Combustor Cap Assembly Baffle for Cooling and Mixing
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Solution Overview
Problem
Current combustor designs face high thermal stresses and decreased turbine efficiency due to incomplete mixing of cooling fluids with the fuel-air mixture, leading to exacerbated NOx and CO2 generation.
Innovation Solution
A combustor design featuring a cap assembly with a first and second shroud, plates, and a baffle that separates fluid flow paths to facilitate the mixing of a cooling medium with compressed working fluid before combustion, ensuring effective pre-mixing and reduced thermal stress on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If effusion cooling is used to cool the cap assembly, then thermal stresses on the cap plate are reduced, but the compressed working fluid enters the combustion zone unmixed with the fuel, exacerbating NOx and CO2 generation and decreasing turbine efficiency
Solution Approach 1:
The cooling function is segmented into two distinct flow paths: a first flow path for cooling the cap assembly and a second flow path for mixing with fuel. The baffle divides these paths, allowing cooling fluid to be directed to the cap plate while preventing direct entry into the combustion zone, thus resolving the contradiction between cooling effectiveness and mixing requirements
Solution Approach 2:
The baffle acts as an intermediary element that separates the cooling fluid flow from the fuel flow. It mediates between the cooling requirement (direct fluid to cap plate) and the mixing requirement (fluid should not enter combustion zone unmixed), allowing both functions to be achieved simultaneously
2Strength
If compressed working fluid is directed to the cap assembly for cooling, then thermal stresses are mitigated, but incomplete mixing with fuel occurs, leading to exacerbated NOx and CO2 generation
Solution Approach 1:
The system segments the fluid flow into dedicated cooling paths and fuel mixing paths. The baffle creates separate flow channels that prevent cooling fluid from directly entering the combustion zone, ensuring complete mixing with fuel and reducing harmful emissions while maintaining cap plate cooling
Solution Approach 2:
Different regions of the cap assembly are assigned different functions: the first flow path provides cooling to specific areas (cap plate) while the second flow path ensures mixing in other regions. This local differentiation allows cooling without compromising mixing quality, reducing NOx and CO2 generation
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 enhances the mechanical life of combustor components, improves gas turbine efficiency, and reduces undesirable emissions by ensuring complete mixing and effective cooling within the combustor.
Implementation Method 1
a baffle that extends from the first shroud to the first plate, wherein the baffle separates the first fluid flow path from the second fluid flow path
Implementation Method 2
at least a portion of the compressed working supplied to the combustor may be used to cool the various components
Implementation Method 3
at least a portion of the compressed working fluid and the fuel are mixed to form a combustible fuel-air mixture
Implementation Method 4
The fuel-air mixture is ignited in a combustion zone that is generally downstream from the fuel nozzles, thus creating a rapidly expanding hot gas
Data Source
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AI summary
A combustor 10 includes a first shroud 50 extending circumferentially inside the combustor 10 and at least partially defining an inlet passage 52. A second shroud 110 extends circumferentially inside the combustor 10. The second shroud 110 defines an outlet passage 112. A first plate 70 extends radially inside the second shroud 110 downstream from the inlet passage 52 of the first shroud 50 and upstream from the outlet passage 112 of the second shroud 110. The first plate 70 generally defines an inlet port 82 and an outlet port 84. A second plate 96 extends radially around the first plate 70 downstream from the inlet port and upstream from the outlet port of the first plate. A first fluid flow path 116 extends from the inlet passage to the inlet port. A second fluid flow path 118 extends from the outlet port to the outlet passage. A baffle 62 extends from the first shroud 50 to the first plate 70. The baffle 62 separates the first and second fluid flow paths.