Gas Turbine Combustor Cap Assembly Pressurized Fluid Conduit
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Solution Overview
Problem
Gas turbines face challenges in maintaining sufficient pressure within the cap assembly of the combustor, leading to inadequate cooling and potential overheating due to pressure losses and dynamic pressure waves, which impede the cooling flow and increase NOx generation.
Innovation Solution
The system includes flow conduits extending through the end cover of the combustor and into the cap chamber, providing pressurized fluid to increase pressure within the cap chamber, enhancing cooling and preventing hot gases from entering the downstream wall during high combustion dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is diverted from the annular passageway through openings in the outer wall of the cap assembly to cool the downstream plate, then cooling of the downstream plate is achieved, but the pressure within the cap assembly becomes insufficient to overcome dynamic pressure waves in the combustion chamber
Solution Approach 1:
A flow conduit is introduced as an intermediary component to deliver pressurized fluid directly into the cap chamber. This conduit bypasses the annular passageway and delivers high-pressure fluid through a discharge end positioned within the cap chamber, thereby maintaining sufficient pressure to overcome dynamic pressure waves while still enabling cooling of the downstream plate.
2Temperature
If a portion of air traveling through the annular passageway is diverted into the cap assembly for cooling, then cooling of the cap assembly is provided, but the percentage of premixed air in the combustor is reduced
Solution Approach 1:
The flow conduit acts as an intermediary that supplies pressurized fluid directly to the cap chamber, separating the cooling function from the premixed air flow path. This allows cooling air to be supplied through the conduit without diverting from the annular passageway, thereby maintaining the premixed air percentage while still achieving cap assembly cooling.
3Reliability
If the air pressure through the downstream wall is increased to overcome dynamic pressure waves, then hot gases are prevented from entering the combustion chamber, but the cooling flow is impeded by the same pressure conditions
Solution Approach 1:
The invention utilizes pneumatic principles by introducing a flow conduit that delivers pressurized fluid directly into the cap chamber. The pressurized fluid creates a pressure barrier that prevents hot gases from entering the combustion chamber through the downstream wall, while the controlled discharge of this pressurized fluid provides cooling to the downstream plate, resolving the contradiction between pressure protection and cooling effectiveness.
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 solution increases the pressure drop between the cap chamber and the combustion chamber, improving cooling efficiency and preventing hot gases from entering the downstream wall, thus reducing the risk of overheating and NOx generation.
Implementation Method 1
Each flow conduit is in flow communication with a pressurized fluid source such that pressurized fluid may be directed through each flow conduit and into the cap chamber
Implementation Method 2
the pressure within the cap chamber may be increased, thereby increasing the pressure drop between the cap chamber and the combustion chamber. Such an increased pressure drop may generally enhance the cooling provided to a downstream wall of the cap assembly
Implementation Method 3
Such an increased pressure drop may generally enhance the cooling provided to a downstream wall of the cap assembly and may also prevent hot gases from being forced into and/or through the downstream wall during periods of high combustion dynamics
Data Source
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AI summary
A system for supplying pressurized fluid to a combustor (100) of a gas turbine is disclosed. The system may include an end cover (110) and a fuel nozzle (112) extending from the end cover (110). The fuel nozzle (112) may include a downstream end. Additionally, the system may include a cap assembly (104) configured to receive at least a portion of the fuel nozzle (112). The cap assembly (104) may include an upstream wall (130) spaced apart from the downstream end, a downstream wall (132) disposed proximate to the downstream end and a cap chamber (134) defined between the upstream and downstream walls (130,132). Moreover, a conduit (102) may extend through the end cover (110) and the upstream wall (132) such that a discharge end (152) of the conduit (102) is in flow communication with the cap chamber (134).