Combustor Sound Attenuator Reduces CO Emissions
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Solution Overview
Problem
Gas turbines produce CO due to incomplete fuel burning, which is environmentally undesirable, and existing combustor designs do not effectively address this issue.
Innovation Solution
A combustor design featuring a sound attenuator and a restrictor, where the restrictor narrows and then widens the flow path within the combustion liner, creating vortices that allow CO produced near the inner surface to mix with high-temperature combustion gas and burn before dispersing, while air from the sound attenuator cools the fuel to prevent incomplete burning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is discharged from the sound attenuator into the combustion liner to cool the inner circumferential side, then the combustion liner is protected from overheating, but the combustible gases are cooled and fuel does not burn completely, producing CO
Solution Approach 1:
The sound attenuator is divided into multiple through-holes positioned at different axial locations. The through-holes are segmented into upstream positions (before the restrictor) and downstream positions (after the restrictor), allowing differentiated cooling functions. Upstream through-holes provide cooling before combustion, while downstream through-holes enable post-combustion CO oxidation without excessive cooling of the combustion zone.
Solution Approach 2:
Different regions of the combustion liner receive different cooling intensities through strategically positioned through-holes. The upstream region receives cooling to protect the liner, while the downstream region receives additional cooling that specifically targets CO oxidation. This local differentiation allows simultaneous protection of the liner and reduction of CO emissions without compromising overall combustion efficiency.
2Object-generated harmful factors
If a restrictor is added to create vortices for CO combustion, then CO emissions are reduced, but the device complexity increases
Solution Approach 1:
The restrictor is integrated into the existing sound attenuator structure, merging two functional components (sound attenuation and flow restriction) into a single unified structure. The plate forming the sound attenuator also serves as the restrictor, with through-holes providing both acoustic damping and flow control functions. This integration reduces overall device complexity while achieving CO emission reduction through vortex-induced post-combustion.
3Object-generated harmful factors
If the restrictor narrows the flow path to create vortices, then CO is burned more effectively, but the flow resistance increases
Solution Approach 1:
The restrictor creates periodic vortex formations as gas flows through the narrowed passage. These vortices provide repeated opportunities for CO oxidation along the flow path, with the gas experiencing multiple cycles of mixing and combustion as it passes through the vortex region. This periodic action enhances CO burnout efficiency while the downstream widening of the passage gradually reduces flow resistance before gas exits the combustion liner.
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 reduces CO emissions by ensuring that CO produced is immediately burned within the combustion liner, thereby minimizing its discharge.
Implementation Method 1
A combustor is provided with a sound attenuator and a restrictor... the restrictor narrows and then widens a flow path of a gas flowing in the combustion liner... creating vortices that allow CO produced near the inner surface to mix with high-temperature combustion gas
Implementation Method 2
the restrictor narrows and then widens a flow path of a gas flowing in the combustion liner... creating vortices that allow CO produced near the inner surface to mix with high-temperature combustion gas and burn
Implementation Method 3
air from the sound attenuator cools the fuel to prevent incomplete burning... Air vibrations produced when the fuel is burned in the combustion liner such as combustion oscillations, or noise, passes through the sound absorbing holes, spreads out within the acoustic case, and is quietened therein
Data Source
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AI summary
A sound attenuator (30) includes part of a plate forming a combustion liner (20) and an acoustic cover (34) defining, in conjunction with this part of the plate, a space on the outer circumferential side of the combustion liner (20). A restrictor (40) that reduces a gas flow path is provided inside the combustion liner (20). At least one through-hole (33) penetrating from inside the combustion liner (20) to the space is defined in the part of the plate. At least one of the through-holes (33) in the sound attenuator (30) is present within a region spanning from a position of a minimum restrictor diameter (43) of the restrictor (40) to positions, on an upstream side and a downstream side, at a distance equivalent to a minimum restrictor radius (R).