Hydrogen 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 limits combustion optimization and are often complex and costly to produce.
Innovation Solution
A fuel injector design featuring a cylindrical tubular 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 incorporating a bulb-shaped shutter and indented nozzle edges to improve turbulence and directionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shutter opens outwards to prevent undesired openings caused by pressure peaks, then the reliability of the fuel injector is improved, but the fuel spray can only be concentric to the longitudinal axis which worsens the mixing between air and fuel
Solution Approach 1:
The injection duct is segmented into a converging initial segment and a diverging final segment, creating a de Laval nozzle configuration. This segmentation allows the fuel spray to achieve supersonic speeds and form a hollow conical shape with lateral air suction, improving mixing efficiency while maintaining the outward-opening shutter configuration for reliability.
Solution Approach 2:
The invention introduces lateral air suction ducts that draw air from the sides, adding a radial dimension to the air-fuel mixing process. This complements the axial spray direction and creates enhanced turbulence and mixing in multiple dimensions, resolving the limitation of concentric spray patterns.
2Ease of manufacture
If a conventional injection duct is used, then the device is simple to manufacture, but the fuel spray does not allow optimizing the mixing between air and fuel
Solution Approach 1:
The injection duct parameters are changed by implementing a converging-diverging cross-sectional area profile along its length. This parameter change creates supersonic flow conditions and optimizes the air-fuel mixing process, while the overall simple cylindrical construction with integrated lateral ducts maintains ease of manufacture.
3Productivity
If the injection duct has a converging-diverging profile to accelerate fuel to supersonic speed, then the mixing between air and fuel is optimized, but the device complexity increases
Solution Approach 1:
The converging and diverging segments of the injection duct are merged into a single integrated component formed as part of the cylindrical support body. The lateral air suction ducts are also merged with the main injection duct, creating a unified structure that achieves complex flow patterns without requiring separate assembled parts, thus limiting the increase in device complexity.
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 air-fuel mixing, enhances combustion efficiency, and is cost-effective to manufacture by simplifying construction, while allowing flexible spray direction and reducing audible noise.
Implementation Method 1
a converging-diverging injection duct, resembling a de Laval nozzle, that accelerates hydrogen to supersonic speeds
Implementation Method 2
The injection duct has a converging initial segment and a diverging final segment
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
Implementation Method 5
the closed position of the shutter is not negatively influenced by the pressure which develops in the combustion chamber; namely, when the shutter opens outwards, the pressure which develops in the combustion chamber pushes the shutter towards the closed position
Implementation Method 6
enhancing mixing and incorporating a bulb-shaped shutter and indented nozzle edges to improve turbulence and directionality
Data Source
AI summary
A fuel injector for a gaseous fuel and having: an injection nozzle; a support body with a tubular shape, which is provided with a feeding channel therein, ending in the injection nozzle; an injection valve; a tubular sleeve, which is arranged around an end part of the support body, entirely contains the shutter therein, and ends with the injection nozzle; and an actuator, which is configured to move the shutter. An injection duct, which is created when the injection valve is in the open position, has a converging initial segment, in which an area of the injection duct progressively decreases from a first maximum value at the beginning of the injection duct to a minimum value, and a diverging final segment, in which the area of the injection duct increases from the minimum value until reaching a second maximum value.