Slinger Combustor Fuel Atomization Low Power Operation
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Solution Overview
Problem
Conventional rotary slingers in gas turbine engines experience poor fuel atomization at low power levels, leading to reduced combustion efficiency and increased emissions during starting and altitude relight conditions due to lower rotation speeds.
Innovation Solution
An annular combustor design with radially inward fuel inlet, fuel atomization zone, and dilution holes oriented to intersect the fuel stream with tangential components, enhancing fuel-air mixing and combustion efficiency by injecting air with matching and opposing swirl components to improve atomization and mixing at low power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the slinger rotates at high speed, then fuel atomization is improved, but the system cannot operate effectively at low power levels
Solution Approach 1:
The combustor is divided into distinct functional zones: a fuel atomization zone with swirler air jets for initial fuel breakdown, and a combustion zone for burning. This segmentation allows each zone to be optimized independently - the atomization zone handles low-speed fuel atomization while the combustion zone maintains efficiency across all power levels.
Solution Approach 2:
Air jets with swirl components are introduced as an intermediary mechanism between the fuel slinger and the combustion zone. These air jets provide the necessary atomization force at low slinger speeds, mediating the fuel preparation process without requiring high slinger rotation speeds.
2Adaptability or versatility
If the slinger rotates at low speed, then the system can operate at low power levels, but fuel atomization deteriorates
Solution Approach 1:
Air jets with swirl components are introduced as an intermediary mechanism between the fuel slinger and the combustion zone. These air jets provide the necessary atomization force at low slinger speeds, mediating the fuel preparation process without requiring high slinger rotation speeds.
Solution Approach 2:
The system changes the dominant atomization mechanism based on operating conditions. At low power levels, air swirler jets provide the primary atomization force. The combustor design allows transition between different atomization regimes to maintain effectiveness across the full power range.
3Quantity of substance
If air is injected with swirl component in the same direction as fuel, then fuel-air mixing is enhanced, but combustion temperature control becomes challenging
Solution Approach 1:
The air injection system is segmented into two functional groups: air jets with swirl components in the same direction as fuel for enhanced mixing in the atomization zone, and dilution air jets with opposite swirl for temperature control in the combustion zone. This segmentation allows independent optimization of mixing and temperature control.
Solution Approach 2:
Dilution air jets are positioned to introduce cooling air with opposite swirl after the main combustion process has been established. This preliminary anti-action counteracts the high temperatures generated by the primary combustion, preventing excessive heat buildup while maintaining efficient fuel-air mixing.
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 design improves fuel atomization and combustion efficiency at low power levels, reducing emissions and enhancing flame stability, leading to lower NOx and smoke emissions, while maintaining efficiency at high power conditions.
Implementation Method 1
a radially inner annular fuel inlet for receiving a spray of fuel centrifuged by a fuel slinger mounted for rotation about the central axis
Implementation Method 2
the dilution axis of at least some of the dilution holes has a tangential component in a direction opposite to the direction of rotation of the fuel slinger
Implementation Method 3
a plurality of nozzle air inlets defined in the fuel atomization zone of the combustor shell, the nozzle air inlets having a nozzle axis intersecting the stream of fuel centrifuged by the fuel slinger and a tangential component in a direction of rotation of the fuel slinger
Data Source
AI summary
A slinger combustor has an annular combustor shell defining a combustion chamber having a radially inner fuel inlet for receiving a spray of fuel centrifuged by a fuel slinger. The combustion chamber has a fuel atomization zone extending radially outwardly from the fuel inlet and merging into a radially outwardly flaring expansion zone leading to a combustion zone. A plurality of nozzle air inlets are defined in the fuel atomization zone of the combustor shell. The nozzle air inlets have a nozzle axis intersecting the stream of fuel and a tangential component in a direction of rotation of the fuel slinger. A plurality of dilution holes are defined in the combustor shell and have a dilution axis intersecting the combustion zone. The dilution axis of at least some of the dilution holes has a tangential component opposite to the direction of rotation of the fuel slinger.