Bluff Body Fuel Injectors for Gas Turbine Combustor Flame Stability
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Solution Overview
Problem
Gas turbine engine combustors face challenges in maintaining flame stability and improving lean blowout performance, particularly in reducing the fuel-air ratio at which combustion is disrupted, due to limitations in existing fuel injector designs and airflow management.
Innovation Solution
The design incorporates a forward bulkhead with bluff body fuel injectors that create turbulent recirculation regions within the combustor, utilizing a double-structured wall configuration with inner and outer heat shields to manage airflow and fuel distribution, optimizing the geometry of air inlet passageways and non-passageway areas to enhance flame stability and airflow, and employing a specific fuel distribution strategy through multiple nozzle arrays to achieve desired combustion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuel injectors are used, then the structure is simple, but flame stability is poor and lean blowout performance is limited
Solution Approach 1:
The fuel injector is divided into multiple nozzle arrays (first, second, third nozzle arrays) arranged in different orientations and positions. Each nozzle array injects fuel in a specific direction to create distinct recirculation zones, thereby enhancing flame stability through distributed fuel injection rather than a single injector design.
Solution Approach 2:
A bulkhead is introduced as an intermediary structure between the fuel injectors and combustion chamber. The bulkhead creates turbulent recirculation regions that mediate between fuel injection and combustion, improving flame stability by establishing controlled recirculation zones that maintain combustion at lower fuel-air ratios.
2Use of energy by moving object
If the fuel-air ratio is reduced to improve efficiency, then energy consumption decreases, but combustion stability deteriorates and lean blowout occurs
Solution Approach 1:
Different regions of the combustion chamber are provided with different fuel injection characteristics through multiple nozzle arrays positioned at various locations and orientations. This local differentiation ensures that each region maintains optimal combustion conditions even when the overall fuel-air ratio is reduced, preventing lean blowout while improving overall efficiency.
Solution Approach 2:
The bulkhead design creates dynamic turbulent recirculation regions that adapt to varying fuel-air ratios. These recirculation zones dynamically adjust the mixing and combustion process, maintaining combustion stability across a wider range of fuel-air ratios including leaner conditions.
3Productivity
If uniform fuel distribution is used, then the injection system is simple, but temperature distribution and combustion efficiency are suboptimal
Solution Approach 1:
The fuel distribution system employs asymmetric nozzle arrangements with different orientations (radial, tangential, axial directions) and positions. This asymmetric configuration creates non-uniform fuel distribution patterns that optimize combustion efficiency by targeting specific combustion zones, rather than attempting uniform distribution across the entire chamber.
Solution Approach 2:
Fuel injection is extended from a single-plane or single-direction approach to multi-dimensional injection through nozzle arrays oriented in radial, tangential, and axial directions. This three-dimensional fuel distribution approach optimizes combustion efficiency by delivering fuel to multiple spatial zones simultaneously.
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 configuration promotes stable combustion, improves lean blowout performance by lowering the fuel-air ratio at which combustion is maintained, and optimizes temperature distribution, thereby enhancing the efficiency and reliability of the gas turbine engine combustor.
Implementation Method 1
bluff body fuel injectors that create turbulent recirculation regions
Implementation Method 2
double-structured wall configuration with inner and outer heat shields
Implementation Method 3
multiple nozzle arrays to achieve desired combustion properties
Implementation Method 4
combustor for gas turbine engines
Data Source
AI summary
A gas turbine engine combustor has inboard and outboard walls. A forward bulkhead extends between the walls and cooperates therewith to define a combustor interior volume. Bluff body fuel injectors are along the bulkhead.