Supersonic Blast Atomization for Slurry Fuel Injection
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Solution Overview
Problem
The injection of coal water slurry fuels into diesel engines faces challenges such as abrasive wear, incomplete combustion, and reduced atomization quality due to high viscosity and abrasive particles, leading to premature injector failure and increased wear on engine components.
Innovation Solution
The implementation of a supersonic blast atomization system where a high-pressure blast of gas impinges on the fuel in the combustion chamber, rather than within the injector, to atomize the particulate slurry fuel, utilizing a convergent-divergent duct to accelerate the blast gas to supersonic velocities and direct it onto the fuel jet for efficient mixing and atomization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure atomisation is used to inject coal water slurry fuel, then fuel injection can be achieved, but nozzle wear and abrasive wear increase rapidly
Solution Approach 1:
The patent extracts the atomization process from the injector nozzle and relocates it to the combustion chamber. The injector simply delivers fuel as a liquid jet, while a separate high-velocity gas jet (from a gas turbine or compressor) performs the atomization function in the combustion chamber, thereby removing the source of abrasive wear from the injector components.
Solution Approach 2:
The patent introduces a high-velocity gas jet as an intermediary medium to perform atomization. This gas jet acts as a mediator between the fuel delivery system and the combustion process, transferring energy to the fuel jet to break it into fine droplets without direct contact between abrasive fuel particles and injector nozzles.
2Manufacturing precision
If high velocity fuel jet is used for rapid atomisation, then atomisation quality improves, but wear and cavitation damage increase
Solution Approach 1:
The patent separates the functions of fuel delivery and atomization. The injector delivers fuel at moderate velocity, while a separate high-velocity gas jet performs the atomization function in the combustion chamber, thereby removing the source of abrasive wear from the injector components.
Solution Approach 2:
The patent uses a high-velocity gas jet (pneumatic system) to atomize the fuel instead of relying on high-pressure liquid fuel flow. The gas jet creates a high-velocity flow that breaks the fuel jet into fine droplets through aerodynamic forces, achieving good atomization without the cavitation and wear associated with high-velocity liquid fuel injection.
3Device complexity
If conventional injector design is used for coal water slurry, then system complexity is minimized, but valve seat wear and nozzle erosion occur
Solution Approach 1:
The patent extracts the atomization function from the injector and relocates it to the combustion chamber. The injector is simplified to a basic fuel delivery device, while a separate gas jet system performs the complex atomization task, thereby reducing wear on injector components.
Solution Approach 2:
The patent segments the injection system into distinct functional components: a simple fuel delivery injector and a separate atomization system using high-velocity gas jet. This segmentation allows each component to be optimized for its specific function, with the injector focusing on fuel delivery and the gas jet focusing on atomization, thereby reducing overall system wear.
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 approach reduces nozzle wear, enhances atomization performance, and extends injector life, allowing for the effective use of coal water slurry fuels in diesel engines by minimizing particle size and promoting complete combustion, while also reducing the energy penalty associated with providing compressed blast gas.
Implementation Method 1
a convergent-divergent duct to accelerate the blast gas to supersonic velocities
Implementation Method 2
accelerate the blast gas so that it emerges from the second outlet as a blast stream of supersonic velocity
Implementation Method 3
the emergent supersonic blast stream is directed into the jet of particulate slurry fuel downstream of the first outlet, thereby atomising the fuel
Implementation Method 4
interaction of the high velocity liquid with the relatively dense compressed air charge in the upper part of the cylinder
Implementation Method 5
propelling the fuel in a finely divided state into the combustion chamber to cause mixing to provide the required rate of combustion
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An atomiser injector includes: a central tube (12) terminating in a first outlet (16) for emitting a jet of particulate slurry fuel along a central axis (11), and structure (20) adjacent to the central tube so as to define with the tube a duct (22) communicating with one or more second outlets (25) for blast gas about the first outlet. This duct is configured (26) to accelerate the blast gas so that it emerges from the second outlet(s) as a blast stream of supersonic velocity. Adjacent the second outlet an internal face or faces (30) of the structure are axially convergent so as to direct the emergent supersonic blast stream into the jet of particulate slurry fuel downstream of the first outlet, thereby atomising the fuel.