Partially Coated Gas Turbine Blade Thermal Management
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Solution Overview
Problem
The addition of thermal barrier coatings to gas turbine engine blades increases their weight, necessitating a balance between protection from high temperature and corrosive conditions and minimizing weight, which existing partial coating configurations have not adequately addressed.
Innovation Solution
A partially coated blade design where only specific portions of the pressure side and leading edge are covered with a thermal barrier coating, with the fillet surface and other areas being free or substantially free of coating, optimizing protection while reducing weight and minimizing thermal gradient risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal barrier coating is applied to the entire blade surface, then protection from high temperature and corrosive conditions is improved, but blade weight increases
Solution Approach 1:
The patent applies thermal barrier coating selectively to specific regions of the blade (pressure side and leading edge within 21% of maximum span from platform section) rather than the entire surface. This local application provides protection where thermal and corrosive exposure is most severe while avoiding unnecessary weight addition in less critical areas such as the suction side and fillet regions.
2Reliability
If thermal barrier coating is applied to the fillet surface, then protection from high temperature is improved, but risk of thermal gradient-induced fissures increases
Solution Approach 1:
The patent specifically excludes the fillet surface from thermal barrier coating application. The fillet region, which connects the airfoil section to the platform section, is left uncoated to avoid creating thermal gradients in this geometrically complex area where coating thickness variations could lead to stress concentrations and fissure formation.
Solution Approach 2:
The blade surface is segmented into coated and uncoated regions based on thermal exposure requirements and structural considerations. The coating is applied only to the pressure side and leading edge within a specific radial distance, while the suction side and fillet areas remain uncoated, creating distinct zones with different thermal protection levels.
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 effectively protects susceptible areas from high temperatures while minimizing weight and reducing the risk of thermal gradient-induced fissures, maintaining structural integrity and efficiency.
Implementation Method 1
a first portion of the pressure side and of the leading edge is covered by a thermal barrier coating
Data Source
AI summary
A partially coated blade for a gas turbine engine, including a fillet surface surrounding the airfoil section and connecting it to the platform section. A radially outermost portion of the pressure side and leading edge is covered by a thermal barrier coating. This portion extends radially from a first limit to the blade tip. The first limit is located at a radial distance from the platform of at most 21% of the maximum span. The fillet surface is free or substantially free of the thermal barrier coating. In another embodiment, a second portion of the pressure side and of the leading edge is free or substantially free of the thermal barrier coating, extending radially from the platform section to a second limit located a radial distance from the platform section corresponding to at least 5% of the maximum span. A method of applying a thermal barrier coating is also discussed.