Lobe Lance Vortex Mixing for Gas Turbine Combustor Efficiency
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Solution Overview
Problem
Current gas turbine combustors with sequential combustion cycles face challenges in achieving low NOx emissions and efficient fuel-air mixing due to self-ignition issues and high-pressure carrier air requirements, which reduce overall efficiency and increase life cycle costs.
Innovation Solution
A lobe lance with multiple streamlined fingers having optimized lobe orientations is introduced, featuring a predetermined pattern of lobe orientations across the fingers to enhance mixing quality and reduce pressure loss, allowing vortices to combine and improve large-scale mixing of fuel, cooling air, and hot gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If cross flow injection concept is used in SEV fuel lances to achieve low NOx emissions and avoid flashback, then mixing quality is improved and flashback is prevented, but high-pressure carrier air supply is required which reduces overall efficiency
Solution Approach 1:
The invention extracts and eliminates the need for high-pressure carrier air from the cross-flow injection system. By using a streamlined body with lobes at the trailing edge, the system achieves fuel-air mixing and flashback prevention without requiring additional high-pressure air supply, thereby removing the energy penalty associated with carrier air compression.
Solution Approach 2:
The streamlined body with lobes generates vortices that automatically enhance fuel-air mixing and prevent flashback without requiring external energy input or control systems. The geometry itself provides the mixing function, making the system self-sufficient and eliminating the need for high-pressure carrier air.
2Reliability
If streamlined bodies with lobes are used to enhance fuel-air mixing and reduce residence time, then mixing quality is improved and auto ignition is prevented, but device complexity increases
Solution Approach 1:
The invention uses streamlined bodies with curved surfaces and lobes at the trailing edge. These curved geometries generate vortices that enhance mixing and control residence time. The streamlined shape reduces flow separation and improves overall flow characteristics while maintaining structural integrity.
Solution Approach 2:
The addition of lobes at the trailing edge of the streamlined bodies introduces a new geometric dimension that generates three-dimensional vortices. This dimensional enhancement improves mixing efficiency and flashback prevention without requiring complex multi-component systems.
3Productivity
If high turbine inlet temperature is used to achieve high efficiency, then power output is improved, but NOx emissions and life cycle costs increase
Solution Approach 1:
The invention changes the flow parameters (velocity distribution, turbulence intensity, residence time) through the use of streamlined bodies with lobes. These parameter changes enable efficient fuel-air mixing that maintains combustion stability while reducing peak temperatures and NOx formation, allowing high power output with lower 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 lobe lance arrangement enhances mixing efficiency, reduces NOx emissions, and improves temperature distribution, thereby increasing the overall efficiency and reducing life cycle costs of gas turbines by optimizing fuel-air mixing and vortex interaction.
Implementation Method 1
lobes running between said nozzles are provided at said trailing edge for improving the mixing quality and reducing pressure loss in said combustor
Implementation Method 2
lobes running between said nozzles are provided at said trailing edge for improving the mixing quality and reducing pressure loss in said combustor
Data Source
AI summary
A lobe lance is disclosed for a gas turbine combustor which includes a plurality of N (N≥4) lobe fingers, each configured as a streamlined body with two lateral surfaces. A plurality of nozzles for injecting a gaseous and/or liquid fuel mixed with air are provided whereby lobes running between the nozzles are provided for improving the mixing quality and reducing pressure loss in said combustor. The lobes of each lobe finger have one of two opposite orientations with respect to said flow direction, and the lobes of all lobe fingers follow a predetermined pattern of orientation across the lobe fingers at least one pair of neighboring lobe fingers has the same lobe orientation resulting in a grouped lobe arrangement ( . . . LL . . . or . . . RR . . . ) such that at least two of the vortices generated by the lobe shape downstream of the lobe fingers combine.