CMC Airfoil Trailing Edge Ejector Apertures
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Solution Overview
Problem
Existing airfoil designs in gas turbine engines face challenges such as clogging of cooling holes due to debris and limited temperature capability, which affect durability and performance.
Innovation Solution
Incorporating a ceramic matrix composite (CMC) trailing edge segment with ejector apertures in the airfoil, which reduces the need for traditional cooling features and enhances temperature resistance, while the ejector apertures help prevent clogging by ejecting debris and providing additional cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional cooling holes are used in airfoils, then cooling effect is provided, but cooling holes may clog with dust or debris reducing cooling effectiveness
Solution Approach 1:
The patent extracts the cooling function from traditional cooling holes and relocates it to the trailing edge segment with ejector apertures. The ejector apertures are positioned at the trailing edge where they are less susceptible to clogging, while still providing effective cooling through the airfoil structure.
Solution Approach 2:
The patent changes the parameters of the cooling system by enlarging the aperture size at the trailing edge compared to traditional cooling holes. This enlargement prevents clogging by dust and debris while maintaining adequate cooling flow through the airfoil.
2Temperature
If non-traditional high temperature materials such as CMC are used, then temperature capability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the airfoil into distinct portions: a body segment made from traditional materials and a trailing edge segment made from CMC material. This segmentation allows the CMC material to be used only where high temperature capability is most needed, reducing overall manufacturing complexity while maintaining temperature resistance benefits.
Solution Approach 2:
The patent employs composite construction by combining traditional airfoil materials with CMC material in the trailing edge segment. This composite approach leverages the superior temperature capability of CMC where needed while maintaining the advantages of traditional materials in other portions of the airfoil.
3Duration of action of stationary object
If cooling features are eliminated to improve durability, then time on wing increases, but temperature management becomes more challenging
Solution Approach 1:
The CMC trailing edge segment inherently provides thermal management capabilities without requiring additional active cooling features. The material's high temperature resistance allows the airfoil to self-regulate thermal loads, eliminating the need for complex cooling systems while extending time on wing.
Data Source
AI summary
Turbine nozzle sections and airfoils having trailing edge segments are provided. In one embodiment, a turbine nozzle section comprises an inner band defining a pocket; an outer band defining an opening therethrough; and an airfoil radially extending from the inner band to the outer band and including pressure and suction sides. The airfoil has a body segment including a cavity and a plurality of ejector apertures defining a passageway from the cavity to an outer surface of the airfoil, and a trailing edge segment including an inner end and an outer end. The body segment defines a projection projecting inwardly from the suction side, and the trailing edge segment defines a notch opening toward the suction side. The projection is received within the notch. The inner end of the trailing edge segment is received within the inner band pocket, and the outer end is positioned within the outer band opening.