Gas Turbine Start Injector Pulsing to Prevent Fuel Coking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engine start injectors experience coking due to high temperatures, leading to inefficient or inoperable nozzles, requiring costly and time-consuming repairs, as existing purge systems leave residual fuel traces that form coke deposits over time.
Innovation Solution
Implementing a method to pulse fresh fuel through the start injector nozzle, ensuring the stagnant fuel is replaced before reaching the coking temperature, with pulse width and period determined by fuel type and engine conditions, using a controller to manage the pulsing process and prevent nozzle wall temperature from exceeding the coking threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If start injectors are exposed to high temperatures during combustion operations, then combustion efficiency is improved, but coke deposits form on the injector nozzle leading to blockage and inoperability
Solution Approach 1:
The patent implements periodic purging cycles where fuel is pulsed through the start injector nozzle at predetermined intervals during combustion operations. This periodic action replaces stagnant fuel that would otherwise reach coking temperature, preventing coke deposit formation while allowing continuous combustion operations at high temperatures.
Solution Approach 2:
The purging system performs preliminary action by replacing stagnant fuel before it reaches the coking temperature threshold. The controller monitors fuel temperature and initiates purging cycles proactively to prevent coke deposit formation, rather than waiting for blockage to occur.
2Loss of energy
If fuel remains stagnant in the start injector nozzle during combustion operations, then fuel consumption is reduced, but the stagnant fuel exceeds coking temperature and forms deposits
Solution Approach 1:
The system uses periodic purging cycles rather than continuous fuel flow through the start injector. Fuel is introduced in controlled pulses at predetermined intervals, sufficient to replace stagnant fuel and prevent coking, while minimizing overall fuel consumption during combustion operations.
Solution Approach 2:
The controller adjusts purging parameters including pulse width, pulse frequency, and pulse timing based on engine operating conditions such as load, speed, and temperature. This dynamic parameter adjustment optimizes the balance between preventing coke deposits and minimizing fuel consumption.
3Reliability
If purge systems are used to clear stagnant fuel, then coking is reduced, but residual fuel traces remain that can form coke deposits over time
Solution Approach 1:
The purging system maintains continuous protection against coking by implementing repeated purging cycles throughout combustion operations. Each cycle replaces any residual fuel traces that may have remained from previous cycles, ensuring continuous nozzle cleanliness and preventing cumulative coke deposit formation.
Solution Approach 2:
The controller uses feedback from temperature sensors and engine operation monitoring to adjust purging frequency and intensity. When conditions indicate higher risk of coking (elevated temperatures, extended idle periods), the system increases purging activity to ensure complete removal of fuel traces.
4Reliability
If frequent purging cycles are implemented to prevent coking, then nozzle cleanliness is maintained, but fuel consumption and system complexity increase
Solution Approach 1:
The controller dynamically adjusts purging parameters including pulse width, pulse frequency, and pulse timing based on real-time engine operating conditions. During high-load operations with lower coking risk, purging frequency is reduced. During idle or low-load conditions with higher coking risk, purging frequency increases, optimizing the balance between nozzle cleanliness and system complexity.
Solution Approach 2:
The system implements purging at predetermined intervals rather than continuously, using partial action sufficient to prevent coking without excessive fuel consumption. The purge duration and frequency are calibrated to provide adequate protection while minimizing interference with normal combustion operations.
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
Prevents coke deposits by continuously replenishing stagnant fuel with cooler fresh fuel, maintaining low nozzle wall temperatures and extending the time before coking occurs, thereby reducing maintenance costs and ensuring efficient engine operation.
Implementation Method 1
pulsing fuel through the start injector nozzle, thereby preventing stagnant fuel in the start injector nozzle from exceed a coking temperature threshold
Data Source
AI summary
A gas turbine engine includes a compressor section, a combustor fluidly connected to the compressor section via a primary flowpath, a turbine section fluidly connected to the combustor via the primary flowpath, and a plurality of fuel injectors disposed within the combustor. The plurality of fuel injectors including at least one start fuel injector. Also included is a controller having a memory and processor. The memory stores instructions configured to cause the at least one start fuel injector to pulse fuel through the start injector nozzle, thereby preventing stagnant fuel in the start injector nozzle from exceed a coking temperature threshold.