Aircraft Afterburner Flame Stabilizer Gutter Design
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Solution Overview
Problem
The existing afterburner designs suffer from significant pressure loss due to the mixing of high-velocity and low-velocity flows between gutters, which limits the thrust increase and engine performance of aircraft engines.
Innovation Solution
The afterburner incorporates gutters with a V-shaped cross-sectional shape and through-holes on the side surfaces, optimizing the mass flow ratio to reduce pressure loss while maintaining flame stabilization performance by ensuring the mass flow rate ratio through the through-holes is between 0.10 and 0.30.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple gutters are arranged radially in the flame stabilizer, then flame stabilization is achieved, but pressure loss increases due to mixing of high-velocity and low-velocity flows between gutters
Solution Approach 1:
The flame stabilizer is segmented into multiple gutters arranged radially, with each gutter forming an independent flame stabilization area. This segmentation allows separate control of flow velocities in different regions, enabling flame stabilization while reducing adverse mixing effects between high- and low-velocity flows.
Solution Approach 2:
Different regions of the afterburner are given different flow characteristics: the flame stabilization areas have low velocity for stable combustion, while the regions between gutters are designed to maintain higher velocities. This local differentiation of flow qualities reduces pressure loss while maintaining flame stability.
2Reliability
If the flow area between neighboring gutters is narrowed, then flame stabilization is enhanced, but velocity increases causing greater pressure loss when mixed with low-velocity flow
Solution Approach 1:
The flow field is segmented into distinct zones: flame stabilization zones within each gutter and high-velocity zones between gutters. This spatial segmentation allows the high-velocity flow to pass through narrow channels without directly mixing with low-velocity flames, maintaining both stabilization and reducing pressure loss.
Solution Approach 2:
The gutter structure acts as an intermediary element that separates high-velocity and low-velocity flows. The gutters channel and direct the flows such that they maintain their velocity characteristics longer, reducing premature mixing and associated pressure losses while still achieving flame stabilization.
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 configuration effectively reduces pressure loss on the downstream side of the flame stabilizer, enhancing the thrust increase and overall engine performance by securing stable flame stabilization and improving thrust rate.
Implementation Method 1
a fuel injector configured to inject the fuel into the liner
Implementation Method 2
an igniter configured to ignite the mixed gas including the fuel inside the liner. The aircraft engine further includes a flame stabilizer (flame holder). The flame stabilizer is provided in the rear of the fuel injector inside the liner, and holds the flame. The flame stabilizer includes multiple gutters which are arranged radially. Each gutter forms a flame stabilization area on its downstream side (immediately downstream side). While the aircraft engine is in operation, the fuel injector continues injecting the fuel inside the liner, and the igniter continues igniting the mixed gas inclusive of the fuel. For this reason, the flame is formed on the downstream side (in the rear) of the flame stabilizer inside the liner, and the mixed gas is burned again with the fuel. Thereby, more thermal energy can be injected into the combustion gas inside the liner
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An aircraft engine (1) includes an afterburner (23) which has a flame stabilizer (37). The flame stabilizer (37) maintains a flame generated from a mixed gas of a combustion gas and air. The flame stabilizer (37) includes multiple gutters (39) each configured to generate a flame stabilization area (FA) for the flame on its downstream side. Each gutter (39) is formed from: a curved apex section (39a) having a stagnation point (P); and flat plate-shaped side surface sections (39b) integrally formed on the respective two sides of the apex section (39a). Each gutter (39) has a V-shaped cross-sectional shape which is opened to the downstream side. At least one through-hole (41) is formed only in each side surface section (39b) of each gutter (39).