Combustor Fuel Injector with Flow Blurring Atomization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing combustion systems face limitations in fuel flexibility, particularly with highly viscous liquids like glycerol or straight vegetable oils, due to suppressed shear layer instabilities and high power requirements in twin-fluid atomization techniques, leading to inefficient droplet break-up and larger droplet sizes, as well as unsteadiness in effervescent atomization methods.
Innovation Solution
The implementation of a Flow Blurring (FB) atomization technique within a combustor assembly, utilizing a fuel injector with a choke portion and a swirler, which includes an inner and outer injector tube, an orifice plate, and a spacer ring, forces atomizing gas through a small gap downstream of the liquid tube exit, creating a turbulent mixing process that reduces energy requirements and produces finer droplets, while the swirler assists in breaking up remaining fuel streaks for low emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If twin-fluid atomization (air-blast) is used to enhance droplet break-up, then atomization effectiveness is improved, but power consumption increases and performance degrades with highly viscous fuels
Solution Approach 1:
The patent uses gas flow through a precisely controlled annular gap (10-50 micrometers) between coaxial tubes to atomize liquid fuel. The gas flow rate is controlled to create turbulent mixing that breaks up liquid into fine droplets, achieving high atomization efficiency with reduced power consumption compared to traditional air-blast methods
Solution Approach 2:
The patent changes the physical parameters of the atomization process by controlling the annular gap dimensions (10-50 micrometers) and gas flow rates to optimize droplet formation. This parameter control enables effective atomization of highly viscous fuels without requiring excessive power input
2Manufacturing precision
If effervescent atomization is used to produce fine droplets, then droplet size is reduced, but spray stability deteriorates due to two-phase mixing unsteadiness
Solution Approach 1:
The patent segments the atomization process into distinct zones: liquid injection through inner tube, gas injection through outer tube, turbulent mixing in the annular gap, and droplet formation at the exit. This segmentation stabilizes the two-phase flow and eliminates the unsteadiness associated with conventional effervescent atomization
Solution Approach 2:
The patent introduces a spacer ring as an intermediary component that precisely positions the annular gap and stabilizes the gas-liquid interaction. This intermediary structure controls the two-phase mixing process to produce stable, fine droplets without the unsteadiness characteristic of conventional effervescent atomizers
3Adaptability or versatility
If conventional fuel injectors are used, then system complexity is reduced, but fuel flexibility is limited
Solution Approach 1:
The patent designs a universal injector structure with coaxial inner and outer tubes that can handle multiple fuel types (conventional and highly viscous alternative fuels) by adjusting operating parameters such as gas flow rate and annular gap dimensions, without requiring fundamental design changes
Solution Approach 2:
The patent incorporates adjustable operating parameters (gas flow rate, liquid flow rate, annular gap dimensions) that allow the injector to dynamically adapt to different fuel viscosities and combustion requirements, providing fuel flexibility while maintaining a relatively simple coaxial tube structure
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 FB atomization technique achieves up to fifty times the surface area to volume ratio and tenfold atomization efficiency compared to air-blast atomization, effectively handling highly viscous fuels with low emissions and reduced power consumption, making it suitable for various heat release rates and scalable for different applications.
Implementation Method 1
forces atomizing gas through a small gap downstream of the liquid tube exit, creating a turbulent mixing process that reduces energy requirements and produces finer droplets
Implementation Method 2
The primary driving force of liquid break up and droplet formation is by the shear forces formed because of the high relative velocities between the two phases
Implementation Method 3
the swirler assists in breaking up remaining fuel streaks for low emissions
Data Source
AI summary
Implementations of a combustor assembly yield low emissions, require low power, are suitable for alternate liquid fuels, including highly viscous fuels, and are scalable for various heat release rates. The combustor assembly includes a fuel injector and a swirler. The fuel injector may include a choke portion and a spacer. The choke portion is disposed just upstream of an outlet of a liquid fuel conduit and prevents atomizing gas from interrupting continuous flow of the liquid fuel through the liquid fuel conduit. The spacer is disposed downstream of the outlet to precisely control the gap and thus, bifurcation of atomizing gas flow, between the outlet of liquid fuel conduit and an inlet of an orifice plate. The swirler is disposed radially outwardly and adjacent the fuel injector and includes a plurality of angled vanes.