Gas Turbine Cooling Hole Recoating Using Airflow Shielding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for repairing thermal barrier coatings on gas turbine engine components, such as blades and vanes, are not cost-effective or operationally effective due to misalignment and duplication of cooling holes during recoating, as the original cooling holes cannot be properly located, leading to inefficient restoration.
Innovation Solution
A method involving the use of 'shop air' at a pressure of 100-200 psi is directed through the cooling holes during the recoating process to prevent coating adhesion within the holes, utilizing a pressurized plenum or bladder system, and a plasma spray system to reapply the top coat, while maintaining the integrity of the cooling holes by minimizing coating deposition through gas momentum and quenching effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coating is stripped with a water jet and re-applied, then the thermal barrier coating is restored, but the cooling holes cannot be properly located due to recoat coverage, resulting in misaligned or duplicate cooling holes
Solution Approach 1:
The patent applies preliminary action by introducing gas through the cooling holes before the coating is applied. This pre-positioning of gas flow paths ensures that the cooling holes remain identifiable and properly aligned during the recoating process, preventing the misalignment and duplication issues that occur with conventional water jet stripping methods
2Temperature
If the component is re-coated to restore thermal barrier, then the thermal protection is improved, but the cooling holes become obscured and cannot be readily located
Solution Approach 1:
The patent uses gas (such as air or inert gas) as an intermediary substance that flows through the cooling holes during the coating process. This intermediary gas flow makes the cooling holes visible and detectable even as coating material is applied, allowing operators to locate and track cooling hole positions without removing the coating afterward
3Ease of manufacture
If conventional coating repair is performed, then the coating wear is addressed, but the process is neither cost-effective nor operationally effective
Solution Approach 1:
The patent implements self-service by allowing the cooling holes to actively participate in their own protection during the coating process. By flowing gas through the cooling holes, the holes themselves guide the coating application and prevent coating accumulation within them, eliminating the need for additional steps to locate or clear the holes after coating
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 method effectively restores the thermal barrier coating without misaligning or duplicating cooling holes, ensuring precise re-drilling and maintaining the component's thermal performance, thus enhancing the durability and temperature resistance of the components.
Implementation Method 1
directed through the cooling holes during the recoating process to prevent coating adhesion within the holes, utilizing a pressurized plenum or bladder system, and a plasma spray system, while maintaining the integrity of the cooling holes by minimizing coating deposition through gas momentum and quenching effects
Implementation Method 2
minimizing coating deposition through gas momentum and quenching effects
Implementation Method 3
a plasma spray system to reapply the top coat
Data Source
Figure 1
Figure 2~8
Figure 3
AI summary
A method of coating a component having a multiple of cooling holes includes removing at least a portion of a prior coating; directing a gas through at least one of the multiple of cooling holes; and applying a coat layer while directing the gas through at least one of the multiple of cooling holes.