Gas Turbine Cooling Hole Design for Thermal Barrier Coating
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Solution Overview
Problem
Existing cooling hole designs in gas turbine engines are compromised by thermal barrier coatings, which alter the shape and functionality of film cooling holes, leading to inefficient coolant distribution and reduced cooling effectiveness due to coating deposition.
Innovation Solution
The method involves forming cooling holes with an enlarged intermediate section to account for expected thermal barrier coating deposition, using experimental or theoretical determination to ensure the final shape remains effective after coating application, incorporating a diffusor section with a central ridge to guide air flow and a crescent-shaped meter section to counteract combustion products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal barrier coating is applied to protect the component from high temperature, then the component's thermal protection is improved, but the cooling hole shape is altered and blocked leading to reduced cooling effectiveness
Solution Approach 1:
The cooling hole is designed with an enlarged intermediate section before the film cooling hole in advance, anticipating the future coating deposition. This preliminary geometric modification ensures that after thermal barrier coating is applied, the coating material has sufficient space to deposit without blocking the final cooling hole shape, thus maintaining cooling effectiveness while still providing thermal protection.
2Reliability
If the cooling hole is designed with precise shape for optimal cooling, then the cooling performance is improved, but the coating deposition blocks or alters the hole shape reducing the cooling effectiveness
Solution Approach 1:
The cooling hole is divided into three distinct sections: an intermediate section with enlarged cross-sectional area, a meter section with controlled dimensions, and a film cooling hole section. This segmentation allows the intermediate section to serve as a buffer zone for coating deposition, while the downstream meter and film cooling sections maintain precise dimensions for optimal cooling performance, thus resolving the conflict between coating accommodation and shape precision.
3Productivity
If the cooling hole shape is optimized for coolant distribution, then the cooling efficiency is improved, but thermal barrier coating deposition alters the shape and reduces effectiveness
Solution Approach 1:
The intermediate section is designed with an enlarged cross-sectional area before the meter section in advance of coating application. This preliminary geometric feature provides a buffer zone that accommodates future thermal barrier coating deposition, ensuring that the downstream meter and film cooling sections maintain their optimized shapes for efficient coolant distribution, thus preserving cooling efficiency despite coating application.
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 approach maintains the desired shape and functionality of cooling holes post-coating application, ensuring effective coolant distribution and enhanced cooling performance by minimizing coating-induced blockage and optimizing air flow.
Implementation Method 1
the thermal barrier coatings have sometimes blocked or at least altered the shape of the cooling holes
Data Source
Figure 1
Figure 2~3B
Figure 4A~4C
AI summary
A method of forming a component for use in a gas turbine engine comprises the steps of determining a desired shape for a cooling hole on a gas turbine engine component, and determining the likely deposition of a coating to be provided on the component into the cooling hole. An intermediate cooling hole is formed that has an enlarged area from the desired shape to account for deposition of the coating. The component is then coated. A component and an intermediate component for use in a gas turbine engine are also disclosed.