Three-Branched Afterburner Flame Holder for Stable, Low-Obstruction Flow
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Solution Overview
Problem
Existing flame-holder devices in turbojet engines face a compromise between flame stabilization and pressure drop, with the flame propagation being concentrated near a circumferential line, leading to suboptimal temperature profiles and performance.
Innovation Solution
A flame-holder device with an annular row of flame-holder arms featuring an inner branch transitioning radially into two outer branches that diverge circumferentially, promoting both radial and circumferential flame propagation, reducing obstruction while maintaining flame stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flame-holder device with arms and connecting rings is used, then flame stabilization is improved, but pressure drop increases due to channel obstruction
Solution Approach 1:
The flame-holder arms are segmented into multiple branches (inner branch and two outer branches) that diverge circumferentially. This segmentation allows the flame to propagate through multiple pathways simultaneously, improving flame holding while reducing the obstruction effect on the gas flow compared to solid continuous arms.
Solution Approach 2:
The flame propagation is extended from a primarily radial direction to include circumferential propagation through the diverging outer branches. This multi-dimensional flame distribution improves combustion efficiency while the open branch structure maintains better flow throughability, reducing pressure drop.
2Productivity
If arms are arranged in an annular row, then flame propagation is promoted, but temperature profile uniformity deteriorates with concentration near circumferential lines
Solution Approach 1:
Different branches of the flame-holder arms serve different functional purposes: the inner branch provides structural support and initial flame anchoring, while the two outer branches diverge to promote circumferential flame propagation. This local differentiation optimizes both flame propagation and temperature distribution.
Solution Approach 2:
The diverging outer branches extend the flame propagation from a single radial line to a circumferential pattern, distributing heat more uniformly across the transverse plane. This multi-directional flame distribution prevents temperature concentration near single circumferential lines.
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 new configuration enhances flame distribution in the transverse plane, reducing obstruction and improving flame-holding performance, or maintaining performance with reduced obstruction.
Implementation Method 1
an annular row of flame-holder arms distributed around an axis of the device and each comprising an inner branch having a free end and another end, opposite to the free end, and two outer branches that extend from the other end of the inner branch, diverging from each other in a direction extending from the free end to the other end of the inner branch
Implementation Method 2
Such a flame-holder device typically comprises an annular row of flame-holder arms extending radially, intended to promote radial propagation of the flame along each of the arms, and a flame-holder ring connecting them in pairs to promote circumferential propagation of the flame
Data Source
AI summary
A flame-holder device for a turbojet afterburner comprises an annular row of flame-holder arms, each having an inner branch having a free end and another end, and two outer branches which extend from the other end and diverge from one another in a direction extending from the free end to the other end, such that the inner branch transitions radially outward into the two outer branches which diverge radially outward from one another in two opposing circumferential directions, thereby forming mutually approaching areas between consecutive flame-holder arms for enabling the flame to spread from arm to arm.