Gas Turbine Fan Case Sliding Panel Attachment
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Solution Overview
Problem
Existing fan case assemblies for gas turbine engines face challenges in securely attaching front acoustic panels while maximizing the acoustically treated area, minimizing weight and cost, and facilitating easy replacement and repair, with bonded panels being difficult to replace and bolted panels having limitations in noise mitigation.
Innovation Solution
A sliding arrangement with removable fastening means is used to attach the front acoustic panel to the fan case, allowing axial movement while inhibiting radial and circumferential movement, utilizing dovetail or Picatinny rails and axial screws or rivets for secure fixation, and overlapping panel members for additional structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonded panels are used to attach the front acoustic panel to the fan case, then the attachment is secure and continuous, but the panels become difficult to replace requiring destructive removal
Solution Approach 1:
The attachment system is divided into modular components: the fan case with integrated rails, the acoustic panel with corresponding sliders, and removable fasteners. This segmentation allows the panel to be securely attached during operation while enabling easy disassembly and replacement by removing the fasteners, eliminating the need for destructive removal associated with bonded panels.
Solution Approach 2:
The attachment system transitions from a static bonded connection to a dynamic, adjustable connection using removable fasteners. The fasteners can be engaged to provide secure attachment during operation and disengaged for panel replacement, allowing the system to adapt between the two operational states (secured and replaceable) as needed.
2Ease of repair
If bolted panels are used to attach the front acoustic panel to the fan case, then the panels are easy to replace, but the acoustically treated area is reduced due to bolting zones
Solution Approach 1:
The attachment mechanism uses localized rails and sliders positioned at the edges or periphery of the acoustic panel, concentrating the mechanical connection points in specific locations rather than distributing bolts across the entire panel surface. This allows the majority of the panel area to remain continuously acoustically treated while providing sufficient attachment points for secure and easy replacement.
Solution Approach 2:
The attachment system moves from a two-dimensional bolt pattern across the panel surface to a one-dimensional rail-slider mechanism along the edges. This dimensional change reduces the number of attachment points needed while maintaining security, thereby preserving more of the panel's acoustically treated area.
3Reliability
If traditional bolting and potting methods are used to secure the front acoustic panel, then the attachment is secure in all directions, but the weight and cost increase
Solution Approach 1:
The system replaces the traditional mechanical bolting and chemical potting combination with a simplified rail-slider-fastener mechanism. The rails and sliders provide structural guidance and positioning, while the removable fasteners provide axial retention, eliminating the need for heavy potting materials and reducing overall weight while maintaining attachment security.
4Reliability
If radial bolting and aft potting are used to secure the front acoustic panel, then the attachment is secure, but the treated acoustic area is broken up and made unusable for noise abatement
Solution Approach 1:
The attachment mechanism concentrates connection points at the panel edges using rails and sliders, leaving the central and majority acoustic treatment areas uninterrupted. This localized attachment approach maintains the continuity of the acoustically treated surface, preserving noise mitigation effectiveness while providing secure attachment.
Solution Approach 2:
The attachment function is segmented into edge-based rails and sliders rather than distributed radial bolts, separating the structural attachment function from the acoustic treatment function. This allows the acoustic panel to maintain its noise abatement capabilities across the treated area while the segmented attachment system provides secure fixation at the boundaries.
Data Source
AI summary
Aspects of the disclosure regard a fan case assembly for a gas turbine engine, the fan case assembly comprising a fan case having an inner surface and an outer surface, a front acoustic panel having an outer surface, and attachment means attaching the front acoustic panel outer surface to the fan case inner surface. The attachment means comprise a sliding arrangement allowing the front acoustic panel to be slid axially into the fan case. The sliding arrangement comprises a first longitudinal member and a second longitudinal member, one of the members being attached to the fan case inner surface and the other member being attached to the front acoustic panel outer surface. The attachment means further comprise removable fastening means fixing the first longitudinal member and the second longitudinal member in the axial direction.