Turbomachine Blade Tip Shroud Cooling Ejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing blade cooling structures in turbomachines often result in inefficient energy extraction due to mixing of cooling air with high-temperature combustion gases, leading to reduced efficiency and increased heat load on the blades.
Innovation Solution
The design incorporates a tip shroud with ejection slots positioned radially outward of the outer surface, directing cooling air away from the hot gas path to prevent mixing with combustion gases, thereby enhancing energy extraction and reducing heat load by configuring the cooling channels and ejection slots to minimize interaction with the hot gas path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is ejected through slots in the tip shroud, then the blade is cooled effectively, but combustion gases mix with the cooling air reducing efficiency
Solution Approach 1:
The ejection slots are positioned radially outward of the outer surface of the tip shroud, extracting the cooling air discharge location from the hot gas path. This spatial separation prevents mixing between cooling air and combustion gases while maintaining effective blade cooling through the tip shroud structure.
Solution Approach 2:
The solution moves the ejection slots from a planar surface to a radially outward position, utilizing the third dimension (radial direction) to relocate the cooling air discharge point outside the hot gas path boundary. This dimensional transition eliminates harmful mixing while preserving cooling functionality.
2Reliability
If cooling channels are configured to allow air ejection, then cooling performance is improved, but heat load on the blade increases due to gas mixing
Solution Approach 1:
The ejection slots are extracted from the hot gas path by positioning them radially outward of the outer surface. This removes the source of harmful mixing from the interaction zone between cooling air and combustion gases, thereby reducing heat load while maintaining cooling performance.
Solution Approach 2:
The tip shroud structure acts as an intermediary element that directs cooling air through channels and ejects it outside the hot gas path. This intermediary structure mediates between the cooling requirement and the efficiency requirement, preventing direct contact between cooling air and combustion gases.
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 improves the efficiency of the turbomachine by preventing combustion gas ingestion into the cooling structures and reducing the heat load on the blades, leading to increased work extraction and extended blade life.
Implementation Method 1
configuring the cooling channels and ejection slots to minimize interaction with the hot gas path
Implementation Method 2
the cooling air flows through various ejection slots, including ejection slots in the tip shroud
Implementation Method 3
cooling air flows through various passages, cavities, and apertures
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A blade (100) for a turbomachine includes an airfoil (114) extending radially between a root (118) and a tip with a tip shroud (116) coupled to the tip of the airfoil. The tip shroud includes a platform having an outer surface extending generally perpendicular to the airfoil. The tip shroud also includes a forward rail (150) extending radially outward from the outer surface of the platform. The forward rail is oriented generally perpendicular to a hot gas path of the turbomachine. A cooling cavity (158) is defined in a central portion of the platform. The tip shroud also includes a cooling channel (160) extending between the cooling cavity and an ejection slot (62) formed in the forward rail. The ejection slot is positioned radially outward of the outer surface of the platform of the tip shroud.