Heat Shield Wall in Electric Motor Compressor Diffuser
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Solution Overview
Problem
High-speed, high-output electric motors in compressors for fuel cells generate significant heat, leading to undesired heat transfer between the motor and the air being compressed, as well as between the motor and the bearings, which needs to be minimized to enhance efficiency and performance.
Innovation Solution
The compressor design includes a heat shield formed separately from the compressor and motor housings, positioned between them to reduce heat transfer, along with cooling air passages and a liquid coolant passage to manage heat, and features like air bearings and seal rings to prevent air leakage and enhance sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a high-speed, high-output electric motor is used to drive the compressor, then the power output and compression capability are improved, but significant heat is generated causing unwanted heat transfer to the compressed air and bearings
Solution Approach 1:
A heat shield is introduced as an intermediary component between the motor and the compressed air path. The heat shield is thermally coupled to the motor housing to conduct heat away from the motor, while being positioned to prevent direct heat transfer to the compressed air and bearings, thus mediating the thermal interaction between these components
Solution Approach 2:
Cooling air passages are implemented to introduce cooling air between the motor housing and the heat shield. This pneumatic cooling system circulates cooling air through defined passages to actively remove heat from the motor housing, preventing heat transfer to the compressed air and bearings while maintaining the high power output
2Device complexity
If the motor is positioned close to the compressor components for compact design, then the device complexity is reduced, but heat transfer to the bearings and compressed air increases
Solution Approach 1:
The heat shield serves as a thermal barrier intermediary that allows the motor to be positioned in close proximity to the compressor components for compact design while preventing thermal coupling. The heat shield is strategically positioned between the motor and the bearing/compressed air paths to block heat transfer despite the close spatial arrangement
Solution Approach 2:
The heat management function is extracted from the basic housing structure by introducing a separate heat shield component. This allows the motor housing to focus on mechanical support while the heat shield specifically addresses thermal isolation, enabling compact integration without compromising thermal management
3Object-affected harmful factors
If cooling air passages are added to the housing assembly, then heat transfer from the motor is reduced, but the device complexity increases
Solution Approach 1:
The housing assembly is designed with multi-functionality, where the housing structure simultaneously provides mechanical support, defines cooling air passages, and integrates with the heat shield to form thermal barriers. This universal design allows the housing to perform multiple functions without proportionally increasing complexity
Solution Approach 2:
The cooling air passages are merged into the housing assembly structure rather than being separate components. The housing walls themselves form the passages, and the heat shield is integrated with the housing to create a unified thermal management system, reducing overall device complexity while maintaining effective heat transfer prevention
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 configuration effectively minimizes heat transfer from the motor to the compressed air and bearings, improving the efficiency and performance of the compressor by reducing thermal interference and ensuring efficient air compression.
Implementation Method 1
a heat shield formed separately from the compressor housing and the motor housing and disposed between them, the heat shield defining one wall of the diffuser for the compressed air delivered into the volute
Implementation Method 2
Cooling air passages are defined in the housing assembly for supplying cooling air to the air bearings
Implementation Method 3
the motor housing defines a liquid coolant passage for circulating a liquid coolant
Implementation Method 4
air bearings that rotatably support the shaft
Data Source
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AI summary
An electric motor-driven compressor includes a housing assembly comprising a motor housing and a compressor housing mounted thereto. The compressor housing contains a centrifugal compressor wheel that is mounted on a shaft of the motor rotor and also defines an air inlet that leads air into the compressor wheel, and a volute that collects the compressed air. Air bearings rotatably support the shaft. Cooling air passages are defined in the housing assembly for supplying cooling air to the air bearings. A diffuser between the exit of the compressor wheel and the volute serves to diffuse the compressed air. The compressor includes a heat shield formed separately from the compressor housing and the motor housing and disposed between them. The heat shield defines one wall of the diffuser and also cooperates with the housing assembly to define part of the cooling air passages for the cooling air supplied to the bearings.