H-Frame Fan Case Connection for Gas Turbine Airflow Efficiency
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Solution Overview
Problem
In modern gas turbine engines with gear reduction, the structural support between the fan case and the core housing is typically provided by fan exit guide vanes, which can limit airflow and introduce additional obstructions.
Innovation Solution
The use of H-frames, which are rigid members extending from the fan case to the core engine, provides additional rigidity while allowing for a reduced number of structural fan exit guide vanes, minimizing airflow obstruction.
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 is limited and obstructions are introduced
Solution Approach 1:
The structural support function is segmented from the fan exit guide vanes by introducing separate H-frames. The H-frames are dedicated structural members that provide rigidity between the fan case and core housing, while the fan exit guide vanes are reduced in number and optimized for airflow guidance rather than structural support.
Solution Approach 2:
H-frames are introduced as intermediary structural members between the fan case and core housing. These H-frames serve as the primary structural connection elements, allowing the fan exit guide vanes to be minimized or eliminated, thereby reducing airflow obstructions while maintaining necessary structural support.
2Stability of the object's composition
If multiple fan exit guide vanes are used for structural support, then rigidity is maintained, but device complexity increases
Solution Approach 1:
The structural support function is extracted from the fan exit guide vanes and transferred to dedicated H-frames. This extraction allows the fan exit guide vanes to be reduced in number or eliminated, simplifying the overall device complexity while maintaining the required rigidity through the H-frame structure.
Solution Approach 2:
The H-frames serve multiple functions: they provide structural support, maintain rigidity between the fan case and core housing, and allow for reduced airflow obstructions. This multi-functionality consolidates what would otherwise require multiple separate components into a single efficient structural element.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A gas turbine engine includes a fan rotor driven by a fan drive turbine about an axis through a gear reduction to reduce a speed of the fan rotor relative to a speed of the fan drive turbine. A fan case (108) surrounds the fan rotor, and a core engine with a compressor section, including a low pressure compressor. The fan rotor delivers air into a bypass duct defined between the fan case (108) and the core engine. A rigid connection (124) between the fan case (108) and the core engine includes a plurality of H-frame (116) connecting members rigidly connected to the fan case (108), and to the core engine. The H-frame (116) connecting members each are defined by two rigid legs (118) which extend between the fan case (108) and to the core engine, along directions which are generally parallel 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 least one of the fan case (108) and the core engine.