Additive Turbine Blade Root Cooling
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Solution Overview
Problem
Conventional impingement cooling inserts face challenges in positioning within curved cavities of turbine rotor blades, leading to ineffective cooling due to centrifugal forces and increased complexity in manufacturing, especially when curved or tapered surfaces require precise standoff distances and continuous cooling coverage.
Innovation Solution
The integration of an additive manufactured impingement cooling structure within the turbine rotor blade, featuring a hollow body with uniformly spaced cooling passages that match the curvature of the blade's inner surface, providing uniform impingement cooling across the blade's radial span and allowing for customizable standoff distances and cooling features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional impingement cooling inserts are positioned in curved cavities of turbine rotor blades, then cooling performance can be improved, but positioning precision and manufacturing complexity increase due to the need for precise standoff distances in curved geometries
Solution Approach 1:
The cavity is divided into multiple cooling zones with impingement inserts positioned at different radial locations. Each zone can be independently optimized for its specific thermal conditions, allowing precise control of standoff distances in curved geometries without requiring the entire insert to conform to the complex curvature
Solution Approach 2:
Different regions of the cavity receive customized cooling solutions based on their local thermal requirements. The impingement inserts are positioned and oriented to provide optimal standoff distances and cooling angles for each specific location, rather than using a uniform approach throughout the curved cavity
2Temperature
If impingement inserts are positioned close to the inner surface for high cooling performance, then cooling effectiveness improves, but the risk of thermal expansion interference and structural integrity issues increases
Solution Approach 1:
A radial clearance or gap is intentionally designed between the impingement insert and the inner surface of the blade. This clearance acts as a thermal buffer that accommodates thermal expansion of both the insert and the blade surface during operation, preventing mechanical interference while maintaining effective cooling through controlled impingement
Solution Approach 2:
The standoff distance between the impingement insert and the inner surface is optimized to balance cooling effectiveness with thermal expansion clearance. The distance is sufficient to prevent contact under thermal load but small enough to maintain high cooling performance, representing an optimal parameter selection that resolves the contradiction
3Adaptability or versatility
If multiple flexible impingement insert sections are used to navigate curved surfaces, then adaptability to complex geometries improves, but device complexity and manufacturing costs increase
Solution Approach 1:
The cooling system is divided into multiple discrete impingement inserts positioned at different locations within the cavity. Each insert can be a simple, easily manufactured component, while the segmented arrangement provides adaptability to the curved geometry through strategic positioning rather than requiring each component to be complex or flexible
4Ease of manufacture
If cooling passages are drilled linearly into the platform, then manufacturing simplicity is maintained, but cooling coverage and effectiveness are reduced due to inadequate cooling of certain platform portions
Solution Approach 1:
The cooling passages are configured with curved or angled trajectories rather than simple linear paths. This allows the coolant to reach broader areas of the platform including the slash face and damping pin seat regions, improving cooling coverage while still using conventional drilling and machining processes
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 solution ensures consistent and enhanced cooling performance across the turbine rotor blade, reducing manufacturing complexity and maintaining structural integrity while accommodating varying thermal expansion coefficients and heat loads.
Implementation Method 1
cooling passages in a wall thereof that allow delivery of a coolant through the cooling passages to impact or impinge on a surface to be cooled
Implementation Method 2
the centrifugal forces experienced by the rotating blades forces the coolant to the radially outer tip end of the blade as it rotates
Data Source
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AI summary
A turbine rotor blade root (144) is additively manufactured and includes a shank (148, 148A) having a radially extending chamber (134) defined therein. A blade mount (146) is at a radial inner end of the shank. The blade mount (146) has a hollow interior (330) defined therein with the hollow interior (330) in fluid communication with the radially extending chamber (134). A lattice support structure (340) is disposed within the hollow interior (330) of the blade mount (146).