Exhaust Diffuser Strut Trailing Member With Stress Relief Slots
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Solution Overview
Problem
Cracking occurs in the proximity of the weld connection between the strut body and flow shield in gas turbine exhaust diffusers due to temperature gradients, vibration-induced mechanical stresses, and the intersection of multiple components, necessitating frequent maintenance and inspection.
Innovation Solution
A trailing member for a strut of a gas turbine exhaust diffuser with a tapered cross-section and stress relief slots in the side walls, allowing for deformation and reducing stress concentrations, along with a cover plate and U-shaped cutouts to avoid weld seam interference and facilitate inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radially outer end of the trailing member is not fixed to the outer diffuser barrel, then the amplitude of vibration is limited and hot gas ingestion is reduced, but cracking occurs due to temperature gradients and vibration-induced mechanical stresses
Solution Approach 1:
The trailing member is divided into multiple side walls that can deform independently through stress relief slots, allowing the structure to segment its response to thermal and mechanical stresses without compromising overall integrity
Solution Approach 2:
The stress relief slots enable changes in the physical state of the trailing member by allowing controlled deformation and stress redistribution, transforming the rigid structure into one that can adapt to varying thermal and mechanical conditions
2Stability of the object's composition
If multiple weld seams and component interconnections are used to attach the strut body and flow shield, then structural stability is achieved, but cracking occurs due to the aggregation of weld seams and temperature gradients
Solution Approach 1:
The stress relief slots extract the problematic stress concentrations from the weld seam regions by providing alternative deformation paths, removing the aggregation effect of multiple weld seams on the trailing member
Solution Approach 2:
The stress relief slots act as intermediary elements between the rigid welded structures and the thermal-mechanical loads, mediating the stress distribution and preventing direct transmission of harmful stresses to the weld seams
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
Reduces mechanical stress and cracking, enhances structural integrity, and allows for easier maintenance by minimizing weld seam interference and stress concentrations, while maintaining aerodynamic efficiency.
Implementation Method 1
stress relief slots in the side walls that open at the edges, allowing for deformation and reducing mechanical stresses
Data Source
AI summary
A trailing member for a strut of a gas turbine exhaust diffuser includes an upstream side a downstream end spaced along a downstream direction from the upstream side, and two side walls extending from the upstream side to the downstream end. A distance between the two side walls decreases along a direction from the upstream side to the downstream end. A longitudinal extent of the trailing member extends along the upstream side between a first longitudinal end and a second longitudinal end. A first edge of each side wall is disposed proximate to the first longitudinal end. A stress relief slot is provided in at least one of the first and second side walls of the two side walls and opens at the first edge of the respective side wall.