Thermal Hood Segmentation for Gas Turbine Coating
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Solution Overview
Problem
Existing thermal barrier coating systems for gas turbine engines face challenges with thermally grown oxide (TGO) layer growth, leading to increased thickness and thermal-mechanical stresses, which contribute to component failure and reduced durability.
Innovation Solution
A coating apparatus and method involving a chamber with a sting assembly and thermal hood system, where the thermal hood is designed with concentric, perforated nickel-based superalloy members to maintain effective coating temperatures and reduce performance degradation by allowing for easy replacement of the inner hood member, enabling efficient deposition of thermal barrier coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a thermal barrier coating is applied to reduce thermal stresses and improve durability, then the component life is extended, but the thermally grown oxide layer continues to grow in thickness over time and cycles, leading to increased thermal-mechanical stresses and potential failure
Solution Approach 1:
A bond coat layer is applied beforehand to the substrate before applying the thermal barrier coating. This bond coat layer serves as a protective intermediary that controls and limits TGO layer growth, preventing excessive oxide formation that would otherwise lead to coating failure and extend the service life of the coated component
2Productivity
If the sting assembly is retracted to replace parts outside the chamber, then part replacement efficiency is improved, but the thermal hood must be replaced along with the part, increasing device complexity and replacement time
Solution Approach 1:
The thermal hood is divided into a fixed outer hood attached to the chamber and a movable inner hood attached to the sting assembly. This segmentation allows the inner hood to be independently replaced with the part during retraction, while the outer hood remains stationary, reducing overall system complexity and replacement time
Solution Approach 2:
The inner hood is designed to move with the sting assembly, transitioning from an inserted position during coating to a retracted position during part replacement. This dynamic design allows the thermal hood to adapt its position and be easily replaced as part of the sting assembly, improving productivity without requiring full hood replacement
3Stability of the object's composition
If the thermal hood remains stationary in the chamber, then coating temperature stability is improved, but the hood accumulates coating material and degrades performance, requiring frequent replacement or maintenance
Solution Approach 1:
The inner hood is designed to move between an inserted position during coating operations and a retracted position during part replacement. This dynamic positioning allows the hood to maintain temperature stability during coating while enabling easy removal and replacement, extending service life by preventing coating material accumulation
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 thermal stresses and improves durability by maintaining consistent coating temperatures and allowing for efficient replacement of the thermal hood, thereby extending the life of gas turbine engine components.
Implementation Method 1
The source may comprise an ingot and an electron beam source positioned to direct a beam to the ingot
Implementation Method 2
a thermal hood comprising a first member and a second member
Data Source
AI summary
An apparatus deposits a coating on a part. The apparatus comprises a chamber and a sting assembly for carrying the part. The sting assembly is shiftable between: an inserted condition where the sting assembly holds the part within the chamber for coating; and a retracted condition where the sting assembly holds the part outside of the chamber. The apparatus comprises a source of the coating material positioned to communicate the coating material to the part in the inserted condition. The apparatus comprises a thermal hood comprising a first member and a second member. The second member is between the first member and the part when the part is in the inserted condition. The second member is carried by the sting assembly so as to retract with the sting assembly as the sting assembly is retracted from the inserted condition to the retracted condition.