Turbine Casing Flange Cut-Outs for Clevis Access
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Solution Overview
Problem
The existing assembly of turbojet exhaust casings with mixers is complex, requiring numerous parts and obstructing access for machining and repair, leading to weight and bulk inefficiencies, as well as difficulties in maintaining mechanical integrity and sealing.
Innovation Solution
The design incorporates access and release cut-outs in the flange, allowing easier machining and repair of clevises, reducing material usage, and incorporating festoon-shaped cut-outs to lighten the downstream flange while maintaining mechanical integrity, facilitating assembly and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the downstream flange is applied to the end of the ferrule to ensure mechanical integrity and sealing, then the mechanical strength and sealing are improved, but the access to the bores in the clevises is obstructed, making machining and repair difficult
Solution Approach 1:
The downstream flange is segmented by introducing access cut-outs that divide the flange structure into functional zones: sealed zones for mechanical integrity and open zones for machining access. This segmentation allows the flange to simultaneously provide structural strength and access pathways to the clevis bores without compromising either function.
Solution Approach 2:
The access cut-outs act as intermediary elements that mediate between the conflicting requirements of flange integrity and clevis accessibility. These cut-outs provide transmission pathways for machining tools to reach the clevis bores while the surrounding flange structure maintains the necessary mechanical strength and sealing capability.
2Strength
If the clevises are positioned radially low to optimize engine bulk and mechanical integrity, then the structural strength is improved, but the weight and bulk of the assembly are not optimal
Solution Approach 1:
The position parameters of the clevises are optimized within the radial constraints. By precisely positioning the clevises at the lowest feasible radial location that still permits access cut-outs, the design achieves maximum structural efficiency while minimizing the moment arm and associated weight penalties.
3Reliability
If numerous parts such as inserts are added to assemble the casing to the support ring, then the mechanical integrity and sealing are improved, but the device complexity and maintenance requirements increase
Solution Approach 1:
The attachment functionality is merged directly into the downstream flange structure through integrated attachment points. This eliminates the need for separate inserts and intermediate components, reducing part count while maintaining the reliable connection between the exhaust casing and support ring.
Solution Approach 2:
The downstream flange is designed as a multi-functional component that simultaneously provides sealing, structural support, access to clevises, and attachment to the support ring. This universal design consolidates multiple functions into a single component, reducing overall assembly complexity.
Data Source
AI summary
The present invention relates to a turbine engine casing (1), in particular a turbojet exhaust casing, including at least one hoop (2) and at least one flange (3, 4) at least partially defining one end of said hoop (2), and at least one cap (5) positioned at least partially on the outer surface of the hoop (2), said cap (5) including a bore (6) capable of receiving an element for fastening the casing (1) to a bracket, the flange including an access cut-out (7a) substantially coaxial with the bore (6) of said at least one cap (5), said access cut-out (7a) enabling access to the bore (6), the access cut-out (7a) being provided at a release cut-out (7b) which is wider than the flange (3, 4) and constitutes a recess on said release cut-out (7b). The invention also relates to a turbine engine including a casing (1) and to a method for machining the latter according to the present invention.