Turbine Blade Abradable Tip for Gas Engine Rubbing
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Solution Overview
Problem
Ceramic matrix composite materials in turbine blades for gas turbine engines are prone to degradation due to rubbing with other engine parts, leading to material damage and efficiency issues.
Innovation Solution
Incorporating a bed of abradable material with ceramic matrix composite retainers in the blade tip or shroud, which protects the primary body from rubbing by engaging with seal elements, thereby preventing material degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic matrix composite materials are used in turbine blades to withstand high temperatures, then temperature resistance is improved, but the materials become prone to rubbing damage and degradation
Solution Approach 1:
The patent introduces an abradable material layer as an intermediary between the ceramic matrix composite airfoil and the seal elements. This abradable layer (made of softer materials like cobalt-chromium alloy or nickel-based superalloy) absorbs the rubbing contact, protecting the hard but brittle ceramic matrix composite from direct mechanical damage. The abradable material acts as a sacrificial buffer that can be worn away without compromising the structural integrity of the primary blade material.
Solution Approach 2:
The turbine blade employs a composite structure combining ceramic matrix composite materials for the primary body (providing heat resistance) with a different material layer for the abradable tip (providing rubbing resistance). This multi-material approach allows each component to perform its specialized function: the ceramic matrix composite withstands thermal environments while the abradable material layer protects against mechanical contact damage.
2Reliability
If an abradable material layer is added to protect the ceramic matrix composite from rubbing, then reliability is improved, but device complexity increases
Solution Approach 1:
The blade tip is segmented into distinct functional zones: the primary ceramic matrix composite structure and the abradable material layer. This segmentation allows each layer to be optimized for its specific function while maintaining overall structural integrity. The abradable layer is applied as a separate coating or overlay on the airfoil surface, creating a clear division between protective and structural functions.
Solution Approach 2:
The abradable material is applied locally only to the blade tip region where rubbing contact occurs, rather than throughout the entire blade structure. This localized application maintains the ceramic matrix composite properties in the main blade body while providing protective qualities only where mechanically needed, optimizing both performance and structural efficiency.
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 abradable material system effectively shields the ceramic matrix composite materials from rubbing damage, maintaining the integrity and performance of the turbine blades during operation.
Implementation Method 1
a blade tip including a bed of abradable material configured to be engaged by a seal element for blocking hot gasses from moving radially-outward over the airfoil without interacting with the airfoil
Data Source
AI summary
The present disclosure relates to turbine blades adapted for use in gas turbine engines. In particular, this disclosure is directed to turbine blades that include components made from ceramic matrix composite materials and that incorporate abradable materials.