Triangular Serpentine Cooling Channels for Gas Turbine Blades
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Solution Overview
Problem
Existing gas turbine blade designs face challenges in effectively cooling the concave pressure side, where temperatures are higher than the convex suction side, due to limitations in internal cooling configurations.
Innovation Solution
The design incorporates a plurality of radially extending cooling channels between the concave pressure wall and convex suction wall, including a leading edge channel, trailing edge channel, and a serpentine cooling circuit with multiple up-pass channels, featuring generally triangular transverse cross-sections, to enhance cooling fluid distribution and heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional cooling channel configurations are used, then the blade structure is simpler, but the cooling effectiveness on the pressure side is insufficient
Solution Approach 1:
The cooling system is divided into multiple serpentine cooling circuits with separate up-pass and down-pass channels, allowing independent optimization of cooling flow paths. This segmentation enables targeted cooling of the pressure side without requiring complete redesign of the entire blade structure.
Solution Approach 2:
The cooling channel cross-sectional area is varied along the flow path, with larger areas in up-pass channels to enhance cooling effectiveness on the pressure side. This local optimization of channel geometry provides superior cooling where needed without unnecessarily complicating the entire blade structure.
2Temperature
If the number of up-pass channels is increased, then the cooling effectiveness on the pressure side is improved, but the distance between channels must be decreased which complicates the design
Solution Approach 1:
The serpentine configuration introduces a third dimension to the cooling channel layout by folding the channels back and forth through the blade thickness. This allows multiple up-pass channels to be arranged in a compact serpentine pattern, achieving close spacing without requiring complex precision manufacturing in a single plane.
3Productivity
If serpentine cooling circuits are implemented, then the cooling fluid distribution is optimized, but the device complexity increases
Solution Approach 1:
Multiple cooling functions are merged into a single serpentine circuit configuration that handles both up-pass and down-pass cooling through interconnected channels. This integration achieves optimized cooling fluid distribution without requiring entirely separate cooling systems for different blade regions.
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 increases the cooling effectiveness on the pressure side by increasing the number of up-pass channels, decreasing the distance between them, and optimizing film cooling hole density, leading to reduced blade temperatures and improved heat transfer.
Implementation Method 1
Cooled blades may include cooling channels, sometimes referred to as passages, in various configurations through which a coolant, such as compressor bleed air, is directed to convectively cool the blade
Implementation Method 2
The blades may also include other cooling features, such as film cooling holes for exhausting the coolant from the cooling channels over the exterior surface of the blade
Data Source
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AI summary
A cooled airfoil (32) includes a concave pressure wall (42) extending radially from a base to a tip of the airfoil, a convex suction wall (44) connected to the concave pressure wall at a leading edge (46) and a trailing edge (48) spaced axially from the leading edge, and cooling channels extending radially between the base and the tip of the airfoil between the concave pressure wall and the convex suction wall and configured to receive a cooling fluid supply through the base of the airfoil. The cooling channels include a leading edge channel (52), a trailing edge channel (54), a serpentine cooling circuit, and a dedicated up-pass channel (58). The serpentine cooling circuit includes a first up-pass channel (56a) forward of the trailing edge channel and configured to be in flow communication with a supply channel through the base of the airfoil, a down-pass channel (56b) forward of and in flow communication with the first up-pass channel, and a second up-pass channel (56c) forward of and in flow communication with the down-pass channel. At least the down-pass channel (56b) and the second up-pass channel (56c) of the serpentine circuit have a generally triangular transverse cross-sectional shape. The dedicated up-pass channel (58) is arranged between the leading edge channel (52) and the second up-pass channel (56c) of the serpentine cooling circuit.