Gas Turbine Combustor Cooling Zones by Connection Angle
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Solution Overview
Problem
The combustor basket and transition piece in gas turbines have a radial step connection, leading to uneven cooling, where the end portion of the combustor basket may not be sufficiently cooled, especially in regions with different shapes, resulting in potential high temperatures and reduced reliability.
Innovation Solution
A combustion cylinder design with a cooling part that includes regions with varying connection angles and radial gaps, where the flow rate of the cooling medium is adjusted based on the connection angle and gap size to ensure efficient cooling, regardless of the transition piece shape, with higher flow rates in regions prone to higher temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a cooling structure is added to cool the end portion of the combustor basket, then the temperature of the end portion is reduced, but the device complexity increases
Solution Approach 1:
The patent applies local quality by providing cooling holes only in specific regions (first and second regions) of the combustor basket end portion, rather than uniformly across the entire structure. The cooling holes are strategically positioned in regions with larger connection angles where combustion gas flows more directly, creating localized cooling zones that match the thermal load distribution without adding unnecessary complexity to the entire structure.
2Productivity
If the transition piece is designed with different shapes in circumferential direction, then the gas flow guidance is improved, but the cooling uniformity of combustor basket end portion deteriorates
Solution Approach 1:
The patent addresses cooling uniformity by creating local cooling zones in specific regions (first and second regions) where cooling holes are provided. These regions correspond to areas with larger connection angles between the combustor basket and transition piece. By concentrating cooling efforts in these specific local areas rather than attempting uniform cooling across the entire circumferential direction, the patent achieves effective temperature control where it is most needed while maintaining the transition piece's functional shape variations.
Solution Approach 2:
The patent uses compressed air from the compressor as the cooling medium, copying the existing working fluid in the system for a dual purpose: both as the combustion working fluid and as the cooling medium. This approach avoids introducing separate cooling systems and utilizes the available resources within the gas turbine system itself.
3Device complexity
If compressed air is used as cooling medium, then the system complexity is reduced, but the energy loss increases
Solution Approach 1:
The patent applies self-service by using compressed air that is already present in the gas turbine system (introduced to the combustor basket from the compressor) as the cooling medium. The compressed air serves dual functions: it is both the working fluid for combustion and the cooling medium for the combustor basket end portion. This eliminates the need for separate cooling systems and reduces overall system complexity while utilizing existing system resources.
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 design effectively cools the combustion cylinder, improving reliability and extending the lifespan of gas turbine components by ensuring consistent cooling across different shapes and configurations of the transition piece.
Implementation Method 1
which is cooled by a cooling medium in a cooling part provided at a connecting portion with the transition piece
Data Source
AI summary
In a combustion cylinder, an outer-side region of a cooling part on an outer side with regard to a reference line orthogonal to a radial direction and an axial direction of a gas turbine and passing through a center of a combustor basket, and an inner-side region of the cooling part on an inner side with regard to the reference line are set. A connection angle at an intersection between an extension line of an outer surface of the combustor basket along the axial direction and an inner surface of a combustor transition piece is set. First regions are set at positions near the reference line, and second regions, with a larger connection angle than the first regions, are set at positions farther from the reference line than the first regions. The second regions are set to have a higher flow rate of a cooling medium than the first regions.