Dual Nozzle Hydrogen Recirculation Device for Fuel Cell Noise Reduction
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Solution Overview
Problem
Fuel cell systems face challenges with hydrogen recirculation, including high costs and corrosion issues with blowers, and complications with ejector assemblies due to high-speed hydrogen gas, leading to pressure loss, noise, and vibration.
Innovation Solution
A hydrogen feed and recirculation device that uses a combination of a first nozzle for low-load operations and a second nozzle utilizing the Coanda Effect for high-load operations, with a pilot valve and mixing diffusion pipe to efficiently supply hydrogen and recirculated hydrogen to the fuel cell stack, reducing nozzle exposure to high-speed gas and minimizing noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the nozzle diameter of the ejector is increased to supply large flow, then the hydrogen supply capacity is improved, but the jet speed decreases and suction performance deteriorates
Solution Approach 1:
The invention divides the single nozzle into two separate nozzles: a first nozzle for low-load operations and a second nozzle for high-load operations. This segmentation allows each nozzle to be optimized for its specific operating condition, with the second nozzle having a larger diameter for high flow capacity while the first nozzle maintains smaller diameter for high jet speed and suction performance.
Solution Approach 2:
The invention implements a dynamic selection mechanism where the system automatically switches between the first and second nozzles based on the hydrogen supply demand. The pilot valve dynamically controls which nozzle is active, allowing the system to adapt its nozzle configuration to match the current load conditions optimally.
2Adaptability or versatility
If two separate ejectors are disposed to handle different load conditions, then the hydrogen supply performance across varying loads is improved, but the device complexity and space requirements increase
Solution Approach 1:
The invention merges two separate ejector systems into a single integrated ejector body that contains both the first nozzle and the second nozzle. This consolidation reduces the overall device complexity and space requirements compared to using two separate ejectors, while still maintaining the ability to handle different load conditions through the pilot valve control mechanism.
Solution Approach 2:
The single ejector body is designed to perform multiple functions by incorporating both nozzles that can be selectively activated. The ejector structure itself serves as a universal component that handles both low-load and high-load conditions, eliminating the need for separate dedicated ejectors for each operating regime.
3Device complexity
If a single ejector with fixed nozzle size is used, then the device complexity is reduced, but the hydrogen supply performance deteriorates under varying load conditions
Solution Approach 1:
The invention introduces dynamic adaptability into the ejector system through the pilot valve mechanism that automatically selects between the first and second nozzles based on real-time hydrogen supply demand. This dynamic configuration allows the system to maintain high productivity across varying load conditions without significantly increasing 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 device ensures efficient hydrogen supply across varying load conditions, prevents nozzle vibration and noise, and maintains hydrogen supply efficiency by using the Coanda Effect to direct hydrogen flow effectively.
Implementation Method 1
a second nozzle utilizing the Coanda Effect for high-load operations
Data Source
AI summary
A hydrogen feed and recirculation device for a fuel cell system supplies hydrogen from a hydrogen tank and unreacted recirculated hydrogen discharged from a stack to the stack. The hydrogen feed and recirculation device can supply hydrogen to the stack through a first nozzle when hydrogen supply pressure is low and supply the hydrogen to the stack through a second nozzle using a Coanda Effect other than the first nozzle when the hydrogen supply pressure is high to satisfy a required hydrogen supply amount through an entire operating area of the fuel cell and prevent nozzle vibration and noise generation.