Coolable Airfoil Attachment Section for Gas Turbine Engines
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Solution Overview
Problem
The space between the faces of fir-tree lobes in rotor blade attachments in gas turbine engines is too small for effective cooling flow at elevated core gas path temperatures, limiting the cooling efficiency of high-efficiency gas turbine engines.
Innovation Solution
Incorporating at least one internal cooling passage along a passage axis through the attachment section of the rotor blade, which extends from the platform section to the airfoil section, allowing cooling airflow to flow from the forward to the aft direction, thereby enhancing thermal energy absorption and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the space between fir-tree lobes is used for cooling flow, then cooling is provided to the attachment section, but the space is too small for effective cooling flow at elevated core gas path temperatures
Solution Approach 1:
The cooling system is segmented into multiple independent cooling passages rather than relying on a single inter-lobar space. The attachment section is divided into multiple cooling channels that can be independently designed and optimized, allowing adequate cooling flow paths without requiring increased overall attachment volume.
Solution Approach 2:
Cooling passages are routed through the thickness of the attachment section rather than relying solely on the radial space between lobes. This three-dimensional cooling architecture allows cooling air to traverse the attachment section in multiple directions, effectively utilizing the volumetric capacity of the attachment rather than being constrained to the limited inter-lobar gaps.
2Temperature
If internal cooling passages are added to the attachment section, then cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The attachment section serves multiple functions: it provides mechanical retention of the blade, structural support, and thermal management through integrated cooling passages. By combining these functions into a single multi-functional component, the overall device complexity is reduced compared to having separate cooling systems and attachment structures.
Solution Approach 2:
The cooling passages are merged directly into the attachment section structure, eliminating the need for separate cooling components. The cooling channels are integrated within the attachment geometry itself, combining the thermal management function with the mechanical attachment function in a unified structure.
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 internal cooling passage facilitates uniform load distribution, reduces bending stresses, and improves cooling efficiency by effectively removing thermal energy from the attachment, platform, and airfoil sections, even at high temperatures.
Implementation Method 1
communicating a cooling airflow from a forward to an aft direction through a blade attachment section through at least one internal cooling passage
Implementation Method 2
The internal cooling passage facilitates uniform load distribution, reduces bending stresses, and improves cooling efficiency by effectively removing thermal energy from the attachment, platform, and airfoil sections
Implementation Method 3
communicating a cooling airflow from a forward to an aft direction through a blade attachment section through at least one internal cooling passage
Data Source
AI summary
A rotor blade suitable for use in a gas turbine engine includes an attachment section which defines at least one internal cooling passage along a passage axis through the attachment section.