Turbine Blade Fir Tree Root Air Intake Design
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Solution Overview
Problem
The design of air intakes in gas turbine engine turbine blades faces challenges in balancing airflow and structural strength, leading to potential stress on the fir tree root and high pressure losses, which can result in blade failure and inefficiencies.
Innovation Solution
The design incorporates a fir tree root with a leading-edge air intake that occupies at least 50% of the base projection's face, featuring a tapered passage and a duct with a taper starting from the tip to guide air into the internal cooling passage, while maintaining structural integrity through offset bases and sides, and a constant radius between the inlet and the base projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional air intake design is used, then the structural strength of the blade is maintained, but the airflow efficiency is reduced and pressure losses increase
Solution Approach 1:
The air intake is divided into multiple sections with different functions: a leading edge intake for primary cooling air, a secondary intake for additional cooling air, and a duct system that segments the airflow into multiple internal passages. This segmentation allows optimized airflow distribution while maintaining structural integrity through distributed loading.
Solution Approach 2:
The air intake design transitions from a single-plane approach to a three-dimensional configuration with the duct extending axially through the blade and multiple intake openings positioned at different locations on the leading edge. This spatial arrangement maximizes airflow capture while distributing structural loads throughout the blade root.
2Productivity
If the air intake size is increased to maximize airflow, then cooling efficiency improves, but stress on the fir tree root increases and blade strength decreases
Solution Approach 1:
The air intake is divided into multiple sections with different functions: a leading edge intake for primary cooling air, a secondary intake for additional cooling air, and a duct system that segments the airflow into multiple internal passages. This segmentation allows optimized airflow distribution while maintaining structural integrity through distributed loading.
Solution Approach 2:
Different regions of the blade root are designed with different properties: the fir tree root maintains its full structural cross-section for strength, while the air intake openings are strategically positioned to maximize airflow without compromising the load-bearing capacity of the root structure. The duct geometry is optimized to provide adequate cooling air flow while minimizing stress concentration at the intake locations.
3Ease of operation
If a duct design is used to direct cooling air, then airflow control is improved, but pressure losses increase and manufacturing complexity increases
Solution Approach 1:
The duct incorporates curved surfaces and rounded transitions instead of sharp angles, which smooths the airflow and reduces turbulence. The leading edge of the duct is curved to match the blade geometry, and the internal passages use rounded corners to minimize flow separation and pressure losses while maintaining effective airflow control.
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 configuration enhances airflow efficiency while maintaining the strength of the turbine blade, reducing the risk of failure and minimizing pressure losses, thereby optimizing cooling air distribution and blade performance.
Implementation Method 1
A duct directs a portion of the cooling air into an internal cooling passage within the blade
Implementation Method 2
In operation the turbine blades require a supply of cooling air into and through the blade. This cooling air is required to allow the blades to operate at temperatures hotter than the melting point of the material that is used to form the blade
Data Source
AI summary
A blade for use in a gas turbine engine, the blade comprising a blade portion and a fir tree root portion, the blade portion and the root portion having a connected passage for allowing cooling air to flow within the blade, the fir tree root portion having an air intake on its leading edge, the air intake allowing cooling air to enter the cooling passage and wherein the fir tree root portion comprises a plurality of projections, including at least a base projection and a top projection; and wherein the air inlet located in the base projection of the fir tree root portion and wherein the air inlet comprises at least 50% of the face of the base projection of the fir tree root portion.