Variable ELBO Fuel System Flame Stabilization
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Solution Overview
Problem
Gas turbines operating at partial power face inefficiencies and increased emissions due to the need for overboard bleed air extraction to maintain bulk flame temperatures within narrow acceptable ranges, which decreases partial power efficiency and increases fuel costs.
Innovation Solution
The implementation of Variable Enhanced Lean Blowout (ELBO) fuel systems that allow for direct fuel injection into the combustion chamber, creating small high-temperature diffusion flames for ignition and optimizing flame stabilization, reducing the reliance on overboard bleed air extraction by enabling operation at lower bulk flame temperatures and varying fuel delivery to manage emissions across a range of power settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If overboard bleed air extraction is used to maintain bulk flame temperature within narrow acceptable ranges, then emissions are controlled, but partial power efficiency decreases
Solution Approach 1:
The patent changes the operating parameters by enabling the combustor to operate at lower bulk flame temperatures through improved flame stabilization mechanisms. This allows the system to maintain acceptable emissions without requiring bleed air extraction, thereby improving partial power efficiency by eliminating the energy loss associated with bleeding compressor air overboard.
Solution Approach 2:
The patent implements self-service by using the combustion system's own resources (fuel injection timing and distribution) to stabilize the flame and control temperature. The variable fuel delivery system adjusts fuel injection to maintain stable combustion at lower temperatures, making the system self-regulating without requiring external bleed air intervention.
2Object-generated harmful factors
If bleed air extraction is increased to maintain acceptable bulk flame temperature bands, then emissions compliance is achieved, but fuel operating expenses increase
Solution Approach 1:
The patent changes the bulk flame temperature parameter to operate at lower temperatures that still achieve emissions compliance. By stabilizing combustion at these lower temperatures through improved fuel injection and flame holding mechanisms, the system eliminates the need for bleed air extraction, thereby reducing fuel consumption and operating expenses.
Solution Approach 2:
The patent implements feedback control through the variable fuel delivery system that continuously adjusts fuel injection based on operating conditions. This feedback mechanism maintains stable combustion and emissions compliance at lower bulk flame temperatures, eliminating the need for energy-wasting bleed air extraction and reducing overall fuel consumption.
3Object-generated harmful factors
If the window of acceptable bulk flame temperatures is narrowed due to stricter emissions regulations, then emissions control is improved, but the engine requires increased use of bleed air
Solution Approach 1:
The patent changes the operating approach by enabling stable combustion at lower bulk flame temperatures through improved flame stabilization. This allows the system to meet narrower emissions temperature windows without requiring increased bleed air extraction, thereby avoiding the complexity and inefficiency associated with expanded bleed air system requirements.
Solution Approach 2:
The patent implements dynamic adjustment through the variable fuel delivery system that adapts fuel injection timing and quantity based on real-time operating conditions. This dynamic control enables the combustor to maintain stable operation within narrower temperature windows required by stringent emissions regulations, eliminating the need for increased bleed air system complexity.
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 approach improves partial power thermal efficiency by up to 3 percentage points, reduces fuel system complexity and cost, and enhances combustion durability while maintaining low emissions, allowing for consistent exit profiles and reduced turbine inlet temperatures.
Implementation Method 1
creating small high-temperature diffusion flames for ignition
Implementation Method 2
fuel injection into the combustion chamber, creating small high-temperature diffusion flames
Data Source
AI summary
A system and method for flame stabilization is provided that forestalls incipient lean blow out by improving flame stabilization. A combustor profile is selected that maintains desired levels of power output while minimizing or eliminating overboard air bleed and minimizing emissions. The selected combustor profile maintains average shaft power in a range of from approximately 50% up to full power while eliminating overboard air bleed in maintaining such power settings. Embodiments allow for a combustor to operate with acceptable emissions at lower flame temperature. Because the combustor can operate at lower bulk flame temperatures during part power operation, the usage of inefficient overboard bleed can be reduced or even eliminated.