Gas Turbine Cooled Vane Baffles for Pressure Loss Reduction
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Solution Overview
Problem
Gas turbine engine components face high thermal loads due to increased operating temperatures and pressure ratios, leading to reduced operational life, particularly in next-generation turbofan engines with higher efficiency designs.
Innovation Solution
The vane design incorporates serpentine turns with space-eater baffles that utilize coolant flow to cool the exterior surfaces, featuring forward and aft baffles separated by middle ribs, allowing for efficient heat transfer and maintaining a seal despite manufacturing tolerances, which affect the positioning of middle ribs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If serpentine turns with space-eater baffles are used to cool exterior surfaces, then cooling efficiency is improved, but pressure loss increases
Solution Approach 1:
The baffle is divided into multiple segments (first baffle segment, second baffle segment, third baffle segment) that can be positioned at different radial locations. This segmentation allows the coolant flow path to be optimized for cooling efficiency while minimizing pressure loss by creating multiple flow paths rather than a single long serpentine path.
Solution Approach 2:
Different portions of the vane receive different cooling strategies. The space-eater baffles are positioned at specific radial locations where they are most effective for cooling exterior surfaces, while other areas maintain simpler passage configurations to reduce overall pressure loss. The cooling intensity is localized to where it is most needed.
2Strength
If middle ribs are used to separate forward and aft passages, then structural integrity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The design incorporates tolerance compensation by allowing the middle rib positioning to vary within a specified range while maintaining functional performance. The passage geometry and baffle positioning are designed to accommodate manufacturing variations, converting a precision-critical design into one that is robust to normal manufacturing tolerances.
Solution Approach 2:
The passage design includes built-in compensation for manufacturing tolerances. The geometry of the passages and the positioning of the middle ribs are designed with margin for error, so that even if the middle ribs are not positioned exactly as specified, the cooling function and structural integrity are maintained.
3Temperature
If coolant passages with serpentine turns are used, then cooling coverage is improved, but flow resistance increases
Solution Approach 1:
The serpentine coolant passage is segmented into multiple sections by the space-eater baffles, creating several shorter flow paths instead of one long serpentine path. This segmentation reduces the total flow resistance while still providing comprehensive cooling coverage across the vane exterior surfaces.
Solution Approach 2:
The cooling approach transitions from a two-dimensional serpentine path on a single plane to a three-dimensional multi-level structure with baffles at different radial positions. This dimensional change creates parallel flow paths that reduce flow resistance while maintaining cooling coverage.
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 design effectively manages high thermal loads by maintaining efficient coolant flow and heat transfer, enhancing the operational life of gas turbine engine components by ensuring consistent cooling across the vane surfaces despite manufacturing variations.
Implementation Method 1
the vanes may define internal passages that receive a flow of coolant such that the coolant can reduce temperatures of exterior surfaces of the vanes
Implementation Method 2
Some of these passages may include serpentine turns which allow the coolant to flow in multiple directions prior to flowing out the vane
Data Source
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AI summary
A vane (200) includes a forward rib (306B) and an aft rib (306C) positioned axially aft of the forward rib (306B). The vane (200) also includes a middle rib (306A) positioned axially between the forward rib (306B) and the aft rib (306C), such that the forward rib (306B) and the middle rib (306A) define a forward passage (304A) configured to receive a forward baffle (308) and the middle rib (306A) and the aft rib (306C) define an aft passage (304B) configured to receive an aft baffle (310). The vane (200) also includes an inner surface (340) extending axially from the forward rib (306B) to the aft rib (306C), being radially separated from the middle rib (306A) via a gap (342) such that air can flow between the aft passage (304B) and the forward passage (304A) via the gap (342), and having a radially outward curve (330) from the forward rib (306B) to the middle rib (306A) and having a radially inward curve (332) from the middle rib (306A) to the aft rib (306C).