Annular Combustion Chamber Fuel Injector Flow Control
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Solution Overview
Problem
The existing gas turbine engine combustion chambers experience inhomogeneous temperature profiles and hot spots downstream due to localized air intake vents, leading to fuel over-richness and increased temperatures, which affects the performance and longevity of high-pressure distributors.
Innovation Solution
An annular combustion chamber design with fuel injectors distributed around the chamber, where one injector close to the air bleed vent has a reduced fuel flow by 3-10% compared to others, achieved through diaphragms or spring-biased valves, to maintain a consistent air-to-fuel ratio and reduce hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If air is extracted through localized intake vents on the combustion chamber casing, then compressed air is supplied to auxiliary functions, but the air-to-fuel ratio becomes uneven in zones downstream of the vents, leading to fuel over-richness and hot spots
Solution Approach 1:
The patent applies local quality by differentiating the fuel flow rate for injectors located near air extraction vents compared to those farther away. Specifically, injectors in the immediate vicinity of sampling vents (within a defined angular or spatial range) receive a reduced fuel flow rate to compensate for the localized air extraction, thereby maintaining a more uniform air-to-fuel ratio across all combustion zones and eliminating hot spots downstream of the vents.
2Productivity
If fuel injectors are distributed annularly around the chamber axis, then combustion occurs in multiple hearths, but localized air extraction creates uneven fuel distribution and temperature inhomogeneity
Solution Approach 1:
The patent implements local quality by assigning different fuel flow rates to different groups of injectors based on their spatial relationship with air extraction vents. Injectors positioned close to sampling vents operate at a reduced fuel flow rate compared to other injectors, creating a non-uniform fuel distribution pattern that compensates for the localized air removal and maintains consistent combustion characteristics across all hearths.
3Device complexity
If standard fuel flow is maintained in all injectors, then fuel distribution is simplified, but hot spots appear downstream of air intake vents reducing component life
Solution Approach 1:
The patent applies local quality by implementing differentiated fuel flow control for injectors near air extraction vents. This is achieved through specific means such as restrictors, adjustable flow control valves, or electronic control adjustments that reduce the fuel flow rate for these specific injectors. The increased complexity in fuel control is localized only to affected injectors, maintaining overall system simplicity while preventing hot spots and improving the reliability of downstream high-pressure distributors.
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 solution homogenizes the fuel richness across the combustion chamber, reducing temperature inhomogeneities and improving the life of high-pressure distributors by limiting hot spots and enhancing the temperature profile at full throttle operation.
Implementation Method 1
a combustion chamber in which the air is mixed with a fuel and burned
Implementation Method 2
the flow reduction means is a spring-biased valve, the flow-reducing means being formed by a spring of determined stiffness
Data Source
Figure 1~2
Figure 3~5
AI summary
The present invention relates to an annular combustion chamber for a gas turbine engine comprising a casing (16) with at least one air intake (20) located at the chamber inlet (11), and a fuel supply device with a plurality of fuel injectors (15) in the chamber distributed annularly, at least one of which (15a to 15d) is located near said intake. The chamber is characterized in that the fuel supply device includes a means for reducing the fuel flow rate in said injector (15a to 15d) located near the intake (20a, 20b) relative to the other fuel injectors (15). The invention reduces hot spots downstream of the combustion chamber caused by the intake.