Variable Flow Rate Fuel Ejector With Movable Needle
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Solution Overview
Problem
Existing fuel cell systems face inefficiencies due to the use of mechanical pumps for hydrogen recirculation, which are energy-intensive, prone to corrosion, and limited by the need for non-lubricated moving parts, and existing ejectors are not adaptable to varying flow rates.
Innovation Solution
A variable flow rate ejector system that uses a primary and secondary nozzle configuration with a movable needle to achieve supersonic and subsonic fluid speeds, enabling efficient recirculation of hydrogen gas by entraining low-pressure gas with high-pressure gas, and controlling flow rates to match fuel cell reaction demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical pumps are used for hydrogen recirculation, then hydrogen can be recirculated, but energy consumption increases and corrosion resistance decreases
Solution Approach 1:
The patent replaces mechanical pumps with a fluid dynamic ejector system that uses high-pressure hydrogen jet to create suction and recirculate low-pressure hydrogen. This eliminates mechanical moving parts, lubrication requirements, and associated energy losses, while providing corrosion-resistant operation in moist hydrogen environments
Solution Approach 2:
The invention uses pneumatic principles by employing a high-pressure hydrogen jet through a nozzle to create a low-pressure region that entrains and recirculates low-pressure hydrogen. The system converts pressure energy directly into fluid motion and suction without mechanical conversion, improving energy efficiency and reliability
2Productivity
If mechanical pumps are used for hydrogen recirculation, then hydrogen can be recirculated, but corrosion resistance decreases
Solution Approach 1:
The patent replaces mechanical pumps with a fluid dynamic ejector system that uses high-pressure hydrogen jet to create suction and recirculate low-pressure hydrogen. This eliminates mechanical moving parts, lubrication requirements, and associated energy losses, while providing corrosion-resistant operation in moist hydrogen environments
Solution Approach 2:
The system uses high-pressure hydrogen, an inert atmosphere, to drive the recirculation process. The hydrogen jet itself creates the suction effect, eliminating the need for mechanical components that would be exposed to corrosive moist hydrogen, thereby improving reliability and corrosion resistance
3Device complexity
If fixed geometry ejectors are used, then结构简单性 improves, but adaptability to varying flow rates deteriorates
Solution Approach 1:
The patent introduces a movable needle member that can adjust the opening area of the primary nozzle dynamically. This allows the ejector to adapt to varying flow rate requirements and pressure conditions while maintaining a relatively simple overall structure. The needle position can be controlled to optimize performance across different operating conditions
Solution Approach 2:
The invention enables parameter changes by allowing the primary nozzle opening area to be adjusted via the movable needle. This changes the flow characteristics and suction capability of the ejector, enabling adaptation to different flow rates and pressure conditions without fundamentally changing the ejector 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 system enhances fuel cell efficiency by optimizing hydrogen recirculation, reducing energy consumption, and maintaining optimal pressure and flow rates, while being resistant to corrosion and adaptable to varying flow requirements.
Implementation Method 1
The primary nozzle opening and the needle are sized to make the flow of the first fluid through the primary nozzle opening have a supersonic speed
Implementation Method 2
The second inlet chamber is disposed so that at least a portion of the second fluid is entrained in the flow of the first fluid from the primary nozzle
Implementation Method 3
a diffuser configured to deliver a flow of the mixed gases at a pressure higher than the second pressure
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Devices, systems, and methods for variable flow rate fuel ejection are disclosed. A variable flow rate ejector comprises primary and secondary inlets, primary and secondary nozzles, and a needle. The primary nozzle is connected to receive a first fluid from the first inlet chamber and transmit the first fluid through a primary nozzle opening. The needle is disposed within the primary nozzle opening and is axially movable to vary an area of primary nozzle opening. The primary nozzle opening and the needle are sized to make the flow of the first fluid have a supersonic speed. The secondary inlet opens into a second inlet chamber positioned outside the primary nozzle opening. A portion of the second fluid is entrained in the flow of the first fluid from the primary nozzle. The secondary nozzle opening is sized to make the flow of the first and second fluids have a subsonic speed.