Gas Turbine Transition Duct Curved Profile
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Solution Overview
Problem
Transition ducts in gas turbine engines face premature deterioration due to high mechanical and thermal stresses, leading to cracking and component failure, particularly with sharp geometric changes and internal air-cooled channels.
Innovation Solution
A transition duct with a novel geometric profile defined by X, Y, and Z Cartesian coordinates, featuring a smooth transition from a circular to a rectangular arc-like shape, combined with effusion cooling through a panel assembly, to minimize stress concentrations and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If internal air-cooled channels are used in transition ducts, then cooling effectiveness is improved, but stress concentrations and cracking occur due to sharp geometric changes
Solution Approach 1:
The patent applies curvature by replacing sharp geometric changes with smooth, rounded transitions in the transition duct profile. The duct geometry is designed with continuous curves instead of abrupt angles, eliminating stress concentration points where cracking typically initiates. This curved transition maintains structural integrity while accommodating the required flow path changes.
Solution Approach 2:
The patent removes internal air-cooled channels from the transition duct design. By eliminating these channels, the source of stress concentrations is removed, as the channels create sharp geometric changes at their intersections with the duct wall. This extraction of the cooling function leads to a simpler geometry that is more resistant to cracking and premature failure.
2Ease of manufacture
If sharp geometric changes are used in transition ducts, then manufacturing simplicity is improved, but high stress and stress concentrations occur leading to premature deterioration
Solution Approach 1:
The patent employs smooth, rounded geometric transitions instead of sharp angles in the duct profile. These curved transitions distribute stresses more evenly throughout the structure, preventing stress concentrations that would otherwise occur at sharp corners. The geometry maintains manufacturability while significantly improving stress resistance and component life.
3Adaptability or versatility
If complex geometry changes are used in transition ducts, then flow path requirements are met, but vibratory issues and premature failure occur
Solution Approach 1:
The patent uses smooth curved transitions to meet flow path requirements while avoiding sharp geometric changes that excite vibratory modes. The rounded geometry reduces stress concentrations that would otherwise lead to fatigue cracking and premature failure under cyclic loading conditions.
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 solution reduces operating stresses, raises natural frequencies to avoid vibratory issues, and provides more uniform cooling, resulting in extended component life and reduced maintenance needs.
Implementation Method 1
the air is directed through a plurality of effusion holes in the panel assembly of the transition duct. Effusion cooling provides more uniform cooling of the transition duct than the plurality of internal cooling channels used in the prior art
Data Source
AI summary
A transition duct having a panel assembly with an inlet end of generally circular cross section and an outlet end having a generally rectangular arc-like cross section is disclosed. The panel assembly has an uncoated internal profile substantially in accordance with coordinate values X, Y, and Z as set forth in Table 1. The coordinates are taken at a sweep angle θ wherein θ is an angle measured from the inlet end and X, Y, and Z are coordinates defining the panel assembly profile at each angle θ from the inlet end. An alternate embodiment is also disclosed defining an envelope for the uncoated internal profile of the panel assembly.