Multi-flow Cooling Circuit for Gas Turbine Vane Backflow Margin
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Solution Overview
Problem
Gas turbine engine flowpath components face challenges in maintaining effective film cooling due to variable angles of attack, which alter the backflow margin and limit the magnitude of angle variance that can be efficiently achieved, as the pressure of cooling air available from internal cavities is insufficient to prevent backflow through film cooling holes.
Innovation Solution
The implementation of isolated first and second internal cooling passages with distinct inlet feeds, where the first passage is radially outward and the second passage is radially inward, ensures sufficient backflow margin by providing separate cooling fluid feeds to the leading and trailing edges of the variable vanes, respectively, using spindles to direct cooling air effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single cooling passage is used with cooling air from one end, then the device complexity is reduced, but the cooling effectiveness deteriorates due to insufficient backflow margin when angle of attack varies
Solution Approach 1:
The cooling system is divided into multiple independent cooling passages, each serving specific regions of the flowpath component. The first cooling passage serves the leading edge region while the second cooling passage serves the trailing edge region, allowing independent optimization of cooling airflow for each region without compromising overall cooling effectiveness
Solution Approach 2:
Different regions of the flowpath component receive cooling air with different properties tailored to their specific thermal and flow conditions. The leading edge receives cooling air optimized for its high heat flux region, while the trailing edge receives cooling air optimized for its different thermal environment, ensuring locally optimal cooling effectiveness
2Adaptability or versatility
If the angle of attack varies to optimize performance, then the adaptability improves, but the backflow margin decreases limiting the magnitude of angle variance
Solution Approach 1:
By segmenting the cooling system into multiple independent passages with separate inlet feeds, each passage can maintain adequate backflow margin across different angle of attack conditions. The isolation between passages prevents backflow in one region from affecting cooling effectiveness in other regions, enabling larger angle of attack variations
Solution Approach 2:
The multi-flow cooling system provides universal cooling effectiveness across a wide range of angle of attack conditions. The isolated cooling passages are designed to function effectively regardless of the specific angle of attack, making the system adaptable to varying operational conditions without compromising cooling performance
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 enhances the backflow margin, preventing backflow and ensuring efficient cooling of the vane surfaces, even as the angle of attack changes, thereby maintaining effective film cooling across varying operational conditions.
Implementation Method 1
cooling passages that expel air along the surface of the flowpath component to create a film cooling effect
Implementation Method 2
cooling passages that expel air along the surface of the flowpath component
Data Source
AI summary
A flowpath component for a gas turbine engine includes a body having a leading edge and a trailing edge. A first exterior wall connects the leading edge to the trailing edge and a second exterior wall connects the leading edge to the trailing edge. At least one first internal cooling passage has a first inlet at a first end of the body. At least one second internal cooling passage has a second inlet at a second end of the body. The at least one first internal cooling passage is isolated from the at least one second internal cooling passage.