Triangular Fan Case Connection for Rigid Core Housing Support
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Solution Overview
Problem
Existing gas turbine engines with gear reduction systems face challenges in providing structural support and rigidity between the fan case and core housing, particularly with longer low pressure compressors, which can lead to mounting issues and airflow obstructions.
Innovation Solution
Incorporation of triangular-frame connections with a combination of structural and non-structural fan exit guide vanes, where structural vanes provide additional rigidity and non-structural vanes offer acoustic functions, reducing airflow obstruction while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fan exit guide vanes are used to provide structural support between fan case and core housing, then structural support is provided, but airflow obstruction increases
Solution Approach 1:
The fan exit guide vanes are segmented into two distinct types: structural fan exit guide vanes that provide mechanical support between the fan case and core housing, and non-structural fan exit guide vanes that are acoustically functional. This segmentation allows each type to perform its specific function without compromising the other, reducing overall airflow obstruction while maintaining structural integrity.
Solution Approach 2:
Different regions of the fan exit guide vane assembly have different properties: structural vanes are positioned and designed to bear mechanical loads, while non-structural vanes are optimized for acoustic treatment with perforated face sheets and chambers. This local differentiation ensures that structural support and airflow management are handled by appropriately designed elements in their respective locations.
2Stability of the object's composition
If multiple fan exit guide vanes are used for structural support, then rigidity between fan case and core housing is improved, but device complexity increases
Solution Approach 1:
The fan exit guide vane assembly serves multiple functions through its dual-type vane configuration: structural support, acoustic treatment, and airflow guidance. By integrating these functions into a single unified assembly rather than separate components, the design achieves high rigidity without proportionally increasing device complexity.
Solution Approach 2:
The structural and non-structural fan exit guide vanes are merged into a single integrated assembly that is collectively secured to the fan case and core housing. This merging allows the assembly to function as a unified structural element while incorporating acoustic treatment, thereby achieving rigidity without the complexity of separate mounting systems.
3Strength
If structural fan exit guide vanes are rigidly secured to fan case and core engine, then structural integrity is improved, but manufacturing complexity increases
Solution Approach 1:
Rather than making all fan exit guide vanes fully structural, the design uses a partial configuration where only certain vanes are structural and rigidly secured, while others are non-structural with acoustic functions. This partial approach achieves the necessary structural integrity without the manufacturing complexity of making every vane fully structural.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A gas turbine engine includes a a fan case (108) surrounding a fan rotor, and a core engine (232) including a low pressure compressor. A rigid connection between the fan case (108) and the core engine (232) includes three triangular-frame connecting members (116) rigidly connected to the fan case (108) at a fan case connection point, and to the core engine (232) at a core engine connection point. The triangular-frame connecting members (116) each are defined by two rigid legs (118, 120) which extend between the fan case (108) and to the core engine (232), along directions each have a component extending radially inwardly and a component in opposed circumferential directions to each other. A plurality of non-structural fan exit guide vanes are provided with an acoustic feature to reduce noise and are rigidly mounted to at the fan case (108) and/or the core engine (232).