Gas Turbine Guide Vane Airfoil Cooling Circuit for Bulging Control
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Solution Overview
Problem
Hollow stationary vanes of a turbine section in gas turbine engines face challenges in achieving desired cooling air flow velocity and heat transfer coefficient while minimizing cooling flow requirements and preventing deflections or bulging due to internal and external pressure differences.
Innovation Solution
A cooling circuit design for gas turbine engine airfoils incorporating axial and radial flow cooling circuits with baffles and ribs to optimize heat transfer and reduce cross-sectional area, featuring impingement cooling holes and tailored heat transfer features to manage heat loads and deflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If internal structures are added to cooling circuits to improve heat transfer and reduce bulging, then heat transfer coefficient and structural stability are improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The cooling circuit is divided into multiple segments with different flow patterns (axial flow sections and radial flow sections) separated by baffles. This segmentation allows each section to perform specific functions - axial flow for heat transfer and radial flow for pressure equalization - thereby reducing overall bulging while maintaining manageable structural complexity
Solution Approach 2:
Different regions of the airfoil are given different cooling characteristics. The axial flow cooling circuit is positioned in regions requiring high heat transfer, while radial flow circuits are placed in regions prone to bulging. This localized approach optimizes performance without uniformly increasing complexity throughout the entire structure
2Temperature
If cooling flow rate is increased to improve heat transfer, then heat transfer coefficient is improved, but cooling flow requirements increase
Solution Approach 1:
The cooling circuit employs dynamic flow distribution where cooling air is actively directed through different pathways (axial and radial) based on thermal and pressure conditions. This dynamic allocation optimizes heat transfer efficiency while minimizing the total quantity of cooling flow required
Solution Approach 2:
The system utilizes pneumatic principles by introducing radial flow cooling circuits that leverage pressure gradients to enhance heat transfer. The radial outflow from the axial cooling circuit creates pressure equalization that improves heat transfer coefficients without requiring proportional increases in cooling flow quantity
3Reliability
If axial and radial flow cooling circuits are combined to optimize heat transfer and reduce bulging, then thermal management and structural stability are improved, but device complexity increases
Solution Approach 1:
The axial flow cooling circuit and radial flow cooling circuit are merged into a single integrated system within the airfoil. The radial flow circuit receives cooling air from the axial circuit, creating a coupled system that simultaneously addresses heat transfer and pressure equalization - improving reliability while consolidating functions rather than adding separate independent systems
Solution Approach 2:
The combined cooling circuit system performs multiple functions: the axial flow section provides primary cooling, the radial flow section provides pressure equalization and secondary cooling, and together they form an integrated thermal management system. This multi-functionality improves reliability without requiring separate dedicated systems for each function
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
The cooling circuit effectively enhances heat transfer and reduces bulging while minimizing cooling flow requirements, achieving improved thermal management and compactness of the gas turbine engine.
Implementation Method 1
A cooling circuit design for gas turbine engine airfoils incorporating axial and radial flow cooling circuits with baffles and ribs to optimize heat transfer
Implementation Method 2
featuring impingement cooling holes and tailored heat transfer features to manage heat loads and deflections
Data Source
Figure 1
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Figure 3
AI summary
An airfoil (62, 62', 62") for a gas turbine engine (20) includes axial flow and radial flow cooling circuits (76, 76', 76", 78, 78', 78") defined within an airfoil body (68). A baffle (80, 122) disposed in spaced relation to an inner surface of the airfoil (62, 62', 62") has a plurality of impingement cooling holes (95, 144) configured to direct a cooling fluid (Fc) at an inner surface of the airfoil body (68) and an axial extent from the leading edge (70) defined by an aft wall (86, 138), with the axial extent being substantially constant between the inner and outer end walls (64, 66) and defined by a plane perpendicular to an engine axis (A). A first radially-extending rib (102, 102', 102") is angled with respect to the baffle (80, 122) to define a first passage (100, 100', 100") between the first rib (102, 102', 102") and the baffle (80, 122) that tapers in cross-sectional area between the inner end wall (64) and the outer end wall (66), becoming larger in cross-sectional area in a direction of cooling fluid (Fc) flow through the first passage (100, 100', 100").