Gas Turbine Ring Segment Cooling Passage Optimization
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Solution Overview
Problem
The conventional cooling systems for gas turbine ring segments suffer from excessive cooling air loss due to increasing combustion gas pressure differential, leading to inefficient cooling and reduced thermal efficiency.
Innovation Solution
The cooling system optimizes the arrangement of cooling passages in the ring segment by varying the opening pitch and area along the flow direction, reducing the amount of cooling air blown into the combustion gas, particularly by increasing the pitch or decreasing the area downstream, to match the changing pressure gradient and heat load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is blown into the combustion gas through cooling passages in the ring segment, then the ring segment is cooled effectively, but the thermal efficiency of the gas turbine decreases due to cooling air loss
Solution Approach 1:
The patent applies local quality by varying the opening pitch and area of cooling passages along the axial direction of the ring segment. The opening pitch increases and opening area decreases from the upstream side to the downstream side, matching the local heat load distribution and pressure gradient. This localized optimization ensures effective cooling where needed while minimizing cooling air loss in regions with lower heat flux, thereby resolving the contradiction between cooling effectiveness and thermal efficiency.
Solution Approach 2:
The patent changes the parameters of the cooling passage openings along the axial direction. Specifically, the opening pitch is increased and the opening area is decreased from upstream to downstream. This parameter variation adapts the cooling system to the changing pressure gradient and heat load distribution in the combustion gas flow, reducing excessive cooling air discharge into the combustion gas while maintaining adequate cooling performance, thus improving thermal efficiency without compromising cooling effectiveness.
2Ease of manufacture
If uniform opening pitch and area are used in cooling passages, then manufacturing is simplified, but cooling air is excessively discharged into the combustion gas due to increasing pressure differential
Solution Approach 1:
The patent implements local quality by making the opening pitch and area vary along the axial direction of the cooling passages. The upstream side has smaller opening pitch and larger opening area, while the downstream side has larger opening pitch and smaller opening area. This localized differentiation addresses the increasing pressure differential from upstream to downstream, preventing excessive cooling air discharge into the combustion gas while maintaining manufacturability through systematic variation patterns.
Solution Approach 2:
The patent applies dynamics by making the cooling passage openings non-uniform along the axial direction. The opening pitch and area dynamically adjust from upstream to downstream to match the changing pressure gradient and heat load conditions. This dynamic adaptation allows the cooling system to respond to varying operating conditions, optimizing cooling air utilization and reducing loss while remaining feasible to manufacture.
3Loss of energy
If the amount of cooling air is reduced to improve thermal efficiency, then energy loss decreases, but the cooling performance of the ring segment deteriorates
Solution Approach 1:
The patent applies local quality by optimizing the opening pitch and area distribution along the axial direction of cooling passages. The upstream side with higher heat load receives more cooling air through smaller opening pitch and larger opening area, while the downstream side with lower heat load uses larger opening pitch and smaller opening area. This localized optimization ensures adequate cooling performance is maintained where heat flux is highest while reducing total cooling air loss, thereby resolving the contradiction between energy efficiency and cooling performance.
Solution Approach 2:
The patent changes the parameters of cooling passage openings along the axial direction to optimize the balance between cooling performance and energy efficiency. By increasing opening pitch and decreasing opening area from upstream to downstream, the system adapts to the pressure gradient and heat load distribution, ensuring sufficient cooling air reaches critical high-heat-load regions while minimizing excessive air discharge that would reduce thermal efficiency.
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 optimization reduces the cooling air amount, enhancing the thermal efficiency of the gas turbine by minimizing air loss and ensuring effective cooling of the ring segment.
Implementation Method 1
a collision plate 64 that is supported from the isolation ring 66 is provided with a plurality of small holes 65, and cooling air CA that is supplied to the casing 67 blows out to below from the small holes 65, and carries out impingement cooling of the upper surface of the main body of the segment body 61
Implementation Method 2
in the segment body 61, a plurality of cooling passages 63 is disposed in the axial direction of the rotating shaft 5, and the cooling air flows in the axial direction inside the main body of the segment body 61, and performs convection cooling of the segment body 61
Implementation Method 3
When cooling air after impingement cooling of the main body of the segment body 61 is supplied to a cooling passage (not illustrated) that is provided in the side end portion 70, and blown out from the openings 33 into the combustion gas, it performs convection cooling of the side end portion 70
Data Source
AI summary
In a cooling system of ring segment that cools a ring segment of a gas turbine, the segment body of the ring segment is constituted from a collision plate that has a small hole that blows out cooling air, a cooling space that is enclosed by the collision plate and the main body of the segment body; a first cavity that is disposed along a side end portion in the axial direction of the rotating shaft, and receives the cooling air from the cooling space; and a first cooling passage, of which one end communicates with the first cavity, and the other end blows out the cooling air from openings that are arranged in the side end portion into combustion gas; the openings of the first cooling passages being arranged so that the arrangement pitch of the openings becomes smaller or the opening area of the openings becomes larger on the upstream in the flow direction of the combustion gas than the openings on the downstream, and are arranged so that the arrangement pitch of the openings becomes larger or the opening area of the openings becomes smaller on the downstream in the flow direction of the combustion gas than the openings on the upstream.