Guide Vane Segment Hook Recesses to Reduce Shroud Bulging
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Solution Overview
Problem
The guide vanes in aircraft engine compressors experience significant thermal stress, leading to bulging of the shroud and increased contact pressure, which results in mechanical deflections and widened gaps, necessitating larger gap dimensions and reinforcements, particularly affecting the hooks and casing grooves.
Innovation Solution
A guide vane segment with a shroud featuring hooks that have recesses at their ends, dividing them into sections to reduce stress accumulation and stiffness, combined with friction plates to minimize leakage and further stabilize the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shroud is designed as a continuous structure to reduce gaps and leakage, then sealing performance is improved, but thermal stress accumulation causes increased bulging and mechanical deflection
Solution Approach 1:
The continuous shroud is divided into multiple discrete segments arranged in the circumferential direction. Each segment is separated by gaps that prevent thermal stress accumulation and reduce bulging while maintaining adequate sealing performance. The segmentation allows each segment to independently accommodate thermal expansion without causing excessive deflection in the entire shroud structure.
2Strength
If the hook arrangement is reinforced to reduce mechanical deflection, then structural strength is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of uniformly reinforcing the entire hook arrangement, reinforcement is applied locally only at critical stress concentration points. The hook segments have varying thicknesses and cross-sectional areas optimized for their specific structural roles, providing necessary strength where needed while minimizing overall material usage and manufacturing complexity.
3Stress or pressure
If larger gap dimensions are designed to accommodate shroud deflection, then mechanical stress is reduced, but sealing performance and aerodynamic efficiency deteriorate
Solution Approach 1:
The gap dimensions between shroud segments are designed to be dynamic rather than fixed, allowing controlled variation to accommodate thermal expansion and mechanical deflection during operation. The gaps are sized to maintain adequate clearance under all operating conditions while minimizing leakage paths, achieving a balance between stress reduction and sealing performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively reduces the deflection and bulging of the shroud, minimizing mechanical stress and leakage while maintaining structural integrity and reducing the need for larger gap dimensions and reinforcements.
Implementation Method 1
During compressor operation, the guide vane segments are exposed to significant temperature differences between the outer and inner regions of the flow channel. These resulting temperature gradients lead to a bulging of the guide vane segment's shroud during aircraft engine operation.
Implementation Method 2
The at least one recess advantageously interrupts stresses within the hook in the circumferential direction and reduces the stiffness of the hooks in the circumferential direction, thereby advantageously reducing bowing. Deformations no longer accumulate but rather occur locally in the hook sections extending in the circumferential direction.
Data Source
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AI summary
The invention relates to a guide vane segment (10) for a flow channel (1c) in a compressor (2) of an aircraft engine (1), and to an aircraft engine (1) having a guide vane segment (10). The guide vane segment (10) is characterized in that at least one hook (41, 42) on a shroud (30) for fastening in the flow channel (1c) and connecting a plurality of guide vanes (20) has at least one recess (45, 46) at a hook end (43, 44), wherein the at least one recess (45, 46) divides the hook end (43, 44) along its longitudinal extent (L) in the circumferential direction (U). This advantageously reduces a cambering effect of the guide vane segment (10) during operation of the aircraft engine (1).