Gas Turbine Ring Segment Cooling via Leakage Air Redirection
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Solution Overview
Problem
In gas turbines, leakage air through poorly sealed fastener systems of stationary rings surrounding hot gas flow paths is wasted and does not contribute to cooling, representing up to 0.2% of the total cooling air flow, which could be used to cool other sectors.
Innovation Solution
A cooling device that channels and directs leakage air from the fastener systems towards the axial ends of the ring segments in contact with hot gas, utilizing upstream and downstream circuits with axial air flow paths to enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fastener systems are used to fasten ring segments onto spacer segments, then the ring segments can be securely assembled, but air leakage occurs through the seals resulting in cooling air waste
Solution Approach 1:
The patent captures the leaked cooling air that would otherwise be wasted and redirects it through axial flow paths to cool the axial ends of ring segments. This converts the harmful leakage into a beneficial cooling effect, reducing energy waste while maintaining assembly reliability.
Solution Approach 2:
The patent introduces intermediary axial flow paths within the fastener system structure that serve as mediators to redirect the leaked air from the impact cavity to the axial ends of ring segments. These flow paths act as conduits that transform the leakage route into a useful cooling channel.
2Temperature
If cooling air is supplied to the impact cavity, then the ring segments can be cooled, but leaked air does not participate in cooling and is wasted
Solution Approach 1:
The patent transforms the harmful effect of air leakage from the impact cavity into a beneficial cooling effect by redirecting the leaked air through axial flow paths to cool the axial ends of ring segments, which are otherwise difficult to cool.
Solution Approach 2:
The fastener system is designed to serve multiple functions: it not only secures the ring segments but also acts as a cooling system by providing flow paths for cooling air to reach the axial ends of ring segments, thereby making the fastener system multi-functional.
3Loss of energy
If axial flow paths are introduced in fastener systems, then leaked air can be redirected for cooling, but device complexity increases
Solution Approach 1:
The patent merges the fastening function and the cooling function into a single integrated fastener system. The axial flow paths are incorporated within the fastener structure itself, combining two functions that would traditionally be separate, thereby reducing overall system complexity.
Solution Approach 2:
The fastener system is designed as a multi-functional component that simultaneously performs mechanical fastening and thermal cooling functions. The axial flow paths are built into the fastener structure, allowing the same component to serve dual purposes without requiring separate cooling infrastructure.
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 solution effectively reduces the temperature of ring segments by up to 20°C, utilizing previously wasted leakage air to improve cooling performance and reduce energy loss.
Implementation Method 1
a cooling device that channels and directs leakage air from the fastener systems towards the axial ends of the ring segments in contact with hot gas, utilizing upstream and downstream circuits with axial air flow paths to enhance cooling efficiency
Data Source
AI summary
A cooling device for a stationary ring surrounding a gas-turbine hot-gas flow path, said ring being made up of a plurality of ring segments that are fastened by upstream and downstream fastener systems onto a plurality of spacer segments forming a support spacer surrounding said ring so as to co-operate therewith to define at least one annular impact cavity into which at least one air supply orifice opens out, each ring segment having walls that are pierced with a plurality of air exhaust holes opening out both into the impact cavity, and into the hot-gas flow path, the device further comprising means for channeling the air coming from leakage through the seals of the fastener systems, and for directing it towards at least one of the axial ends of the ring segments so as to cool said end(s).