Turbine Blade Tip Cooling via Circumscribing Rail Microchannel
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Solution Overview
Problem
Conventional gas turbine blade tip designs fail to adequately reduce leakage and efficiently cool the blade tips, particularly due to the limitations of existing microchannel cooling technologies in integrating benefits effectively.
Innovation Solution
The design incorporates a circumscribing rail microchannel that extends around the inner surface of the tip cavity, forming a looped cooling circuit with multiple inputs and outlets, which is efficiently formed using machining or coating methods to position microchannels very close to the surface for enhanced cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional blade tip designs are used, then the structure is simple, but leakage is not adequately reduced and cooling effectiveness is insufficient
Solution Approach 1:
The cooling system is divided into multiple microchannels distributed along the blade tip surface, with each channel independently cooling specific regions. This segmentation allows targeted cooling of high-temperature zones while maintaining overall structural simplicity.
Solution Approach 2:
The microchannels are nested within the blade tip structure, utilizing the existing geometric space. The channels are positioned within the tip cavity and extend along the surface, effectively using available volume without adding external complexity.
2Reliability
If more coolant is used to improve cooling effectiveness, then cooling performance increases, but compressor bypass air usage increases reducing overall efficiency
Solution Approach 1:
Coolant flow is optimized for specific local regions where heat generation is highest. The microchannel configuration provides enhanced cooling at critical locations such as the leading edge and tip surfaces, while reducing coolant flow in lower-temperature zones, thereby minimizing overall bypass air consumption.
Solution Approach 2:
The system changes the distribution parameters of coolant flow by utilizing multiple small channels instead of few large channels. This parameter change in channel configuration allows more uniform heat removal with lower total coolant flow requirements, improving compressor efficiency.
3Object-generated harmful factors
If tip clearance is minimized to prevent leakage, then leakage is reduced, but tip rub against shroud occurs during operation
Solution Approach 1:
The blade tip geometry is designed with flexibility to accommodate thermal and mechanical expansion. The microchannel cooling system contributes to thermal management, allowing the tip to dynamically adjust its dimensions during operation without causing rub against the shroud, while maintaining low clearance for leakage prevention.
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 effectively reduces leakage and enhances cooling efficiency at the blade tip, minimizing compressor bypass air usage and improving overall turbine performance with reduced coolant requirements.
Implementation Method 1
a circumscribing rail microchannel, which may include a microchannel that extends around at least a majority of the length of the inner rail surface
Implementation Method 2
cooling the airfoils... a portion of pressurized air bled therefrom is received for use in cooling the airfoils
Data Source
AI summary
A turbine rotor blade for a gas turbine engine is described. The turbine rotor blade includes an airfoil that includes a tip at an outer radial end. The tip includes a rail that defines a tip cavity; and the rail includes a circumscribing rail microchannel. The circumscribing rail microchannel is a microchannel that extends around at least a majority of the length of the inner rail surface.