Thermal Barrier Coating Cooling Hole Clogging Prevention
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Solution Overview
Problem
The existing methods for applying thermal barrier coatings on heat-resistant members, such as those used in aircraft engines, often result in clogging of cooling holes due to the material entering these holes during the coating process, leading to increased trouble with removing masking pins as the number of holes increases.
Innovation Solution
A method involving thermal spraying of a top coat layer on a bond coat layer, while ejecting gas from the cooling holes to prevent material entry and clogging, using techniques like high velocity flame spraying and suspension high velocity oxygen fuel spraying, with controlled temperature and cooling to maintain optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If masking pins are inserted into each cooling hole to prevent clogging, then the cooling holes are protected from material entry, but the complexity and time required for removing masking pins increases with the number of holes
Solution Approach 1:
The patent extracts the harmful function of masking pins by replacing them with a gas ejection system that actively prevents material entry without requiring physical insertion or removal. The gas flow is ejected through the cooling holes during thermal spraying to create a protective barrier, eliminating the masking pin removal step entirely.
Solution Approach 2:
The patent applies pneumatic principles by using gas ejection through the cooling holes to prevent thermal spray material from entering and clogging the holes. The gas flow creates a protective atmosphere that actively repels molten material, replacing the mechanical masking pin approach with a fluid-based solution.
2Ease of manufacture
If thermal spraying is used to form the top coat layer, then the manufacturing cost and equipment complexity are reduced, but the risk of material entering and clogging cooling holes increases
Solution Approach 1:
The patent performs preliminary action by ejecting gas through the cooling holes before and during the thermal spraying process. This pre-established gas flow creates a protective barrier that prevents thermal spray material from entering the cooling holes, allowing the use of cost-effective thermal spraying equipment without compromising hole patency.
Solution Approach 2:
The patent introduces gas flow as an intermediary between the thermal spray material and the cooling holes. This intermediary gas layer acts as a barrier that allows the thermal spraying process to proceed effectively while preventing material contamination of the cooling holes.
3Temperature
If the number of cooling holes is increased to improve cooling performance, then the heat dissipation capability is enhanced, but the trouble and time required for masking pin removal increases
Solution Approach 1:
The patent extracts the time-consuming masking pin removal operation by replacing it with a gas ejection system that prevents clogging during the thermal spraying process itself. This allows for increased numbers of cooling holes to be processed without proportionally increasing the time required for masking operations.
Solution Approach 2:
The patent enables continuous operation by maintaining gas ejection throughout the thermal spraying process, preventing material entry into cooling holes in real-time. This continuous protective action eliminates the need for discrete masking pin insertion and removal steps for each hole, making the process scalable to higher hole counts.
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 effectively suppresses clogging of cooling holes, reduces manufacturing costs, and ensures thermal barrier properties and heat cycle durability equivalent to electron beam physical vapor deposition methods, while simplifying the process and reducing equipment costs.
Implementation Method 1
ejecting a gas from a plurality of holes opened in a surface of the heat-resistant alloy base material
Implementation Method 2
forming a top coat layer on a bond coat layer, which is formed on a heat-resistant alloy base material, by thermal spraying
Data Source
AI summary
A method for applying a thermal barrier coating according to at least one embodiment of the present disclosure includes: a step of forming a top coat layer on a bond coat layer, which is formed on a heat-resistant alloy base material, by thermal spraying, while ejecting a gas from a plurality of holes opened in a surface of the heat-resistant alloy base material.