Sequential Combustion Burner with Tilted Fuel Nozzle
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Solution Overview
Problem
Existing gas turbine burners face challenges in achieving low gas-pressure drop and homogeneous fuel-air mixing, especially at high inlet temperatures and with high reactivity fuels, while maintaining efficient combustion and reducing nitric oxide emissions.
Innovation Solution
A burner with a convexly curved, non-rectangular combustion chamber and a combined mixing and injection device featuring streamlined bodies with lobed trailing edges and multi-point fuel injection, which creates vortices for efficient mixing and reduces the need for high-pressure carrier air, allowing for low-pressure carrier air to be used for cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-pressure carrier air is used to penetrate fuel into vortices for mixing, then mixing quality is improved, but device complexity and energy consumption increase
Solution Approach 1:
The patent combines the carrier air supply and fuel injection functions into a single integrated nozzle structure. The carrier air and fuel are mixed and injected together through the same nozzle, eliminating the need for separate high-pressure carrier air lines and reducing device complexity while maintaining effective fuel penetration and mixing quality.
Solution Approach 2:
The nozzle serves multiple functions: it supplies carrier air, injects fuel, and creates the mixing process all in one component. This multi-functional design replaces what would traditionally require separate systems for air supply and fuel injection, simplifying the overall device structure.
2Reliability
If residence time in mixing region is reduced to prevent auto ignition, then safety is improved, but mixing quality deteriorates
Solution Approach 1:
The patent applies preliminary anti-action by using carrier air to pre-cool and dilute the fuel before injection, reducing the fuel's reactivity and self-ignition tendency. This allows the fuel-air mixture to be injected with sufficient momentum to penetrate vortices and achieve good mixing while the carrier air prevents auto-ignition during the injection process.
Solution Approach 2:
Carrier air acts as an intermediary substance between the fuel and the main combustion chamber. It provides a protective medium that prevents premature ignition while facilitating the mixing process, allowing the fuel to be distributed evenly without exceeding the self-ignition delay time.
3Power
If high inlet temperature is used to enhance efficiency, then power output is improved, but nitric oxide emissions increase
Solution Approach 1:
The patent performs preliminary mixing of fuel and air in the nozzle before the mixture enters the high-temperature combustion chamber. This pre-mixing ensures homogeneous distribution of fuel throughout the air stream, promoting complete combustion at lower peak temperatures and reducing the formation of thermal nitric oxide emissions while maintaining efficient power generation.
4Speed
If momentum flux of fuel is increased to penetrate into vortices, then mixing penetration is improved, but pressure drop increases
Solution Approach 1:
The patent uses pneumatic principles by utilizing carrier air flow to transport and inject the fuel. The carrier air provides the necessary momentum for fuel penetration into the vortices without requiring the fuel itself to be pressurized to high levels, thereby achieving effective mixing while minimizing pressure drop across the injection system.
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 achieves low pressure drop, efficient fuel-air mixing, and reduced nitric oxide emissions, enabling increased gas turbine efficiency and the ability to handle high reactivity fuels without the need for high-pressure carrier air, while maintaining mechanical integrity and manufacturability.
Implementation Method 1
creates vortices for efficient mixing
Implementation Method 2
the momentum flux of the fuel is adjusted relative to the momentum flux of the main flow so as to penetrate in to the vortices
Implementation Method 3
the operating conditions allow self-ignition (spontaneous ignition or auto ignition) of the fuel air mixture without additional energy being supplied to the mixture
Data Source
Figure 1~4
Figure 5a~5d
Figure 6a~7b
AI summary
The present invention relates to a streamlined body (22) for a sequential gas turbine burner, the streamlined body (22) having two lateral surfaces that are arranged essentially parallel to a main-flow direction (14) with a central plane there-between, wherein the lateral surfaces are joined to one another at upstream sides of the lateral surfaces to form a leading edge of the body and are joined at downstream sides of the lateral surfaces to form a trailing edge of the body, the streamlined body (22) extending perpendicularly to the main-flow direction (14) and along a first transverse direction (49), and having a cross-section perpendicular to the first transverse direction (49) that is shaped as a streamlined profile, and being provided with a mixing structure and with at least one fuel nozzle (15) located at the trailing edge (24), wherein at least one fuel nozzle (15) provided at the trailing edge (24) is tilted to inject the fuel jet away from the wall towards a close vortex at an inclination angle with respect to the main flow direction (14) ranging from and including 0° to 60°.