Integral Impingement Sleeve for Curved Turbine Rotor Blade Cooling
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Solution Overview
Problem
Turbine rotor blades in turbomachines face challenges in achieving effective impingement cooling due to the difficulty in positioning impingement inserts within curved cavities, leading to inadequate cooling performance and increased manufacturing complexity and cost, especially when centrifugal forces disrupt coolant distribution across the blade's inner surface.
Innovation Solution
The integration of an additively manufactured impingement cooling structure within the turbine rotor blade, featuring a hollow body with uniformly spaced cooling passages that extend along the radial span, allowing coolant to impinge on the airfoil inner surface, and non-linear cooling passages in the platform to enhance cooling efficiency across the blade's surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impingement inserts are positioned close to the interior surface to achieve high cooling performance, then cooling effectiveness improves, but positioning becomes increasingly difficult in tapered or curved cavities
Solution Approach 1:
The impingement insert is merged with the turbine rotor blade to form a single integral component through additive manufacturing. This eliminates the positioning difficulties associated with separate inserts in curved cavities, as the cooling structure is directly formed as part of the blade itself, maintaining the desired Z/D parameter throughout the radial span.
Solution Approach 2:
The impingement cooling structure is divided into multiple longitudinal sections that can be manufactured separately and then assembled. This segmentation allows each section to be optimized for its specific location in the curved cavity while maintaining overall cooling performance, and simplifies the manufacturing process for complex geometries.
2Ease of manufacture
If flexible impingement insert sections are used to ease insertion into curved cavities, then ease of manufacture improves, but cooling performance deteriorates due to discontinuous coolant flow
Solution Approach 1:
Multiple impingement insert sections are merged into a single integral structure through additive manufacturing. This creates continuous coolant flow paths through the entire radial span of the blade, eliminating the discontinuities that occur with separate flexible sections, while maintaining the ability to navigate curved cavities during manufacturing.
Solution Approach 2:
The impingement cooling structure incorporates curved geometries that match the tapered and curved cavities of the turbine rotor blade. This allows the cooling passages to follow the natural curvature of the blade cavity, maintaining proper Z/D parameters throughout while enabling seamless integration with the blade 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
This solution enables uniform impingement cooling coverage along the blade's radial span, improves cooling performance by maintaining the desired Z/D parameter, and reduces manufacturing complexity and cost by eliminating the need for multiple insert sections, while also providing enhanced structural strength and weight reduction.
Implementation Method 1
A plurality of cooling passages through the hollow body and in fluid communication with the radially extending chamber to allow the coolant flow to pass from the interior surface of the hollow body to impinge on at least the airfoil inner surface
Data Source
AI summary
A turbine rotor blade is additively manufactured and includes an airfoil body with a radially extending chamber for receiving a coolant flow, a tip end at a radial outer end of the airfoil body, and a shank at a radial inner end of the airfoil body. The radially extending chamber extends at least partially into the shank to define a shank inner surface. An integral impingement cooling structure is within the radially extending chamber. The integral impingement cooling structure allows an exterior surface of a hollow body thereof to be uniformly spaced from the airfoil inner surface despite the curvature of the chamber. The turbine rotor blade has impingement cooling throughout the blade.