Turbine Exhaust Casing Recesses for Strut Fatigue Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engine components, particularly turbine exhaust casings, face significant challenges due to extreme temperature differentials and cyclical loads, leading to thermally induced stresses and reduced fatigue life, which complicates the design of radial struts connecting the shroud and hub while maintaining aerodynamic performance.
Innovation Solution
The design incorporates radially inward or outward recesses at the leading or trailing edges of struts within the inner surface of the flow channel, allowing for a smooth, continuous surface that minimizes stress and maintains laminar airflow, with corresponding increased shroud wall thickness to reinforce the outer surface, optimizing strut strength and reducing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the shroud wall thickness is increased to reinforce the outer surface corresponding to the recess, then the strength and fatigue life of the strut connection are improved, but the overall weight of the turbine exhaust casing increases
Solution Approach 1:
The shroud wall thickness is increased only in the specific region corresponding to the recess area where the strut connects, rather than uniformly throughout the entire shroud. This localized reinforcement provides the necessary strength at the critical stress point while minimizing the additional weight compared to a uniform thickness design.
2Duration of action of stationary object
If recesses are provided at the leading or trailing edge of struts to reduce stress concentration, then the fatigue life of the struts is enhanced, but the aerodynamic performance may be compromised due to surface disruption
Solution Approach 1:
The recesses are strategically positioned at specific locations on the strut edges where stress concentration occurs, with controlled depth and dimensions that prioritize stress reduction while maintaining acceptable aerodynamic characteristics in the surrounding flow field.
Solution Approach 2:
The recesses are designed with specific dimensional parameters (depth, width, position) that provide sufficient stress relief to enhance fatigue life without creating excessive disruption to the aerodynamic flow. The dimensions are optimized to achieve the minimum necessary modification for fatigue improvement while preserving aerodynamic performance.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention concerns a turbine exhaust casing (TEC) for a gas turbine engine in which portions of the inner surface of the casing against which exhaust gas flows are provided with recesses extending into the surfaces. The recesses are positioned proximate to the leading edges of struts which extend between an outer shroud and inner hub of the casing.