Gas Turbine Combustor Radial Gap Cooling Design
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Solution Overview
Problem
Small gas turbines face challenges in maintaining adequate heat resistance in the combustion region, leading to insufficient cooling performance, which is not addressed by existing ceramic combustor configurations.
Innovation Solution
A combustor design featuring a combustion cylinder with a radial-direction gap for film air introduction between the cylinder and a combustion-chamber forming member, along with an elastic retention system using a spring portion and inward flange, enhances cooling performance by allowing film air to cool the inner surface of the combustion cylinder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the temperature of the combustion region is increased to suppress NOx and CO, then emission control is improved, but the heat resistance of the parts in the combustion region becomes insufficient
Solution Approach 1:
The combustor is divided into distinct functional zones: a high-temperature combustion chamber where fuel burns to generate power, and a separate combustion cylinder that receives cooling air through radial gaps. This segmentation allows the combustion region to operate at high temperatures for emission control while the combustion cylinder is cooled separately to maintain structural integrity.
Solution Approach 2:
Cooling air acts as an intermediary substance that is introduced through radial gaps between the combustion cylinder and combustion-chamber forming member. This cooling air mediates the thermal load, allowing the combustion cylinder to be cooled without interfering with the high-temperature combustion process in the combustion chamber.
2Temperature
If a ceramic material is used for the combustor to improve heat resistance, then thermal stability is improved, but the design does not provide adequate cooling for the combustion cylinder
Solution Approach 1:
Different parts of the combustor have different thermal management requirements. The combustion chamber maintains high temperature for efficient combustion and emission control, while the combustion cylinder requires active cooling through radial gaps. This local differentiation of thermal conditions allows each component to operate under optimal temperature conditions for its specific function.
3Temperature
If a radial-direction gap is formed between the combustion cylinder and combustion-chamber forming member to introduce film air, then cooling performance is improved, but structural complexity increases
Solution Approach 1:
The radial-direction gap creates a dynamic cooling system where cooling air flows radially inward between the combustion cylinder and combustion-chamber forming member. This dynamic flow pattern allows effective heat transfer from the combustion cylinder surface to the cooling air, improving cooling performance while maintaining a relatively simple structural configuration.
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, suppressing NOx and CO emissions while maintaining structural integrity and reducing vibration and noise, thereby ensuring reliable operation of the gas turbine.
Implementation Method 1
A radial-direction gap for introducing film air is formed between the combustion cylinder and the combustion-chamber forming member
Implementation Method 2
a spring portion for elastically supporting the combustion-chamber forming member
Data Source
AI summary
A combustor includes: a combustion cylinder; and a combustion-chamber forming member disposed so as to be at least partially inserted into the combustion cylinder and forming a combustion chamber with the combustion cylinder. A radial-direction gap for introducing film air is formed between the combustion cylinder and the combustion-chamber forming member. A gas turbine includes a combustor; a compressor for generating compressed air; and a turbine configured to be rotary driven by combustion gas from the combustor.