Gas Turbine Blade Trailing Edge Cooling via Segmented Cover
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Solution Overview
Problem
The existing manufacturing processes for gas turbine blades face limitations in reducing wall thickness at the trailing edge region, which restricts the design freedom and heat transfer efficiency, making it difficult to integrate filigree structures and position cooling channels close to the trailing edge.
Innovation Solution
A method involving forming a groove on the outer surface of the airfoil and joining a cover to create a cooling channel with reduced wall thickness, allowing for improved heat transfer and increased design freedom by positioning the cooling channel closer to the trailing edge, where the cover is dimensioned separately and joined to the blade body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the wall thickness is reduced in the trailing edge region to improve heat transfer, then heat transfer efficiency is improved, but manufacturing difficulty increases and design freedom is limited
Solution Approach 1:
The blade is divided into two separate parts: the blade body and the cover. The cover is manufactured separately and then joined to the blade body, allowing the trailing edge region to be segmented from the main structure. This segmentation enables independent optimization of the trailing edge wall thickness without compromising the integrity of the entire blade during casting.
Solution Approach 2:
The groove is pre-formed in the blade body at the trailing edge region before the cover is attached. This preliminary action creates a prepared receptacle that guides the cover positioning and ensures proper alignment. The groove geometry is designed in advance to accommodate the thin-walled cover structure, enabling subsequent precise attachment.
2Reliability
If the wall thickness is reduced to allow cooling channels closer to the trailing edge, then cooling effectiveness is improved, but manufacturing precision requirements increase
Solution Approach 1:
By segmenting the blade into blade body and cover, the manufacturing precision requirements are distributed separately. The blade body can be cast with standard tolerances, while the cover can be manufactured with high precision using additive manufacturing or precision machining. This segmentation allows each component to be optimized for its specific manufacturing process without compromising overall precision.
Solution Approach 2:
The manufacturing method changes from traditional casting to a hybrid approach combining casting with additive manufacturing or precision machining for the cover. This parameter change in the manufacturing process enables achieving much tighter tolerances and more precise geometries for the thin-walled cover structure, allowing cooling channels to be positioned closer to the trailing edge with controlled precision.
3Ease of operation
If integrated cooling channels are used within the wall cross-section, then cooling fluid distribution is improved, but design freedom in the trailing edge region is limited
Solution Approach 1:
The cooling channel system is segmented into two parts: channels within the blade body and channels within the cover. The cover acts as a separate module that can be designed with various cooling channel configurations depending on the specific thermal requirements of the trailing edge region. This modular segmentation provides design freedom while maintaining effective cooling fluid distribution.
Solution Approach 2:
The cover can be designed with adjustable or variable geometry cooling channels that adapt to different operational conditions. The separate cover allows for dynamic optimization of the cooling channel layout in the trailing edge region without affecting the overall blade structure, enabling versatile design configurations for different operating scenarios.
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 approach enhances heat transfer between the cooling fluid and the blade surface, reduces thermal stress, increases blade lifetime, and improves the overall efficiency of the gas turbine by reducing the mass flow of cooling fluid required, while allowing for more precise design and easier maintenance.
Implementation Method 1
heat transfer between the cooling fluid flowing in the cooling channels and an outer surface of the blade
Data Source
AI summary
A method for manufacturing a blade for a gas turbine includes forming a blade body including an airfoil, forming a groove adjacent to a trailing edge of the airfoil in an outer surface of the airfoil, positioning a cover on the blade body such that it covers the groove and such that an outer surface of the cover forms a continuous surface with the outer surface of the airfoil, and joining the cover to the airfoil so that the cover and the groove define a cooling channel.