Gaseous Fuel Injector Nozzle for Supersonic Air-Fuel Mixing
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Solution Overview
Problem
Existing fuel injectors for gaseous fuels, particularly hydrogen, suffer from inefficient mixing of air and fuel due to concentric fuel sprays, which hinder optimal combustion, and are limited in design complexity and cost-effectiveness.
Innovation Solution
A fuel injector design featuring a cylindrical support body with a converging-diverging injection duct, resembling a de Laval nozzle, that accelerates hydrogen to supersonic speeds and incorporates lateral ducts for air suction, enhancing mixing and allowing angled fuel spray directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shutter opens outwards to ensure reliable closed position under pressure, then the sealing reliability is improved, but the fuel spray pattern becomes limited to concentric configuration which reduces mixing efficiency
Solution Approach 1:
The shutter is made to open inwards towards the valve seat instead of outwards. This inversion allows the shutter to maintain reliable sealing when closed while enabling the fuel spray to exit through lateral openings in the support body, creating a non-concentric spray pattern that improves mixing efficiency.
Solution Approach 2:
The fuel spray is redirected from a single axial dimension to multiple dimensions by introducing lateral openings in the support body. The spray now exits both axially through the injection nozzle and laterally through the side openings, creating a three-dimensional spray pattern that enhances fuel-air mixing.
2Device complexity
If a conventional injection duct is used, then the device complexity is reduced, but the fuel spray velocity and mixing performance are insufficient
Solution Approach 1:
The injection duct is designed with converging and diverging sections that change the geometric parameters along the flow path. The converging section increases fuel velocity by reducing cross-sectional area, while the diverging section allows expansion and mixing, achieving high-speed spray without excessive device complexity.
3Ease of manufacture
If the injection duct has a simple cylindrical shape, then the manufacturing cost is reduced, but the fuel-air mixing efficiency is compromised
Solution Approach 1:
The injection system is segmented into distinct functional zones: a converging section for acceleration, a throat region for maximum velocity, and a diverging section for expansion and mixing. This segmentation achieves superior mixing efficiency while maintaining manufacturing simplicity through standardized geometric transitions.
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 design optimizes fuel-air mixing through high-speed, angled fuel sprays, improving combustion efficiency while being simple and cost-effective to produce.
Implementation Method 1
a converging-diverging injection duct, resembling a de Laval nozzle, that accelerates hydrogen to supersonic speeds
Implementation Method 2
a converging-diverging injection duct, resembling a de Laval nozzle, that accelerates hydrogen to supersonic speeds
Implementation Method 3
an electromagnetic actuator. The injection valve is provided with a needle, which is moved by the action of the electromagnetic actuator
Implementation Method 4
against the action of a closing spring which pushes the needle towards the closed position
Data Source
Figure 1
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AI summary
A fuel injector (1) for a gaseous fuel and having: an injection nozzle (3); a support body (4) with a tubular shape, which is provided with a feeding channel (5) therein, ending in the injection nozzle (3); an injection valve (7); a tubular sleeve (12), which is arranged around an end part of the support body (4), entirely contains the shutter (9) therein, and ends with the injection nozzle (3); and an actuator (6), which is configured to move the shutter (9). An injection duct (14), which is created when the injection valve (7) is in the open position, has a converging initial segment, in which an area of the injection duct (14) progressively decreases from a first maximum value at the beginning of the injection duct (14) to a minimum value, and a diverging final segment, in which the area of the injection duct (14) increases from the minimum value until reaching a second maximum value.