Gas Turbine Aerofoil Blade Nested Loop Cooling Passage
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Solution Overview
Problem
In gas turbine engines, the existing cooling air distribution in turbine blades and vanes is inefficient, as most cooling air passes through the hottest section briefly or not at all, and cooling air diverted to the lower parts of the trailing edge does not effectively address the peak thermal load, leading to suboptimal engine efficiency and reduced component lifespan.
Innovation Solution
The cooling air passages in the aerofoil blades or vanes are configured to form nested loops, with the innermost loop extending along one side of a fence, wrapping around, and extending along the other side, ensuring more cooling air traverses the hottest section, and surface formations like trip steps and pedestals enhance heat transfer, while effusion holes allow air to flow into the working gas annulus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air passages are configured in traditional linear patterns, then manufacturing is simpler, but cooling air utilization is inefficient and peak temperatures are not adequately reduced
Solution Approach 1:
The cooling air passage is divided into multiple segments: a first passage portion extending from the inlet toward the trailing edge, and a second passage portion extending from the first passage portion back toward the inlet, creating a segmented flow path that forces cooling air to traverse the peak thermal load region multiple times
Solution Approach 2:
The passage configuration transitions from a simple linear path to a three-dimensional loop structure with multiple portions, adding spatial complexity to the flow path. This dimensional transformation allows cooling air to circulate through the hottest section repeatedly, maximizing cooling effectiveness without requiring additional cooling air supply
2Temperature
If more cooling air is supplied to the turbine blade, then peak temperatures are reduced, but engine efficiency decreases due to lost work extraction opportunity
Solution Approach 1:
The loop configuration enables continuous circulation of the same cooling air through the peak thermal load region multiple times, maintaining continuous cooling action without requiring additional cooling air supply. The cooling air remains in the blade longer, repeatedly traversing the hottest section to maximize cooling effectiveness
Solution Approach 2:
Instead of discarding cooling air after a single pass through the blade, the loop configuration recovers the cooling air and redirects it back through the peak thermal load region. This recovery and reuse of cooling air eliminates the need to supply additional cooling air, thereby preventing energy loss while maintaining effective cooling
3Temperature
If cooling air is diverted to the lower parts of the trailing edge, then that region is cooled, but the peak thermal load region receives insufficient cooling
Solution Approach 1:
The passage configuration provides non-uniform cooling distribution tailored to local thermal requirements. The loop structure concentrates cooling air flow through the peak thermal load region (the hottest section), while still providing cooling to other areas. This localized quality adjustment ensures that the most critical region receives the most cooling attention
Solution Approach 2:
Instead of allowing cooling air to naturally exit at the trailing edge after a single pass, the invention inverts the conventional approach by redirecting the cooling air back toward the inlet through the second passage portion. This inversion forces the cooling air to return through the peak thermal load region, ensuring that the hottest section receives maximum cooling rather than allowing cooling air to be wasted at less critical locations
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 utilization of cooling air, forcing it to work more effectively through the peak thermal load region, reducing peak temperatures at the trailing edge and enhancing overall engine efficiency and component lifespan.
Implementation Method 1
Internal convection and external films are the prime methods of cooling the gas path components
Implementation Method 2
effusion holes allow air to flow into the working gas annulus
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An aerofoil blade or vane for the turbine of a gas turbine engine is provided. The blade or vane includes an aerofoil portion which, in use, extends radially across a working gas annulus of the engine. A coolant inlet is formed at an end of the aerofoil portion for entry of a flow of cooling air into the aerofoil portion. A corresponding coolant exhaust is formed at the trailing edge of the aerofoil portion for the flow of spent cooling air from the aerofoil portion. A passage within the aerofoil portion connects the inlet to the exhaust. The blade or vane further includes a fence within the aerofoil portion. The fence extends radially and forwardly from a start position at said end of the aerofoil portion adjacent the trailing edge to an end position. The passage forms a loop which extends along one side of the fence, wraps around the end position, and extends along the other side of the fence to connect the inlet to the exhaust.