Gas Turbine Combustor Cooling Guide Design
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Solution Overview
Problem
Conventional gas turbine combustors face reduced cooling efficiency due to the low heat resistance of their liners, particularly in the flow direction of compressed air, necessitating enhanced cooling methods.
Innovation Solution
The combustor design includes an inner liner surrounded by an outer liner with cooling guides installed around its inner circumferential surface, arranged in staggered axial rows, featuring an air guiding surface with a concave curve to effectively guide compressed air and create impinging jets for improved cooling, enhancing the cooling efficiency by directing airflow more effectively towards the inner liner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional band-shaped cooling guides are used in the combustor liner, then the structure is simple, but the cooling efficiency is reduced in the flow direction of compressed air
Solution Approach 1:
The cooling guide features a curved guiding surface that directs compressed air flow toward the inner liner surface. This curvature optimizes the flow path to create effective impinging jets, resolving the contradiction by maintaining structural simplicity while significantly improving cooling efficiency through geometric optimization of the air flow direction.
Solution Approach 2:
The cooling guide geometry is optimized with specific parameters including a guiding surface angle of 10-30 degrees relative to the compressed air flow direction, and a protrusion length of 5-20mm from the outer liner inner surface. These parameter changes transform the simple band structure into an efficient cooling device that maintains manufacturing ease while achieving reliable cooling performance.
2Ease of manufacture
If the liner is made of heat-resistant alloy with low service temperature, then manufacturing is easier, but the temperature resistance is insufficient for high-temperature combustion gas
Solution Approach 1:
Compressed air serves as an intermediary cooling medium between the combustion chamber and the liner. The cooling guides direct this compressed air to create impinging jets that cool the inner liner surface, allowing the use of heat-resistant alloys with lower temperature ratings while maintaining structural integrity against high-temperature combustion gases.
Solution Approach 2:
The system utilizes pneumatic cooling by introducing compressed air through the cooling guides. This pneumatic cooling mechanism creates high-velocity impinging jets that efficiently remove heat from the liner inner surface, enabling the use of materials with lower inherent heat resistance while operating in high-temperature environments.
3Reliability
If cooling guides are arranged in staggered axial rows, then cooling coverage is improved, but device complexity increases
Solution Approach 1:
The cooling guides are segmented into multiple discrete units arranged in staggered axial rows around the combustor. This segmentation allows each cooling guide to cover a specific zone, and the staggered arrangement ensures comprehensive cooling coverage without requiring complex integrated structures, thus improving cooling effectiveness while maintaining reasonable device complexity.
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 significantly enhances the cooling efficiency of the inner liner by ensuring that compressed air is directed more effectively, reducing temperature and improving the thermal management of the combustor, thereby increasing the operational efficiency of the gas turbine.
Implementation Method 1
Impinging jet cooling is a method of indirectly lowering the temperature of the liner by injecting jets of cooling fluid onto the outer surface of the inner liner
Implementation Method 2
compressed air flows through the cooling passage to cool the inner liner
Implementation Method 3
Each cooling guide may include an air guiding surface facing the flow of the compressed air to guide the compressed air toward the inner liner. The air guiding surface may include a concave curve.
Data Source
AI summary
A combustor includes an inner liner forming a combustion chamber; an outer liner surrounding the inner liner to form a cooling passage in which compressed air flows; and a plurality of cooling guides installed around an inner circumferential surface of the outer liner to surround the combustion chamber, each of the cooling guides protruding from the inner circumferential surface to create an impinging jet from the compressed air flowing in the cooling passage. The plurality of cooling guides surrounding the combustion chamber are installed at regular intervals in a flow direction of the compressed air, and are arranged in staggered axial rows. Each cooling guide includes an air guiding surface facing the flow of the compressed air to guide the compressed air toward the inner liner. Accordingly, liner cooling efficiency can be enhanced by more effectively guiding the impinging jet toward the inner liner.