Convex Inner Bearing Geometry for Variable-Pitch Compressor Vanes
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Solution Overview
Problem
Existing adjustable guide vanes in gas turbines experience increased point and surface loads in the inner bearing sections, leading to undesirable wear due to force transmission issues.
Innovation Solution
A variable-pitch guide vane design with a radially inner bearing section as a journal having a convex circumferential surface with a radius of curvature at least twice the maximum diameter of the bearing section, allowing for partial-surface contact and optimized load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spherical or cylindrical inner bearing section is used, then the guide vane can be rotatably mounted, but force transmission leads to increased point loads and surface loads causing undesirable wear
Solution Approach 1:
The inner bearing section is designed with a convex circumferential surface having a radius of curvature at least twice the maximum diameter of the bearing section. This specific curvature geometry transforms the contact pattern from point or full-surface contact to partial-surface contact, distributing loads more effectively and reducing wear while maintaining rotational capability
2Stability of the object's composition
If full-surface contact is achieved between the bearing section and sliding bearing, then stability is improved, but surface loads increase leading to increased wear
Solution Approach 1:
The convex circumferential surface with its specific radius of curvature creates optimal partial-surface contact that balances stability and wear reduction. The curvature is designed to be large enough to prevent point contact but small enough to avoid full-surface contact, achieving the ideal intermediate state
3Object-affected harmful factors
If point contact is achieved, then wear is reduced, but the bearing section becomes unstable during operation
Solution Approach 1:
The convex circumferential surface geometry provides a medium between point and full-surface contact. The specific radius of curvature ensures sufficient contact area for stability while maintaining low contact pressure to minimize wear, resolving the contradiction between these two requirements
Data Source
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AI summary
A variable displacement guide vane (50) for a compressor (16), in particular a high-pressure compressor (29), of a gas turbine (10), in particular an aviation gas turbine, is described, comprising a radially outer bearing section (56), a radially inner bearing section (52), and a blade section (54) extending radially (RR) between the outer bearing section (56) and the inner bearing section (52), wherein the outer and inner bearing sections (52, 56) are designed such that the variable displacement guide vane (50) can be rotatably mounted about a blade axis (SA) in the compressor (16, 29), and wherein the radially inner bearing section (52) is designed as a journal and has a circumferential surface (58) with respect to the blade axis (SA), which is convex. It is provided that the radius of curvature (KR) of the convex surface (58) is at least twice the maximum diameter (DM) of the bearing section (52).Furthermore, a gas turbine with several such adjustable guide vanes (50) is described.