Turbine Water Recirculation Path for Fuel Cell Compressor Stability
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Solution Overview
Problem
Conventional fuel cell compressor devices face issues with liquid water ingestion, which can inhibit turbine section operation, cause rotational surging, and overload bearings, negatively affecting the compressor device's efficiency.
Innovation Solution
A turbine section design with a recirculation flow path that allows liquid water to recirculate from the turbine wheel upstream area back to the circumferential inlet passage, reducing the liquid's impact on turbine wheel rotation and alleviating bearing loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the turbine section ingests liquid water exhausted from the fuel cell stack, then water can be removed from the system, but turbine operation is inhibited, rotational surging occurs, and bearing loads increase
Solution Approach 1:
The flow path is segmented into two separate paths: a first flow path for gas flow through the turbine wheel, and a second flow path for liquid water recirculation that bypasses the turbine wheel. This segmentation allows liquid water to be removed from the system while preventing it from directly contacting and interfering with the turbine wheel operation.
Solution Approach 2:
A recirculation passage acts as an intermediary pathway that redirects liquid water from the turbine wheel upstream area back to the circumferential inlet passage. This intermediary path prevents liquid water from accumulating in the turbine wheel area and causing operational issues, while still allowing the system to handle water effectively.
2Quantity of substance
If liquid water is present in the turbine wheel upstream area, then water can be transported through the system, but bearing loads increase and operational life decreases
Solution Approach 1:
The liquid water is extracted from the main gas flow path at the turbine wheel upstream area through a recirculation passage. By taking out the liquid water component separately and recirculating it through a dedicated path, the harmful effects of liquid water on bearing loads and operational life are eliminated while maintaining water transport capability.
3Reliability
If a recirculation flow path is added to handle liquid water, then water ingestion capability is enhanced and turbine protection is improved, but device complexity increases
Solution Approach 1:
The recirculation passage is merged with the existing housing structure of the turbine section, integrating the water management function into the existing design rather than adding a separate external system. This combining approach enhances water ingestion capability while minimizing the increase in overall 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 recirculation flow path enhances water ingestion capability, minimizing the braking effect on the turbine wheel, reducing rotational surging, and extending the turbomachine's operational life by balancing loads on the bearing.
Implementation Method 1
a recirculation flow path that extends from the circumferential inlet passage, through the turbine wheel upstream area, and back to the circumferential inlet passage
Implementation Method 2
The turbine wheel is configured to be driven in rotation by an exhaust stream from the fuel cell system
Data Source
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AI summary
A turbine section (113) of a turbomachine (101) includes a housing (188) that houses and supports the rotating group (118) for rotation about an axis. The housing defines a circumferential inlet passage (192) that extends about the axis. The housing defines a turbine wheel upstream area (174) that is disposed downstream of the circumferential inlet passage and upstream of the turbine wheel (131). The housing defines an outlet (194) that is downstream of the turbine wheel. Furthermore, the turbine section includes a first flow path (180) that extends from the circumferential inlet passage, through the turbine wheel upstream area, across the turbine wheel, to the outlet. Moreover, the turbine section includes a recirculation flow path (182) that extends from the circumferential inlet passage, through the turbine wheel upstream area, and back to the circumferential inlet passage.