Air Directed Fuel Injection for Gas Turbine Ignition
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Solution Overview
Problem
Gas turbines face challenges in reliable ignition of liquid fuel due to unstable lean fuel mixtures and poor aerodynamics during start-up, leading to inefficient combustion and potential coke buildup, with existing solutions like gas assisted ignition and plasma ignitors being costly or having short lifetimes.
Innovation Solution
A combustion chamber design featuring a pilot burner device with an air blast injector that directs an air blast to the fuel injector and ignitor unit, ensuring reliable fuel ignition without additional fluid guiding elements, using a recessed fuel injector and air blast injector arrangement to stabilize the flame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pilot burner device is used with separate fuel injector and ignitor, then the device can be manufactured with standard components, but the ignition reliability is poor during start-up due to unstable lean fuel mixtures and poor aerodynamics
Solution Approach 1:
The fuel injector and air blast injector are integrated into a single pilot burner device structure, allowing coordinated control of fuel and air flow directly at the ignition zone. This merging enables the air blast to be directed precisely toward the fuel spray and ignitor, improving ignition reliability during start-up while avoiding the need for separate complex fluid guiding elements.
Solution Approach 2:
An air blast is introduced as an intermediary substance to facilitate the ignition process. The air blast acts as a mediator that directs the fuel spray toward the ignitor and stabilizes the flame during start-up, overcoming the poor aerodynamic conditions without requiring complex mechanical guidance systems.
2Reliability
If gas assisted ignition or plasma ignitors are used to improve ignition reliability, then ignition reliability is improved, but the operating cost increases or the component lifetime decreases
Solution Approach 1:
The pilot burner device uses the turbine's own air supply system to provide the air blast for ignition, eliminating the need for external gas bottles or complex plasma generation systems. This self-service approach reduces operating costs and avoids the use of short-lived components like plasma ignitors, while maintaining reliable ignition through the coordinated action of the integrated fuel and air injectors.
3Productivity
If the aerodynamics are optimized for full load operation, then fuel combustion efficiency is improved, but the aerodynamics at the ignitor become poor during start-up and lightning phase
Solution Approach 1:
The air blast injector is designed to dynamically adjust air flow based on operational requirements. During start-up and lightning phases, the air blast is directed toward the fuel spray and ignitor to improve ignition reliability. During full load operation, the system transitions to normal combustion aerodynamics, optimizing combustion efficiency. This dynamic adaptation allows the system to overcome the aerodynamic compromises inherent in conventional fixed designs.
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
Enhances ignition reliability by ensuring a consistent fuel flow to the ignitor unit during start-up, reducing coke buildup and improving combustion efficiency without additional fluid costs or short-lived components.
Implementation Method 1
an air blast injector (104) adapted for injecting an air blast into the inner volume. The air blast injector (104) comprises an air blast outlet at the pilot surface (101), wherein the air blast is injectable in the direction to the fuel outlet (102) and the ignitor unit (103) for directing the fuel to the ignitor unit (103)
Implementation Method 2
a fuel injector (102) comprising a fuel outlet for injecting a fuel into the inner volume
Implementation Method 3
an ignitor unit (103) adapted for igniting the fuel inside the inner volume
Implementation Method 4
The pilot flame comprises a rich or richer fuel mixture, wherein the rich or richer pilot flame is more stable than the lean main flame and the heat and radicals produced from this hot stable pilot frame stabilizes the main flame
Implementation Method 5
In combustion chambers for gas turbines, it is an aim to reduce the emissions, such as nitrogen oxides NOx and/or carbon monoxide CO. The temperatures inside the combustion chamber cause high CO and NOx emissions.
Data Source
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AI summary
The present invention relates to a combustion chamber (120) for a gas turbine. The combustion chamber (120) comprises a pilot burner device, a fuel injector (102), an ignitor unit (103) and an air blast injector (104). The pilot burner device comprises a pilot body (100) with a pilot surface (101) which is facing an inner volume of the combustion chamber (120). The fuel injector (102) comprises a fuel outlet for injecting a fuel into the inner volume, wherein the fuel outlet which is arranged at the pilot surface (101). The ignitor unit (103) is arranged at the pilot surface (101) such that fuel which passes the ignitor unit (103) is ignitable. The air blast injector (104) is adapted for injecting an air blast into the inner volume, wherein the air blast injector (104) comprises an air blast outlet which is arranged at the pilot surface (101) such that the air blast is injectable in the direction to the fuel outlet and the ignitor unit (103) for directing the fuel to the ignitor unit (103).