Turbomachine Fan Rotor Segmented Platform for Large Clearances
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Solution Overview
Problem
Current sealing technologies fail to effectively bridge clearances exceeding 8 millimeters between fan blades and aerodynamic surfaces in fan rotors, leading to degraded seal performance, particularly at the trailing edge of the blades.
Innovation Solution
The aerodynamic surface of each fan platform is axially split into two independent longitudinal portions, with the upstream portion fixed and the downstream portion pivotally connected to the disc, allowing it to follow the displacements of the leading and trailing edges of the blades, respectively, enabling better seal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the aerodynamic surface is made as a single fixed platform, then the structural simplicity is maintained, but the sealing performance deteriorates when blade displacements exceed 8 millimeters
Solution Approach 1:
The aerodynamic surface is divided into two independent longitudinal portions: an upstream portion fixed to the disc and a downstream portion that is mobile relative to the first portion. This segmentation allows each portion to independently accommodate different displacement conditions, with the mobile downstream portion specifically addressing the sealing challenge at the trailing edge where displacements exceed 8 millimeters.
Solution Approach 2:
The downstream longitudinal portion is designed to be mobile relative to the upstream portion, enabling it to dynamically follow the tangential displacements of the blade trailing edges. This dynamic capability allows the platform to adapt to varying displacement conditions during operation, maintaining effective sealing despite large clearance variations.
2Adaptability or versatility
If the platform is made rigid and fixed, then the manufacturing simplicity is maintained, but the adaptability to blade displacements deteriorates
Solution Approach 1:
The platform is segmented into two independent longitudinal portions that can be manufactured separately and then assembled. This segmentation allows each portion to be optimized for its specific function while simplifying the overall manufacturing process compared to creating a single complex movable structure.
Solution Approach 2:
The downstream longitudinal portion is designed with mobile capability to follow blade displacements, providing the necessary adaptability. This dynamic feature is localized only where needed (at the downstream portion) rather than requiring the entire platform to be complex and movable.
3Reliability
If a single seal is used across the entire aerodynamic surface, then the seal simplicity is maintained, but the sealing effectiveness deteriorates due to varying clearances from leading edge to trailing edge
Solution Approach 1:
The sealing system is divided into two independent sealing zones corresponding to the two longitudinal portions. Each sealing zone can be equipped with appropriate sealing technology matched to its specific clearance conditions, with the downstream portion using sealing solutions adapted for larger clearances exceeding 8 millimeters.
Solution Approach 2:
Different sealing approaches can be applied to different locations: the upstream portion near the leading edge (with minimal clearance) uses one sealing approach, while the downstream portion near the trailing edge (with large clearance exceeding 8mm) uses a different sealing approach optimized for larger gaps.
Data Source
AI summary
The invention relates to a fan rotor for a turbomachine, including a fan disk, fan blades with a leading edge and a trailing edge, platforms inserted between the blades and fixed to the periphery of the disk, each including an aerodynamic surface extending from the leading edges to the trailing edges of the blades. The aerodynamic surface includes an upstream longitudinal portion on the side of the leading edges and a downstream longitudinal portion on the side of the trailing edges, the upstream longitudinal portion being supported by a first member of the platform fixed to the disk in a pivotable manner, and the downstream longitudinal portion being independent of the upstream longitudinal portion and supported by a second member of the platform which is independent of the first member and fixed to the disk in a pivotable manner.