Turbine Blade Hot-Corrosion Coating via Localized Application
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Solution Overview
Problem
Gas turbine engine turbine blades experience excessive wear and fractures due to hot-corrosion, which existing protective coatings like platinum aluminide fail to adequately address without increasing stress and reducing lifespan.
Innovation Solution
A hot-corrosion-resistant coating made of high-chromium content material is applied exclusively to the leading edge and a partial region of the airfoil within the radially inner half of the span-wise length, minimizing the coating's coverage and weight, thereby reducing stress and extending blade lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a platinum aluminide coating is applied to the entire exterior surface of the airfoil, then hot-corrosion resistance is improved, but blade weight increases and stress increases reducing lifespan
Solution Approach 1:
The patent applies hot-corrosion-resistant coating exclusively to the leading edge region (radially inner half of the span-wise length) rather than the entire airfoil surface. This localized application targets the area most susceptible to hot-corrosion while minimizing coating material usage, thereby reducing blade weight and associated stresses compared to full-surface coating.
Solution Approach 2:
The airfoil surface is segmented into different coating zones: the leading edge region (radially inner half) receives hot-corrosion-resistant coating, while the remaining portions (radially outer half and trailing edge) remain uncoated. This segmentation allows selective protection where needed most while avoiding unnecessary weight addition in less critical areas.
2Reliability
If a platinum aluminide coating is applied to the entire exterior surface of the airfoil, then hot-corrosion resistance is improved, but blade stress increases reducing lifespan
Solution Approach 1:
The patent applies hot-corrosion-resistant coating exclusively to the leading edge region (radially inner half of the span-wise length) rather than the entire airfoil surface. This localized application targets the area most susceptible to hot-corrosion while minimizing coating material usage, thereby reducing blade weight and associated stresses compared to full-surface coating.
Solution Approach 2:
The airfoil surface is segmented into different coating zones: the leading edge region (radially inner half) receives hot-corrosion-resistant coating, while the remaining portions (radially outer half and trailing edge) remain uncoated. This segmentation allows selective protection where needed most while avoiding unnecessary weight addition in less critical areas.
3Weight of moving object
If a hot-corrosion-resistant coating is applied only to the leading edge region, then weight and stress are reduced, but coating effectiveness may be compromised
Solution Approach 1:
The patent applies hot-corrosion-resistant coating exclusively to the leading edge region (radially inner half of the span-wise length) rather than the entire airfoil surface. This localized application targets the area most susceptible to hot-corrosion while minimizing coating material usage, thereby reducing blade weight and associated stresses compared to full-surface coating.
Solution Approach 2:
The patent identifies and protects the leading edge region in advance, where hot-corrosion susceptibility is highest based on temperature profiles and operational conditions. By pre-applinging coating to this critical zone before service, the blade achieves adequate protection against hot-corrosion while minimizing unnecessary coating in less vulnerable areas.
Data Source
AI summary
A turbine blade of a gas turbine engine is described which includes an airfoil extending away from the hub platform to a blade tip. The airfoil defines a leading edge, a trailing edge, and a span-wise length extending between the platform and the blade tip. A hot-corrosion-resistant coating is located on the leading edge of the airfoil within a radially inner portion thereof, the radially inner portion extending away from the hub platform a desired distance along the span-wise length.