Two-Stage Ejector Nozzle for Fuel Cell Hydrogen Recirculation
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Solution Overview
Problem
Existing hydrogen supply systems face challenges in securing airtightness and pressure resistance at the hydrogen supply terminal, particularly in high-output sections, and the use of multiple ejectors increases system size, while blower components are prone to erosion from condensate.
Innovation Solution
An ejector with a two-stage nozzle structure featuring a poppet and a damage prevention member, where the poppet is moved by pressure and a spring, and an additional flow path is created based on output section, allowing hydrogen to flow through varying orifices to manage flow rates and pressures effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a blower is used to recirculate hydrogen, then recirculation performance is improved, but the system becomes complex and components are prone to erosion
Solution Approach 1:
The patent replaces the mechanical blower system with a fluid dynamics-based ejector system. The ejector uses high-pressure hydrogen flow to create suction and recirculate gas without moving mechanical parts, eliminating bearings and motors while maintaining recirculation performance.
Solution Approach 2:
The ejector utilizes pneumatic principles where high-pressure hydrogen supplied to the nozzle creates a low-pressure region that draws recirculation gas through the system. This pneumatic mechanism replaces the mechanical blower while achieving the same recirculation function.
2Productivity
If pressure at the upstream end of the ejector is increased to secure recirculation performance, then recirculation in low-output section is improved, but airtightness and pressure resistance at the hydrogen supply terminal deteriorate
Solution Approach 1:
The ejector is divided into two separate stages: a first ejector for recirculation function and a second ejector for hydrogen supply function. This segmentation allows each stage to be optimized independently - the first stage can operate at high pressure for recirculation while the second stage maintains airtightness and pressure resistance for hydrogen supply.
Solution Approach 2:
The ejector system dynamically adapts to different output sections by adjusting operating parameters. In low-output sections, the first ejector operates at higher pressure for recirculation, while in high-output sections, the system transitions to rely more on the second ejector for hydrogen supply, maintaining balance between recirculation performance and supply terminal integrity.
3Productivity
If two ejectors are used to secure both recirculation performance and maximum supply performance, then performance across all output sections is improved, but the size of the hydrogen supply system increases
Solution Approach 1:
The patent merges the recirculation function and hydrogen supply function into a single integrated ejector assembly. The first and second ejectors are combined in one structure, sharing common components such as the housing and control mechanisms, thereby achieving dual functionality without proportionally increasing system size.
Solution Approach 2:
The integrated ejector assembly performs multiple functions: the first ejector handles recirculation while the second ejector handles hydrogen supply. This multi-functional design eliminates the need for separate dedicated systems, reducing overall system size while maintaining both recirculation performance and maximum supply performance.
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 design enhances hydrogen flow rate and suction performance in low-output sections and provides sufficient flow volume in high-output sections, maintaining system integrity and responsiveness by adjusting the flow path dynamically.
Implementation Method 1
the poppet is moved by a pressure of the hydrogen supplied to the housing and a spring
Implementation Method 2
the poppet is moved by the spring based on the pressure applied to the poppet
Implementation Method 3
hydrogen to flow through varying orifices to manage flow rates and pressures effectively
Implementation Method 4
a space between the poppet and the housing serves as a flow path through which the hydrogen is supplied
Data Source
AI summary
An ejector has a two-stage nozzle structure. The ejector is installed on a fuel cell recirculation line to supply new hydrogen and a recirculation gas. The ejector includes a housing having a first orifice defined therein and a poppet that is disposed in the housing and having a second orifice defined therein. A damage prevention member is disposed on a surface of the poppet to contact an inner surface of the housing, in which the damage prevention member contacts or is separated from the inner surface of the housing based on a pressure applied to the poppet.