial loading, then the flow control accuracy improves, but the sliding portion is exposed to fluid leakage and corrosion
Solution Approach 1:
The sealing member acts as a protective intermediary that shields the sliding portion from fluid exposure during rotation. This allows the variable stator vane to be rotated for precise flow control without the sliding interface being damaged by corrosive fluid contact.
Solution Approach 2:
The sealing structure provides preliminary protection against fluid leakage before any corrosion can occur. By preventing fluid from reaching the sliding portion in advance, the system maintains angle control accuracy over extended operational cycles without degradation from corrosion.
3Loss of energy
If droplets are vaporized in the compressor to reduce mainstream temperature, then the compressor work decreases and efficiency improves, but blade loading distribution changes requiring complex engineering
Solution Approach 1:
The sealing structure is extracted as an independent component that does not interfere with the droplet vaporization process. This allows the intermediate cooling function to reduce compressor work while the sealing member independently manages the fluid leakage issue, avoiding the need for complex blade loading re-engineering.
4Reliability
If a sealing structure is added to prevent fluid leakage, then the reliability improves, but the device complexity increases
Solution Approach 1:
The sealing member is implemented as a simple, inexpensive O-ring that can be easily replaced if needed. This disposable-like approach to sealing provides reliable protection against fluid leakage without the complexity of elaborate sealing mechanisms, maintaining device reliability while minimizing structural complexity.
Solution Approach 2:
The O-ring sealing member utilizes a flexible elastic shell to create an effective seal between the variable stator vane and casing. This flexible sealing approach achieves reliable fluid leakage prevention with minimal structural complexity, as the elastic deformation of the O-ring adapts to the interface geometry without requiring precision machining or complex mounting structures.
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 prevents fluid leakage and reduces corrosion, enhancing the reliability and performance of the axial compressor by maintaining accurate angle control and reducing the risk of rotating stall and rust formation.
Implementation Method 1
a sealing structure which is provided in a sliding portion between a member slid relative to the casing during rotation of the rotational shaft and the casing
Implementation Method 2
the sealing member is an O-ring
Data Source
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AI summary
An axial compressor includes: a spray nozzle (32) that supplies droplets to a working fluid before compression or being compressed; a variable stator vane (56) having a stem section (94) inserted in an insertion hole (73) in a casing (54), the variable stator vane (56) having an angle of attack varied through sliding motion relative to the casing caused by rotation of the stem section; a sealing groove (93) provided in a sliding portion between a thrust washer (82) slid relative to the casing during rotation of the stem section and the casing; and a sealing member (92) housed in the sealing groove.