Turbine Diffuser Axial Movement Lap Joint
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Solution Overview
Problem
Traditional diffuser sections in gas turbine engines experience high stresses due to high temperatures and exhaust gas configurations, leading to increased wear and reduced mechanical integrity.
Innovation Solution
The implementation of a modified diffuser section design featuring a circumferential lap joint, discrete brackets, and a circumferential groove to facilitate axial movement and reduce stress, along with a spinning process to form the desired curvature of the diffuser components, which includes forming the inner and outer barrels from axial segments to minimize residual stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional diffuser section is used with fixed configuration, then the structural simplicity is maintained, but high stresses and wear occur due to thermal expansion and exhaust gas exposure
Solution Approach 1:
The diffuser section is designed with movable outer barrel that can expand and contract axially relative to the turbine outlet, transforming the fixed structure into a dynamic one. This allows the diffuser to accommodate thermal expansion and contraction caused by high temperatures, reducing stress accumulation and improving mechanical integrity during operation
Solution Approach 2:
The diffuser section is divided into separate components including the outer barrel, inner barrel, and turbine outlet as distinct segments. These segmented parts are connected through lap joints that allow relative movement, enabling each segment to respond independently to thermal stresses and reducing overall structural stress
2Stability of the object's composition
If the diffuser section is made rigid to maintain structural stability, then positioning accuracy is improved, but thermal expansion causes increased stress and potential damage
Solution Approach 1:
The system allows change in the axial position parameter of the outer barrel relative to the turbine outlet through the lap joint mechanism. This parameter change enables the diffuser to adapt to thermal expansion while maintaining circumferential positioning stability, effectively managing thermal stress without compromising structural stability
Solution Approach 2:
The lap joint acts as an intermediary mechanism between the rigid turbine outlet and the movable outer barrel. It provides a controlled interface that allows axial movement while maintaining structural connection, mediating between the need for stability and the need to accommodate thermal expansion
Data Source
AI summary
A system includes a circumferential lap joint between a downstream end of an outer wall of a turbine outlet and an upstream end of an outer barrel of a diffuser section, where the circumferential lap joint facilitates axial movement of the outer barrel relative to the outer wall, an upstream lip of the outer barrel is disposed radially within a downstream lip of the outer wall, and both the turbine outlet and the diffuser section are configured to receive an exhaust gas.