Trapped Vortex Combustor Driver Airflow Channel
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Solution Overview
Problem
Current trapped vortex combustors in gas turbine engines face limitations in achieving sufficient pre-mixing and pre-vaporization of fuel and air before combustion, which affects combustion efficiency and exhaust emission levels.
Innovation Solution
A trapped vortex combustor design featuring an outer and inner vortex chamber with a dome and channels that direct airflow to provide a continuous annular airflow, enhancing pre-mixing and pre-vaporization by ensuring at least 15% of the total airflow passes through these channels, and includes fuel nozzle openings that facilitate efficient combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fuel injectors are disposed axially upstream from the combustion chamber to allow fuel and air to mix and pre-vaporize, then pre-mixing and pre-vaporization are improved, but the combustor length increases
Solution Approach 1:
The patent introduces a radial dimension to the airflow path by creating a driver airflow channel that directs air radially inward through the dome structure. This radial flow component adds a new dimension to the mixing process, allowing fuel and air to mix more effectively in the radial direction rather than only axially, thereby improving pre-mixing quality without proportionally increasing combustor length.
Solution Approach 2:
The dome structure serves as an intermediary element that facilitates the mixing process. It creates a dedicated driver airflow channel that acts as a mediator between the incoming air and fuel, directing the airflow to enhance pre-vaporization and mixing before the mixture reaches the combustion chamber, thus improving combustion efficiency without requiring excessive combustor length.
2Productivity
If the combustor is made shorter to meet advanced technology requirements, then productivity and compactness are improved, but pre-mixing and pre-vaporization time is reduced
Solution Approach 1:
The driver airflow channel performs preliminary action by pre-conditioning the air flow before it mixes with fuel. The channel directs and accelerates the airflow, creating a more energetic and effective mixing process that occurs more rapidly. This preliminary airflow preparation allows sufficient pre-mixing and pre-vaporization to occur within a shorter combustor length, maintaining high productivity while ensuring adequate mixing time.
Solution Approach 2:
The patent changes the flow parameters by introducing a radial flow component and increasing airflow velocity through the driver airflow channel. By modifying the flow regime and velocity distribution, the system achieves more effective mixing in less time, allowing the combustor to be shorter while maintaining adequate pre-mixing and pre-vaporization for high productivity.
3Object-generated harmful factors
If driver airflow channels are added to enhance pre-mixing, then combustion cleanliness is improved, but device complexity increases
Solution Approach 1:
The dome structure is designed to serve multiple functions simultaneously: it acts as a structural component of the combustor, creates the driver airflow channel for enhanced mixing, and provides a mounting surface for fuel injectors. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while still achieving improved combustion cleanliness and reduced exhaust emissions.
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
The enhanced pre-mixing and pre-vaporization lead to cleaner combustion, improving the performance and reducing exhaust emissions of gas turbine engines, while allowing for a more efficient combustor design with potential reductions in length and increased operating range.
Implementation Method 1
The channel extends along the circumferential direction at the forward end of the outer vortex chamber wall, the channel configured to receive an airflow through or around the outer vortex chamber wall, the dome, or both and provide such airflow as a continuous annular airflow to the inner surface of the outer vortex chamber wall
Implementation Method 2
trapped vortex combustors have been developed in an attempt to achieve these goals. As used herein, the term 'trapped vortex combustor' generally refers to a combustor having one or more sections (e.g., inner and/or outer trapped vortex chambers) upstream of a combustion chamber configured to at least partially pre-mix and pre-vaporize a fuel in a swirling vortex of pressurized air
Implementation Method 3
all openings in the dome outward of the fuel nozzle opening along the radial direction, excepting any effusion cooling holes having a diameter less than about 0.035 inches, being in airflow communication with the channel
Data Source
AI summary
A trapped vortex combustor for use in a gas turbine engine includes an outer vortex chamber wall and a dome attached to, or formed integrally with, the outer vortex chamber wall. The dome, the outer vortex chamber wall, or both define at least in part an outer trapped vortex chamber and a channel. The channel extends along the circumferential direction at a forward end of the outer vortex chamber wall, the channel configured to receive an airflow through or around the outer vortex chamber wall, the dome, or both and provide such airflow as a continuous annular airflow to the inner surface of the outer vortex chamber wall. The dome further defines a fuel nozzle opening, with all openings in the dome outward of the fuel nozzle opening along the radial direction, excepting any effusion cooling holes having a diameter less than about 0.035 inches, being in airflow communication with the channel.