Double-Walled Gas Turbine Platform Cooling via Segmented Airflow
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Solution Overview
Problem
Existing cooling devices for gas turbine guide vane rings struggle to achieve effective film cooling due to intermixing of cooling air with hot gas flows, especially due to manufacturing limitations that restrict the insertion of cooling air bores at desired angles and orientations.
Innovation Solution
A double-layered wall configuration with a hollow space is implemented, allowing cooling air to be blown in through the outer wall and blown out at an optimal angle through the inner wall, facilitating efficient cooling of platform surfaces independent of manufacturing constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling air blow-out openings are arranged at an optimal angle for film cooling, then cooling efficiency is improved, but manufacturing complexity increases due to the need for precise angled bores in the platform
Solution Approach 1:
The cooling device is divided into two separate walls: an outer wall receiving cooling air from the secondary air area, and an inner wall forming the platform surface. This segmentation allows the cooling air path to be optimized independently from the platform structure, enabling optimal cooling angles without complex angled bores in the platform itself.
Solution Approach 2:
The cooling air is guided from the outer wall through a hollow space to the inner wall, adding a spatial dimension to the cooling air path. This dimensional transition allows cooling air to reach the platform surface at optimal angles without requiring complex angled openings in the platform, thereby improving cooling efficiency while maintaining manufacturing simplicity.
2Reliability
If cooling air is guided directly to platform surfaces, then cooling effect is improved, but intermixing with hot gas flow occurs reducing effectiveness
Solution Approach 1:
The hollow space acts as an intermediary chamber between the cooling air source and the platform surface. Cooling air is guided through this intermediate space and discharged through the inner wall at optimized angles, forming an effective cooling film that prevents direct mixing with hot gas while maintaining strong cooling effect on the platform surfaces.
3Adaptability or versatility
If cooling air blow-in openings are arranged in the outer wall, then installation flexibility is improved, but device complexity increases due to the double-layered wall structure
Solution Approach 1:
The outer wall serves multiple functions: it forms part of the structural boundary, receives cooling air from the secondary air area, and provides mounting surfaces for cooling air blow-in openings. The inner wall similarly serves as both structural element and cooling air discharge surface. This multi-functionality justifies the double-layered structure while providing installation flexibility.
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
This design ensures effective film cooling across all surface areas of the guide vane ring platforms, enhancing cooling efficiency by directing cooling air optimally and avoiding manufacturing-related obstacles, thereby improving heat shielding and cooling performance.
Implementation Method 1
the hollow space is impinged by cooling air through at least one cooling air blow-in opening in the outer wall, and at least one cooling air blow-out opening is arranged inside the inner wall, extending in the downstream direction with respect to the surfaces of the platforms
Implementation Method 2
the cooling effect on the platform surfaces and the formation of an effective cooling film on them
Data Source
AI summary
A cooling device for cooling platforms of a guide vane ring of a gas turbine is arranged downstream inside a main flow channel of a combustion chamber. Cooling air passages are arranged in a wall of the platforms or of an intermediate piece that is connected therewith to guide cooling air for film cooling the surfaces of the platforms. At least in certain areas, the wall is configured with at least two layers having—as viewed from the main flow channel—an outer wall and a spaced apart inner wall forming a hollow space, wherein the hollow space can be impinged by cooling air through at least one cooling air blow-in opening inside the outer wall, and at least one cooling air blow-out opening is arranged inside the inner wall extending in the downstream direction to the surfaces of the platforms.