Gas Turbine Combustor Liner Cooling with Effusion Holes
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Solution Overview
Problem
Gas turbines with air-cooled combustors face inefficiencies due to high pressure drops and cooling air consumption in the combustor channels, which reduce the overall efficiency and power output.
Innovation Solution
The design incorporates a nozzle at the beginning of the cover plate and very long effusion holes, eliminating impingement cooling at the upstream end of the liner, with the effusion holes extending beyond 15 mm and being partially bordered by grooves for manufacturing, to reduce pressure drop and enhance convective cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If impingement cooling is used to cool the upstream end of the liner, then cooling effectiveness is improved, but pressure drop increases significantly
Solution Approach 1:
The patent applies different cooling methods to different sections of the liner: effusion cooling for the upstream end and impingement cooling for the downstream end. This local differentiation allows optimal cooling effectiveness in each zone while minimizing overall pressure drop, as effusion cooling is less pressure-sensitive than impingement cooling.
Solution Approach 2:
The liner cooling system is segmented into two distinct zones: an upstream section cooled by effusion cooling and a downstream section cooled by impingement cooling. This segmentation allows each zone to use the most appropriate cooling method for its specific thermal conditions, resolving the contradiction between cooling effectiveness and pressure drop.
2Temperature
If cooling air consumption is increased to improve liner cooling, then cooling effectiveness is improved, but gas turbine efficiency decreases
Solution Approach 1:
The patent changes the cooling air parameters by using lower pressure drop effusion cooling in the upstream section, which reduces the compression work required and allows more cooling air to be used effectively without penalizing gas turbine efficiency. This parameter optimization resolves the contradiction between cooling effectiveness and energy efficiency.
3Stress or pressure
If channel geometry is optimized to reduce pressure drop, then pressure drop is reduced, but cooling effectiveness may be compromised
Solution Approach 1:
The patent optimizes channel geometry locally for each cooling section: the effusion cooling section uses geometry optimized for low pressure drop, while the impingement cooling section uses geometry optimized for high cooling effectiveness. This local optimization allows both pressure drop reduction and effective cooling to be achieved in their respective zones.
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 approach significantly reduces cooling air pressure drop, minimizing the need for high-pressure compression, thereby increasing the efficiency and power output of the gas turbine.
Implementation Method 1
the pressure drop due to turbulences of the cooling air at the entrance into the channel is reduced
Implementation Method 2
The liners 7 are cooled by impingement cooling and convective cooling using compressed cooling air
Implementation Method 3
The cooling air flows through the channels 9
Data Source
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AI summary
A design for an effectively cooling a liner (7) of a gas turbine combustor by means of convective cooling is disclosed.