Turbomachine Blade Cooling Circuit with Segmented Ventilation Cavities
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Solution Overview
Problem
High-pressure turbine blades face challenges in withstanding high operating temperatures due to limitations in existing cooling circuit designs, which often compromise vein temperature, cooling flow efficiency, and blade lifespan.
Innovation Solution
A blade cooling circuit design featuring multiple internal ventilation cavities with specific geometries, including ascending and descending portions, that maximize the use of Coriolis force for efficient cooling, particularly targeting the trailing and intrados/extrados walls, and strategically positioned orifices to enhance cooling flow distribution and reduce pressure losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a classic cooling circuit configuration with paper clip cavity is used, then the cooling circuit structure is established, but it no longer makes it possible to follow the increase in temperatures planned in the latest models of turbomachines
Solution Approach 1:
The cooling circuit is divided into multiple separate ventilation cavities (first cavity along leading edge, second cavity along trailing edge, third paper clip cavity between them) instead of a single integrated cavity. Each cavity can be independently optimized for its specific location and thermal requirements, allowing the overall system to adapt to higher temperatures while maintaining proper cooling distribution across different blade surfaces.
2Reliability
If cooling flow is increased to cool the blade, then blade lifespan is improved, but losses of the turbomachine increase
Solution Approach 1:
Different regions of the blade are cooled by dedicated cavities with cooling flows optimized for their specific thermal requirements. The leading edge cavity (first cavity) and trailing edge cavity (second cavity) provide localized cooling where needed most, reducing the need for excessive overall cooling flow while maintaining blade lifespan through targeted cooling at critical high-temperature zones.
3Temperature
If cooling flow is provided to the trailing edge, then trailing edge cooling is improved, but cooling flow is lost before reaching the top of the cavity due to trailing edge orifices
Solution Approach 1:
The trailing edge cooling is provided by a dedicated second ventilation cavity that is separate from the paper clip cavity. This segmented approach allows the trailing edge cavity to maintain its cooling flow independently, with orifices strategically positioned to deliver cooling to the trailing edge without excessive loss, while the paper clip cavity handles cooling for other blade regions.
4Productivity
If vein temperature is maximized to increase turbine efficiency, then turbine efficiency is improved, but blade cooling capability is reduced
Solution Approach 1:
The blade cooling circuit is segmented into multiple independent cavities that can be optimized for different thermal zones. This allows the vein temperature to be maximized for turbine efficiency while the segmented cavities provide targeted cooling where absolutely necessary, minimizing the impact on overall turbine efficiency while maintaining blade integrity.
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 design allows for improved cooling efficiency, increased operating temperatures, and extended blade lifespan, enhancing turbomachine performance without significant loss in cooling flow, thereby increasing turbine efficiency and reducing maintenance needs.
Implementation Method 1
thanks to this ascending portion provided on the intrados side, it is possible to take maximum advantage of the Coriolis force which thus presses the cooling air against the intrados wall when the cooling air rises in the ascending portion
Data Source
Figure 1~2
Figure 3A~4D
Figure 5~6
AI summary
A blade for a turbomachine, extending longitudinally between a base and an apex, comprising a lower surface wall (16), an upper surface wall (17), a leading edge (14) and a trailing edge (15) and comprising a plurality of internal ventilation cavities (21, 22, 23, 27) which form a cooling circuit (20) of the blade, wherein at least one ventilation cavity is a ventilation cavity of a first type (21, 22, 23) comprising at least one ascending portion (21a, 22a, 23a) which extends substantially longitudinally between the base and the apex, engaged with the lower surface wall (16) and spaced from the upper surface wall (17), and at least one discharge portion (21c, 22c, 23c) which extends substantially transversely and which opens at the trailing edge (15) via at least one port of the trailing edge (21d, 22d, 23d), and wherein at least one ventilation cavity of the first type (22, 23) further comprises at least one descending portion (22b, 23b) which extends substantially longitudinally from the apex, engaged with the upper surface wall (17) and spaced from the lower surface wall (16).