Gas Turbine Combustor Cooling Structure With Non-Collinear Passages
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Solution Overview
Problem
The existing closed air cooling cycle cooling structure in gas turbine combustors experiences reduced cooling performance due to uniform passage structure, leading to increased metal temperature and localized stress at the bled pressurized air outlet, resulting in decreased fatigue life.
Innovation Solution
The cooling medium passages are divided via a passage transition groove, with non-collinear centerlines and uniform pitch, allowing for collision and separation of the cooling medium, which increases the heat transfer coefficient and optimizes cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform passage structure is used in the cooling air passage, then the structure is simple and easy to manufacture, but the cooling performance decreases at the outlet portion where heat load is high
Solution Approach 1:
The passage cross-sectional area is varied along the flow direction, with smaller areas at the outlet portion and larger areas at the inlet portion. This local variation in passage geometry provides enhanced cooling performance at high heat load regions (outlet) while maintaining manufacturing feasibility through a systematic gradient design rather than complex localized modifications.
Solution Approach 2:
The passage cross-sectional area parameter is changed continuously or in steps along the flow direction of the cooling air. This parameter variation optimizes the heat transfer coefficient at different locations, with smaller outlet areas increasing cooling efficiency where metal temperatures are highest, while the overall gradual change maintains structural integrity and manufacturability.
2Temperature
If the passage cross-sectional area is reduced at the outlet portion, then cooling performance increases, but the passage structure becomes more complex
Solution Approach 1:
The cooling air passage is divided into multiple sections along the flow direction, with each section having a different cross-sectional area. This segmentation allows systematic reduction of passage area from inlet to outlet, optimizing cooling at each stage while maintaining a modular, manufacturable structure through defined geometric transitions rather than complex continuous variations.
3Temperature
If cooling air flow rate is increased to improve cooling performance, then metal temperature decreases, but pressure loss and energy consumption increase
Solution Approach 1:
The passage cross-sectional area is locally optimized at different positions along the flow path. Smaller areas at the outlet portion where heat load is highest enhance heat transfer efficiency without requiring increased overall flow rate, thereby reducing pressure loss while achieving effective cooling where it is most needed.
Solution Approach 2:
The passage geometry parameters are changed along the flow direction to match the heat load distribution. This parameter optimization improves the heat transfer coefficient at critical locations, allowing effective cooling at lower cooling air flow rates and reducing the associated pressure loss and energy consumption.
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 cooling efficiency with a low cooling medium flow rate and pressure loss, improving cycle performance and allowing for increased combustion and turbine inlet temperatures.
Implementation Method 1
the passage structure (i.e. MT fin structure) capable of decreasing the metal temperature at locations with high heat load and low fatigue life such as the region near the bled pressurized air outlet hole 104b portion
Implementation Method 2
This configuration enhances cooling efficiency with a low cooling medium flow rate and pressure loss
Data Source
AI summary
A gas turbine combustor comprising a plurality of cooling air passages (27A) through which bled pressurized air flows from downstream of a combustion gas flow toward upstream, the plurality of cooling air passages (27A) being disposed in a wall portion (26) side by side and aligned in a flow direction of a combustion gas; wherein the plurality of cooling air passages (27A) are divided via a passage transition groove portion (33) into upstream cooling air passages (27A1) disposed closer to bled pressurized air inlet holes (30a) and downstream cooling air passages (27A2) disposed closer to bled pressurized air outlet holes (30b), and center lines (C1) of the upstream cooling air passages are non-collinear with center lines (C2) of the downstream cooling air passages.