Gas Turbine Exhaust Cone Flange Assembly Guide
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Solution Overview
Problem
The existing methods for attaching the exhaust cone to the exhaust casing in turbojet engines are cumbersome, leading to difficulties in mounting and demounting, which can result in jamming, incorrect angular orientation, and degradation of functional faces, especially for large-diameter parts, posing risks to operators and complicating maintenance.
Innovation Solution
The use of axial annular flanges with a guiding system, featuring radial piercings and screws with embedded heads to reduce aerodynamic impact, along with a foolproofing mechanism and scalloped flanges to facilitate easier alignment and assembly, allowing for predetermined angular positioning and reduced manipulations during mounting and demounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the exhaust cone is attached to the exhaust casing using traditional bolting methods with pockets and closure cowls, then the mechanical connection is achieved, but the mounting and demounting operations become complex and time-consuming
Solution Approach 1:
The connection system is divided into modular components: the exhaust cone with integrated flange, the exhaust casing with flange, and the bolt set. This segmentation allows for standardized, pre-drilled alignment holes that simplify the bolting process while maintaining strong mechanical connection.
Solution Approach 2:
The alignment holes are pre-drilled and positioned on the flanges during manufacturing. This preliminary action eliminates the need for complex pocket structures and closure cowls, allowing operators to directly insert bolts through pre-positioned holes, significantly reducing mounting and demounting time.
2Strength
If multiple pockets with closure cowls are provided for bolt access, then the exhaust cone can be securely attached, but the aerodynamic impact increases and gas stream continuity is disrupted
Solution Approach 1:
The flange structure merges the attachment function with the aerodynamic surface. The flat flange surfaces provide bolt access while maintaining gas stream continuity, eliminating the need for separate pockets and closure cowls that would disrupt the aerodynamic flow.
3Device complexity
If the exhaust cone is made as a single piece, then the structure is simpler, but the demounting becomes difficult and operator safety risks increase
Solution Approach 1:
The exhaust cone is segmented from the exhaust casing through the flange connection design. This allows the exhaust cone to be easily detached by removing the bolts, providing safe and easy access to rear bearing cavities while maintaining a simple overall structure.
4Ease of manufacture
If axial flanges with pre-positioned holes are used for connection, then the mounting process is simplified, but the angular orientation precision must be ensured
Solution Approach 1:
The flange design incorporates asymmetric features such as keyways, asymmetric hole patterns, or positioning lugs that ensure correct angular orientation during assembly. This asymmetry provides foolproof alignment, preventing incorrect installation while maintaining simple bolting procedures.
Data Source
AI summary
An assembly including an exhaust casing and an exhaust cone for a gas turbine engine, each including an axial annular flange, the two flanges being inserted into one another, one being radially external and the other radially internal, and held together by a mechanical attachment, and the assembly further including a guide by which, during operation of assembling the annular flanges to each other, the exhaust cone is in a predetermined angular position relative to the exhaust casing.