Side Channel Compressor Water Drainage for Fuel Cell Cold Starts
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Solution Overview
Problem
In fuel cell systems, the radial gap between the impeller wheel and housing in side channel compressors leads to increased shear friction due to liquid water, which can cause operational speed issues and compromise cold start capability due to potential freezing at low temperatures.
Innovation Solution
A side channel compressor design featuring an annular channel connected to a housing bore, allowing for the radial displacement and safe discharge of liquid water, reducing shear friction and preventing freezing by creating a back-pressure for water removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a radial gap remains between the impeller wheel and housing, then the side channel compressor can operate with simple structure, but liquid water accumulates in the gap causing increased shear friction and speed loss
Solution Approach 1:
The patent extracts the harmful liquid water from the radial gap by introducing a drainage channel that connects the radial gap to the discharge side. This allows the water to be removed from the problematic area while maintaining the simple radial gap structure, thus resolving the contradiction between structural simplicity and operational efficiency.
Solution Approach 2:
The drainage channel acts as an intermediary element that provides a controlled path for liquid water to move from the radial gap to the discharge side. This mediator structure enables water removal without complicating the main compression mechanism, preserving both simplicity and productivity.
2Device complexity
If a radial gap remains between the impeller wheel and housing, then the compressor structure remains simple, but liquid water can freeze at low temperatures compromising cold start capability
Solution Approach 1:
The drainage channel extracts liquid water from the radial gap before it can accumulate and freeze. By continuously removing water during operation, the system maintains cold start capability without requiring complex heating or insulation systems, thus preserving structural simplicity while improving reliability.
3Device complexity
If liquid water is present in the radial gap, then no additional water removal components are needed, but shear friction increases causing speed loss
Solution Approach 1:
The drainage channel is merged with the existing housing structure, integrating the water removal function into the existing component rather than adding a separate external system. This combines the structural simplicity with the ability to maintain impeller speed by removing water that would otherwise cause shear friction.
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 ensures efficient operation by eliminating water-related friction and freezing issues, maintaining desired speed and enhancing cold start capability.
Implementation Method 1
Due to the high centrifugal forces in the side channel compressor, the remaining liquid water fraction is forced into a radial gap surrounding the impeller wheel
Implementation Method 2
Due to the high centrifugal forces in the side channel compressor, the remaining liquid water fraction is forced into a radial gap surrounding the impeller wheel by an axial gap between the impeller wheel and the housing
Implementation Method 3
the annular channel is connected to an outlet of the side channel compressor via at least one housing bore... liquid water displaced radially outward from the at least one side channel during operation of the side channel compressor can be accommodated and discharged via the at least one housing bore to the outlet
Data Source
AI summary
The invention relates to a side channel compressor (1) for a fuel cell system (2) for delivering and/or compressing a gaseous medium, in particular hydrogen or a gas containing hydrogen, comprising a housing (3) and an impeller wheel (4) which can be driven by an electric motor and which is accommodated in the housing (3), thus forming at least one side channel (5) disposed axially in relation to the impeller wheel (4), wherein the side channel (5) is connected, via an axial gap (6) remaining between the housing (3) and the impeller wheel (4), to an annular channel (7) which is disposed radially in relation to the impeller wheel (4). According to the invention, the annular channel (7) is connected to an outlet (10) of the side channel compressor (1) via at least one housing bore (8, 9).The invention also relates to a fuel cell system (2) having a side channel compressor (1) according to the invention, and to the use of a side channel compressor (1) according to the invention as a recirculation fan in a fuel cell system (2).