Multipoint Fuel Injection Device with Parallel Conduits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multipoint fuel injection systems for aircraft engines face challenges in maintaining uniform fuel flow and reducing head losses, especially in smaller volume designs, which can lead to inefficient combustion and increased pollutant emissions due to non-uniform injection distribution and potential coking of fuel in inactive injection holes.
Innovation Solution
The implementation of a multipoint fuel injection device with parallel conduits connected to each injection hole, manufactured using additive methods to form a unitary structure, allowing for adjustable head losses and uniform flow distribution, and using connecting tubes with identical length-to-diameter ratios to ensure consistent fuel penetration and prevent coking by surrounding the crown with a pilot injection fuel flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the cavity section of the crown is reduced to decrease injection system volume, then the device size is reduced, but head losses increase and flow uniformity deteriorates
Solution Approach 1:
The fuel distribution system is segmented into multiple parallel conduits (at least three) that distribute fuel independently to different injection holes. This segmentation allows each conduit to have optimized dimensions and flow characteristics, reducing overall head losses while maintaining compact volume. The segmentation enables better flow control and uniformity across multiple injection points without requiring a large central cavity.
Solution Approach 2:
Each parallel conduit is designed with specific local characteristics (different lengths, diameters, or flow resistance) tailored to the requirements of its associated injection hole. This local quality adjustment ensures that fuel flow is optimized for each specific location, compensating for variations in distance and pressure drop, thereby maintaining uniform flow distribution while minimizing total system volume and energy losses.
2Volume of moving object
If the cavity section of the crown is reduced to decrease injection system volume, then the device size is reduced, but flow uniformity through injection holes deteriorates
Solution Approach 1:
The fuel distribution is segmented into multiple independent parallel conduits, each supplying a specific injection hole. This allows precise control and optimization of flow to each hole independently, ensuring uniform flow distribution even in compact designs. The segmentation enables manufacturing precision to be achieved through individual conduit design rather than relying on a large uniform cavity.
Solution Approach 2:
Each conduit is designed with local quality characteristics (varying lengths, diameters, or flow resistance) to compensate for positional differences and ensure uniform fuel flow to all injection holes. This local customization maintains flow uniformity while allowing the overall system volume to be minimized through optimized conduit routing and dimensions.
3Manufacturing precision
If parallel conduits of different lengths are used to reach injection holes, then individual flow adjustment is possible, but manufacturing complexity increases
Solution Approach 1:
Multiple parallel conduits of different lengths are merged into a single integrated crown structure manufactured by additive manufacturing. This combining approach allows complex multi-length conduit configurations to be produced as one unified component, eliminating the need for separate fabrication and assembly of individual conduits, thereby reducing manufacturing complexity while maintaining the flow uniformity benefits of varied conduit lengths.
Solution Approach 2:
The manufacturing method is changed from traditional subtractive or assembly-based approaches to additive manufacturing, which enables the production of complex multi-length conduit structures with varying geometric parameters in a single process. This parameter change in manufacturing methodology allows conduits of different lengths and configurations to be manufactured easily as a unitary structure, reducing assembly complexity while achieving precise flow rate uniformity.
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 ensures uniform fuel distribution and reduced head losses across all injection points, enhancing combustion efficiency and stability while preventing coking, thereby reducing pollutant emissions and maintaining consistent fuel penetration depths in the combustion chamber.
Implementation Method 1
The risks of coking of the fuel of the multipoint injection while it is inactive are thereby avoided, thanks to a constant cooling procured by the fuel of the pilot injection
Data Source
AI summary
The fuel injection conduits in a multipoint device surrounding a so-called pilot central injection device include tubes of circumferential orientation. By separating the injection conduits from each other, it is possible to attribute to them different head losses which compensate the differences in length that the fuel has to travel: a uniform flow of fuel may be hoped for, for each of the injection holes. The tubes are individual but joined to form a crown that is unitary or composed of two almost symmetrical unitary portions, which lends itself well to manufacture by addition of material.