Gas Turbine Fan Blade External Cavities Weight Reduction
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Solution Overview
Problem
Fan blades of gas turbine engines face a challenge in balancing weight reduction and structural integrity, particularly in withstanding events like bird strikes, while maintaining aerodynamic performance.
Innovation Solution
The implementation of external cavities in the fan blades that extend from the pressure side to the suction side, partially through the blade thickness, and internal cavities covered by a secure cover, which reduce weight without affecting aerodynamic efficiency or structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If internal cavities are employed to reduce weight, then weight reduction is achieved, but the blade requires additional covers to prevent airflow through cavities
Solution Approach 1:
The blade is segmented into multiple sections with external cavities distributed throughout the blade structure. These cavities are positioned in non-aerodynamic regions, allowing the blade to be divided into functional zones that serve different purposes - some areas for weight reduction, others for maintaining aerodynamic integrity without requiring covers.
Solution Approach 2:
The invention transitions from internal cavities (three-dimensional enclosed spaces requiring covers) to external cavities (surface-level or partially exposed voids). This dimensional change allows cavities to be positioned in the blade structure without creating airflow pathways through the aerodynamic surface, eliminating the need for covers while maintaining weight reduction benefits.
2Weight of moving object
If fan blades are made thin to reduce weight, then weight reduction is achieved, but structural integrity to withstand bird strikes is compromised
Solution Approach 1:
The blade structure is segmented with multiple external cavities distributed throughout, creating a cellular or lattice-like internal architecture. This segmentation reduces overall material usage and weight while the distributed cavity structure provides structural reinforcement similar to engineering I-beams or honeycomb structures, maintaining strength-to-weight ratio.
Solution Approach 2:
Different regions of the blade have different cavity configurations optimized for their specific functional requirements. High-stress areas near the root have fewer or smaller cavities to maintain structural integrity for withstanding bird strikes, while lower-stress areas have larger or more numerous cavities for maximum weight reduction, creating locally optimized structural quality throughout the blade.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A blade of a gas turbine engine includes a blade portion. The blade portion includes a first portion located radially outwardly that is located in a flow path and a second portion located radially inwardly of the first portion that is not located in the flow path. A plurality of external cavities is in the second portion of the blade portion.