Seal Assembly Bow Wave Cooling for Gas Turbine Vanes
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Solution Overview
Problem
The interface between the combustor exit and the first vane stage in gas turbine engines experiences elevated temperatures due to bow wave phenomena and gaps at the leading edge of vanes, which affects thermal and propulsive efficiencies.
Innovation Solution
A seal assembly with a plurality of openings communicating cooling airflow into the gap between the combustor and the first vane stage, including angled openings and circumferentially spaced slots aligned with the leading edge of vanes, is used to direct cooling airflow and prevent hot gas flow into the gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a gap is maintained between the combustor and the first vane stage, then thermal expansion and manufacturing tolerances are accommodated, but elevated temperatures occur at the leading edge of vanes due to bow wave phenomena
Solution Approach 1:
A seal assembly is introduced as an intermediary component between the combustor and the first vane stage. This seal assembly includes a cooling airfoil that directs cooling airflow across the gap to the leading edge of the vanes, mediating the thermal interaction between the hot combustor gases and the vane leading edges while maintaining the necessary mechanical gap
Solution Approach 2:
Cooling airflow is utilized as a pneumatic mechanism to transport thermal energy away from the vane leading edges. The seal assembly incorporates openings that direct this cooling airflow across the gap, using fluid dynamics to cool the critical areas without requiring direct physical contact or closing the gap
2Temperature
If cooling airflow is directed into the gap between the combustor and the first vane stage, then temperature variations are reduced, but device complexity increases due to the seal assembly with multiple openings and slots
Solution Approach 1:
The seal assembly performs multiple functions simultaneously: it maintains the gap between components, directs cooling airflow to critical areas, and seals the interface between the combustor and vane stage. This multi-functionality reduces the need for separate components and simplifies the overall structure despite the sophisticated cooling function
Solution Approach 2:
The seal assembly incorporates openings and slots positioned at specific circumferential locations corresponding to the leading edges of individual vanes. This localized approach directs cooling airflow precisely where it is needed most, rather than uniformly across the entire interface, optimizing thermal management while minimizing the number of openings required
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 effectively reduces temperature variations and improves thermal and propulsive efficiencies by cooling the interface between the combustor and the first vane stage, mitigating bow wave-induced temperature increases.
Implementation Method 1
A seal assembly is disposed between the combustor and the first vane stage. The seal assembly includes a plurality of openings communicating cooling airflow into a gap between an aft end of the combustor and the first vane stage.
Implementation Method 2
the plurality of openings are disposed in groups spaced circumferentially spaced to correspond with the circumferential positions of the plurality of slots
Data Source
AI summary
A gas turbine engine includes a combustor. A turbine section is in fluid communication with the combustor. The turbine section includes a first vane stage aft of the combustor. A seal assembly is disposed between the combustor and the first vane stage. The seal assembly includes a plurality of openings communicating cooling airflow into a gap between an aft end of the combustor and the first vane stage. A combustor assembly and method are also disclosed.