Reheat Combustor Cooling via Exhaust Gas Splitting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gas turbine engines face efficiency losses due to the high demand for cooling air in reheat combustors, which reduces the engine's overall efficiency and introduces cooling challenges for flame stabilization devices in open-centered designs.
Innovation Solution
A method for cooling a reheat combustor in a gas turbine engine involves splitting the expanded combustion gas into three streams, where the second stream cools the outer liner and flame stabilizers, and the third stream, combined with a portion of the second stream, cools the inner liner, reducing the need for compressor air extraction and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is extracted from the compressor to cool the reheat combustor, then the reheat combustor can be cooled effectively, but the engine efficiency decreases due to reduced air available for expansion in the high pressure turbine
Solution Approach 1:
The reheat combustor is cooled using its own hot exhaust gases rather than external compressor air. The cooling system utilizes the hot gas recirculation inherent in the reheat combustor operation, allowing the system to cool itself without extracting valuable compressor air, thereby maintaining engine efficiency while achieving effective cooling
Solution Approach 2:
The hot exhaust gases that would otherwise be wasted or cause overheating are converted into a beneficial cooling resource. By directing these hot gases through the liner and flame stabilizer passages, the system uses the harmful hot environment to provide the necessary cooling effect, eliminating the need for compressor air extraction
2Device complexity
If an open centered reheat combustor design is used with cantilevered flame stabilization devices, then the combustor structure is simplified, but cooling issues arise for the flame stabilization devices due to hot gas recirculation
Solution Approach 1:
The combustor is divided into distinct functional zones with separate cooling pathways. The liner and flame stabilizers are segmented as independent cooling circuits, allowing hot gases to be directed through specific passages around and through these components. This segmentation enables targeted cooling of critical parts while maintaining the overall simplicity of the open-centered design
Solution Approach 2:
The liner acts as an intermediary structure that mediates between the hot combustion chamber and the flame stabilizers. Hot gases flow through the liner first, and then continue through the flame stabilizer passages, providing a controlled cooling path that protects both components without requiring complex additional cooling systems
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 approach decreases the quantity of compressor air needed for cooling, improving engine efficiency and stabilizing the combustor by effectively managing hot gas recirculation and providing active cooling for critical components.
Implementation Method 1
an outer liner and one or more flame stabilizers of the reheat combustor are cooled using the second stream of the expanded combustion gas
Implementation Method 2
an inner liner of the reheat combustor is cooled using the third stream of the expanded combustion gas
Implementation Method 3
a pressure loss device for developing a pressure differential between the second stream and the third stream
Data Source
AI summary
A gas turbine engine and method for operating a gas turbine engine includes compressing an air stream in a compressor and generating a post combustion gas by combusting a compressed air stream exiting from the compressor in a combustor. The post combustion gas is expanded in a first turbine. The expanded combustion gas exiting from the first turbine is split into a first stream, a second stream and a third stream. The first stream of the expanded combustion gas is combusted in a reheat combustor. An outer liner and flame stabilizer of the reheat combustor are cooled using the second stream of the expanded combustion gas. An inner liner of the reheat combustor is cooled using the third stream of the expanded combustion gas and a portion of the second stream of the expanded combustion gas passing through the one or more flame stabilizers.