Annular Combustor Multipoint Fuel Injection Radial Staging
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Solution Overview
Problem
Existing multipoint fuel injection systems for gas turbine engines struggle to maintain low NOx emissions across both high and low power operations, and are not optimized for ease of manufacturing and use.
Innovation Solution
An annular combustor with a multipoint fuel injection system featuring a plurality of fuel manifolds and injectors arranged circumferentially, with radial staging and specific injector designs to optimize air-fuel mixing, reduce recirculation zones, and control temperature distribution, including airblast and air assist pressure atomizer injectors to manage flame impingement and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If multipoint lean direct injection is used to reduce NOx emissions at high power conditions, then NOx emissions are significantly reduced, but performance at low power conditions such as start, ground idle, and flight idle deteriorates
Solution Approach 1:
The fuel injection system is segmented into multiple independent manifolds (first manifold, second manifold, third manifold) with separate control capabilities. Each manifold can be independently activated or deactivated based on operating conditions, allowing the system to optimize fuel injection patterns for both high power (reducing NOx) and low power (maintaining stability) conditions
Solution Approach 2:
The system dynamically adjusts fuel injection by selectively activating different manifolds based on power demand. The control system transitions between manifolds and injection patterns dynamically, enabling the combustor to adapt to varying operating conditions from idle to high power while maintaining low NOx emissions and stable combustion
2Ease of manufacture
If conventional fuel injection systems are used, then ease of manufacture is maintained, but NOx emissions reduction and combustion efficiency are insufficient
Solution Approach 1:
The fuel injection system is divided into multiple independent manifolds (first manifold, second manifold, third manifold) with separate control capabilities. Each manifold can be independently activated or deactivated based on operating conditions, allowing the system to optimize fuel injection patterns for both high power (reducing NOx) and low power (maintaining stability) conditions
Solution Approach 2:
The system changes operational parameters by selectively activating different manifolds and adjusting fuel injection patterns based on power demand. This parameter adjustment enables optimization of both emissions performance and combustion stability across the operating range while maintaining manufacturing feasibility
3Ease of manufacture
If fuel injectors are oriented perpendicular to the longitudinal axis, then manufacturing is simplified, but flame impingement on combustor walls occurs
Solution Approach 1:
The injector orientation is optimized locally based on position. Outboard injectors are angled inward at specific angles (e.g., 15-30 degrees) to direct flames away from combustor walls, while inboard injectors may have different orientations. This localized quality adjustment eliminates flame impingement on walls while maintaining manufacturing feasibility
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 system achieves significant reduction in NOx emissions across a wide power range while maintaining stability and ease of manufacturing, with reduced nozzle count and improved air-fuel mixing rates, enhancing combustion efficiency and emissions control.
Implementation Method 1
Each injector of the inboard, outboard, inner intermediate, and outer intermediate sets of injectors is an airblast injector that includes an inner air swirler defining an interior flow passage configured and adapted for fluid communication of compressor discharge air through the interior flow passage such that swirl is imparted on air flow through the interior flow passage
Implementation Method 2
Air assist pressure atomizer injectors to manage flame impingement and stability
Implementation Method 3
The system achieves significant reduction in NOx emissions across a wide power range while maintaining stability and ease of manufacturing, with reduced nozzle count and improved air-fuel mixing rates
Implementation Method 4
The injectors of separate respective manifolds are spaced radially apart from one another for separate radial staging of fuel flow to each respective manifold
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A multipoint fuel injection system (100) includes a plurality of fuel manifolds (102-110). Each manifold is in fluid communication with a plurality of injectors (112-120) arranged circumferentially about a longitudinal axis for multipoint fuel injection. The injectors of separate respective manifolds are spaced radially apart from one another for separate radial staging of fuel flow to each respective manifold.