Jet in Cross Flow Fuel Nozzle for Gas Turbine Combustion Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines experience combustion instability at sub-idle and idle conditions, leading to excessive wear and inefficient fuel consumption due to undesirable fuel/air mixing and re-circulation zones in existing fuel nozzle assemblies.
Innovation Solution
A fuel nozzle assembly with a centerbody and outer sleeve design that provides discrete fuel exit openings for crossflow mixing with air, featuring converging exit portions and independent fuel passages to mitigate combustion instability and promote stable part-load operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If prefilming airblast atomizing fuel nozzles are used to address combustion stability issues, then fuel atomization is improved, but undesirable fuel/air re-circulation zones and flame stabilization problems occur
Solution Approach 1:
The fuel nozzle divides the fuel flow into multiple discrete streams through separate fuel passages (first fuel passage and second fuel passage) with distinct exit openings. This segmentation prevents the formation of large re-circulation zones by breaking up the fuel/air mixing into smaller, more controlled segments, thereby maintaining combustion stability while achieving good atomization.
Solution Approach 2:
The nozzle provides different fuel delivery characteristics at different locations: the first fuel passage provides fuel at a first location with specific atomization characteristics, while the second fuel passage provides fuel at a second location with different characteristics. This local differentiation allows optimization of atomization in one region without creating harmful re-circulation zones that would affect overall combustion stability.
2Productivity
If high pressure liquid fuel is used to improve fuel delivery, then fuel flow rate is increased, but undesirable fuel filming on outer sleeve surfaces occurs
Solution Approach 1:
The design extracts or removes the problematic prefilming function that causes fuel to adhere to outer sleeve surfaces. Instead of using a prefilming surface that allows fuel to travel along and deposit on external surfaces, the fuel is delivered directly through discrete passages to the combustion zone, maintaining high flow rates while preventing harmful external fuel filming.
3Quantity of substance
If primary and secondary fuel injection are used to improve fuel distribution, then fuel/air mixing is enhanced, but undesired mixing or collusion of the primary and secondary fuel/air streams occurs
Solution Approach 1:
The fuel injection system segments the fuel delivery into separate passages that maintain independent flow paths. The first fuel passage and second fuel passage deliver fuel through distinct routes with separate exit openings, preventing the streams from colluding or interacting in undesirable ways while still achieving comprehensive fuel distribution across the combustion zone.
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 design improves fuel atomization and combustion stability by reducing interaction between fuel flows, attenuating combustion acoustics, and enabling efficient fuel/air mixing, allowing for stable operation at sub-idle and idle conditions.
Implementation Method 1
The first flow of fuel defines a jet in crossflow mixing with the first flow of air
Data Source
AI summary
The present disclosure is directed to a fuel nozzle assembly for a gas turbine engine. The fuel nozzle assembly includes a centerbody extended along a nozzle centerline axis and generally concentric thereto and an outer sleeve surrounding the centerbody and extended along the nozzle centerline axis and generally concentric thereto. The centerbody defines an outer wall extended at least partially along the nozzle centerline axis in which the centerbody defines a first fuel passage therewithin and one or more first fuel exit openings through the outer wall. Each first fuel exit opening is discrete from another along the outer wall. The outer sleeve and centerbody together define a first air passage therebetween. The first fuel passage and the first fuel exit opening are in fluid communication with the first air passage. The fuel nozzle assembly provides a first flow of fuel through the first fuel passage and first exit opening and a first flow of air through the first air passage, the first flow of fuel defines a jet in crossflow mixing with the first flow of air.