Cavity Coupled Fuel Injector for Gas Turbine Augmentor
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Solution Overview
Problem
Deep fuel penetration in gas turbine engine augmentor sections reduces atomized fuel near vane walls, leading to unstable flames and increased screech due to insufficient mixing with core gas.
Innovation Solution
A fuel injection system with a nozzle block, cavity block, and airflow apertures that inject fuel into a cavity with a larger cross-sectional area, mixing it with air to enhance atomization and stability, using a biasing element to position the cavity block effectively and directing airflow to strip fine droplets and increase atomized fuel concentration near the gas path surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel penetrates deep into core gas to increase mixing, then augmentor efficiency and supplemental thrust increase, but atomized fuel concentration near vane walls decreases, causing flame instability and increased screech
Solution Approach 1:
The fuel injection system is segmented into multiple functional components: a fuel injection aperture for deep penetration, a cavity chamber for fuel-air mixing, and an outlet aperture for distributed discharge. This segmentation allows the fuel to first penetrate deep into the core gas, then mix with air in the cavity to create atomized fuel that can be discharged in a controlled manner to maintain flame stability near vane walls.
Solution Approach 2:
The cavity chamber acts as an intermediary between the fuel injection aperture and the core gas flow. Fuel injected through the first aperture enters the cavity where it mixes with air introduced through airflow apertures, creating atomized fuel droplets. This intermediary mixing process ensures that sufficient atomized fuel reaches the vane walls to maintain flame stability while still achieving deep penetration for augmentor efficiency.
2Power
If fuel penetrates deep into core gas, then supplemental thrust magnitude increases, but atomized fuel near vane walls decreases, increasing screech
Solution Approach 1:
The injection system segments the fuel delivery process into deep penetration injection followed by cavity mixing and then controlled discharge. This allows the fuel to achieve deep penetration for high thrust while the cavity mixing ensures adequate atomization to reduce screech near the vane walls.
Solution Approach 2:
The system changes the physical parameters of the fuel by introducing it into a cavity where it mixes with air, transforming the fuel from a concentrated jet into atomized droplets. This parameter change in fuel atomization level allows the system to maintain both high thrust and low screech.
3Quantity of substance
If a cavity with larger cross-sectional area is used for fuel mixing, then atomized fuel concentration near gas path surface increases, but device complexity increases
Solution Approach 1:
The cavity mixing chamber merges multiple functions into a single component: it serves as both the mixing chamber for fuel and air, and as part of the injection system structure. The airflow apertures are integrated into the cavity block, combining the air introduction function with the cavity structure itself, thereby reducing overall device complexity while maintaining high atomized fuel concentration.
Solution Approach 2:
The cavity block serves multiple functions simultaneously: it provides the mixing chamber volume, contains the airflow apertures for air introduction, and structures the fuel discharge path. This multi-functionality reduces the number of separate components needed, managing device complexity while achieving high atomized fuel concentration near the gas path surface.
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
Improves flame stability and reduces screech by increasing atomized fuel concentration adjacent to the gas path surface, enhancing mixing and combustion efficiency in the augmentor section.
Implementation Method 1
The nozzle aperture... injects fuel received from the fuel delivery conduit into the cavity
Implementation Method 2
The airflow aperture directs air to the cavity that mixes with the injected fuel
Implementation Method 3
A fuel injection system with a nozzle block, cavity block, and airflow apertures that inject fuel into a cavity with a larger cross-sectional area, mixing it with air to enhance atomization
Implementation Method 4
using a biasing element to position the cavity block effectively
Data Source
AI summary
A fuel injection system for a gas turbine engine includes a fuel delivery conduit, a nozzle block with a nozzle aperture, and a cavity block with a cavity. The nozzle aperture has a first cross sectional area, and injects fuel received from the fuel delivery conduit into the cavity. The cavity has a second cross sectional area that is greater than the first cross sectional area.