Angled Fuel Premixer for Gas Turbine Combustion
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Solution Overview
Problem
Gas turbine combustors face challenges in achieving efficient fuel/air mixing at high combustion temperatures to meet aggressive emission requirements, requiring improved mixing techniques to occur within short auto-ignition times.
Innovation Solution
A fuel-air premixer design featuring annular passages with angled fuel and air inlets, generating a tangential swirl in the fuel flow to ensure efficient mixing within a specific length, ensuring thorough vaporization and combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high combustion temperatures are used to improve combustion efficiency, then combustion efficiency is improved, but auto-ignition time decreases requiring faster fuel/air mixing
Solution Approach 1:
The mixing device divides the fuel flow into multiple smaller streams using a plurality of fuel flow distributors arranged circumferentially. Each distributor creates individual fuel streams that are separately mixed with air, increasing the total mixing surface area and enabling faster mixing within the reduced auto-ignition time window while maintaining combustion efficiency.
Solution Approach 2:
The device uses pressurized air introduced through air holes in the fuel flow distributors to atomize and mix with the fuel streams. This pneumatic mixing mechanism enables rapid fuel/air mixing to occur within the short auto-ignition time period, allowing high combustion temperatures to be utilized effectively.
2Object-generated harmful factors
If high level fuel/air mixing is implemented to meet emission requirements, then emission compliance is improved, but device complexity increases
Solution Approach 1:
The fuel flow distributors serve multiple functions simultaneously: they distribute fuel circumferentially, introduce pressurized air for mixing, atomize the fuel streams, and position the fuel/air mixture for optimal combustion. This multi-functionality achieves emission compliance without proportionally increasing device complexity.
Solution Approach 2:
The fuel flow distributors incorporate air holes that allow pressurized air to pass through and mix with the fuel streams. This porous structure enables efficient fuel/air mixing and atomization, achieving the required mixing level for emission compliance while maintaining a relatively simple device structure.
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 premixer effectively mixes fuel and air within a short time frame, enhancing combustion properties and reducing emissions, thereby improving the operational efficiency and power density of gas turbine engines.
Implementation Method 1
generating a tangential swirl in the fuel flow to ensure efficient mixing within a specific length
Implementation Method 2
The premixer effectively mixes fuel and air within a short time frame
Implementation Method 3
ensuring thorough vaporization and combustion efficiency
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A fuel-air premixer for a combustor of a gas turbine engine includes a central passage disposed along an axis and operable to communicate a first airflow and an outer annular passage about the axis operable to communicate a second airflow. The fuel-air premixer further includes an inner annular passage about the axis and between the central passage and the outer annular passage for communicating fuel flow. The inner annular passage including an inner exit angled for directing fuel flow toward the axis into a mixer passage downstream of the outer and inner exits for mixing the fuel flow with the first and second airflows.